Engine torque abnormality determination device and hybrid vehicle equipped with the same

Abstract

To provide a torque abnormality determination device for an engine which can determine an abnormal state in which an estimation value of torque becomes too low, and a hybrid vehicle including the same.SOLUTION: A torque abnormality determination device for an engine comprises: a first calculation unit which calculates a first estimation value of torque of an engine; a second calculation unit which calculates a second estimation value of the torque by means of a different method from the calculation method of the first estimation value; and a torque determination unit which determines whether the first estimation value is normal or is in an abnormal state in which it becomes too low relative to the second estimation value on the basis of a difference between the first estimation value and the second estimation value.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an engine torque abnormality determination device and a hybrid vehicle equipped with the same. [Background technology]

[0002] There is known a technique for estimating engine torque and determining an abnormal state in which the estimated torque becomes excessive (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-014973 Summary of the Invention [Problem to be solved by the invention]

[0004] It is conceivable that an abnormal state may occur in which the estimated value is too small. For example, if such an estimated value is too small, problems may arise if various controls are performed based on this estimated value.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an engine torque abnormality determination device that can determine an abnormal state in which the estimated torque value is too low, and a hybrid vehicle equipped with the same. [Means for solving the problem]

[0006] The object is to provide a torque determination device that includes a first calculation unit that calculates a first estimated value of engine torque, a second calculation unit that calculates a second estimated value of the torque by a method different from the method for calculating the first estimated value, and a torque determination unit that determines whether the first estimated value is normal or an abnormal state in which the first estimated value is too small compared to the second estimated value, based on the difference between the first estimated value and the second estimated value. The first calculation unit calculates the first estimated value based on the intake air amount of the engine, the second calculation unit calculates the second estimated value based on the throttle opening degree of the engine, the second calculation unit calculates a first load factor of the engine based on the throttle opening degree, and calculates the second estimated value based on the first load factor. This can be achieved by an engine torque abnormality determination device.

[0009] A load factor determination unit is provided for determining whether the first load factor calculated based on the throttle opening is normal or abnormal. When the first load factor is determined to be normal by the load factor determination unit, the torque determination unit may determine whether the first estimated value is normal or in an abnormal state where it is too small relative to the second estimated value based on the difference between the first estimated value and the second estimated value.

[0010] A third calculation unit is provided for calculating a third estimated value of the torque by a method different from the first and second estimated values. When the first load factor is determined to be abnormal by the load factor determination unit, the torque determination unit may determine whether the first estimated value is normal or in an abnormal state where it is too small relative to the third estimated value based on the difference between the first estimated value and the third estimated value.

[0011] The third calculation unit calculates a second load factor of the engine based on the required shaft torque to the engine, calculates the third estimated value based on the second load factor, and the load factor determination unit may determine whether the first load factor is normal or abnormal based on the difference between the torque calculated based on the first load factor and the torque calculated based on the second load factor.

[0012] The above object can also be achieved by a hybrid vehicle including the above torque abnormality determination device and a motor that outputs an assist torque for assisting the torque of the engine based on the first estimated value.

Advantages of the Invention

[0013] According to the present invention, an engine torque abnormality determination device capable of determining an abnormal state in which an estimated value of torque becomes too small and a hybrid vehicle including the same can be provided.

Brief Description of the Drawings

[0014]

Figure 1

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[0015] [Hybrid vehicle configuration] Figure 1 is a schematic configuration diagram of the hybrid vehicle 1. In the hybrid vehicle 1, a K0 clutch 14, a motor 15, a wet clutch 18, and a transmission 19 are sequentially provided in the power transmission path from the engine 10 to the drive wheels 13. The engine 10 and the motor 15 are mounted as the driving power sources of the hybrid vehicle 1. The engine 10 is, for example, a V-type 6-cylinder gasoline engine, but the number of cylinders is not limited to this, and it may be an in-line gasoline engine or a diesel engine. The K0 clutch 14, the motor 15, the wet clutch 18, and the transmission 19 are provided in the transmission unit 11. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a differential 12.

