JP6919318B2 - Piston temperature estimation device and piston temperature estimation method - Google Patents

Description

The present invention relates to a piston temperature estimation device and a piston temperature estimation method.

Conventionally, a system for detecting the degree of deterioration of engine components over time is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2008-208751

By the way, the piston, which is a component of the engine, is damaged by heat. Therefore, the product life of the piston can be calculated by calculating the accumulated amount of damage to the piston. By determining the product life of the piston, it can be useful for detecting defects related to the engine equipped with the piston.

Engine-related defects are required to be detected with high accuracy. Therefore, in order to accurately determine the product life of the piston, it is required to accurately estimate the temperature of the piston.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to provide a piston temperature estimation device and a piston temperature estimation method capable of accurately estimating the piston temperature.

The piston temperature estimation device according to the first aspect of the present invention includes an estimation unit that estimates the piston temperature that indicates the temperature of the piston included in the internal combustion engine, and an injection amount that indicates the amount of fuel injected into the combustion chamber of the internal combustion engine. When the acquisition unit for acquiring information and the injection amount indicated by the injection amount information acquired by the acquisition unit exceed the first threshold value, the piston temperature is corrected, and when the injection amount is equal to or less than the first threshold value, the piston temperature is corrected. It is provided with a correction unit that controls the piston temperature so as not to be corrected.

The acquisition unit acquires intake air amount information indicating the intake air amount of the air supplied to the internal combustion engine, and the correction unit indicates the intake air amount information when the injection amount exceeds the first threshold value. The piston temperature may be corrected based on the amount of intake air.

The acquisition unit acquires injection timing information indicating the injection timing of the fuel supplied to the internal combustion engine, and the correction unit sets the injection timing indicated by the injection timing information when the injection amount exceeds the first threshold value. The piston temperature may be corrected based on the above.

When the injection amount of the correction unit exceeds the first threshold value and the injection amount indicated by the injection amount information newly acquired by the acquisition unit exceeds the second threshold value larger than the first threshold value. The piston temperature may be corrected so as not to correct the piston temperature when the injection amount indicated by the injection amount information newly acquired by the acquisition unit is equal to or less than the second threshold value.

The piston temperature estimation method according to the second aspect of the present invention includes a step of estimating the piston temperature indicating the temperature of the piston included in the internal combustion engine, which is executed by a computer, and the amount of fuel injected into the combustion chamber included in the internal combustion engine. When the injection amount indicated by the injection amount information acquired in the acquisition step and the injection amount information indicating the above exceeds the first threshold value, the piston temperature is corrected and the injection amount is the first threshold value. A step of controlling the piston temperature so as not to be corrected in the following cases is provided.

According to the present invention, there is an effect that the temperature of the piston can be estimated with high accuracy.

It is a figure which shows the structure of the piston temperature estimation apparatus which concerns on this embodiment. It is a figure which shows an example of the structure of the intake air temperature selection part which concerns on this embodiment. It is a figure which shows another example of the structure of the intake air temperature selection part which concerns on this embodiment. It is a figure which shows the structure of the piston temperature estimation part which concerns on this embodiment. It is a figure which shows the structure of the hydraulic pressure correction calculation part which concerns on this embodiment. It is a figure which shows the structure of the oil temperature correction calculation part which concerns on this embodiment. It is a figure which shows the structure of the intake air temperature correction calculation part which concerns on this embodiment. It is a figure which shows the structure of the intake air amount correction calculation part which concerns on this embodiment. It is a figure which shows the structure of the injection timing correction calculation unit which concerns on this embodiment. It is a figure which shows the structure of the piston temperature correction part which concerns on this embodiment. It is a figure which shows the detail of the structure of the selection part and the correction part which concerns on this embodiment.

[Overview of Piston Temperature Estimator 1]
FIG. 1 is a diagram showing a configuration of a piston temperature estimation device 1 according to the present embodiment. The piston temperature estimation device 1 is a computer that estimates the temperature of the piston included in the engine E, which is an internal combustion engine mounted on the vehicle V. The vehicle V is, for example, a large vehicle such as a bus or a truck. The piston temperature estimation device 1 is mounted on the vehicle V, and acquires engine state information indicating the state of the engine E from various sensors provided on the vehicle V. The piston temperature estimation device 1 estimates the temperature of the piston based on the engine state information.

Here, the engine E is a diesel engine. Further, it is assumed that the vehicle V is equipped with an EGR (Exhaust Gas Recirculation) system that returns the exhaust gas of the engine E to the intake side and mixes it with the intake air. Further, the temperature of the piston is assumed to be the surface temperature of the piston. Further, in the present embodiment, engine state information indicating the state of the engine E is acquired from various sensors, but the present invention is not limited to this. The piston temperature estimation device 1 may acquire engine state information by calculating or estimating the state of the engine E.

As shown in FIG. 1, the piston temperature estimation device 1 includes a storage unit 2 and a control unit 3.
The storage unit 2 is, for example, a hard disk or a memory. The storage unit 2 stores the piston temperature estimated by the control unit 3.

The control unit 3 is, for example, an ECU (Engine Control Unit). The control unit 3 includes an intake air temperature selection unit 4, a piston temperature estimation unit 5, and a piston temperature correction unit 6, and estimates the piston temperature.

The intake air temperature selection unit 4 selects the temperature measured at a position suitable for estimating the piston temperature as the intake air temperature to be output to the piston temperature estimation unit 5. As a result, the piston temperature estimation unit 5 can accurately estimate the piston temperature based on the intake air temperature. The details of the intake air temperature selection unit 4 will be described later.

The piston temperature estimation unit 5 estimates the piston temperature based on the engine speed included in the engine state information and the fuel injection amount. Here, it is assumed that the estimated piston temperature is an instantaneous value of the piston temperature. The piston temperature estimation unit 5 calculates a correction value for the piston temperature based on the engine state information and the estimated piston temperature. The state of the engine E is, for example, the fuel injection amount, which is the injection amount of fuel into the combustion chamber of the engine E, or the rotation speed of the crank of the engine E, which corresponds to the rotation speed. And the intake temperature. The piston temperature estimation unit 5 corrects the estimated piston temperature based on the calculated correction value. By doing so, the piston temperature estimation unit 5 can accurately estimate the piston temperature based on the engine state information indicating the state of the engine E. The details of the piston temperature estimation unit 5 will be described later. Hereinafter, the piston temperature corrected by the piston temperature estimation unit 5 is also referred to as a first corrected piston temperature.

It takes time for the actual temperature of the piston to change to the first corrected piston temperature calculated by the piston temperature estimation unit 5. Therefore, the piston temperature correction unit 6 selects a time constant corresponding to the state of the engine E, and corrects the first correction piston temperature estimated by the piston temperature estimation unit 5 based on the time constant. As a result, the piston temperature correction unit 6 can further correct the first correction piston temperature by reflecting the actual temperature change of the piston.
Subsequently, the details of the intake air temperature selection unit 4, the piston temperature estimation unit 5, and the piston temperature correction unit 6 will be described. First, the details of the intake air temperature selection unit 4 will be described.

[Details of intake air temperature selection unit 4]
FIG. 2 is a diagram showing an example of the configuration of the intake air temperature selection unit 4 according to the present embodiment. The intake air temperature selection unit 4 includes a selection unit 41 and an acquisition unit 42.

The selection unit 41 selects one predetermined temperature measurement sensor from among a plurality of temperature measurement sensors provided at different locations of the engine E to measure the temperature of the intake air sucked by the engine E.

The storage unit 2 stores either 0, 1, or 2 as a parameter for selecting the temperature measurement sensor. Parameter 0 is a parameter corresponding to the first temperature measurement sensor. Parameter 1 is a parameter corresponding to the second temperature measurement sensor. Parameter 2 is a parameter corresponding to the third temperature measurement sensor.

The engine E has a first temperature measuring sensor, a second temperature measuring sensor, and a third temperature measuring sensor. The first temperature measurement sensor is a temperature measurement sensor provided at the outlet of the intercooler that cools the intake air. The second temperature measurement sensor is a temperature measurement sensor provided at the outlet of the intake manifold that distributes the intake air to the cylinder included in the engine E. The third temperature measurement sensor is a temperature measurement sensor provided upstream of the compressor that compresses the air sucked into the internal combustion engine.

