JP2007270766A - Temperature estimating device and control device for electric compressor for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature estimating device for an electric compressor capable of easily estimating the temperature of a portion of the compressor with an electric motor which has the possibility of excessive temperature rise based on existing data, and a control device capable of avoiding burning of the electric compressor. <P>SOLUTION: This temperature estimating device and control device are provided with the compressor 6 provided on an intake passage 4 of an internal combustion engine 1 and driven by the electric motor 25; a compressor rotational frequency detecting means 26 for detecting the rotational frequency Nc of the compressor 6; and a temperature estimating means for estimating the temperature of a predetermined portion of the electric compressor 6, based on primary delay rotational frequency Nc' determined by performing first delay processing of the compressor rotational frequency Nc. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a temperature estimation device and a control device for an electric compressor that are arranged in an intake passage of an internal combustion engine and that perform supercharging by driving a compressor by an electric motor.

  As a means for increasing the output of an internal combustion engine, an intake pressurizing compressor is known as an exhaust supercharger that uses exhaust energy as a driving force, or a compressor with a driving source that uses the rotational force of an engine or the rotational force of an electric motor. ing. Among these, a compressor using an electric motor has an advantage that it can be easily driven and controlled in an operation region where intake pressurization is required without being restricted by the pressurization operation region.

  By the way, the compressor with an electric motor mounted on a vehicle has a large operating range and is likely to change suddenly. In particular, due to continuous supercharging, repeated supercharging and non-supercharging, etc., the temperature of parts that may overheat, such as bearings in the motor, motor windings, and control board heat sinks, has an upper limit. If exceeded, there is a risk of bearing seizure in the electric motor, damage to the motor winding, damage to the substrate of the control drive circuit. For this reason, it is important to understand the temperature of each part (bearing part, motor winding part, control board heat sink part, etc.) of the electric compressor.

  Therefore, in order to ensure the durability of the part that may be excessively heated, it is necessary to accurately grasp the temperature of the part and suppress supercharging before the upper limit is exceeded. For this reason, it is possible to arrange a temperature sensor in the electric motor, for example. In Japanese Patent Laid-Open No. 2003-284375 (Patent Document 1), a current sensor is used to detect the coil current of an electric motor, and the temperature of the electric motor is estimated based on the current value. I'm trying to suppress it.

JP 2003-284375 A

However, providing a temperature sensor or using a current sensor in the electric motor for grasping the temperature of a portion where there is a possibility of overheating as described above leads to an increase in cost.
For this reason, it is desirable to estimate the temperature of a part where there is a possibility of excessive temperature rise without using such a sensor, but there is currently no known method for obtaining an estimated temperature sufficiently close to the actual temperature. Therefore, the improvement is desired.

  The present invention has been made based on the above problems, and is an electric compressor that can easily estimate the temperature of a portion of the electric compressor that may be excessively heated without requiring a temperature sensor or a current sensor. An object of the present invention is to provide a temperature estimation device and a control device capable of avoiding burning of the electric compressor.

  The temperature estimation device for an electric compressor for an internal combustion engine according to claim 1 of the present invention includes an electric compressor provided in an intake passage of the internal combustion engine and driven by the electric motor, and a compressor rotation speed detecting means for detecting the rotation speed of the electric compressor. And a temperature estimating means for estimating a temperature of a predetermined part of the electric compressor based on a first-order lag rotation speed obtained by performing a predetermined first-order lag process on the compressor rotation speed. .

  The temperature estimation device for an electric compressor for an internal combustion engine according to claim 2 of the present invention is the temperature estimation device for the electric compressor for an internal combustion engine according to claim 1, wherein the vehicle speed of the vehicle on which the internal combustion engine is mounted is detected. The temperature estimation unit is further configured to set a filter gain used for the first-order lag process larger than in other cases when the vehicle speed is equal to or lower than a predetermined value.

  The temperature estimation device for an electric compressor for an internal combustion engine according to claim 3 of the present invention is the temperature estimation device for an electric compressor for an internal combustion engine according to claim 2, wherein the temperature estimation means is configured such that the vehicle speed is equal to or lower than a predetermined vehicle speed. When the rotational speed of the electric compressor is equal to or lower than a predetermined rotational speed, the filter gain used for the first-order lag processing is set to be larger than in other cases.