[0016] The K0 clutch 14 is provided between the engine 10 and the motor 15 on the same power transmission path. The K0 clutch 14 receives hydraulic pressure supply from the released state and becomes engaged, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 becomes released in response to the stop of the hydraulic pressure supply, cutting off the power transmission between the engine 10 and the motor 15. The engaged state means a state in which both engaging elements of the K0 clutch 14 are connected and the engine 10 and the motor 15 have the same rotational speed. The released state means a state in which both engaging elements of the K0 clutch 14 are separated.

[0017] The motor 15 is connected to the battery 16 via an inverter 17. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supply from the battery 16, and also functions as a generator that generates electric power for charging the battery 16 in response to power transmission from the engine 10 or the drive wheels 13. The electric power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

[0018] The inverter 17 is controlled by an ECU 100, which will be described later, and converts the DC voltage from the battery 16 into an AC voltage or converts the AC voltage from the motor 15 into a DC voltage. In the case of a power running operation in which the motor 15 outputs torque, the inverter 17 converts the DC voltage of the battery 16 into an AC voltage and adjusts the power supplied to the motor 15. In the case of a regenerative operation in which the motor 15 generates electricity, the inverter 17 converts the AC voltage from the motor 15 into a DC voltage and adjusts the power supplied to the battery 16.

[0019] The transmission 19 is a stepped automatic transmission that switches the gear ratio in multiple steps by switching the gear stage, but is not limited thereto and may be a continuously variable transmission. The transmission 19 is provided between the motor 15 and the drive wheels 13 on the power transmission path. A wet clutch 18 is provided that is supplied with hydraulic pressure and engages to directly connect the motor 15 and the transmission 19.

[0020] The transmission unit 11 is further provided with an oil pump 21 and a hydraulic control mechanism 22. The hydraulic pressure generated by the oil pump 21 is supplied to the K0 clutch 14, the wet clutch 18, and the transmission 19 via the hydraulic control mechanism 22, respectively. The hydraulic control mechanism 22 is provided with respective hydraulic circuits for the K0 clutch 14, the wet clutch 18, and the transmission 19, and various hydraulic control valves for controlling their operating hydraulic pressures. Note that instead of the wet clutch 18, a torque converter equipped with a lock-up clutch may be provided.

[0021] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as a control device for the vehicle. The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle, and a memory in which control programs and data are stored. The ECU 100 is an example of a torque abnormality determination device, and specifically functionally realizes a first calculation unit, a second calculation unit, a third calculation unit, a torque determination unit, and a load factor determination unit, which will be described later.

[0022] The ECU 100 controls the driving of the engine 10 and the motor 15. Specifically, the ECU 100 controls the throttle opening, ignition timing, and fuel injection amount of the engine 10 to control the torque and rotational speed of the engine 10. The ECU 100 controls the inverter 17 to adjust the amount of power transfer between the motor 15 and the battery 16, thereby controlling the rotational speed and torque of the motor 15. Further, the ECU 100 performs drive control of the K0 clutch 14, the wet clutch 18, and the transmission 19 through the control of the hydraulic control mechanism 22.