The selection unit 41 determines the temperature of the intake air taken in by the engine E from any of the first temperature measurement sensor, the second temperature measurement sensor, and the third temperature measurement sensor based on the parameters stored in the storage unit 2. Select as the temperature measurement sensor to measure.

The acquisition unit 42 acquires information indicating the intake air temperature of the engine E. Specifically, the acquisition unit 42 acquires information indicating the temperature measured by the temperature measurement sensor selected by the selection unit 41 as information indicating the intake air temperature. For example, when the selection unit 41 selects the first temperature measurement sensor, the acquisition unit 42 acquires information indicating the temperature of the air passing through the outlet of the intercooler that cools the intake air as information indicating the intake air temperature.

Further, for example, when the selection unit 41 selects the second temperature measurement sensor, the acquisition unit 42 takes in information indicating the temperature of the air passing through the outlet of the intake manifold that distributes the intake air to the cylinders constituting the engine E. Obtained as information indicating the temperature. Further, for example, when the selection unit 41 selects the third temperature measurement sensor, the acquisition unit 42 indicates the intake air temperature with information indicating the temperature of the air upstream of the compressor that compresses the air sucked into the engine E. Get as information.

Here, if one predetermined temperature measurement sensor cannot measure the intake air temperature due to a failure or the like, the piston temperature cannot be estimated. Therefore, the selection unit 41 may select one temperature measurement sensor that is operating normally from the plurality of temperature measurement sensors.

FIG. 3 is a diagram showing another example of the configuration of the intake air temperature selection unit 4 according to the present embodiment. As shown in FIG. 3, the selection unit 41 is normal based on a predetermined order of the operating state of the first temperature measuring sensor, the operating state of the second temperature measuring sensor, and the operating state of the third temperature measuring sensor. Select one temperature measurement sensor operating in. The predetermined order is determined based on the accuracy of estimating the piston temperature.

Since the first temperature measurement sensor is provided between the intercooler and the engine E, the temperature measured by the first temperature measurement sensor is the temperature after the intake air is cooled by the compressor operating point and the intercooler. .. Therefore, the temperature measured by the first temperature measuring sensor is close to the temperature of the intake air flowing into the engine E.

However, between the intercooler and the engine E, the EGR gas is mixed with the intake air discharged from the intercooler. Therefore, due to the influence of the heat contained in the EGR gas, there is a difference between the temperature measured by the first temperature measuring sensor and the temperature of the intake air flowing into the piston. However, the temperature difference can be corrected based on the correction value of the intake air amount calculated by the intake air amount correction calculation unit 57 provided in the correction value calculation unit 53, which will be described later. Therefore, the temperature measured by the first temperature measurement sensor is the most suitable as the intake air temperature used for estimating the piston temperature.

Since the second temperature measurement sensor is provided between the intake manifold and the engine E, the temperature measured by the second temperature measurement sensor is the intake air cooled by the intercooler and the EGR gas cooled by the EGR cooler. Is the temperature of the air mixed with. Therefore, the temperature measured by the second temperature measuring sensor is the temperature of the intake air flowing into the engine E.

However, when the temperature measured by the second temperature measurement sensor is selected as the intake air temperature used for estimating the piston temperature, the intake air temperature correction calculation unit 56 included in the correction value calculation unit 53 described later may be the second temperature measurement sensor. The correction value of the piston temperature is calculated based on the temperature measured in. Further, the intake air amount correction calculation unit 57 included in the correction value calculation unit 53, which will be described later, calculates the correction value of the piston temperature based on the flow rate of the air sucked into the engine E.

Here, when the flow rate of the exhaust gas mixed with the intake air by the EGR increases, the amount of air taken into the engine E increases and the temperature measured by the second temperature measurement sensor rises. As a result, the piston temperature is estimated to be higher. On the other hand, in the engine E, since the oxygen concentration decreases due to the increase in the EGR flow rate, the combustion efficiency deteriorates and the actual piston temperature decreases. Therefore, when the temperature measured by the second temperature measuring sensor is used as the intake air temperature used for estimating the piston temperature, the piston temperature is estimated more accurately than when the temperature measured by the first temperature measuring sensor is used. You may not be able to.

Since the third temperature measurement sensor is provided upstream of the compressor, the temperature measured by the third temperature measurement sensor is the temperature of the outside air. Since the temperature of the outside air is affected by various factors, when the temperature measured by the third temperature measurement sensor is used as the intake air temperature used to estimate the piston temperature, the first temperature measurement sensor and the second temperature measurement sensor are used. It may not be possible to estimate the piston temperature more accurately than when using the temperature measured in.

According to the above priority order, the selection unit 41 selects the first temperature measurement sensor when the first temperature measurement sensor is operating normally. Further, the selection unit 41 selects the second temperature measurement sensor when the first temperature measurement sensor is not operating normally and the second temperature measurement sensor is operating normally. Further, the selection unit 41 selects the third temperature measurement sensor when the first temperature measurement sensor and the second temperature measurement sensor are not operating normally and the third temperature measurement sensor is operating normally. do.

By predetermining the priority order for the plurality of temperature measurement sensors provided in the engine E in this way, the intake air temperature selection unit 4 measures the intake air temperature due to a failure or the like of one predetermined temperature measurement sensor. Even if this is not possible, the temperature measurement sensors that are operating normally can be selected in descending order of accuracy in estimating the piston temperature.

[Details of piston temperature estimation unit 5]
Subsequently, the details of the piston temperature estimation unit 5 will be described. FIG. 4 is a diagram showing the configuration of the piston temperature estimation unit 5 according to the present embodiment. The piston temperature estimation unit 5 includes an acquisition unit 51, an estimation unit 52, a correction value calculation unit 53, and a correction unit 59.

The acquisition unit 51 is an interface for acquiring various information from the outside. The acquisition unit 51 acquires engine state information from various sensors and the intake air temperature selection unit 4. Specifically, the acquisition unit 51 obtains fuel injection amount information indicating the fuel injection amount, rotation speed information indicating the engine rotation speed, hydraulic information indicating the hydraulic pressure, oil temperature information indicating the oil temperature, and intake air temperature. The intake air temperature information shown, the intake air amount information indicating the intake air amount, the injection timing information indicating the injection timing, and the intake air amount detection state are acquired as engine state information. Further, the acquisition unit 51 includes information indicating the intercooler temperature detection state, information indicating the intake manifold outlet temperature detection state, information indicating the intake outlet temperature detection state, information indicating the oil temperature detection state, and a check valve open / closed state. And the information indicating the oil pressure detection state are acquired as the engine state information.

The oil pressure is the pressure of the oil supplied to the engine E. The oil temperature is the temperature of the oil supplied to the engine E. The intake air temperature is the intake air temperature of the air supplied to the engine E. The intake air amount is the intake amount of air supplied to the engine E. The injection timing is the injection timing of the fuel supplied to the engine E.

The estimation unit 52 determines the piston temperature, hydraulic pressure, oil temperature, intake air temperature, intake air amount, and injection timing based on the fuel injection amount indicated by the fuel injection amount information acquired by the acquisition unit 51 and the engine rotation speed indicated by the rotation speed information. To estimate. Specifically, the estimation unit 52 includes piston temperature map information, hydraulic pressure map information, oil temperature map information, intake air temperature map information, intake air amount map information, and intake air amount map information stored in advance in the storage unit 2. The piston temperature, oil pressure, oil temperature, intake air temperature, intake air amount, and injection timing are estimated based on the injection timing map information.

The piston temperature map information is information in which the fuel injection amount, the engine speed, and the piston temperature are associated with each other. The oil pressure map information is information in which the fuel injection amount, the engine speed, and the oil pressure are associated with each other. The oil temperature map information is information that associates the fuel injection amount, the engine speed, and the oil temperature. The intake air temperature map information is information that associates the fuel injection amount, the engine speed, and the intake air temperature. The intake air amount map information is information in which the fuel injection amount, the engine speed, and the intake air amount are associated with each other. The injection timing map information is information in which the fuel injection amount, the engine speed, and the fuel injection timing are associated with each other.

In the present embodiment, it is decided to have a plurality of map information corresponding to each of the piston temperature, the oil pressure, the oil temperature, the intake air temperature, the intake air amount, and the injection timing, but the present invention is not limited to this. For example, the storage unit 2 associates the fuel injection amount, the engine speed, the piston temperature, the oil pressure, the oil temperature, the intake air temperature, the intake air amount, and the injection timing instead of the plurality of map information. Only one map information may be stored.