  The temperature estimation device for an electric compressor for an internal combustion engine according to claim 4 of the present invention is the temperature estimation device for an electric compressor for an internal combustion engine according to claim 1, 2, or 3, wherein the outside air temperature detecting means for detecting the outside air temperature is provided. Further, the temperature estimation means calculates a deviation between the primary delay outside air temperature obtained by subjecting the outside air temperature to a predetermined primary delay process and a predetermined reference temperature as an outside air temperature correction value, and calculates the primary delay rotational speed. And a temperature of a predetermined portion of the electric compressor based on the outside air temperature correction value.

  The temperature estimation device for an electric compressor for an internal combustion engine according to claim 5 of the present invention is the temperature estimation device for an electric compressor for an internal combustion engine according to any one of claims 1 to 4, wherein the temperature estimation means is The filter gain is configured to individually estimate the temperature of the bearing portion and the temperature of the winding portion of the electric motor as the temperature of the predetermined portion of the electric compressor, and is used for the first-order lag processing in the temperature estimation of the bearing portion. Is set to be larger than the filter gain used for the first-order lag processing in the temperature estimation of the winding portion of the electric motor.

  The temperature estimation device for an electric compressor for an internal combustion engine according to claim 6 of the present invention is the temperature estimation device for an electric compressor for an internal combustion engine according to any one of claims 1 to 4, wherein the temperature estimation means is The temperature of the heat sink part and the temperature of the bearing part are individually estimated as the temperature of the predetermined part of the electric compressor, and the filter gain used for the first-order lag process in the temperature estimation of the heat sink part is determined as the bearing. It is set to be larger than the filter gain used for the first-order lag processing in the temperature estimation of the part.

  The temperature estimation device for an electric compressor for an internal combustion engine according to claim 7 of the present invention is the temperature estimation device for an electric compressor for an internal combustion engine according to any one of claims 1 to 4, wherein the temperature estimation means is The filter gain is configured to individually estimate the temperature of the heat sink portion and the temperature of the winding portion of the electric motor as the temperature of the predetermined portion of the electric compressor, and is used for the first-order lag processing in the temperature estimation of the heat sink portion. Is set to be larger than the filter gain used for the first-order lag processing in the temperature estimation of the winding portion of the electric motor.

  According to an eighth aspect of the present invention, there is provided a control device for an electric compressor for an internal combustion engine, wherein the temperature of the predetermined portion is inputted from the temperature estimation device for the electric compressor for the internal combustion engine according to any one of the first to seventh aspects. The compressor rotation control means for reducing the output of the electric compressor by a predetermined amount when the temperature exceeds a predetermined upper limit temperature is provided.

  In the first aspect of the invention, since the compressor rotation speed is detected and the detected compressor rotation speed is subjected to first-order lag processing, the first-order lag rotation speed as an index having a high correlation with temperature can be easily obtained. Since the temperature of the predetermined part of the electric compressor is estimated based on the first-order lag rotation speed, the temperature can be estimated with high accuracy. In particular, it is possible to estimate the temperature of a predetermined portion of the electric compressor only by performing arithmetic processing without using a detection means such as a temperature sensor or a current sensor, and it is possible to realize temperature estimation with high accuracy at low cost.

  According to the second aspect of the present invention, when the vehicle speed is equal to or lower than the predetermined value, the filter gain used for the first-order lag processing is set larger than in other cases, so that the temperature estimation can be performed with higher accuracy according to the state of the vehicle. I can do it.

  In the third aspect of the invention, when the vehicle speed is equal to or lower than a predetermined value and the rotational speed of the electric compressor is equal to or lower than the predetermined rotational speed, the filter gain used for the first-order lag processing is set larger than in other cases. Therefore, the temperature can be estimated with higher accuracy.

  According to the invention of claim 4, the outside air temperature correction value calculated based on the deviation between the first order delayed outside air temperature obtained by subjecting the outside air temperature highly correlated with the temperature to the predetermined first order lag processing and the predetermined reference temperature is obtained. Since it is used, the temperature can be estimated more accurately.

  In the invention of claim 5, the filter gain used for the first-order lag processing in the temperature estimation of the bearing portion is set larger than the filter gain used for the first-order lag processing in the temperature estimation of the winding portion of the motor. Therefore, the temperature of the bearing portion and the temperature of the winding portion of the electric motor can be estimated individually with high accuracy.

  According to the sixth aspect of the present invention, the filter gain used for the first order lag processing in the heat sink portion temperature estimation is set larger than the filter gain used in the first order lag processing in the bearing portion temperature estimation. The temperature of the part and the temperature of the bearing part can be estimated individually and accurately.