[0023] Signals from the ignition switch 71, the crank angle sensor 72a, the motor rotational speed sensor 72b, the vehicle speed sensor 73, the air flow meter 74, the throttle opening sensor 75, the intake pressure sensor 76a, the in-manifold pressure sensor 76b, the atmospheric pressure sensor 76c, the water temperature sensor 77a, and the oil temperature sensor 77b are input to the ECU 100. The crank angle sensor 72a detects the rotational speed of the crankshaft of the engine 10, that is, the engine rotational speed. The motor rotational speed sensor 72b detects the rotational speed of the output shaft of the motor 15. The vehicle speed sensor 73 detects the traveling speed of the hybrid vehicle 1. The air flow meter 74 detects the intake air amount of the engine 10. The throttle opening sensor 75 detects the opening of the throttle valve 40 described later. The intake pressure sensor 76a detects the pressure (hereinafter referred to as the intake pressure) in the intake passage 35 described later on the upstream side of the throttle valve 40. The in-manifold pressure sensor 76b detects the pressure (hereinafter referred to as the in-manifold pressure) in the intake passage 35 on the downstream side of the throttle valve 40. The atmospheric pressure sensor 76c detects the atmospheric pressure. The water temperature sensor 77a detects the temperature of the cooling water of the engine 10 (hereinafter referred to as the water temperature). The oil temperature sensor 77b detects the temperature of the lubricating oil of the engine 10 (hereinafter referred to as the oil temperature).

[0024] The ECU 100 drives the hybrid vehicle in either a motor mode or a hybrid mode. In the motor mode, the ECU 100 releases the K0 clutch 14 and runs on the power of the motor 15. In the hybrid mode, the ECU 100 switches the K0 clutch 14 to the engaged state and runs at least on the power of the engine 10. Note that the hybrid mode includes a mode of running on the power of only the engine 10 and a mode of running with both the engine 10 and the motor 15 as power sources by powering the motor 15.

[0025] The switching of the driving mode is performed based on the required driving force of the vehicle obtained from the vehicle speed and the accelerator opening degree, the state of charge of the battery 16, etc. For example, when the required driving force is relatively small and the SOC (State Of Charge) indicating the power storage amount of the battery 16 is relatively high, the motor mode with the engine 10 stopped is selected to improve fuel efficiency. When the required driving force is relatively large or the SOC of the battery 16 is relatively low, the hybrid mode with the engine 10 driven is selected.

[0026] [Schematic Configuration of Engine] Figure 2 is a schematic configuration diagram of the engine 10. The engine 10 has cylinders 30, pistons 31, connecting rods 32, a crankshaft 33, an intake passage 35, intake valves 36, an exhaust passage 37, and exhaust valves 38. Only one of the plurality of cylinders 30 of the engine 10 is shown in Figure 2. Combustion of the air-fuel mixture takes place in the cylinder 30. The piston 31 is reciprocally accommodated in each cylinder 30 and is connected to the crankshaft 33, which is the output shaft of the engine 10, via the connecting rod 32. The connecting rod 32 converts the reciprocating motion of the piston 31 into the rotational motion of the crankshaft 33.

[0027] The intake passage 35 is connected to the intake port of each cylinder 30 via an intake valve 36. The exhaust passage 37 is connected to the exhaust port of each cylinder 30 via an exhaust valve 38. The intake passage 35 is provided with an air flow meter 75, an intake pressure sensor 76a, an intake manifold pressure sensor 76b, and a throttle valve 40 for adjusting the intake air amount. The exhaust passage 37 is provided with a catalyst 43 for exhaust purification.

[0028] The cylinder 30 is provided with an in-cylinder injection valve 41. The in-cylinder injection valve 41 injects fuel directly into the cylinder 30. Incidentally, instead of the in-cylinder injection valve 41, or in addition to the in-cylinder injection valve 41, a port injection valve for injecting fuel toward the intake port may be provided. Each cylinder 30 is provided with an ignition device 42 for igniting the air-fuel mixture of the intake air introduced through the intake passage 35 and the fuel injected by the in-cylinder injection valve 41 by spark discharge.

[0029] [Abnormal state of torque] When the driving mode is the hybrid mode, the ECU 100 calculates the shaft torque of the engine 10 (hereinafter referred to as the Ga system shaft torque) based on the air flow meter 74, regards the Ga system shaft torque as the actual engine shaft torque, and controls the assist torque of the motor 15. Specifically, the assist torque of the motor 15 is controlled so that the total torque, which is the sum of the shaft torque of the engine 10 and the assist torque of the motor 15, becomes the required torque. FIG. 3A is an example of a timing chart showing the transition of the total torque when the Ga system shaft torque is normal. FIG. 3A shows a case where the motor 15 is driven from a state where the engine 10 and the motor 15 are stopped to slip the K0 clutch 14 to start the engine 10.