The estimation unit 52 refers to the piston temperature map information stored in the storage unit 2, and specifies the piston temperature associated with the fuel injection amount acquired by the acquisition unit 51 and the engine speed, thereby specifying the piston temperature. To estimate. The estimation unit 52 outputs information indicating the estimated piston temperature to the correction value calculation unit 53 and the correction unit 59. Hereinafter, the piston temperature estimated by the estimation unit 52 is also referred to as an estimated piston temperature.

Similarly, the estimation unit 52 refers to the oil pressure map information, the oil temperature map information, the intake air temperature map information, the intake air amount map information, and the injection timing map information stored in the storage unit 2, and is acquired by the acquisition unit 51. Estimate the oil pressure, oil temperature, intake air temperature, intake air amount, and injection timing by specifying the oil pressure, oil temperature, intake air temperature, intake air amount, and injection timing associated with the fuel injection amount and engine speed. do. The estimation unit 52 outputs the estimated oil pressure, oil temperature, intake air temperature, intake air amount, and injection timing to the correction value calculation unit 53.

The correction value calculation unit 53 calculates the correction value of the estimated piston temperature based on the state of the engine E indicated by the engine state information and the estimated piston temperature estimated by the estimation unit 52. The correction value calculation unit 53 includes a hydraulic pressure correction calculation unit 54, an oil temperature correction calculation unit 55, an intake air temperature correction calculation unit 56, an intake air amount correction calculation unit 57, and an injection timing correction calculation unit 58. Hereinafter, the details of the oil pressure correction calculation unit 54, the oil temperature correction calculation unit 55, the intake air temperature correction calculation unit 56, the intake air amount correction calculation unit 57, and the injection timing correction calculation unit 58 will be described.

(Flood control correction calculation unit 54)
First, the details of the oil pressure correction calculation unit 54 will be described. The oil pressure correction calculation unit 54 determines the difference between the oil pressure estimated by the estimation unit 52 and the oil pressure indicated by the oil pressure information acquired by the acquisition unit 51, the estimated piston temperature estimated by the estimation unit 52, and the engine rotation speed. Based on this, the first correction value, which is the correction value of the estimated piston temperature due to the difference in oil pressure, is calculated. Further, the oil pressure correction calculation unit 54 controls whether or not to output the first correction value based on the oil pressure indicated by the oil pressure information acquired by the acquisition unit 51, the oil pressure detection state, and the check valve open / closed state.

FIG. 5 is a diagram showing the configuration of the oil pressure correction calculation unit 54 according to the present embodiment. As shown in FIG. 5, the hydraulic correction calculation unit 54 includes a subtractor 54A, a multiplier 54B, a multiplier 54C, a divider 54D, a multiplier 54E, an adder 54F, an adjuster 54G, and a switch. It includes 54H, an OR circuit 54I, and a switch 54J.

The subtractor 54A subtracts the estimated value of the oil pressure estimated by the estimation unit 52 from the oil pressure indicated by the oil pressure information acquired by the acquisition unit 51, and calculates the difference in the oil pressure.

The multiplier 54B multiplies the first oil pressure correction coefficient by the estimated piston temperature estimated by the estimation unit 52.
The multiplier 54C multiplies the difference in oil pressure output from the subtractor 54A by the multiplication value of the first oil pressure correction coefficient and the estimated piston temperature.
The divider 54D calculates the first oil pressure correction value by dividing the multiplication value of the oil pressure difference, the first oil pressure correction coefficient, and the estimated piston temperature, which is output from the multiplier 54C, by the engine speed.

The multiplier 54E calculates the second oil pressure correction value by multiplying the difference in the oil pressure output from the subtractor 54A by the second oil pressure correction coefficient.
The adder 54F adds the first oil pressure correction value output from the divider 54D and the second oil pressure correction value output from the multiplier 54E. As a result, the first correction value is calculated.

The oil pressure correction calculation unit 54 is provided with the adjuster 54G and the switch 54H to output the first correction value when the oil pressure exceeds the first oil pressure threshold value, and the first correction when the oil pressure is equal to or less than the first oil pressure threshold value. Control not to output the value. Further, the oil pressure correction calculation unit 54 exceeds the second oil pressure threshold value in which the oil pressure indicated by the oil pressure information newly acquired by the acquisition unit 51 exceeds the first oil pressure threshold value in a state where the oil pressure does not exceed the first oil pressure threshold value. In this case, the first correction value is output, and the acquisition unit 51 controls so as not to output the first correction value when the oil pressure indicated by the newly acquired oil pressure information is equal to or less than the second oil pressure threshold value.

Whether or not the regulator 54G enables the first correction value based on the oil pressure indicated by the oil pressure information acquired by the acquisition unit 51, the first oil pressure threshold value, and the second oil pressure threshold value larger than the first oil pressure threshold value. Generate a judgment value to judge whether or not. Specifically, the regulator 54G outputs a determination value 0 indicating that the first correction value is invalidated when the oil pressure indicated by the oil pressure information acquired by the acquisition unit 51 is equal to or less than the first oil pressure threshold value. do. Further, the regulator 54G outputs a determination value 1 indicating that the first correction value is valid when the oil pressure indicated by the oil pressure information acquired by the acquisition unit 51 is equal to or higher than the second oil pressure threshold value.

The regulator 54G operates as follows in order to prevent chattering in the determination value due to the fluctuation of the oil pressure between the first oil pressure threshold value and the second oil pressure threshold value. The regulator 54G is in a state where the oil pressure indicated by the oil pressure information acquired by the acquisition unit 51 does not exceed the first oil pressure threshold value, while the oil pressure indicated by the oil pressure information newly acquired by the acquisition unit 51 is less than the second oil pressure threshold value. Keeps the determination value at 0. Further, the regulator 54G outputs a determination value 1 indicating that the first correction value is valid when the oil pressure indicated by the oil pressure information newly acquired by the acquisition unit 51 exceeds the second oil pressure threshold value.

Further, the regulator 54G continuously determines when the determination value output by itself is 1, and the oil pressure indicated by the oil pressure information newly acquired by the acquisition unit 51 exceeds the first oil pressure threshold value. A value of 1 is output, and a determination value of 0 is output when the value is equal to or less than the first oil pressure threshold. By doing so, in the regulator 54G, chattering occurs in the determination value due to the oil pressure indicated by the oil pressure information newly acquired by the acquisition unit 51 fluctuating between the first oil pressure threshold value and the second oil pressure threshold value. Can be prevented.

The switch 54H switches whether or not to output the first correction value based on the determination value output by the regulator 54G. Specifically, the switch 54H outputs the first correction value output from the adder 54F when the determination value output by the regulator 54G is 1. The switch 54H outputs 0 when the determination value output by the regulator 54G is 0. That is, the switch 54H controls so that the first correction value is not output when the determination value output by the regulator 54G is 0.

The OR circuit 54I functions as a detection unit that detects the presence or absence of oil injection to the piston. The OR circuit 54I detects the presence or absence of oil injection by detecting whether or not the oil check valve that injects oil into the piston is closed.

Specifically, the OR circuit 54I outputs the logical product of the value indicated by the oil pressure detection state and the value indicated by the check valve open / closed state. Here, it is assumed that the value indicated by the oil pressure detection state is 0 when the oil pressure can be detected, and the value indicated by the oil pressure detection state is 1 when the oil pressure cannot be detected. .. When the check valve is closed and the jet is not injected, the value indicated by the check valve open / closed state is 1, and when the check valve is open and the jet is injected. It is assumed that the value indicated by the check valve open / closed state is 0.

The switch 54J switches whether or not to output the value output by the switch 54H based on the value output by the OR circuit 54I. Specifically, the switch 54J outputs 0 when the value output by the OR circuit 54I is 1. When the value output by the OR circuit 54I is 0, the switch 54J outputs the value output by the switch 54H. As a result, the oil pressure correction calculation unit 54 calculates the correction value of the estimated piston temperature based on the difference between the estimated oil pressure and the oil pressure indicated by the oil pressure information and the presence or absence of oil injection detected in the OR circuit 54I. do.

Here, dop hydraulic pressure difference, the first hydraulic correction coefficient _{k op1,} a second hydraulic correction coefficient _{k op2,} the estimated piston temperature _{T ps,} the engine speed _{N eng,} the first correction value and _{dT ps1} .. When the first correction value output from the adder 54F is output by the switch 54H and the switch _54J , the first correction value dT ps1 is represented by the following equation (1).

