JP6848524B2 - Engine control - Google Patents

Description

The present invention relates to the calculation of the deviation amount of the injection amount of the fuel injected in the engine.

In a fuel injection device for an internal combustion engine such as a diesel engine, the fuel injection amount commanded by the control device due to individual differences or changes over time (hereinafter referred to as the command injection amount) and the fuel injection amount actually injected (hereinafter referred to as the command injection amount). Hereinafter, it may be described as the actual injection amount). Therefore, for example, it is conceivable to calculate the actual injection amount from the air-fuel ratio or the like and learn the difference between the calculated actual injection amount and the command injection amount as the deviation amount of the injection amount. For example, Japanese Patent Application Laid-Open No. 2008-95615 (Patent Document 1) discloses a technique for detecting an oxygen concentration in exhaust gas and learning a deviation in fuel injection amount based on a difference between the detected oxygen concentration and a predicted value. Will be done.

Japanese Unexamined Patent Publication No. 2008-95615

However, when the load of the internal combustion engine fluctuates, it may not be possible to accurately learn the deviation amount of the fuel injection amount. This is because the position of the air-fuel ratio sensor provided in the exhaust passage is far from the cylinder, so that the output value of the sensor is greatly affected by the time delay when the load fluctuates. Furthermore, the oxygen concentration in the exhaust gas is averaged until the exhaust gas reaches the position of the air-fuel ratio sensor, and the residual oxygen concentration in the EGR gas introduced into the intake air is in an equilibrium state after the load fluctuates. It is not possible to calculate the air-fuel ratio with high accuracy when the load fluctuates. As a result, it may not be possible to learn the deviation amount of the fuel injection amount with high accuracy. For such a problem, for example, it is conceivable to learn the amount of deviation during steady operation such as when the internal combustion engine is idle, but in an engine mounted on a construction machine or the like, there is an opportunity to operate in a transient state. In some cases, the amount of deviation cannot be learned with high accuracy.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to accurately adjust the deviation of the injection amount of fuel injected in the engine when the operation is performed in a transient state. It is to provide the control device of the engine to calculate.

The engine control device according to a certain aspect of the present invention is an engine control device including a cylinder and a fuel injection device for supplying fuel to the cylinders. The control device sets a control command value corresponding to the fuel injection amount according to the state of the engine, controls the fuel injection device based on the control command value. The control device calculates the actual injection amount per predetermined time based on the actual air-fuel ratio in the cylinder and the amount of air sucked into the cylinder, and integrates the calculated actual injection amount to calculate the first integrated value. The control device calculates the command injection amount per predetermined time based on the control command value and the engine speed, and integrates the calculated command injection amount to calculate the second integrated value. Controller calculates the deviation rate of the actual injection quantity and the command injection quantity by using the first integration value and the second integrated value. The control device corrects the fuel injection amount by adding the deviation amount between the actual injection amount and the command injection amount, which is calculated by using the deviation rate, with respect to the fuel injection amount corresponding to the control command value. The deviation rate is the ratio of the difference between the first integrated value and the second integrated value with respect to the second integrated value.

In this manner, by calculating the displacement rate of the actual injection quantity and the command injection quantity by using the second integration value obtained by integrating the first integrated value and the command injection quantity obtained by integrating the actual injection quantity, under transient conditions Even when the engine is often operated, the amount of deviation between the actual injection amount and the command injection amount can be calculated with high accuracy.

An engine control device according to another aspect of the present invention is an engine control device including a cylinder and a fuel injection device for supplying fuel to the cylinders. This control device sets a control command value corresponding to the fuel injection amount according to the state of the engine, and controls the fuel injection device based on the control command value. The control device calculates the actual injection amount per predetermined time based on the actual air-fuel ratio in the cylinder and the amount of air sucked into the cylinder, and calculates the first average value of the calculated actual injection amount. The control device calculates the command injection amount per predetermined time based on the control command value and the engine speed, and calculates the second average value of the calculated command injection amount. The control device calculates the deviation rate between the actual injection amount and the command injection amount using the first average value and the second average value. The control device corrects the fuel injection amount by adding the deviation amount between the actual injection amount and the command injection amount, which is calculated by using the deviation rate, with respect to the fuel injection amount corresponding to the control command value. The deviation rate is the ratio of the difference between the first mean value and the second mean value to the second mean value.

By doing so, by calculating the deviation rate using the first average value of the actual injection amount and the second average value of the command injection amount, even if there are many opportunities for the engine to be operated in the transient state, it is actually The amount of deviation between the injection amount and the command injection amount can be calculated with high accuracy.

Good Mashiku, the control device calculates one of an average value any of the command injection quantity and the actual injection quantity, and calculates the shift amount using the average value of one which is calculated and the deviation rate. The control device corrects the fuel injection amount by adding the deviation amount to the fuel injection amount corresponding to the control command value .

In this way, the deviation amount between the actual injection amount and the command injection amount can be calculated with high accuracy by using the average value and the deviation rate of either one of the command injection amount and the actual injection amount.