[0030] The motor 15 starts driving (at time t1), releases the K0 clutch 14 and starts slipping to crank the engine 10 (at time t2). When the total torque increases to the required torque (at time t3), the engine 10 starts and the K0 clutch 14 engages (at time t4). Thereafter, the actual engine shaft torque is increased, and the assist torque of the motor 15 is reduced to 0 accordingly (at time t5), and the total torque is maintained at the required torque. Here, as described above, the ECU 100 regards the estimated Ga system shaft torque as the actual engine shaft torque and controls the reduction of the assist torque of the motor 15.

[0031] Here, the Ga system shaft torque is calculated based on the air flow meter 74 as described above. For this reason, for example, when the air flow meter 74 or other sensors and actuators fail, or when a memory defect (RAM corruption) occurs in which various sensor values become abnormal, the Ga system shaft torque may become an abnormal state in which it drops significantly beyond the allowable error with respect to the actual engine shaft torque. FIG. 3B is an example of a timing chart showing the transition of the total torque in the case of an abnormal state where the Ga system shaft torque is too small. As shown in FIG. 3B, when the Ga system shaft torque becomes too small, the ECU 100 increases the assist torque of the motor 15 so as to compensate for the shortage. However, since the actual engine shaft torque is actually normal, the total torque may become excessive with respect to the required torque, and there is a risk that the hybrid vehicle 1 accelerates unnecessarily and gives the driver a sense of discomfort. Therefore, the ECU 100 executes torque abnormality determination control for determining an abnormal state in which the Ga system shaft torque is too small beyond the allowable error with respect to the actual engine shaft torque.

[0032] [Torque Abnormality Determination Control] FIG. 4 is a flowchart showing an example of torque abnormality determination control executed by the ECU 100. In this control, it is repeatedly executed at a predetermined cycle while the ignition is on.

[0033] The ECU 100 determines whether the driving mode is the hybrid mode and whether the K0 clutch 14 and the wet clutch 18 are engaged (step S10). If the answer is No in step S10, this control ends. If the answer is Yes in step S10, the ECU 100 acquires sensor values (step S20). Specifically, the ECU 100 acquires the throttle opening, engine speed, vehicle speed, intake air amount, intake pressure, in-manifold pressure, atmospheric pressure, water temperature, and oil temperature by the above-described sensors.

[0034] Next, the ECU 100 calculates the Ga system shaft torque based on the intake air amount as described above (step S25). Specifically, the Ga system shaft torque is calculated by a model formula based on the intake air amount, throttle opening, intake pressure, water temperature, oil temperature, etc. The calculation of the Ga system shaft torque is not limited to such a model formula as long as it is based on the intake air amount, and it may be calculated by other known methods. The Ga system shaft torque is an example of a first estimated value. Step S25 is an example of a process executed by the first calculation unit.

[0035] Next, the ECU 100 calculates the engine 10 shaft torque (hereinafter referred to as the TA system shaft torque) based on a method different from that of the Ga system shaft torque, which will be described in detail later (step S30). The TA system shaft torque is an example of a second estimated value. Step S30 is an example of a process executed by the second calculation unit.

[0036] Next, the ECU 100 calculates the difference obtained by subtracting the Ga system shaft torque from the TA system shaft torque (hereinafter referred to as the TA system difference) (step S40). Next, the ECU 100 determines whether the Ga system shaft torque is normal or in an abnormal state where it is too small with respect to the TA system shaft torque based on the TA system difference (hereinafter referred to as the TA system determination) (step S50). Step S50 is an example of a process executed by the torque determination unit.