  In the invention of claim 7, the filter gain used for the first-order lag processing in the temperature estimation of the heat sink portion is set larger than the filter gain used for the first-order lag processing in the temperature estimation of the winding portion of the motor. Therefore, the temperature of the heat sink part and the temperature of the winding part of the electric motor can be estimated individually and accurately.

  According to the eighth aspect of the present invention, when the estimated temperature of the predetermined portion exceeds the upper limit temperature, the output of the electric compressor is reduced by a predetermined amount, so that excessive temperature rise can be suppressed and the durability of the electric compressor can be ensured.

FIG. 1 shows an engine 1 that is an internal combustion engine equipped with an electric compressor temperature estimation device and control device according to an embodiment of the present invention.
The engine 1 is a multi-cylinder engine, and intake air is supplied to the combustion chamber C in the cylinder of each cylinder from the intake passage 4 and exhaust gas is discharged from the exhaust passage 11. In each combustion chamber C, fuel is injected by the fuel injection valve 2, and the air-fuel mixture is ignited by the spark plug 3, whereby a piston crank mechanism (not shown) converts combustion energy into rotational energy and is not shown. The configuration is such that the rotational driving force is transmitted to the driving wheel side.

  In the intake passage 4 of the engine 1, an air cleaner 5, an electric compressor 6 with an electric motor, an intercooler 7, a throttle valve 8, an intake manifold 9, and each combustion chamber C are arranged in this order. The exhaust passage 11 is opened to the atmosphere through an exhaust manifold 111, a catalytic converter 112 which is an exhaust gas purification device, a muffler (not shown), and the like.

  The electric compressor 6 in the intake passage 4 includes a rotating shaft 22 pivotally supported by a casing 21 via a plurality of bearings (not shown), a rotating impeller 23 attached to one end thereof, and an acceleration on the other end. The machine 24 and the electric motor 25 are formed. An optical compressor rotation sensor 26 (compressor rotation speed detection means) is disposed opposite to the rotation shaft 22, and a pulse signal output thereby is input to an electronic control unit (ECU) 12 described later, and the electronic control unit 12 The compressor rotation speed calculation function unit (not shown) is configured to calculate the compressor rotation speed Nc.

A part of the rotating shaft 22 forms a rotor 251, and a stator coil 252 is annularly arranged around the rotor 251, and the stator coil is connected to the battery 34 through a heat sink 253 including a control base. The control signal input unit of the heat sink 253 is connected to the ECU 12. Here, when the compressor rotation speed Nc is excessively high and the operation is continued, the bearings, the stator coil, the heat sink, etc. rapidly increase the heat generation amount. It is necessary to suppress the continuation of rotational operation.
An outside air temperature sensor (outside air temperature detecting means) 15 is attached to a part of the casing 21 of the air cleaner 5 described above, and the outside air temperature To is input to the electronic control unit 12 described later.

  A bypass passage 29 that bypasses the electric compressor 6 is formed in the intake passage 4. The bypass passage 29 is provided with a reed valve 31 that allows only intake air to flow in the forward direction toward the engine body. The reed valve 31 includes a reed valve 32 that opens and closes according to the difference in intake pressure between the upstream side and the downstream side of the bypass passage 29, thereby preventing the flow from the downstream side of the compressor to the air cleaner 5 side. Thus, the intake pressure can be prevented from leaking, and the downstream side of the compressor can be operated at a pressure lower than that of the air cleaner 5 to prevent the intake resistance from excessively increasing.

The electric motor 25 is composed of a DC motor, and is connected to the battery 34 via an electric compressor drive circuit (hereinafter simply referred to as a drive circuit 33) that controls the drive current. The drive circuit 33 is composed of a current control circuit, and a current value increase / decrease command signal Di to the current control circuit is output by a compressor drive control means A2 (see FIG. 2) of the electronic control unit 12 to be described later. In is supplied to the electric motor 25.
A generator 23 driven by the engine 1 is mounted on the engine 1. The generator 23 is connected to the battery 34 through a charging circuit 135 whose operation is controlled by the ECU 12.

  An air-cooled intercooler 7 that lowers the temperature of the intake air whose temperature has been increased by the intake air pressurization by the electric compressor 6 is arranged on the downstream side of the intake passage of the electric compressor 6. The charging efficiency of the engine 1 is improved. Note that an intake pressure sensor 41 is attached to this part, whereby the intake pressure Pi in the intake pipe 4 is detected and output to the ECU 12.