The engine control device according to still another aspect of the present invention is an engine control device including a cylinder and a fuel injection device for supplying fuel to the cylinder. This control device sets a control command value corresponding to the fuel injection amount according to the state of the engine, and controls the fuel injection device based on the control command value. The control device integrates the actual air-fuel ratio in the cylinder to calculate the first integrated value. The control device calculates the commanded air-fuel ratio based on the amount of air sucked into the cylinder, the commanded injection amount, and the engine speed, and integrates the calculated commanded air-fuel ratio to calculate the second integrated value. The control device calculates the deviation rate between the actual injection amount and the command injection amount using the calculated first integrated value and the second integrated value. The control device corrects the fuel injection amount by adding the deviation amount between the actual injection amount and the command injection amount, which is calculated by using the deviation rate, with respect to the fuel injection amount corresponding to the control command value. The deviation rate is the ratio of the difference between the first integrated value and the second integrated value with respect to the second integrated value.

In this way, by calculating the deviation rate using the first integrated value obtained by integrating the actual air-fuel ratio and the second integrated value obtained by integrating the commanded air-fuel ratio, the actual injection amount and the command injection amount can be changed due to the load fluctuation. Even when it fluctuates, the amount of deviation between the actual injection amount and the command injection amount can be calculated with high accuracy.

More preferably, the control device has a deviation rate between the start of the predetermined period and the elapse of the predetermined period when the state in which the change width of the deviation rate converges within the predetermined range continues until the predetermined period elapses. Is used to set the final deviation rate. The control device corrects the fuel injection amount by adding the deviation amount calculated using the final deviation rate to the fuel injection amount corresponding to the control command value .

In this way, the converged deviation rate can be set as the final deviation rate, so that the deviation amount of the fuel injection amount can be calculated with high accuracy.

According to the present invention, it is possible to provide an engine control device that accurately calculates the deviation of the injection amount of fuel injected in the engine when the operation is often performed in a transient state.

It is the figure which showed the whole structure of the engine schematicly. It is a figure which shows the arithmetic block which is formed in the control device. It is a flowchart which shows the control process executed by a control device. It is a time chart which shows the change of the injection amount, the integrated injection amount and the deviation rate. It is a flowchart which shows the control process executed by the control apparatus which concerns on 1st modification. It is a flowchart which shows the control process executed by the control apparatus which concerns on 2nd modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a diagram schematically showing the overall configuration of the engine 10. The engine 10 shown in FIG. 1 is an internal combustion engine such as a diesel engine. The engine 10 is mounted as a drive source for, for example, a vehicle or a construction machine.

As shown in FIG. 1, the engine 10 includes a cylinder 11, an intake passage 8, and an exhaust passage 7. An air cleaner or the like (not shown) is provided at one end of the intake passage 8. The other end of the intake passage 8 is connected to the cylinder 11. An air flow meter 2 is provided between one end of the intake passage 8 and the confluence position with the EGR passage 18.

The air flow meter 2 detects the flow rate (intake air amount) of fresh air introduced into the engine 10 from the intake passage 8 and outputs a signal indicating the detected intake air amount to the control device 100.

An intake throttle valve 16 is provided at a position downstream of the air flow meter 2. The intake throttle valve 16 is provided with a throttle valve sensor 17 that detects the opening degree of the intake throttle valve 16. The throttle valve sensor 17 outputs a signal indicating the detected opening degree of the intake throttle valve 16 to the control device 100. The intake throttle valve 16 opens and closes according to a control signal from the control device 100.

The cylinder 11 includes a cylinder 11a and a piston 11b. A fuel injection device 13 is provided at the top of the cylinder 11. The fuel injection device 13 is composed of, for example, an injector having a body in which a injection hole is formed and a needle provided inside the body and opening and closing the injection hole. The fuel injection device 13 is connected to the fuel pump 14 and the fuel tank 12 via the common rail 15. The fuel pump 14 supplies the fuel in the fuel tank 12 to the common rail 15 so that the pressure of the fuel in the common rail 15 becomes a predetermined pressure in response to the control signal from the control device 100. The fuel injection device 13 operates the needle in response to a control signal from the control device 100 to open the injection holes, thereby supplying the fuel in the common rail 15 to the combustion chamber in the cylinder 11.

The control device 100 determines a control command value corresponding to the fuel injection amount injected in one cycle in the fuel injection device 13. The control device 100 controls the fuel injection device 13 based on the determined control command value. The control command value is, for example, a value indicating the fuel injection time (opening time of the injection hole) or the injection amount of the fuel from the fuel injection device 13.

The piston 11b is connected to a crankshaft (not shown), and the crankshaft is provided with an engine speed sensor 20 that detects the rotation speed of the crankshaft (engine speed). The engine speed sensor 20 is connected to the control device 100 and transmits a signal indicating the detected engine speed to the control device 100.

The exhaust passage 7 includes a first passage 7a, a second passage 7b, a third passage 7c, and a fourth passage 7d, and includes a first passage 7a, a second passage 7b, a third passage 7c, and a fourth passage. The passages 7d are connected in this order. The end of the fourth passage 7d is connected to an outlet that releases exhaust gas to the atmosphere.