As shown in the equation (1), the oil pressure correction calculation unit 54 calculates the first correction value so that the correction value increases as the estimated piston temperature rises. Further, the oil pressure correction calculation unit 54 calculates the first correction value so that the correction value becomes smaller as the engine speed increases. In the cooling channel provided in the piston, the oil is agitated by the behavior of the piston. As the engine speed increases, the oil in the cooling channel is agitated, and the amount of correction that accompanies the rise in piston temperature is suppressed. On the other hand, the hydraulic correction calculation unit 54 divides the estimated piston temperature by the engine speed so that the correction amount due to the rise in the piston temperature is suppressed in response to the increase in the engine speed. Can be calculated.

(Oil temperature correction calculation unit 55)
Subsequently, the details of the oil temperature correction calculation unit 55 will be described. The oil temperature correction calculation unit 55 is based on the difference between the oil temperature estimated by the estimation unit 52 and the oil temperature indicated by the oil temperature information acquired by the acquisition unit 51, and the estimated piston temperature estimated by the estimation unit 52. Therefore, the second correction value, which is the correction value of the estimated piston temperature due to the difference in oil temperature, is calculated. Further, the oil temperature correction calculation unit 55 controls whether or not to output the second correction value based on the oil temperature detection state acquired by the acquisition unit 51.

FIG. 6 is a diagram showing the configuration of the oil temperature correction calculation unit 55 according to the present embodiment. As shown in FIG. 6, the oil temperature correction calculation unit 55 includes a multiplier 55A, a multiplier 55B, a multiplier 55C, a multiplier 55D, an adder 55E, a multiplier 55F, a multiplier 55G, and the like. It includes a multiplier 55H, an adder 55I, a comparator 55J, a switch 55K, and a switch 55L.

The subtractor 55A subtracts the oil temperature estimated value, which is the oil temperature estimated by the estimation unit 52, from the oil temperature indicated by the oil temperature information acquired by the acquisition unit 51, and calculates the difference in oil temperature.

The multiplier 55B multiplies the first oil temperature rise correction coefficient by the estimated piston temperature estimated by the estimation unit 52.
The multiplier 55C first multiplies the difference in oil temperature output from the subtractor 55A by the multiplication value of the first oil temperature rise correction coefficient output from the multiplier 55B and the estimated piston temperature. Calculate the correction value when the oil temperature rises.

The multiplier 55D calculates the second oil temperature rise correction value by multiplying the difference in oil temperature output from the subtractor 55A by the second oil temperature rise correction coefficient.
The adder 55E adds the first oil temperature rise correction value output from the multiplier 55C and the second oil temperature rise correction value output from the multiplier 55D, thereby increasing the oil temperature rise correction value. Is calculated.

The multiplier 55F multiplies the first oil temperature drop correction coefficient by the estimated piston temperature estimated by the estimation unit 52.
The multiplier 55G is the first by multiplying the difference in oil temperature output from the subtractor 55A by the multiplication value of the first oil temperature drop correction coefficient output from the multiplier 55F and the estimated piston temperature. Calculate the correction value when the oil temperature drops.

The multiplier 55H calculates the second oil temperature drop correction value by multiplying the difference in oil temperature output from the subtractor 55A by the second oil temperature drop correction coefficient.
The adder 55I adds the first oil temperature drop correction value output from the multiplier 55G and the second oil temperature drop correction value output from the multiplier 55H, thereby adding the oil temperature drop correction value. Is calculated.

The comparator 55J determines whether or not the difference in oil temperature output from the subtractor 55A is 0 or more. The comparator 55J outputs 1 when the difference in oil temperature is 0 or more, and outputs 0 when the difference in oil temperature is less than 0.

The switch 55K switches between outputting the correction value when the oil temperature rises and outputting the correction value when the oil temperature drops, based on the value output by the comparator 55J. Specifically, when the value output by the comparator 55J is 1, the switch 55K outputs the correction value when the oil temperature rises, which is output from the adder 55E. When the value output by the comparator 55J is 0, the switch 55K outputs the correction value when the oil temperature drops, which is output from the adder 55I.

The switch 55L switches whether or not to output the value output by the switch 55K based on the value indicated by the oil temperature detection state. Here, when the oil temperature is in a detectable state, the value indicated by the oil temperature detection state is 0, and when the oil temperature cannot be detected, the value indicated by the oil temperature detection state is 1. Suppose there is. Specifically, the switch 55L outputs 0 when the value indicated by the oil temperature detection state is 1. When the value indicated by the oil temperature detection state is 0, the switch 55L outputs a value output by the switch 55K, that is, a correction value when the oil temperature rises or a correction value when the oil temperature falls.

Here, the difference in oil temperature is dot, the correction coefficient when the first oil temperature rises is _kotu1 , the correction coefficient when the second oil temperature rises is _kotu2 , the correction coefficient when the first oil temperature falls is _kotd1 , and the second oil temperature. The lowering correction coefficient is _quad2 , the estimated piston temperature is T _ps , and the second correction value is dT _ps2 . When the oil temperature rise correction value is output as the second correction value by the switch 55K and the switch 55L, the second correction value dT _ps2 is expressed by the following equation (2). When the oil temperature drop correction value is output as the second correction value by the switch 55K and the switch 55L, the second correction value dT _ps2 is represented by the following equation (3).

（２）、（３）式に示すように、油温補正計算部５５が、推定ピストン温度の上昇に応じて補正値が大きくなるように第２補正値を算出することが確認できる。

As shown in the equations (2) and (3), it can be confirmed that the oil temperature correction calculation unit 55 calculates the second correction value so that the correction value increases as the estimated piston temperature rises.

(Intake air temperature correction calculation unit 56)
Subsequently, the details of the intake air temperature correction calculation unit 56 will be described. The intake air temperature correction calculation unit 56 is based on the difference between the intake air temperature estimated by the estimation unit 52 and the intake air temperature indicated by the intake air temperature information acquired by the acquisition unit 51, and the estimated piston temperature estimated by the estimation unit 52. Then, the third correction value, which is the correction value of the estimated piston temperature due to the difference in the intake air temperature, is calculated. Further, the intake air temperature correction calculation unit 56 controls whether or not to output the third correction value based on the intercooler temperature detection state, the intake manifold outlet temperature detection state, and the intake / outlet temperature detection state.

FIG. 7 is a diagram showing the configuration of the intake air temperature correction calculation unit 56 according to the present embodiment. As shown in FIG. 7, the intake temperature correction calculation unit 56 includes a subtractor 56A, a multiplier 56B, a multiplier 56C, a multiplier 56D, an adder 56E, a switch 56F, and a switch 56G.

The subtractor 56A calculates the difference in intake air temperature by subtracting the intake air temperature estimated value, which is the intake air temperature estimated by the estimation unit 52, from the intake air temperature indicated by the intake air temperature information acquired by the acquisition unit 51.

The multiplier 56B multiplies the first intake air temperature correction coefficient by the estimated piston temperature estimated by the estimation unit 52.
The multiplier 56C multiplies the difference in the intake air temperature output from the subtractor 56A by the multiplication value of the first intake air temperature correction coefficient output from the multiplier 56B and the estimated piston temperature to obtain the first intake air temperature. Calculate the correction value.

The multiplier 56D calculates the second intake air temperature correction value by multiplying the difference in the intake air temperature output from the subtractor 56A by the second intake air temperature correction coefficient.
The adder 56E calculates the intake air temperature correction value by adding the first intake air temperature correction value output from the multiplier 56C and the second intake air temperature correction value output from the multiplier 56D.

The switch 56F is set to 0 or 0 based on the selection value set in the selection unit 41 of the intake air temperature selection unit 4, the intercooler temperature detection state, the intake manifold outlet temperature detection state, and the value indicated by the intake air outlet temperature detection state. Output 1 Here, when the temperature of the intercooler is in a detectable state, the value indicated by the intercooler temperature detection state is 0, and when the temperature of the intercooler cannot be detected, the value indicated by the intercooler temperature detection state is 0. It is assumed that it is 1. Further, when the temperature of the intake manifold outlet temperature is in a detectable state, the value indicated by the intake manifold outlet temperature detection state is 0, and when the temperature of the intake manifold outlet temperature cannot be detected, the intake is taken. It is assumed that the value indicated by the manifold outlet temperature detection state is 1. Further, when the temperature of the intake outlet is in a detectable state, the value indicated by the intake outlet temperature detection state is 0, and when the temperature of the intake outlet cannot be detected, the intake outlet temperature detection state is The value shown is assumed to be 1.