  A throttle valve 8 for adjusting the intake air amount Qa is disposed downstream of the intercooler 7. The throttle valve 8 is of an electronic control type, and an operation amount θa of the accelerator pedal 9 is detected by an accelerator opening sensor 11, and the electronic control unit 12 opens the throttle valve 8 based on the detection result and other information amount. Is to determine. The throttle valve 8 is opened / closed by a throttle motor 13 provided therewith, but a link operation system is also provided as an auxiliary. Further, a throttle position sensor 14 that is disposed opposite to the throttle valve 8 and detects the opening degree θs is also provided.

The ECU 12 includes a CPU 121, a ROM 122, a RAM 123, a nonvolatile RAM 124, input / output interfaces 125 and 126, and a timer counter (not shown), and comprehensive control of the compressor drive control device including the engine 1 by the electronic control unit 12. Is done.
The electronic control unit 12 receives a signal of the engine speed Ne from the engine speed sensor 16, a signal of the compressor speed Nc from the compressor speed sensor (compressor speed detection means) 26, and a signal of the accelerator speed θa from the accelerator position sensor 11. The outside air temperature To signal from the outside air temperature sensor 15 and the intake air pressure Pi signal in the intake pipe 4 from the intake air pressure sensor 41 are input. Further, other signals are input from various sensors and actuators not shown in the figure.

As shown in FIG. 2, the electronic control unit 12 controls the operation of the fuel injection valve 2, the spark plug 3, the generator 23, etc. of the engine 1 based on various input signals as the engine control means A1, and the compressor The drive control means A2 includes a motor temperature estimation means A3 that controls the compressor rotation speed Nc and further calculates the estimated motor temperature Tcm by calculating the compressor rotation speed Nc.
Here, the compressor drive control means A2 calculates the pressure ratio β (= Pc / Po) from a preset pressure ratio map (see FIG. 6) from the intake air amount Qa as the engine load and the engine speed Ne. A target intake pressure increase value Pc corresponding to the determined pressure ratio β and atmospheric pressure Po is determined, and the current drive current In is corrected to a current value ± δi so that the current intake pressure value Pcn approaches the target intake pressure increase value Pc. Then, it is corrected and output to the driver circuit 33. Moreover, when an excessive temperature described later is detected, if a rotation restriction command Ss is input, the drive current In is reduced and corrected by the unit restriction current −δi every control cycle, and the reduction control is sequentially performed to zero.

Specifically, the motor temperature estimating means A3 is a means for selectively performing the bearing temperature estimation, the stator coil temperature estimation, and the heat sink temperature estimation sequentially. Here, the bearing temperature estimation is mainly described, and the other descriptions are simplified. Turn into.
The motor temperature estimating means A3 first calculates the compressor rotation speed Nc as the first-order delay rotation speed Nc ′ by performing the first-order delay processing as shown in the equation (1). In this case, if the compressor rotation speed is Nc and the current value is n,
Nc ′ (n) = FG · Nc ′ (n−1) + (1−FG) · Nc (n) (1)
Calculate by calculating with Here, FG is a filter gain used for the first-order lag processing, and a relatively large value, for example, 0.9 or more is used here. This filter gain FG is switched depending on the vehicle condition, and the filter gain FG2 used as FG when the vehicle is stopped and the compressor speed Nc is idling (Nc idling) is based on the filter gain FG1 used otherwise. It is set large. The time constant in the first-order lag process varies depending on the setting of FG, but is preferably 100 seconds or more.

FIG. 4A shows an actual change characteristic when the actual compressor rotational speed: Nc is calculated as the first-order lag rotational speed Nc ′ based on the characteristic of the equation (1). Here, the actual compressor speed Nc suddenly decreases while the vehicle is stopped, whereas the primary delay speed Nc ′ gradually decreases due to the relatively large filter gain FG. It is clear.
Calculated by the primary delay estimation bearing temperature corresponding to the rotational speed Nc '(motor temperature variation) T _B primary formula of predetermined temperature coefficients a, b are set (2).

T _B = a · Nc ′ + b (2)
This formula (2) is adopted for the following reason. Figure 5 a temperature distribution diagram of (a) the actual bearing temperature per actual compressor rotational speed Nc shown in T _{B r} (℃), replacing the temperature distribution diagram of the actual bearing temperature T _{B r} to the primary lag speed Nc ' The characteristic shown in FIG. 5B is obtained, and it can be seen that the correlation between the first-order lag rotation speed Nc ′ and the temperature is high. This characteristic can be expressed by a substantially linear expression shown in the above formula (2). Here, the temperature coefficient a and the correction value b are obtained from the data distribution characteristics (experimental values) shown in FIG.