An exhaust treatment device 1 is provided in the exhaust passage 7. The exhaust treatment device 1 includes a DPF (Diesel Particulate Filter) 4 and an oxidation catalyst 9. DPF4 is formed of ceramic, stainless steel, or the like. The DPF 4 is housed in the third passage 7c. The DPF4 collects particulate matter from the passing exhaust gas while allowing the passing of the exhaust gas.

The oxidation catalyst 9 is housed in the second passage 7b upstream of the DPF 4. The oxidation catalyst 9 allows the exhaust gas to pass through and oxidizes hydrocarbons (HC), nitrogen oxides (NOx), carbon oxides (COx), etc. in the passing exhaust gas.

An exhaust temperature sensor 5 is provided at the inlet of the second passage 7b of the exhaust passage 7. The exhaust temperature sensor 5 detects the gas temperature of the exhaust gas on the upstream side (inlet) of the oxidation catalyst 9 and transmits a signal indicating the detection result to the control device 100.

The air-fuel ratio sensor 3 is provided in the fourth passage 7d and detects the air-fuel ratio, which is the ratio of the oxygen concentration and the unburned fuel concentration in the exhaust gas passing through the fourth passage 7d. The air-fuel ratio sensor 3 transmits a signal indicating the detected air-fuel ratio to the control device 100. The control device 100 calculates the air-fuel ratio in the cylinder 11 based on the detection result of the air-fuel ratio sensor 3. The control device 100 adjusts the injection amount of fuel injected from the fuel injection device 13 by feedback control or the like so that the calculated air-fuel ratio in the cylinder 11 becomes the target air-fuel ratio set according to the operating state of the engine 10. To do.

The engine 10 is further provided with an EGR (exhaust gas recirculation) system. The EGR system includes an EGR passage 18 and an EGR valve 19. The EGR passage 18 communicates the exhaust passage 7 and the intake passage 8 without passing through the cylinder 11, and returns a part of the exhaust gas discharged to the exhaust passage 7 to the intake passage 8. The EGR valve 19 adjusts the gas flow rate circulated by the EGR passage 18 in response to a control signal from the control device 100. The control device 100 controls the opening degree of the EGR valve 19 based on the operating state of the engine 10.

Specifically, the control device 100 sets a target value of the EGR rate based on, for example, the fuel injection amount and the engine speed. In the memory 150 described later of the control device 100, for example, a map showing the relationship between the fuel injection amount, the engine speed, and the target value of the EGR rate is stored. The control device 100 sets a target value of the EGR rate from the fuel injection amount corresponding to the control command value, the engine speed, and the map described above. The control device 100 controls the opening degree of the EGR valve 19 so that the EGR rate becomes a target value.

The control device 100 includes a CPU (Central Processing Unit) (not shown) that performs various processes, a ROM (Read Only Memory) that stores programs and data, and a RAM (Random Access Memory) that stores the processing results of the CPU. It includes a memory 150 including an input port and an output port (neither shown) for exchanging information with an external device of the control device 100. An air flow meter 2, an air-fuel ratio sensor 3, an exhaust temperature sensor 5, a throttle valve sensor 17, an engine rotation speed sensor 20, and the like are connected to the input port.

The control device 100 receives a signal from each device connected to the input port, and based on the received signal, controls the throttle valve sensor 17, the fuel injection device 13, the fuel pump 14, the EGR valve 19, and the like connected to the output port. Control.

In the above configuration, in the fuel injection device 13, the fuel injection amount (hereinafter, referred to as the command injection amount) commanded by the control device 100 due to individual differences in the injection holes, needles, etc., changes over time, etc., and the actual fuel injection amount. There may be a discrepancy with the injected fuel injection amount (hereinafter referred to as the actual injection amount). Therefore, for example, it is conceivable to calculate the actual injection amount from the air-fuel ratio or the like and learn the difference between the calculated actual injection amount and the command injection amount as the deviation amount of the injection amount.

However, when the load of the engine 10 fluctuates, it may not be possible to learn the deviation amount of the fuel injection amount with high accuracy. This is because the position of the air-fuel ratio sensor 3 provided in the exhaust passage 7 is far from the cylinder 11, so that the output value of the air-fuel ratio sensor 3 when a load fluctuation occurs is greatly affected by the time delay. .. Further, the oxygen concentration in the exhaust gas is averaged until the exhaust gas reaches the position of the air-fuel ratio sensor 3, and the residual oxygen concentration in the EGR gas introduced into the intake air is balanced after the load fluctuation occurs. Since it changes until it reaches the state, the actual air-fuel ratio when the load fluctuates cannot be calculated with high accuracy. As a result, it may not be possible to learn the deviation amount of the fuel injection amount with high accuracy. Therefore, for example, it is conceivable to learn the amount of deviation during steady operation such as when the engine 10 is idle, but in an engine mounted on a construction machine or the like, there are many opportunities for operation to be performed in a transient state, and the amount of deviation can be determined. It may not be possible to learn with high accuracy.

Therefore, in the present embodiment, the control device 100 shall perform the following operations. That is, the control device 100 acquires the actual injection amount and the command injection amount based on the actual air-fuel ratio, the intake air amount, the control command value, and the engine speed in the cylinder 11. The control device 100 calculates the first integrated value and the second integrated value by integrating each of the actual injection amount and the command injection amount. The control device 100 calculates the deviation rate between the actual injection amount and the command injection amount using the first integrated value and the second integrated value.