The switch 56F outputs the value indicated by the intercooler temperature detection state when the value indicated by the selection value is 0, and outputs the value indicated by the intake manifold outlet temperature detection state when the value indicated by the selection value is 1. Then, when the value indicated by the selected value is 2, the value indicated by the intake outlet temperature detection state is output. As a result, the switch 56F can output information indicating whether or not the intake air temperature can be detected.

The switch 56G switches whether or not to output the value output by the adder 56E based on the value output from the switch 56F. Specifically, the switch 56G outputs 0 when the value output from the switch 56F is 1. When the value output from the switch 56F is 0, the switch 56G outputs the value output by the adder 56E.

Here, the difference in intake air temperature is dat, the first intake air temperature correction coefficient is _kat1 , the second intake air temperature correction coefficient is _kat2 , the estimated piston temperature is T _ps , and the third correction value is dT _ps3 . When the intake air temperature correction value is output by the switch 56G, the third correction value dT _ps3 is expressed by the following equation (4).

（４）式に示すように、吸気温度補正計算部５６が、推定ピストン温度の上昇に応じて補正値が大きくなるように第３補正値を算出することが確認できる。

As shown in the equation (4), it can be confirmed that the intake air temperature correction calculation unit 56 calculates the third correction value so that the correction value increases as the estimated piston temperature rises.

Subsequently, the details of the intake air amount correction calculation unit 57 will be described. The intake air amount correction calculation unit 57 has a difference between the intake air amount estimated by the estimation unit 52 and the intake air amount indicated by the intake air amount information acquired by the acquisition unit 51, and the estimated piston estimated by the estimation unit 52. Based on the temperature, the fourth correction value, which is the correction value of the estimated piston temperature due to the difference in the intake air amount, is calculated. Further, the intake air amount correction calculation unit 57 controls whether or not to output the fourth correction value based on the fuel injection amount and the intake air amount detection state acquired by the acquisition unit 51.

(Intake air amount correction calculation unit 57)
FIG. 8 is a diagram showing the configuration of the intake air amount correction calculation unit 57 according to the present embodiment. As shown in FIG. 8, the intake air amount correction calculation unit 57 includes a multiplier 57A, a multiplier 57B, a multiplier 57C, a multiplier 57D, an adder 57E, a multiplier 57F, and a multiplier 57G. , A multiplier 57H, an adder 57I, a comparator 57J, a switch 57K, a regulator 57L, a switch 57M, and a switch 57N.

The subtractor 57A subtracts the intake air amount estimated value, which is the intake air amount estimated by the estimation unit 52, from the intake air amount indicated by the intake air amount information acquired by the acquisition unit 51, and calculates the difference in the intake air amount. ..

The multiplier 57B multiplies the first suction amount increase correction coefficient by the estimated piston temperature estimated by the estimation unit 52.
The multiplier 57C is obtained by multiplying the difference in the intake air amount output from the subtractor 57A by the multiplication value of the first suction amount rising correction coefficient output from the multiplier 57B and the estimated piston temperature. 1 Calculate the correction value when the inhalation amount increases.

The multiplier 57D calculates the second suction amount increase correction value by multiplying the difference in the intake air amount output from the subtractor 57A by the second intake amount increase correction coefficient.
The adder 57E adds the first inhalation amount increase correction value output from the multiplier 57C and the second inhalation amount increase correction value output from the multiplier 57D to obtain the inhalation amount increase correction value. Is calculated.

The multiplier 57F multiplies the first suction amount reduction correction coefficient by the estimated piston temperature estimated by the estimation unit 52. Here, when the acquired intake air amount is smaller than the estimated intake air amount, the EGR rate, which is the ratio of the flow rate of the exhaust gas mixed with the intake air by the EGR to the flow rate on the intake side, increases. When the EGR rate increases, the combustion temperature decreases, so that the piston temperature tends to decrease. Therefore, the correction coefficient when the first inhalation amount decreases is smaller than the correction coefficient when the first inhalation amount increases.

The multiplier 57G is obtained by multiplying the difference in the intake air amount output from the subtractor 57A by the multiplication value of the first suction amount decrease correction coefficient output from the multiplier 57F and the estimated piston temperature. 1 Calculate the correction value when the inhalation amount decreases.

The multiplier 57H calculates the second suction amount reduction correction value by multiplying the difference in the intake air amount output from the subtractor 57A by the second suction amount reduction correction coefficient.
The adder 57I adds the first inhalation amount decrease correction value output from the multiplier 57G and the second inhalation amount decrease correction value output from the multiplier 57H, thereby increasing the inhalation amount decrease correction value. Is calculated.

The comparator 57J determines whether or not the difference in the amount of intake air output from the subtractor 57A is 0 or more. The comparator 57J outputs 1 when the difference between the intake air amounts is 0 or more, and outputs 0 when the difference between the intake air amounts is less than 0.

The switch 57K switches between calculating the correction value when the inhalation amount increases and calculating the correction value when the inhalation amount decreases based on the value output by the comparator 57J. Specifically, when the value output by the comparator 57J is 1, the switch 57K outputs the correction value when the suction amount increases, which is output from the adder 57E. When the value output by the comparator 57J is 0, the switch 57K outputs the correction value when the suction amount decreases, which is output from the adder 57I.

The intake air amount correction calculation unit 57 includes the regulator 57L and the switch 57M, so that the intake air amount information can be obtained when the injection amount indicated by the fuel injection amount information acquired by the acquisition unit 51 exceeds the first injection amount threshold value. The fourth correction value based on the indicated intake air amount and the estimated intake air amount is output, and control is performed so that the fourth correction value is not output when the injection amount is equal to or less than the first injection amount threshold value. Further, in the intake air amount correction calculation unit 57, when the injection amount does not exceed the first injection amount threshold value, the injection amount indicated by the fuel injection amount information newly acquired by the acquisition unit 51 is larger than the first injection amount threshold value. A fourth correction value is output when a large second injection amount threshold value is exceeded, and a fourth correction value is output when the injection amount indicated by the fuel injection amount information newly acquired by the acquisition unit 51 is equal to or less than the second injection amount threshold value. Control not to output.

Here, the first injection amount threshold value is a threshold value for determining whether or not the fuel has not been injected. When the fuel injection amount is lower than the first injection amount threshold value, that is, when the fuel is not injected, the influence of EGR on the change in piston temperature is small. Therefore, when the fuel injection amount is lower than the first injection amount threshold value, the intake air amount correction calculation unit 57 controls so as not to correct the intake air amount.

The regulator 57L determines whether or not to enable the fourth correction value based on the injection amount indicated by the fuel injection amount information acquired by the acquisition unit 51, the first injection amount threshold value, and the second injection amount threshold value. Generate a judgment value for judgment. Specifically, the regulator 57L outputs a determination value 0 indicating that the fourth correction value is invalidated when the fuel injection amount acquired by the acquisition unit 51 is equal to or less than the first injection amount threshold value. .. Further, the regulator 57L has a determination value 1 indicating that the fourth correction value is valid when the fuel injection amount indicated by the fuel injection amount information acquired by the acquisition unit 51 is equal to or greater than the second injection amount threshold value. Is output.

The regulator 57L operates as follows in order to prevent chattering in the determination value due to the fuel injection amount fluctuating between the first injection amount threshold value and the second injection amount threshold value. The regulator 57L has a fuel injection amount indicated by the fuel injection amount information newly acquired by the acquisition unit 51 in a state where the injection amount indicated by the fuel injection amount information acquired by the acquisition unit 51 does not exceed the first injection amount threshold value. The determination value is maintained at 0 while is less than the second injection amount threshold value. Further, the regulator 57L has a determination value 1 indicating that the fourth correction value is valid when the fuel injection amount indicated by the fuel injection amount information newly acquired by the acquisition unit 51 exceeds the second injection amount threshold value. Is output.

Further, the regulator 57L continues when the determination value output by itself is 1, and the fuel injection amount indicated by the fuel injection amount information newly acquired by the acquisition unit 51 exceeds the first injection amount threshold value. The determination value 1 is output, and the determination value 0 is output when the injection amount is equal to or less than the first injection amount threshold value. By doing so, in the regulator 57L, chattering occurs because the injection amount indicated by the injection amount information newly acquired by the acquisition unit 51 fluctuates between the first injection amount threshold value and the second injection amount threshold value. Can be prevented.