This estimated bearing temperature fluctuation value T _B is corrected by a predetermined temperature correction value αt and corrected as an estimated bearing temperature T _B (= T _B ± αt). Incidentally, the estimated bearing temperature T _B calculated by equation (2) is the uncorrected for temperature correction value [alpha] t, in the following order to avoid confusion is used as uncorrected bearing temperature T _{B f} (n).
Here, the temperature correction value αt is calculated as follows.

First, if the outside temperature is Tg, the current value is n, and the previous value is n−1,
Tg '(n) = FGt.Tg' (n-1) + (1-FGt) .Tg (n) .. (3)
The first-order lag outside air temperature Tg ′ (n) is calculated. Here, FGt is a filter gain used for the first-order lag processing, and a relatively large value, for example, 0.9 or more is used here. In this case, the time constant is 200 seconds, and the actual outside temperature Tg is actually annealed by this process, and as shown in FIG. 4B, a first-order lag outside temperature: Tg ′ having a moderate fluctuation value is obtained. .
The deviation of the primary delayed outside air temperature Tg ′ with respect to a predetermined reference temperature (for example, 35 ° C.) is obtained as a deviation temperature ΔTg ′ (n) by the equation (4), and the deviation temperature ΔTg ′ (n) is a temperature correction value here. Adopted as αt.

ΔTg ′ (n) (= αt) = Tg ′ (n) − (reference temperature) (4)
Based on the pre-correction bearing temperature T _B f (n) and the deviation temperature ΔTg ′ (n) which is the temperature correction value αt here, the estimated bearing temperature T _B o (° C.) (= T _B f (n) + ΔTg ′ (n)) is calculated.

Then, when the estimated bearing temperature T _B o (° C.) thus obtained exceeds a predetermined excess temperature, for example, Tmax, a rotation restriction command Ss is issued, and the drive current In is expressed by a unit restriction current −δi every control cycle. Are sequentially reduced.
As described above, when the engine 1 of FIG. 1 is driven, the electronic control unit 12 drives the fuel injection valve 2 by fuel injection control for driving the engine in accordance with a main routine (not shown), and the ignition plug 3 is ignited. It is driven by timing control. Further, the electronic control unit 12 switches the motor generator 23 to a power generation state via a charging circuit (inverter) 35 and charges the battery 34. Further, the electronic control unit 12 reaches the compressor driving routine of FIG. 7 in the middle of the main routine.

  In step s1 of this compressor drive control routine, the latest engine drive information, that is, the engine speed Ne, the compressor speed Nc, the accelerator opening θa, the outside air temperature To, and the intake pressure Pi are taken in from each sensor. Next, an outside air temperature correction value calculating routine for calculating an outside air temperature correction value αt at step s2, a bearing temperature calculating routine at step s3, a motor winding temperature calculating routine at step s4, and a heat sink temperature calculating routine at step s5. When it reaches step s6, it determines whether or not there is a temperature abnormality, branches to steps s7 and 8 depending on whether or not there is an abnormality, performs the compressor rotation restricting process when it determines abnormality and reaches step s7, If no abnormality is determined and step s8 is reached, normal compressor drive processing is performed, and the process returns to a main routine (not shown).

Here, in the outside air temperature correction value calculation routine for calculating the outside air temperature correction value αt in step s2, as shown in FIG. 8, the current outside air temperature Tg is fetched in step b1, and the filter gain set in advance in step b2 is set. FGt is read, and in step b3, the first-order lag outside temperature Tg ′ (n) is calculated using the previous value: Tg ′ (n−1) and the current value: Tg (n) according to the above-described equation (3). To do.
Next, when step b4 is reached, here, the deviation from the reference temperature is obtained as the deviation temperature ΔTg ′ (n) by equation (4), the temperature correction value αt is obtained, and the process proceeds to the bearing temperature calculation routine of step s3.

When the bearing temperature calculation routine in step s3 is reached, here, as shown in FIG. 9, the latest compressor rotation speed Nc is fetched in step a1, and it is determined in step a2 whether the vehicle is stopped and Nc idle. , Yes, go to step a3, otherwise go to step a4 during steady driving.
When step a4 is reached during steady driving, the temperature range and the heat dissipation change are relatively large during traveling, the filter gain FG1 is set to a relatively large value, and step a3 is reached while the vehicle is stopped and Nc idle. Then, the filter gain FG2 is set to a larger value so as to obtain characteristics approximating the temperature fluctuation.