In this way, the deviation rate between the actual injection amount and the command injection amount can be calculated using the first integrated value and the second integrated value, so that the actual injection amount and the command injection amount fluctuate due to the load fluctuation. Even in this case, the amount of deviation between the actual injection amount and the command injection amount can be calculated with high accuracy.

FIG. 2 is a diagram showing an arithmetic block configured in the control device 100. As shown in FIG. 2, the control device 100 includes an actual injection amount calculation unit 102, a command injection amount calculation unit 104, an average injection amount calculation unit 106, an integration unit 108, a deviation rate calculation unit 110, and a convergence test. The unit 112, the deviation rate setting unit 114, and the deviation amount calculation unit 116 are included.

The actual injection amount calculation unit 102 calculates the actual injection amount based on the actual air-fuel ratio and the intake air amount in the cylinder 11 acquired by using the air-fuel ratio sensor 3. Specifically, the actual injection amount calculation unit 102 acquires, for example, the intake air amount from the air flow meter 2 and calculates the intake air amount per predetermined time. The actual injection amount calculation unit 102 calculates the actual injection amount per predetermined time by dividing the calculated intake air amount per predetermined time by the actual air-fuel ratio. The predetermined time is, for example, a unit time.

The command injection amount calculation unit 104 calculates the command injection amount based on the control command value and the engine speed acquired by using the engine speed sensor 20. Specifically, the command injection amount calculation unit 104 calculates the number of operation cycles of the engine 10 from the engine speed per predetermined time, and multiplies the calculated number of operation cycles by the fuel injection amount corresponding to the control command value. By doing so, the command injection amount per predetermined time is calculated.

The average injection amount calculation unit 106 calculates the average value (average command injection amount) of the command injection amount per predetermined time. Specifically, the average injection amount calculation unit 106 divides the integration command injection amount calculated by the integration unit 108, which will be described later, by the elapsed time from the time when the calculation of the integration command injection amount is started to obtain a predetermined time. Calculate the average command injection amount per hit. The calculation of the integrated command injection amount is started when the execution conditions described later are satisfied. Further, the calculated average command injection amount is stored in the memory 150.

The integration unit 108 integrates the actual injection amount calculated by the actual injection amount calculation unit 102 to calculate the integrated actual injection amount, and also integrates the command injection amount calculated by the command injection amount calculation unit 104 to generate the integration command. Calculate the injection amount. For example, each time the command injection amount is calculated from the time when the execution condition is satisfied, the integration unit 108 adds the calculated command injection amount to the previously calculated integrated command injection amount to obtain the current integrated command injection amount. Is calculated. Similarly, each time the actual injection amount is calculated from the time when the execution condition is satisfied, the integration unit 108 adds the calculated actual injection amount to the previously calculated integrated actual injection amount to obtain the current integrated actual injection amount. Calculate the amount. The calculated integrated command injection amount and integrated actual injection amount are stored in the memory 150.

The deviation rate calculation unit 110 calculates the deviation rate between the actual injection amount and the command injection amount by using the integrated command injection amount and the integrated actual injection amount. The deviation rate calculation unit 110 calculates, for example, a difference value obtained by subtracting the integrated command injection amount from the integrated actual injection amount. The deviation rate calculation unit 110 calculates the ratio of the difference value to the integrated command injection amount as the deviation rate between the actual injection amount and the command injection amount. The deviation rate calculation unit 110 calculates the deviation rate by the formula of deviation rate = (integrated actual injection amount-integrated command injection amount) / integrated command injection amount, for example. The deviation rate calculation unit 110 may calculate the deviation rate as a percentage by multiplying the value calculated by the equation by "100". The deviation rate calculation unit 110 calculates the deviation rate each time the integration command injection amount and the integration actual injection amount are calculated by the integration unit 108. The calculated deviation rate is stored in the memory 150.

The convergence test unit 112 determines whether or not the deviation rate has converged based on the calculated history of the deviation rate. The convergence test unit 112 determines that the deviation rate has converged, for example, when the state in which the difference between the maximum value and the minimum value is within a predetermined range continues until a predetermined period elapses. .. The convergence test unit 112 specifies, for example, the maximum value and the minimum value of the deviation rate in the immediately preceding period (≧ predetermined period), and the difference between the specified maximum value and the minimum value is a predetermined range. If the value is within, it is determined that the deviation rate has converged when a predetermined period has elapsed from the earlier of the maximum value and the minimum value.

The deviation rate setting unit 114 sets the final deviation rate when it is determined by the convergence test unit 112 that the deviation rate has converged. The deviation rate setting unit 114 sets the final deviation rate using the deviation rate after the start time of the predetermined period described above. The deviation rate setting unit 114 may set, for example, the deviation rate calculated at the time when it is determined that the deviation rates have converged as the final deviation rate. Alternatively, the deviation rate setting unit 114 may set, for example, the average value of the deviation rates in a predetermined period immediately before the time when the deviation rates are determined to have converged as the final deviation rate. Alternatively, the deviation rate setting unit 114 may set the final deviation rate using the deviation rate calculated after the time when the deviation rate is determined to have converged. The set final deviation rate is stored in the memory 150.