The switch 57M switches whether or not to output the value output by the switch 57K based on the determination value output by the regulator 57L. Specifically, when the determination value output by the regulator 57L is 1, the switch 57M outputs a value output by the switch 57K, that is, a correction value when the intake amount increases or a correction value when the intake amount decreases. .. The switch 57M outputs the determination value 0 when the determination value output by the regulator 57L is 0.

The switch 57N switches whether to output the value output by the switch 57M based on the value indicated by the intake air amount detection state. Here, when the intake air amount can be detected, the value indicated by the intake air amount detection state is 0, and when the intake air amount cannot be detected, the value indicated by the oil temperature detection state. Is assumed to be 1. The switch 57N outputs 0 when the value indicated by the intake air amount detection state is 1. The switch 55L outputs a value output by the switch 57M when the value indicated by the intake air amount detection state is 0.

Here, the difference in the intake air amount is dmaf, the first suction amount increase correction coefficient is _kmafu1 , the second suction amount increase correction coefficient is _kmafu2 , the first suction amount decrease correction coefficient is _kmafd1 , and the second suction amount is second. the amount decreases when the correction coefficient _{k mafd2,} the estimated piston temperature _{T ps,} the fourth correction value and _{dT ps4.} When the inhalation amount rising correction value is output as the fourth correction value by the switch 57K, the switch 57M and the switch 57N, the fourth correction value dT _ps4 is represented by the following equation (5). When the inhalation amount reduction correction value is output as the fourth correction value by the switch 57K, the switch 57M, and the switch 57N, the fourth correction value dT _ps4 is represented by the following equation (6).

（５）、（６）式に示すように、吸入空気量補正計算部５７が、推定ピストン温度の上昇に応じて補正値が大きくなるように第４補正値を算出することが確認できる。

As shown in the equations (5) and (6), it can be confirmed that the intake air amount correction calculation unit 57 calculates the fourth correction value so that the correction value increases as the estimated piston temperature rises.

(Injection timing correction calculation unit 58)
Subsequently, the details of the injection timing correction calculation unit 58 will be described. The injection timing correction calculation unit 58 is based on the difference between the injection timing estimated by the estimation unit 52 and the injection timing indicated by the injection timing information acquired by the acquisition unit 51, and the estimated piston temperature estimated by the estimation unit 52. Therefore, the fifth correction value, which is the correction value of the estimated piston temperature due to the difference in injection timing, is calculated. Further, the injection timing correction calculation unit 58 controls whether or not to output the fifth correction value based on the fuel injection amount.

FIG. 9 is a diagram showing the configuration of the injection timing correction calculation unit 58 according to the present embodiment. As shown in FIG. 9, the injection timing correction calculation unit 58 includes a subtractor 58A, a multiplier 58B, a multiplier 58C, a multiplier 58D, an adder 58E, a regulator 58F, and a switch 58G. ..

The subtractor 58A subtracts the injection timing estimated value, which is the injection timing estimated by the estimation unit 52, from the injection timing indicated by the injection timing information acquired by the acquisition unit 51, and calculates the difference in the injection timing.

The multiplier 58B multiplies the first injection timing correction coefficient by the estimated piston temperature estimated by the estimation unit 52.
The multiplier 58C multiplies the difference in injection timing output from the subtractor 58A by the multiplication value of the first injection timing correction coefficient output from the multiplier 58B and the estimated piston temperature to obtain the first injection timing. Calculate the correction value.

The multiplier 58D calculates the second injection timing correction value by multiplying the difference in injection timing output from the subtractor 58A by the second injection timing correction coefficient.
The adder 58E calculates the injection timing correction value by adding the first injection timing correction value output from the multiplier 58C and the second injection timing correction value output from the multiplier 58D.

The injection timing correction calculation unit 58 includes the regulator 58F and the switch 58G, so that when the injection amount indicated by the fuel injection amount information acquired by the acquisition unit 51 exceeds the first injection amount threshold value, the injection indicated by the injection timing information The fifth correction value based on the timing and the estimated injection timing is output, and control is performed so that the fifth correction value is not output when the injection amount is equal to or less than the first injection amount threshold value. Further, in the injection timing correction calculation unit 58, when the injection amount does not exceed the first injection amount threshold value, the injection amount indicated by the fuel injection amount information newly acquired by the acquisition unit 51 exceeds the second injection amount threshold value. In this case, the fifth correction value is output, and the acquisition unit 51 controls so as not to output the fifth correction value when the injection amount indicated by the newly acquired fuel injection amount information is equal to or less than the second injection amount threshold value.

Here, the first injection amount threshold value is a threshold value for determining whether or not the fuel has not been injected. When the fuel injection amount is lower than the first injection amount threshold value, that is, when the fuel is not injected, the influence of the injection timing on the change in the piston temperature is small. Therefore, when the fuel injection amount is lower than the first injection amount threshold value, the injection timing correction calculation unit 58 controls so as not to output the fifth correction value and to perform the correction related to the injection timing.

The regulator 58F determines whether or not to enable the fifth correction value based on the fuel injection amount acquired by the acquisition unit 51, the first injection amount threshold value, and the second injection amount threshold value. Generate a value. Since the function of the regulator 58F is the same as that of the regulator 57L provided in the intake air amount correction calculation unit 57, the description thereof will be omitted.

The switch 58G switches whether or not to output the value output by the adder 58E based on the value output from the regulator 58F. Specifically, the switch 58G outputs the value output by the adder 58E when the value output from the regulator 58F is 1. The switch 58G outputs 0 when the value output from the regulator 58F is 0.

Here, the difference in injection timing is dsoi, the first injection timing correction coefficient is k _soi1 , the second injection timing correction coefficient is k _soi2 , the estimated piston temperature is T _ps , and the fifth correction value is dT _ps5 . When the injection timing correction value is output as the fifth correction value by the switch 58G, the fifth correction value dT _ps5 is expressed by the following equation (7).

（７）式に示すように、噴射時期補正計算部５８が、推定ピストン温度の上昇に応じて補正値が大きくなるように第５補正値を算出することが確認できる。

As shown in the equation (7), it can be confirmed that the injection timing correction calculation unit 58 calculates the fifth correction value so that the correction value increases as the estimated piston temperature rises.

The explanation is returned to FIG. The correction unit 59 corrects the estimated piston temperature estimated by the estimation unit 52 based on the correction value calculated by the correction value calculation unit 53. Specifically, the correction unit 59 corrects the estimated piston temperature by adding the first correction value to the fifth correction value calculated by the correction value calculation unit 53 to the estimated piston temperature estimated by the estimation unit 52. .. The correction unit 59 outputs the corrected estimated piston temperature to the piston temperature correction unit 6 as the first correction piston temperature.

[Details of Piston Temperature Compensator 6]
Subsequently, the details of the piston temperature correction unit 6 will be described. The piston temperature correction unit 6 corrects the first correction piston temperature estimated by the piston temperature estimation unit 5 based on the engine state information. FIG. 10 is a diagram showing the configuration of the piston temperature compensating unit 6 according to the present embodiment. The piston temperature correction unit 6 includes an acquisition unit 61, a selection unit 62, and a correction unit 63.

The relationship between the first corrected piston temperature output by the correction unit 59 and the actual piston temperature may differ depending on the state of the engine E. Then, the time constant corresponding to the speed of change of the first correction piston temperature changes depending on the state of the engine E. Therefore, the piston temperature correction unit 6 corrects the first correction piston temperature based on the state of the engine E, so that the first correction piston temperature is based on the time constant of the first correction piston temperature corresponding to the state of the engine E. Is further corrected.

The acquisition unit 61 is an interface for acquiring various information from the outside. The acquisition unit 61 acquires, for example, engine state information indicating the state of the engine E. Specifically, the acquisition unit 61 uses the engine speed information indicating the engine speed, the fuel injection amount information indicating the fuel injection amount into the combustion chamber of the engine E, and the oil temperature information indicating the oil temperature. Acquire as status information. Further, the acquisition unit 61 acquires the first corrected piston temperature output by the piston temperature estimation unit 5.