When step a3 reaches step a5 from step a3, 4, the preset filter gain FG1 (FG2) is used, and the compressor rotation speed Nc ′ (n) is set to the first-order lag rotation speed Nc ′ from the above equation (1). (Refer to a reference Nc ′ in FIG. 4A).
In steps a6 and a7, a preset temperature coefficient a and a correction value b for calculating the estimated bearing temperature are selected. Furthermore, most recent first-order lag rotational speed Nc 'using, by using the above arithmetic expression (2), the pre-correction bearing temperature (motor temperature _{variation) T B f (= a ·} Nc' calculates a + b), Proceed to step a8.

In step a8, the estimated temperature T _B o is obtained by adding the predetermined temperature correction value αt in step s2 and the pre-correction bearing temperature T _B f in step a7.

Here the estimated bearing temperature T _{B o} in, as shown in FIG. 4 (c), shows almost the same variation value between the actual bearing temperature T _{B r.}
Here, so as to be substantially the same variation value between the actual bearing temperature T _{B r} shown in FIG. 4 (c), i.e., change adjust filter gain FG1, FG2 used in step a4, a3, overheating thereof, the heat dissipation A filter gain that matches the characteristics is employed. In addition, obtained as a deviation temperature ΔTg deviation between the estimated bearing temperature T _B and the actual bearing temperature TBr is a temperature correction value for the reference temperature '(n). By this way and the set value is set as appropriate, and can correct the deviation between the estimated bearing temperature T _B and the actual bearing temperature T _{B r} more accurately.

After step s3, when step s4 is reached, the motor winding temperature calculation routine is executed in accordance with a calculation processing method substantially similar to the bearing temperature calculation routine in step s3.
In this case, the filter gains used in the above equations (1) to (4) are relatively large values for FG1 and FG2, but are smaller than those for bearing temperature estimation. In addition, FG3 and temperature coefficient The values of a and the correction value b are appropriately set according to the actual vehicle data. FIG. 10A shows data characteristics of the calculated estimated motor winding temperature TC and actual motor winding temperature TCr. Also in this case, the error between the estimated motor winding temperature TC and the actual motor winding temperature TCr is relatively small.

Next, when step s5 is reached, the heat sink temperature restriction control routine is executed by almost the same calculation process as the bearing temperature restriction control routine in step s3.
In this case, the filter gain used in the equations (1) to (4) is set to a larger value than the filter gain FG1 (, FG2 in this case for the estimation of the bearing temperature. In addition, FG3, temperature coefficient a, correction values of b showed the data characteristic of being set as appropriate. and computed estimated heat sink temperature T _H and the actual heat sink temperature T _{H r} in accordance with the actual vehicle data in Figure 10 (b). in this case also, the error of the estimated heat sink temperature TH and the actual heat sink temperature T _{H r} is relatively small.

When step s6 is reached, it is determined whether the current estimated bearing temperature T _B o (° C.), the estimated motor winding temperature TC, and the estimated heat sink temperature TH exceed a predetermined excess temperature, for example, Tmax (= 80 ° C.). Thus, it is determined whether or not there is a temperature abnormality, and if there is no abnormality, the process proceeds to step s8, and it is determined that even one temperature abnormality is present, and the process proceeds to step s7.

  When step s8 is reached at normal times, normal compressor drive processing is performed. Here, the intake air amount Qa, the engine speed Ne, and the pressure ratio β (= Pc / Po) corresponding to the atmospheric pressure Po are calculated from the pressure ratio map (see FIG. 6), and the target intake air intake corresponding to the pressure ratio β is calculated. The pressure value Pc is obtained, and the current drive current In is adjusted by the correction current value ± δi so that the current intake pressure value Pcn approaches the intake pressurization value Pc. Return to the main routine.

  On the other hand, when it is determined that the temperature is abnormal and the process reaches step s7, in order to regulate the rotation of the compressor, the unit regulation current -δi is corrected to be decreased from the current drive current In every control cycle and output to the driver. End control and return to main routine. In addition, while reaching step s7, the control for correcting the current drive current In to decrease by the unit regulation current −δi is continued, and the current drive current In is continued to zero, that is, to the idle rotation state.