The deviation amount calculation unit 116 calculates the deviation amount of the fuel injection amount by multiplying the average command injection amount calculated by the average injection amount calculation unit 106 and the final deviation rate determined by the deviation rate setting unit 114. To do.

Next, with reference to FIG. 3, the control process executed by the control device 100 in the present embodiment will be described. FIG. 3 is a flowchart showing a control process executed by the control device 100. The process shown in this flowchart is called and executed from the main routine (not shown) at predetermined control cycles (= unit time). Each step included in these flowcharts is basically realized by software processing by the control device 100, but a part or all of them (for example, a part or all of the configuration shown in the calculation block diagram of FIG. 2). May be realized by the hardware (electric circuit) manufactured in the control device 100.

At step 100 (hereinafter, step is referred to as S) 100, the control device 100 determines whether or not the execution condition is satisfied. The execution condition includes, for example, a condition that the air-fuel ratio is within a predetermined range of a predetermined value or less, and a condition that the warm-up of the engine 10 is completed. The predetermined range is, for example, a range in which the air-fuel ratio is a value on the rich side. Further, the control device 100 determines, for example, that the warm-up of the engine 10 is completed when the water temperature of the engine 10 is higher than the threshold value. When it is determined that the execution condition is satisfied (YES in S100), the process is transferred to S102.

In S102, the control device 100 calculates the command injection amount per predetermined time. In S104, the control device 100 calculates the actual injection amount per predetermined time. Since the calculation method of the command injection amount and the actual injection amount is as described above, the detailed description thereof will not be repeated.

In S106, the control device 100 calculates the integrated command injection amount and the integrated actual injection amount. In S108, the control device 100 calculates the average injection amount per predetermined time.

In S110, the control device 100 calculates the deviation rate by using the calculated integrated command injection amount, the integrated actual injection amount, and the above equation.

In S112, the control device 100 determines whether or not the change width of the deviation rate has converged within a predetermined range based on the calculated history of the deviation rate. Since the determination method is as described above, the detailed description thereof will not be repeated. When it is determined that the change width of the deviation rate has converged within a predetermined range (YES in S112), the process is transferred to S114.

In S114, the control device 100 sets the final deviation rate. In S116, the control device 100 calculates the deviation amount of the fuel injection amount per predetermined time by multiplying the average injection amount calculated in S108 and the deviation rate set in S114.

If the execution condition is not satisfied in S100 (NO in S100), the process is transferred to S118. In S118, the control device 100 clears the integrated command injection amount, the integrated actual injection amount, and the average injection amount stored in the memory 150, and resets the initial value (for example, zero). Further, when it is determined in S112 that the change width of the deviation rate does not converge within a predetermined range (NO in S112), this process ends.

The operation of the control device 100 in the present embodiment based on the above structure and flowchart will be described with reference to FIG. FIG. 4 is a timing chart showing changes in the injection amount, the integrated injection amount, and the deviation rate. The vertical axis of FIG. 4 shows the actual injection amount, the command injection amount, the integrated injection amount and the deviation rate from the upper graph, and the horizontal axis of FIG. 4 shows the time. LN1 (broken line) in FIG. 4 shows the change in the actual injection amount. LN2 (solid line) in FIG. 4 shows the change in the command injection amount. LN3 (broken line) in FIG. 4 indicates the integrated actual injection amount. LN4 (solid line) in FIG. 4 indicates the integrated command injection amount. LN5 (solid line) in FIG. 4 shows the change in the deviation rate.

For example, assume that the execution condition is satisfied at time T (0). When the execution condition is satisfied (YES in S100), the command injection amount and the actual injection amount are calculated as shown in LN1 and LN2 in FIG. 4 (S102, S104). As shown in LN3 of FIG. 4, the current integrated actual injection amount is added to the integrated actual injection amount calculated in the previous calculation to calculate the current integrated actual injection amount (S106). Further, as shown in LN4 of FIG. 4, the current command injection amount is added to the integrated command injection amount calculated in the previous calculation to calculate the current integrated command injection amount. Then, the integrated command injection amount is divided by the elapsed time from the time T (0) to calculate the average value of the command injection amount per predetermined time (S108).

As shown in LN5 of FIG. 4, the deviation rate is calculated using the calculated integrated command injection amount and the integrated actual injection amount (S110), and whether or not the change width of the deviation rate has converged within a predetermined range. Is determined (S112). When it is determined that the change width of the deviation rate has not converged within a predetermined range (NO in S112), the process is terminated and it is determined again whether or not the execution condition is satisfied (S100).