[0037] Unlike the Ga-axis torque described above, the TA-axis torque is calculated based on the throttle opening degree rather than the intake air amount. Therefore, for example, when the air flow meter 75 malfunctions and the intake air amount cannot be accurately detected, an abnormal state in which the Ga-axis torque becomes too small with respect to the TA-axis torque can be determined based on the TA-axis difference.

[0038] Next, the TA-axis determination control will be described. FIG. 5 is a flowchart showing an example of the TA-axis determination control. The ECU 100 sets a torque threshold value (step S51). The setting of the torque threshold value will be described later.

[0039] Next, the ECU 100 determines whether the TA-axis difference is equal to or greater than the torque threshold value (step S52). If Yes in step S52, the ECU 100 increments the time counter (step S53). The time counter is a value obtained by counting the elapsed time since the torque threshold value was set. Next, the ECU 100 sets a time threshold value (step S54). The setting of the time threshold value will be described later. Next, the ECU 100 determines whether the time counter is equal to or greater than the time threshold value (step S55).

[0040] If Yes in step S55, the ECU 100 determines that the Ga-axis torque is in an abnormal state (step S56). If No in step S55, the ECU 100 determines that the Ga-axis torque is normal (step S57). Also, if No in step S52, the ECU 100 clears the time counter to zero (step S58) and determines that the Ga-axis torque is normal (step S57). That is, when the TA-axis difference is equal to or greater than the torque threshold value and the time counter is equal to or greater than the time threshold value, it is determined that the Ga-axis torque is in an abnormal state.

[0041] Next, a method for setting the torque threshold and the time threshold will be described. FIG. 6 is an example of a map that defines the torque threshold and the time threshold. The vertical axis represents torque and the horizontal axis represents duration. This map is stored in advance in the ROM of the ECU 100. The map in FIG. 6 defines three torque thresholds α1 to α3 and time thresholds β1 to β3 corresponding to the torque thresholds α1 to α3, respectively. For example, the torque threshold α1 is set when the TA system difference is equal to or greater than the torque threshold α1. The torque threshold α2 is set when the TA system difference is less than the torque threshold α1 but is equal to or greater than the torque threshold α2. The torque threshold α3 is set when the TA system difference is less than the torque threshold α2. Furthermore, when the torque threshold α1 is set, the time threshold β1 is set. When the torque threshold α2 is set, the time threshold β2 is set. When the torque threshold α3 is set, the time threshold β3 is set. The torque thresholds α1 to α3 are determined based on the allowable error of the Ga system shaft torque relative to the actual engine shaft torque, assuming that the TA system shaft torque is the actual engine shaft torque. In this embodiment, the allowable error is an error that does not affect the control based on the Ga system shaft torque and does not cause discomfort to the driver.

[0042] For example, if a torque threshold value α1 and a time threshold value β1 are set, the Ga system shaft torque is determined to be normal if the duration during which the TA system difference is equal to or greater than the torque threshold value α1 is less than the time threshold value β1, and if this duration is equal to or greater than the time threshold value β1, the Ga system shaft torque is determined to be in an abnormal state. Similarly, if a torque threshold value α2 and a time threshold value β2 are set, the Ga system shaft torque is determined to be normal if the duration during which the TA system difference is equal to or greater than the torque threshold value α2 is less than the time threshold value β2, and if this duration is equal to or greater than the time threshold value β2, the Ga system shaft torque is determined to be in an abnormal state. The same applies when a torque threshold value α3 and a time threshold value β3 are set. Note that the map in FIG. 6 differs depending on the vehicle speed, and the faster the vehicle speed, the higher the torque threshold values α1 to α3 are set and the longer the time threshold values β1 to β3 are set. Even if the torque threshold values set in this way are small, if the duration during which the TA system difference is equal to or greater than the torque threshold value is long, the driver may feel uncomfortable, and therefore the Ga system shaft torque is determined to be in an abnormal state. Furthermore, even if the set torque threshold is large, if the duration for which the TA system difference is equal to or greater than the torque threshold is short, the Ga system shaft torque is determined to be normal since there is little risk of the driver feeling uncomfortable.