Thus, the engine 1 equipped with the temperature estimation device and the control device for the electric compressor in FIG. 1 detects the compressor rotation speed Nc, corrects the detected compressor rotation speed to the first-order lag rotation speed Nc ′, and performs the same rotation. the number Nc 'is calculated by a linear expression as uncorrected bearing temperature T _{B f} (2), the uncorrected bearing temperature T _{B f} and modified by a predetermined outside air temperature correction value αt estimated bearing temperature T _{B (the} estimated motor Temperature). Here, in particular, the estimated bearing temperature T _B o (estimated motor temperature) can be obtained only by performing arithmetic processing without using a detection means such as a compressor temperature sensor or a current sensor, A highly accurate estimated motor temperature with little deviation can be obtained.

Further, the outside air temperature Tg is detected, and the primary delayed outside air temperature Tg ′ (n) of the outside air temperature Tg is obtained by the equation (3), and the primary delayed outside air temperature To ′ (n) and a predetermined reference temperature are obtained. Since the deviation temperature ΔTg ′ (n) is calculated as the outside air temperature correction value αt, the estimated bearing temperature (estimated motor temperature T _B o) can be calculated by adding the outside air temperature correction value αt and the motor temperature fluctuation value T _B f. In particular, it is possible to obtain a highly accurate estimated bearing temperature (estimated motor temperature T _B o) with less deviation from the actual motor temperature T _B r.

Estimated bearing temperature (estimated motor temperature T _{B o),} and the output of the estimated motor winding temperature TC or estimated heat sink temperature T _H is above the upper limit temperature set respectively the motor-driven compressor 6 is reduced a predetermined amount, the compressor with an electric motor Therefore, it is possible to suppress the excessive temperature increase in the portion where there is a possibility of excessively increasing the temperature and to ensure the durability of the compressor with an electric motor.

  The electric turbocharger in FIG. 1 is the electric compressor 6 that performs intake air pressurization by the electric motor 25, but instead of this, an exhaust supercharger 6a with an electric motor as shown in FIG. 11 may be used. That is, the multi-cylinder engine 1a here has a configuration similar to that of the engine 1 in FIG. 1, and the exhaust turbine 50 of the exhaust supercharger 6a is disposed downstream of the exhaust manifold 111 upstream of the exhaust passage 11a. The exhaust gas purification device 51 and the like are sequentially arranged downstream thereof. An air cleaner 53, a supercharger compressor 54, an intercooler 55, a throttle valve 56, and an intake manifold 57 are arranged in the intake passage 4a from the upstream side. The exhaust supercharger 6a is disposed between the intake passage 4a and the exhaust passage 11a, and the impellers of the exhaust turbine 50 and the compressor 54 are integrally connected to both ends of a rotating shaft 49 pivotally supported by a casing (not shown). Has been. An electric motor 25 a is attached to the vicinity of the center of the rotating shaft 49.

  The electric motor 25a is a DC motor, and a drive circuit 33a for controlling the drive current In is connected to the electric motor 25a, and a battery 34a as a power source is connected through the drive circuit 33a. The electric motor 25a is controlled by the current setting means A2 of the electronic control unit 12a via the drive circuit 33a.

  Even in the exhaust supercharger 6a that is supercharged by such exhaust energy, forced supercharging drive control can be performed when necessary, and in that case, the estimated motor temperature is similarly calculated based on the compressor rotational speed, Estimated motor temperature can be obtained only by performing temperature control and performing arithmetic processing without using a detection means such as a temperature sensor or a current sensor. Similar effects can be obtained.

It is a schematic block diagram of the control apparatus of the compressor with an electric motor as one Embodiment of this invention. It is a block diagram of the control part of the electric compressor of FIG. It is a block diagram explaining the estimated bearing temperature calculation function of the control part of the electric compressor of FIG. FIG. 2 is a drive characteristic diagram of the electric compressor of FIG. 1, in which (a) is a compressor rotation characteristic diagram, (b) is an outside air temperature, vehicle speed characteristic diagram, and (c) is a bearing temperature characteristic diagram. FIG. 1 shows the bearing temperature-compressor rotational speed characteristics of the electric compressor in FIG. 1, where (a) shows actual data and (b) shows data that has undergone the first-order lag processing. FIG. 2 is an intake air amount-pressure ratio characteristic diagram used in the control device for the electric compressor of FIG. 1. 3 is a flowchart of a compressor drive control routine performed by the electric compressor control device of FIG. 1. It is a flowchart of the external temperature correction value calculation routine which the control apparatus of the electric compressor of FIG. It is a flowchart of the bearing temperature regulation value calculation routine which the control apparatus of the electric compressor of FIG. 1 performs. FIG. 2 is a temperature variation characteristic diagram of the electric compressor of FIG. 1, (a) is a winding temperature variation characteristic diagram, and (b) is a temperature variation characteristic diagram of a heat sink. It is the schematic of the control apparatus of the exhaust gas supercharger which is other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 4 Intake passage 6 Compressor with electric motor 11 Exhaust passage 25 Electric motor 26 Compressor rotation speed detection means 33 Drive circuit 34 Accumulator (power supply)
αt Outside air temperature correction value A1 Engine control means A2 Compressor drive control means A3 Motor temperature estimation means In Output current value Nc Compressor rotation speed Nc 'Primary delay rotation speed T _B 0 Estimated bearing temperature (estimated motor temperature)
ΔTg '(n) Outside air temperature correction value