While the execution condition is satisfied, the above-mentioned processing is repeated. Then, at time T (1), the difference between the maximum value and the minimum value of the deviation rate change width is within a predetermined range, and a predetermined time has elapsed from the time when the difference is within the predetermined range. When it is determined in T (2) that the change width of the deviation rate has converged within a predetermined range (YES in S112), the final deviation rate is set (S114). The deviation amount of the fuel injection amount is calculated by multiplying the set deviation rate and the average injection amount (S116). The calculated deviation amount of the fuel injection amount is used for correcting the fuel injection amount when, for example, the target value of the EGR rate is set by the fuel injection amount and the engine speed as described above. That is, for example, the control device 100 adds a deviation amount to the fuel injection amount corresponding to the control command value set according to the state of the engine 10, and the deviation amount is added to the fuel injection amount and the engine rotation speed. Set the target value of EGR rate. As a result, an appropriate target value of the EGR rate is set with respect to the actual injection amount.

As described above, according to the engine control device according to the present embodiment, the deviation rate between the integrated command injection amount and the integrated actual injection amount is calculated as the deviation rate between the actual injection amount and the command injection amount. Even when the engine 10 is often operated in the transient state, the deviation amount between the actual injection amount and the command injection amount can be calculated with high accuracy. Therefore, it is possible to provide an engine control device that accurately calculates the deviation of the injection amount of the fuel injected in the engine when the operation is often performed in the transient state.

Further, by setting the final deviation rate when the change width of the deviation rate converges within a predetermined range, the deviation amount of the fuel injection amount can be calculated with high accuracy using the set deviation rate.

Further, since the deviation amount of the fuel injection amount per predetermined time can be calculated by multiplying the average value of the command injection amount per predetermined time and the deviation rate, the fuel injection amount can be corrected with high accuracy. it can. Therefore, the engine 10 can be appropriately controlled by setting a target value of the EGR rate using the corrected fuel injection amount.

Hereinafter, a modified example will be described.
In the above-described embodiment, the execution conditions include the condition that the air-fuel ratio is within a predetermined range of a predetermined value or less, and the condition that the warm-up of the engine 10 is completed. However, for example, in addition to these conditions, the condition that the rotation speed of the engine 10 is within a predetermined range corresponding to the normal use range and the intake air temperature are within a predetermined range corresponding to the normal temperature. The condition that there is, the condition that the atmospheric pressure is within the predetermined range corresponding to the atmospheric pressure on the flat ground, and the condition that the predetermined period has passed since the last setting of the final deviation rate. At least one of the following conditions may be included.

Further, in the above-described embodiment, the case where the engine 10 does not have a turbocharger configuration has been described as an example, but the engine 10 may have a turbocharger configuration. In this case, the EGR system is limited to an HPL (High Pressure Loop) -EGR configuration in which a part of the exhaust gas discharged from the cylinder 11 to the exhaust passage 7 is returned to the intake passage downstream of the compressor of the turbocharger. Instead, it may have an LPL (Low Pressure Loop) -EGR configuration that returns to the intake passage upstream of the compressor of the turbocharger.

Further, in the above-described embodiment, it is determined that the deviation rate has converged when the state in which the difference between the maximum value and the minimum value is within a predetermined range continues until a predetermined period elapses. However, for example, when the value indicating the elapsed time from the time when the execution condition is satisfied becomes equal to or greater than the threshold value, it may be determined that the change width of the deviation rate has converged within a predetermined range. .. The threshold value may be set based on the state of the engine 10, such as the engine speed and the intake air amount.

Further, in the above-described embodiment, it has been described that the ratio of the difference value obtained by subtracting the integrated command injection amount from the integrated actual injection amount with respect to the integrated command injection amount is calculated as the deviation rate of the fuel injection amount. The ratio of the difference value to the injection amount may be calculated as the deviation rate of the fuel injection amount. In this case, the deviation amount of the fuel injection amount may be calculated by multiplying the average value of the actual injection amount and the deviation rate.

Further, in the above-described embodiment, the final deviation rate is set when the deviation rate converges within a predetermined range, but when the final deviation rate is already set (in the memory 150). If it is stored), it is newly set when the difference between the previously set deviation rate (the value stored as the final deviation rate in the memory 150) and the newly set value is equal to or greater than the threshold value. It may be updated to the value set in, or it may be updated to the value obtained by adding a predetermined ratio of the difference to the previously set deviation rate.

Further, in the above-described embodiment, the deviation rate and the average command injection amount per predetermined time are multiplied to calculate the deviation amount of the fuel injection amount per predetermined time. The deviation amount of the fuel injection amount per cycle may be calculated by multiplying the average command injection amount per cycle.

Further, in the above-described embodiment, the deviation rate is calculated when the execution conditions including the air-fuel ratio condition and the warm-up condition are satisfied. For example, the engine speed and the intake air are calculated. A plurality of operating areas may be set based on the amount, and the deviation rate may be calculated for each set operating area. In this way, the deviation amount of the fuel injection amount can be calculated with higher accuracy according to the operating state of the engine 10.

Further, in the above-described embodiment, the deviation rate between the integrated actual injection amount and the integrated command injection amount has been described as the deviation rate between the actual injection amount and the command injection amount. , The deviation rate of the command injection amount from the second average value may be calculated as the deviation rate between the actual injection amount and the command injection amount.

Hereinafter, the control process executed by the control device 100 according to this modification (hereinafter referred to as the first modification) will be described with reference to FIG. FIG. 5 is a flowchart showing a control process executed by the control device 100 according to the first modification.