[0043] Next, the TA system shaft torque calculation control of the ECU 100 will be described. Fig. 7 is a flowchart showing an example of the TA system shaft torque calculation control. The ECU 100 calculates the TA system load factor (step S31). The TA system load factor is calculated using a model formula based on the throttle opening, engine speed, intake pressure, intake manifold pressure, atmospheric pressure, etc., acquired in step S20.

[0044] Next, the ECU 100 calculates the injection cylinder rate (step S32). Specifically, this can be calculated by dividing the number of injection cylinders at 720° CA of the engine 10 by the number of cylinders of the engine 10. The injection cylinder rate takes into account, for example, the case where fuel injection is stopped in a predetermined cylinder order when a fuel cut is performed, or the case where there are cylinders that are deactivated. Therefore, unless there is a request to perform a fuel cut and there are no deactivated cylinders, the injection cylinder rate is calculated as 1.

[0045] Next, the ECU 100 calculates the torque when the ignition timing is at MBT (Minimum Advance for the Best Torque) based on the TA system load factor (hereinafter referred to as the TA system MBT torque) (step S33). The TA system MBT torque is calculated by referring to a map that defines the relationship between the TA system load factor, the engine speed, and the MBT torque, and multiplying this MBT torque by the injection cylinder ratio. This map is stored in the ROM of the ECU 100 in advance.

[0046] Next, the ECU 100 calculates the torque efficiency based on the TA system load factor (hereinafter referred to as the TA system load factor) (step S34). The TA system torque efficiency is calculated by referring to a map that defines the relationship between the ignition retard angle amount, the TA system load factor, the engine speed, and the TA system torque efficiency. This map is stored in the ROM of the ECU 100 in advance. The ignition retard angle amount is calculated by subtracting the MBT ignition timing from the required ignition timing. The MBT ignition timing is calculated by referring to a map that defines the relationship between the TA system load factor, the engine speed, and the base MBT ignition timing, and adding various ignition timing correction amounts to the base MBT ignition timing. This map is stored in the ROM of the ECU 100 in advance. The various ignition timing correction amounts are, for example, the VVT correction amount, the low temperature correction amount, the atmospheric pressure correction amount, etc. The VVT correction amount is, for example, the correction amount of the ignition timing according to the opening and closing timing of the intake valve 36 and the exhaust valve 38 controlled by a valve timing mechanism (variable valve mechanism). The low temperature correction amount is, for example, the correction amount of the ignition timing according to the coolant temperature. The atmospheric pressure correction amount is the correction amount of the ignition timing according to the atmospheric pressure.

[0047] Next, the ECU 100 calculates the indicated torque based on the TA system MBT torque and the TA system torque efficiency (hereinafter referred to as the TA system indicated torque) (step S35). The TA system indicated torque is calculated by multiplying the TA system MBT torque by the TA system torque efficiency.

[0048] Next, the ECU 100 calculates the TA system shaft torque (step S36). The TA system shaft torque is calculated by subtracting the pump loss torque and the friction / auxiliary load torque from the TA system indicated torque. The pump loss torque is the loss torque due to the pumping loss of the engine 10. The friction / auxiliary load torque is the sum of the loss torque due to the friction of the rotating parts of the engine 10 and the loss torque due to the auxiliary machines driven by the engine 10. The auxiliary machines are, for example, the air conditioner device and the power steering device mounted on the hybrid vehicle 1. The pump loss torque and the friction / auxiliary load torque are negative torques opposite to the rotation direction of the engine 10. The pump loss torque is calculated by referring to a map that defines the intake manifold pressure, the engine speed, and the pump loss torque. The friction / auxiliary load torque is calculated by referring to the drive state of the auxiliary machines and the map. This map defines the friction / auxiliary load torque according to the engine speed, the TA system load factor, the water temperature, and the oil temperature. This map is stored in advance in the ROM of the ECU 100.