Claims (8)

An electric compressor provided in an intake passage of the internal combustion engine and driven by an electric motor;
Compressor speed detecting means for detecting the speed of the electric compressor;
Temperature estimation means for estimating a temperature of a predetermined portion of the electric compressor based on a first-order lag rotation speed obtained by performing a predetermined first-order lag process on the compressor rotation speed;
An apparatus for estimating the temperature of an electric compressor for an internal combustion engine. In the temperature estimation device for an electric compressor for an internal combustion engine according to claim 1,
Vehicle temperature detection means for detecting the vehicle speed of the vehicle on which the internal combustion engine is mounted is further provided. The temperature estimation means sets a filter gain used for the first-order lag processing larger than that in other cases when the vehicle speed is a predetermined value or less. An apparatus for estimating the temperature of an electric compressor for an internal combustion engine, characterized in that: In the temperature estimation device for an electric compressor for an internal combustion engine according to claim 2,
The temperature estimating means is configured to set a filter gain used for the first-order lag processing larger than in other cases when the vehicle speed is equal to or lower than a predetermined vehicle speed and the rotation speed of the electric compressor is equal to or lower than a predetermined rotation speed. An apparatus for estimating the temperature of an electric compressor for an internal combustion engine. In the temperature estimation device for an electric compressor for an internal combustion engine according to claim 1, 2, or 3,
It further comprises an outside air temperature detecting means for detecting the outside air temperature,
The temperature estimating means calculates a deviation between the primary lag outside air temperature obtained by subjecting the outside air temperature to a predetermined reference lag process and a predetermined reference temperature as an outside air temperature correction value, and calculates the primary lag rotation speed and the outside air temperature. An apparatus for estimating a temperature of an electric compressor for an internal combustion engine, wherein the temperature of a predetermined part of the electric compressor is estimated based on an air temperature correction value. In the temperature estimation device for a compressor with an electric motor for an internal combustion engine according to any one of claims 1 to 4,
The temperature estimating means is configured to individually estimate the temperature of the bearing portion and the temperature of the winding portion of the electric motor as the temperature of the predetermined portion of the electric compressor, and the first order lag processing in the temperature estimation of the bearing portion A filter gain used for the internal combustion engine is set to be larger than a filter gain used for the first-order lag processing in the temperature estimation of the winding portion of the motor. In the temperature estimation device for a compressor with an electric motor for an internal combustion engine according to any one of claims 1 to 4,
The temperature estimating means is configured to individually estimate the temperature of the heat sink portion and the temperature of the bearing portion as the temperature of the predetermined portion of the electric compressor, and is used for the first-order lag processing in the temperature estimation of the heat sink portion. An apparatus for estimating the temperature of an electric compressor for an internal combustion engine, wherein the filter gain is set to be larger than a filter gain used for the first-order lag process in estimating a temperature of a bearing portion. In the temperature estimation device for a compressor with an electric motor for an internal combustion engine according to any one of claims 1 to 4,
The temperature estimating means is configured to individually estimate the temperature of the heat sink portion and the temperature of the winding portion of the electric motor as the temperature of the predetermined portion of the electric compressor, and the first order lag processing in the temperature estimation of the heat sink portion A filter gain used for the internal combustion engine is set to be larger than a filter gain used for the first-order lag processing in the temperature estimation of the winding portion of the motor.   The temperature of the predetermined part is inputted from the temperature estimation device for an electric compressor for an internal combustion engine according to any one of claims 1 to 7, and when the temperature exceeds a predetermined upper limit temperature, the output of the electric compressor is controlled. An apparatus for controlling an electric compressor for an internal combustion engine, comprising compressor rotation control means for driving at a reduced amount.

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