The flowchart of FIG. 5 has a point that the processing of S106, S110 and S118 is replaced with the processing of S206, S210 and S218, respectively, and a point that the processing of S108 is omitted as compared with the flowchart of FIG. Except, the process is the same as that in FIG. The same step number is assigned to the same process. Therefore, the detailed explanation of them will not be repeated.

In S206, the control device 100 calculates the average value of the command injection amount per cycle from the time when the execution condition is satisfied to the present time (hereinafter, referred to as the average command injection amount). Specifically, the control device 100 calculates the average command injection amount by dividing the integrated command injection amount from the time when the execution condition is satisfied by the number of operation cycles of the engine 10 from the time when the execution condition is satisfied. ..

Further, the control device 100 calculates an average value (hereinafter, referred to as an average actual injection amount) of the actual injection amount per cycle from the time when the execution condition is satisfied to the present time. Specifically, the control device 100 calculates the average actual injection amount by dividing the integrated actual injection amount from the time when the execution condition is satisfied by the number of operation cycles of the engine 10 from the time when the execution condition is satisfied. .. The calculated average command injection amount and average actual injection amount are stored in the memory 150.

In S210, the control device 100 calculates the deviation rate of the fuel injection amount using the average command injection amount and the average actual injection amount. Specifically, the control device 100 calculates, for example, a difference value obtained by subtracting the average command injection amount from the average actual injection amount. The control device 100 calculates the ratio of the difference value to the average command injection amount as the deviation rate. That is, the control device 100 calculates the deviation rate by the formula of, for example, deviation rate) (average actual injection amount-average command injection amount) / average command injection amount. The calculated deviation rate is stored in the memory 150.

In S218, the control device 100 clears the average command injection amount and the average actual injection amount stored in the memory 150 and resets the initial value (for example, zero).

In this way, the engine 10 is often operated in a transient state by calculating the deviation rate between the average command injection amount and the average actual injection amount as the deviation rate between the actual injection amount and the command injection amount. Even in this case, the deviation amount between the actual injection amount and the command injection amount can be calculated with high accuracy. The average command injection amount and the average actual injection amount may be the average value of the command injection amount per predetermined time and the average value of the actual injection amount per predetermined time, respectively.

Further, in the above-described embodiment, the deviation rate between the integrated actual injection amount and the integrated command injection amount has been described as the deviation rate between the actual injection amount and the command injection amount, but the value correlates with the actual injection amount and the command injection amount. The deviation rate may be calculated using. As values that correlate with the actual injection amount and the command injection amount, for example, the deviation rate may be calculated using the actual air-fuel ratio and the command air-fuel ratio.

Hereinafter, the control process executed by the control device 100 according to this modification (hereinafter referred to as the second modification) will be described with reference to FIG. FIG. 6 is a flowchart showing a control process executed by the control device 100 according to the second modification.

The flowchart of FIG. 6 is different from the flowchart of FIG. 3, except that the processes of S102, S104, S106, S110 and S118 are replaced by the processes of S302, S304, S306, S310 and S318, respectively. It is the same as the processing of. The same step number is assigned to the same process. Therefore, the detailed explanation of them will not be repeated.

In S302, the control device 100 calculates the command air-fuel ratio. Specifically, the control device 100 calculates the command air-fuel ratio based on the control command value, the engine speed, and the intake air amount. The control device 100 calculates the command injection amount per predetermined time based on, for example, the control command value and the engine speed. Further, the control device 100 calculates the intake air amount per predetermined time. The control device 100 calculates the command air-fuel ratio from the calculated command injection amount and intake air amount per predetermined time.

In S304, the control device 100 calculates the actual air-fuel ratio. Specifically, the actual air-fuel ratio in the cylinder 11 is calculated based on the output value of the air-fuel ratio sensor 3.

In S306, the control device 100 integrates the actual air-fuel ratio and the commanded air-fuel ratio to calculate the integrated actual air-fuel ratio and the integrated commanded air-fuel ratio.

For example, every time the command air-fuel ratio is calculated from the time when the execution condition is satisfied, the control device 100 adds the calculated command air-fuel ratio to the previously calculated integrated command air-fuel ratio to obtain the current integrated command air-fuel ratio. Is calculated. Similarly, the control device 100 adds the calculated actual air-fuel ratio to the previously calculated integrated air-fuel ratio each time the actual air-fuel ratio is calculated from the time when the execution condition is satisfied. Calculate the fuel ratio. The calculated integrated actual air-fuel ratio and integrated command air-fuel ratio are stored in the memory 150.

In S310, the control device 100 calculates the deviation rate between the actual injection amount and the command injection amount by using the integrated command air-fuel ratio and the integrated actual air-fuel ratio. The control device 100 calculates, for example, a difference value obtained by subtracting the integrated command air-fuel ratio from the integrated actual air-fuel ratio. The control device 100 calculates the ratio of the difference value to the integrated command air-fuel ratio as the deviation rate. That is, the control device 100 may calculate the deviation rate by the formula of, for example, deviation rate = (integrated actual air-fuel ratio-integrated command air-fuel ratio) / integrated command air-fuel ratio. The calculated deviation rate is stored in the memory 150.