The selection unit 62 selects a time constant indicating the degree of temperature change of the first correction piston temperature based on the change state of the first correction piston temperature. Specifically, the selection unit 62 selects the time constant based on the change state of the first correction piston temperature and the engine state information. More specifically, the selection unit 62 selects the time constant based on the change state of the first correction piston temperature, the rotation speed information, and the fuel injection amount information.

The correction unit 63 corrects the first correction piston temperature based on the time constant selected by the selection unit 62. Specifically, the correction unit 63 divides the difference value between the first correction piston temperature newly acquired by the acquisition unit 61 and the first correction piston temperature acquired one cycle before by a time constant by 1. The first corrected piston temperature is corrected by adding it to the first corrected piston temperature before the cycle. Here, the temperature after the first corrected piston temperature is corrected is also referred to as the second corrected piston temperature.

When the first correction piston temperature changes quickly, the selection unit 62 selects a relatively small time constant. As a result, the second corrected piston temperature reflects more of the newly acquired first corrected piston temperature. Further, when the change in the temperature of the first correction piston is slow, the selection unit 62 selects a relatively large time constant. As a result, the second corrected piston temperature reflects more of the first corrected piston temperature acquired one cycle before. The correction unit 63 can correct the calculated value to the piston temperature corresponding to the gradient of the actual piston temperature change by adding the calculated value to the first correction piston temperature one cycle before.

FIG. 11 is a diagram showing details of the configuration of the selection unit 62 and the correction unit 63 according to the present embodiment. As shown in FIG. 11, the selection unit 62 includes the regulator 62A, the switch 62B, the regulator 62C, the switch 62D, the OR circuit 62E, the switch 62F, the first-order lag calculator 62G, and the comparator 62H. And a switch 62I. Further, the correction unit 63 includes a divider 63A, a subtractor 63B, a multiplier 63C, and an adder 63D.

In the regulator 62A, the engine E is stopped based on the engine speed indicated by the rotation speed information acquired by the acquisition unit 61, the first rotation speed threshold value, and the second rotation speed threshold value larger than the first rotation speed threshold value. Generate a judgment value to judge whether or not it is done. Specifically, the regulator 62A is a determination value indicating that the engine E is stopped when the engine speed indicated by the rotation speed information acquired by the acquisition unit 61 is equal to or less than the first rotation speed threshold value. Output 0. Further, the regulator 62A outputs a determination value 1 indicating that the engine E is driving when the engine speed indicated by the rotation speed information acquired by the acquisition unit 61 is equal to or higher than the second rotation speed threshold value. do.

The regulator 62A operates as follows in order to prevent chattering in the determination value due to the engine speed fluctuating between the first speed threshold and the second speed threshold. In the regulator 62A, the engine speed indicated by the rotation speed information newly acquired by the acquisition unit 61 is the engine speed indicated by the rotation speed information newly acquired by the acquisition unit 61 in a state where the engine speed indicated by the rotation speed information acquired by the acquisition unit 61 does not exceed the first rotation speed threshold. While it is less than the second rotation speed threshold, the determination value is maintained at 0. Further, the regulator 62A outputs a determination value 1 indicating that the engine E has been driven when the engine speed indicated by the rotation speed information newly acquired by the acquisition unit 61 exceeds the second rotation speed threshold value.

Further, when the determination value output by the regulator 62A is 1, the engine speed indicated by the rotation speed information newly acquired by the acquisition unit 61 exceeds the first rotation speed threshold value. , The determination value 1 is continuously output, and the determination value 0 is output when it is equal to or less than the first rotation speed threshold value. By doing so, the regulator 62A determines that the engine speed indicated by the speed information newly acquired by the acquisition unit 61 fluctuates between the first speed threshold and the second speed threshold. It is possible to prevent chattering of the value.

The switch 62B outputs the time constant when the first corrected piston temperature is lowered, the fuel is not injected and the engine is driven, or the first corrected piston temperature is lowered, the fuel is not injected and the engine is driven, based on the determination value output by the regulator 62A. Switches whether to output the time constant at the time of stop. Specifically, when the determination value output by the regulator 62A is 1, the switch 62B indicates a second correction piston temperature drop, no fuel injection, and a time constant when the engine is driven. Output the time constant. When the value output by the regulator 62A is 0, the switch 62B outputs the first time constant indicating the time constant when the first correction piston temperature is lowered and the engine is stopped.

Here, when the temperature of the first corrected piston drops, the engine E operates, and the fuel is not injected, the oil and cooling water supplied to the engine E circulate in the engine E, so that the change in the first corrected piston temperature changes. It will be faster. When the temperature of the first corrected piston drops, the engine E stops, and the fuel is not injected, the circulation of the oil and the cooling water supplied to the engine E stops, so that the change in the temperature of the first corrected piston becomes slow. Therefore, the value of the first time constant is smaller than that of the second time constant.

The regulator 62C determines whether or not fuel is being injected based on the fuel injection amount indicated by the fuel injection amount information acquired by the acquisition unit 61, the first injection amount threshold value, and the second injection amount threshold value. Generate a judgment value for judgment. Specifically, the regulator 62C is a determination value indicating that the fuel injection is stopped when the fuel injection amount indicated by the fuel injection amount information acquired by the acquisition unit 61 is equal to or less than the first injection amount threshold value. Output 0. Further, the regulator 62C outputs a determination value 1 indicating that fuel injection is being performed when the fuel injection amount indicated by the fuel injection amount information acquired by the acquisition unit 61 is equal to or greater than the second injection amount threshold value. do. Since the function of the regulator 62C is the same as that of the regulator 57L shown in FIG. 8, the description thereof will be omitted.

The switch 62D outputs the time constant when the first corrected piston temperature is lowered and the fuel is injected, or outputs the time constant when the first corrected piston temperature is lowered and the fuel is not injected, based on the value output by the regulator 62C. To switch. Specifically, when the value output by the regulator 62C is 1, the switch 62D outputs a third time constant indicating a decrease in the temperature of the first correction piston and a time constant at the time of fuel injection. When the value output by the regulator 62C is 0, the switch 62D has a value output by the switch 62B, that is, a first time constant indicating a time constant when the first correction piston temperature drops and the engine is stopped, or a first time constant. 1 Corrected Outputs a second time constant that indicates the time constant when the piston temperature drops and fuel is not injected.

Here, when the temperature of the first corrected piston is lowered and the fuel is injected, the engine E is burning the fuel, so that the temperature of the first corrected piston is lowered. Therefore, in this case, the rate of decrease in the temperature of the first corrected piston becomes slower than in the case where the engine E is stopped and the fuel is not injected. Therefore, the value of the third time constant is smaller than that of the first time constant.

The OR circuit 62E outputs the logical sum of the value output by the regulator 62A and the value output by the regulator 62C. Specifically, the OR circuit 62E outputs 0 when the engine is stopped and no fuel is injected, and outputs 1 in other cases.

The switch 62F switches whether to output the first correction piston temperature acquired by the acquisition unit 61 or to output the oil temperature acquired by the acquisition unit 61 based on the value output by the OR circuit 62E. Specifically, the switch 62F outputs the first correction piston temperature when the value output by the OR circuit 62E is 1. The switch 62F outputs the oil temperature when the value output by the OR circuit 62E is 0.

The primary delay calculator 62G outputs the value of the first corrected piston temperature one cycle before the first corrected piston temperature output by the adder 63D described later. Here, the first-order lag calculator 62G outputs the oil temperature acquired by the acquisition unit 61 at the first output when the first correction piston temperature one cycle before cannot be acquired.

The comparator 62H determines whether or not the value output from the switch 62F is equal to or higher than the first correction piston temperature one cycle before the first-order lag calculator 62G, thereby determining the first correction piston temperature. Judges whether is rising or falling, and outputs the judgment value. When the value output from the switch 62F of the comparator 62H is equal to or higher than the temperature of the first correction piston one cycle before the output from the first-order lag calculator 62G, the temperature of the first correction piston has risen. The judgment value 1 indicating that is output. When the value output from the switch 62F of the comparator 62H is lower than the temperature of the first correction piston one cycle before the output from the first-order lag calculator 62G, the temperature of the first correction piston is lowered. The judgment value 0 indicating that is output.

The switch 62I switches between outputting the time constant when the temperature of the first correction piston rises and outputting the time constant when the temperature of the first correction piston falls, based on the value output by the comparator 62H. Specifically, when the value output by the comparator 62H is 1, the switch 62I outputs a fourth time constant indicating a time constant when the temperature of the first correction piston rises. When the value output by the comparator 62H is 0, the switch 62I has a value output by the switch 62D, that is, a first time constant and a second time constant indicating a time constant when the temperature of the first correction piston drops. Or output the third time constant.
Here, the value of the fourth time constant is smaller than that of the third time constant because the temperature of the first correction piston has risen.