In S318, the control device 100 clears the integrated command air-fuel ratio, the integrated actual air-fuel ratio, and the average injection amount stored in the memory 150, and resets the initial value (for example, zero).

By doing so, by calculating the deviation rate using the integrated command air-fuel ratio and the integrated actual air-fuel ratio, the actual injection amount and the command injection amount can be combined even when the engine 10 is often operated in a transient state. The amount of deviation can be calculated with high accuracy.

The above-mentioned modification may be carried out in whole or in combination.
It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Exhaust treatment device, 2 Air flow meter, 3 Air-fuel ratio sensor, 5 Exhaust temperature sensor, 7 Exhaust passage, 7a 1st passage, 7b 2nd passage, 7c 3rd passage, 7d 4th passage, 8 Intake passage, 9 Oxidation catalyst 10, engine, 11 cylinder, 11a cylinder, 11b piston, 12 fuel tank, 13 fuel injection device, 14 fuel pump, 15 common rail, 16 intake throttle valve, 17 throttle valve sensor, 18 EGR passage, 19 EGR valve, 20 engine rotation Number sensor, 100 control device, 102 actual injection amount calculation unit, 104 command injection amount calculation unit, 106 average injection amount calculation unit, 108 integration unit, 110 deviation rate calculation unit, 112 convergence judgment unit, 114 deviation rate setting unit, 116 Deviation amount calculation unit, 150 memories.

Claims (5)

An engine control device including a cylinder and a fuel injection device for supplying fuel to the cylinder.
The control device is
A control command value corresponding to the fuel injection amount is set according to the state of the engine.
Controlling the fuel injection device based on the control command value,
The actual injection amount per predetermined time is calculated based on the actual air-fuel ratio in the cylinder and the amount of air sucked into the cylinder, and the calculated actual injection amount is integrated to calculate the first integrated value. The command injection amount per predetermined time is calculated based on the control command value and the engine speed , and the calculated command injection amount is integrated to calculate the second integrated value, which is combined with the first integrated value . by using the second integrated value to calculate the deviation ratio between the command injection quantity and the actual injection quantity,
The fuel injection amount is corrected by adding the deviation amount between the actual injection amount and the command injection amount, which is calculated by using the deviation rate, with respect to the fuel injection amount corresponding to the control command value. ,
The deviation rate is the ratio of the difference between the first integrated value and the second integrated value with respect to the second integrated value, which is an engine control device. An engine control device including a cylinder and a fuel injection device for supplying fuel to the cylinder.
The control device is
A control command value corresponding to the fuel injection amount is set according to the state of the engine.
The fuel injection device is controlled based on the control command value, and the fuel injection device is controlled.
Based on the amount of air taken into the cylinder between the actual air-fuel ratio in the cylinders to calculate the actual injection quantity per predetermined time, it calculates a first mean value of the calculated the actual injection quantity, the control command value wherein based on the rotational speed of the engine to calculate the directive injection amount per the predetermined time, calculates a second mean value of the calculated the command injection amount, the first average value and the second mean value using preparative calculates a deviation ratio between the command injection quantity and the actual injection quantity,
The fuel injection amount is corrected by adding the deviation amount between the actual injection amount and the command injection amount, which is calculated by using the deviation rate, with respect to the fuel injection amount corresponding to the control command value. ,
The displacement rate is said the first average value with respect to the second average value which is a difference ratio of the second average value, the control unit of the engine. The control device is
The command injection amount and to calculate either the average value of the actual injection quantity, and calculates the amount Re not a prior SL using calculated average value of said one and the said displacement rate,
The engine control device according to claim 1 or 2 , wherein the fuel injection amount is corrected by adding the deviation amount to the fuel injection amount corresponding to the control command value. An engine control device including a cylinder and a fuel injection device for supplying fuel to the cylinder.
The control device is
A control command value corresponding to the fuel injection amount is set according to the state of the engine.
The fuel injection device is controlled based on the control command value, and the fuel injection device is controlled.
The actual air-fuel ratio in the cylinder was integrated to calculate the first integrated value, and the command air-fuel ratio was calculated and calculated based on the amount of air sucked into the cylinder, the command injection amount, and the engine speed. The commanded air-fuel ratio is integrated to calculate the second integrated value, and the calculated deviation rate between the actual injection amount and the commanded injection amount is calculated using the calculated first integrated value and the second integrated value .
The fuel injection amount is corrected by adding the deviation amount between the actual injection amount and the command injection amount, which is calculated by using the deviation rate, with respect to the fuel injection amount corresponding to the control command value. ,
The displacement rate is said the first integrated value to the second cumulative value is a difference between the ratio of the second integrated value, the control device of the engine. In the control device, when the state in which the change width of the deviation rate converges within the predetermined range continues until the predetermined period elapses, the deviation between the start of the predetermined period and the elapse of the predetermined period. set the final misalignment factor, using the rate,
Any of claims 1 to 4, wherein the fuel injection amount is corrected by adding the deviation amount calculated by using the final deviation rate to the fuel injection amount corresponding to the control command value. The engine control device described in.

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