The divider 63A calculates a value obtained by dividing a predetermined predetermined value by a time constant output from the switch 62I. Here, the predetermined value is, for example, a value indicating a sampling interval.
The subtractor 63B subtracts the first corrected piston temperature one cycle before output from the first-order lag calculator 62G from the value output from the switch 62F, that is, the first corrected piston temperature or the oil temperature, and first. Calculate the difference in the corrected piston temperature.

The multiplier 63C multiplies the value obtained by dividing the predetermined value output from the divider 63A by a time constant and the difference of the first correction piston temperature output from the subtractor 63B.
The adder 63D adds the value output from the multiplier 63C and the temperature of the first correction piston one cycle before output from the first-order lag calculator 62G to calculate the second correction piston temperature. The adder 63D stores, for example, the calculated information indicating the second corrected piston temperature and the information indicating the time in the storage unit 11 as temperature change information indicating a change in the piston temperature in association with each other.

Here, the first correction piston temperature calculated by the adder 63D is T _ps , the first correction piston temperature one cycle before is T _pso , the predetermined value is X, and the time constant is τ. When the first corrected piston temperature is output by the adder 63D, the second corrected piston temperature _Tps is expressed by the following equation (8).

As shown in the equation (8), the correction unit 63 acquires the first correction piston temperature estimated one cycle before based on a predetermined sampling interval, and newly estimated the first correction piston temperature. By adding the temperature obtained by dividing the difference value between the temperature and the first corrected piston temperature estimated one cycle before by a time constant to the first corrected piston temperature estimated one cycle ago. 2 Correction The piston temperature is corrected.

Further, the fourth time constant is smaller than the third time constant, the third time constant is smaller than the first time constant, and the first time constant is smaller than the second time constant. Accordingly, as shown in equation (8), the degree of influence of the second correction piston temperature T _ps adder 63D is calculated, at 4th constant, at the third constant, the first time constant, time second constant It increases in the order of, and the reaction of temperature change becomes faster.

In this way, the piston temperature correction unit 6 selects the time constant according to the state of the engine E and corrects the first correction piston temperature based on the time constant, so that it corresponds to the gradient of the actual piston temperature change. It can be corrected to the piston temperature.

[Effects of the present embodiment]
As described above, the piston temperature estimation device 1 according to the present embodiment estimates the piston temperature indicating the temperature of the piston included in the engine E, acquires the engine state information indicating the state of the engine E, and obtains the engine state information. A correction value of the estimated piston temperature is calculated based on the state of the engine E shown and the estimated piston temperature, and the estimated piston temperature is corrected based on the correction value. By doing so, the piston temperature estimation device 1 can reflect the state of the engine E in the piston temperature and estimate the piston temperature with high accuracy. Further, the piston temperature estimation device 1 can correct the first corrected piston temperature by using the time constant to obtain the piston temperature that reflects the actual temperature change of the piston.

Further, the correction value calculation unit 53 is based on the difference between the values of each element (oil pressure, oil temperature, intake air temperature, intake air amount, injection timing) specified based on the map information and the measured values of each element. Each correction value (first correction value to fifth correction value) is calculated. By doing so, the correction value calculation unit 53 can calculate the correction value with higher accuracy than in the case of calculating the correction value based only on the measured values of each element. As a result, the piston temperature estimation device 1 can accurately estimate the piston temperature.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention.

For example, in the above-described embodiment, the oil temperature correction calculation unit 55 calculates the second correction value using different correction coefficients when the oil temperature rises and when the oil temperature decreases, and the intake air amount correction calculation unit 57 calculates the second correction value. The fourth correction value was calculated using different correction coefficients when the inhalation amount increased and when the inhalation amount decreased. Similarly, in the oil pressure correction calculation unit 54, the intake air temperature correction calculation unit 56, and the injection timing correction calculation unit 58, the correction values are set using different correction coefficients according to the changes in the oil pressure, the intake air temperature, and the injection timing. It may be calculated. By doing so, the piston temperature estimation device 1 can make the characteristic of the correction formula shown by the correction formula correspond to the non-linear characteristic when the characteristic of the correction value is non-linear.

1 ... Piston temperature estimation device 2 ... Storage unit 3 ... Control unit 4 ... Intake air temperature selection unit 41 ... Selection unit 42 ... Acquisition unit 5 ... Piston temperature estimation unit 51.・ ・ Acquisition unit 52 ・ ・ ・ Estimating unit 53 ・ ・ ・ Correction value calculation unit 54 ・ ・ ・ Hydraulic correction calculation unit 55 ・ ・ ・ Oil temperature correction calculation unit 56 ・ ・ ・ Intake air temperature correction calculation unit 57 ・ ・ ・ Intake air Amount correction calculation unit 58 ... Injection timing correction calculation unit 59 ... Correction unit 6 ... Piston temperature correction unit 61 ... Acquisition unit 62 ... Selection unit 63 ... Correction unit E ... Engine V ... Vehicle

Claims (5)

An estimation unit that estimates the piston temperature, which indicates the temperature of the piston of the internal combustion engine,
An acquisition unit that acquires injection amount information indicating the injection amount of fuel into the combustion chamber provided in the internal combustion engine and intake air amount information indicating the intake amount of air supplied to the internal combustion engine.
When the injection amount indicated by the injection amount information acquired by the acquisition unit exceeds the first threshold value, the piston temperature is corrected based on the intake air amount indicated by the intake air amount information , and the injection amount is the first. A correction unit that controls not to correct the piston temperature when it is below the threshold value,
A piston temperature estimator equipped with. An estimation unit that estimates the piston temperature, which indicates the temperature of the piston of the internal combustion engine,
An acquisition unit that acquires injection amount information indicating the injection amount of fuel into the combustion chamber provided in the internal combustion engine and injection timing information indicating the injection timing of fuel supplied to the internal combustion engine.
When the injection amount indicated by the injection amount information acquired by the acquisition unit exceeds the first threshold value, the piston temperature is corrected based on the injection timing indicated by the injection timing information, and the injection amount is equal to or less than the first threshold value. In the case of, a correction unit that controls not to correct the piston temperature, and
A piston temperature estimator equipped with. An estimation unit that estimates the piston temperature, which indicates the temperature of the piston of the internal combustion engine,
An acquisition unit that acquires injection amount information indicating the injection amount of fuel into the combustion chamber provided in the internal combustion engine, and an acquisition unit.
When the injection amount indicated by the injection amount information acquired by the acquisition unit exceeds the first threshold value, the piston temperature is corrected, and when the injection amount does not exceed the first threshold value, the acquisition unit newly obtains. When the injection amount indicated by the acquired injection amount information exceeds the second threshold value larger than the first threshold value, the piston temperature is corrected, and the injection amount newly acquired by the acquisition unit is the injection amount indicated by the injection amount information. A correction unit that controls not to correct the piston temperature when it is equal to or lower than the second threshold value.
A piston temperature estimator equipped with. Computer runs,
The step of estimating the piston temperature, which indicates the temperature of the piston of the internal combustion engine,
A step of acquiring injection amount information indicating the injection amount of fuel into the combustion chamber provided in the internal combustion engine and intake air amount information indicating the intake amount of air supplied to the internal combustion engine.
When the injection amount indicated by the injection amount information acquired in the acquisition step exceeds the first threshold value, the piston temperature is corrected based on the intake air amount indicated by the intake air amount information , and the injection amount is the injection amount. A step of controlling the piston temperature so as not to be corrected when the threshold value is equal to or less than the first threshold value.
A piston temperature estimation method comprising. Computer runs,
The step of estimating the piston temperature, which indicates the temperature of the piston of the internal combustion engine,
A step of acquiring injection amount information indicating the injection amount of fuel into the combustion chamber provided in the internal combustion engine and injection timing information indicating the injection timing of fuel supplied to the internal combustion engine.
When the injection amount indicated by the injection amount information acquired in the acquisition step exceeds the first threshold value, the piston temperature is corrected based on the injection timing indicated by the injection timing information, and the injection amount is the first. A step of controlling the piston temperature so as not to be corrected when it is below the threshold value, and
A piston temperature estimation method comprising.

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