[0049] As described above, unlike the Ga system shaft torque calculated based on the intake air amount, the TA system shaft torque is calculated based on the throttle opening without using the intake air amount. Therefore, even if the Ga system shaft torque is in an abnormal state, the TA system shaft torque is calculated as a normal value approximated to the actual engine shaft torque. Therefore, based on the TA system difference, it is possible to determine the abnormal state of the Ga system shaft torque.

[0050] Incidentally, when the Ga system shaft torque is determined to be in an abnormal state in this way, the ECU 100 may, for example, release the wet clutch 18. Further, the warning lamp provided on the instrument panel of the vehicle of the ECU 100 may be turned on.

[0051] [Modification Example of Torque Abnormality Judgment Control] Next, a modified example of the torque abnormality determination control will be described. FIG. 8 is a flowchart showing a modified example of the torque abnormality determination control. When the answer is Yes in step S10, after the execution of steps S20 and S25, the ECU 100 calculates the TA system MBT torque (step S30a). The TA system MBT torque is calculated by executing the same processes as the processes in steps S31 to S33 in the present embodiment described above.

[0052] Next, the ECU 100 calculates, although details will be described later, the torque (hereinafter referred to as the required system MBT torque) when the ignition timing becomes MBT based on the required shaft torque (step S30b). Next, the ECU 100 calculates the absolute value of the difference between the TA system MBT torque and the required system MBT torque (hereinafter referred to as the MBT difference) (step S40a). Next, the ECU 100 executes a load ratio determination for determining whether the TA system load ratio is normal or abnormal based on the MBT difference, although details will be described later (step S40b). The TA system load ratio is an example of the first load ratio. Step S40b is an example of the process executed by the load ratio determination unit.

[0053] Next, the ECU 100 calculates the TA system shaft torque (step S50a). The TA system shaft torque is calculated by executing the same processes as the processes in steps S34 to S36 in the present embodiment described above. Next, the ECU 100 calculates, although details will be described later, the shaft torque of the engine 10 (hereinafter referred to as the required system shaft torque) by a calculation method different from that of the Ga system shaft torque and the TA system shaft torque (step S50b). The required system shaft torque is an example of the third estimated value. Step S50b is an example of the process executed by the third calculation unit.

[0054] Next, the ECU 100 calculates the TA system difference (step S60a). The calculation of the TA system difference is calculated by executing the same process as the process in step S40 in the present embodiment described above. Next, the ECU 100 executes a TA system provisional determination based on the TA system difference, although details will be described later (step S60b). Step S60b is an example of the process executed by the torque determination unit.

[0055] Next, the ECU 100 calculates a difference obtained by subtracting the Ga-axis torque from the required-axis torque (hereinafter referred to as the required-axis difference) (step S70a). Next, as will be described in detail later, the ECU 100 executes a provisional required-axis determination based on the required-axis difference (step S70b). Step S70b is an example of the process executed by the torque determination unit. Next, as will be described in detail later, the ECU 100 executes a main determination as to whether the Ga-axis torque is normal or in an abnormal state where it is too small based on the results of the TA-axis provisional determination and the required-axis provisional determination (step S80). Step S80 is an example of the process executed by the torque determination unit.

[0056] Next, the load factor determination control will be described. FIG. 9 is a flowchart showing an example of the load factor determination control. The ECU 100 sets a torque threshold (step S41b). The setting of the torque threshold is performed by executing the same process as the process of step S51 in the above-described present embodiment.

[0057] Next, the ECU 100 determines whether or not the MBT difference is equal to or greater than the torque threshold (step S42b). If Yes in step S42b, the ECU 100 increments a time counter (step S43b). The time counter is a time counter for load factor determination. Next, the ECU 100 sets a time threshold (step S44b). The setting of the time threshold is performed by executing the same process as the process of step S54 in the above-described present embodiment. Next, the ECU 100 determines whether or not the time counter is equal to or greater than the time threshold (step S45b).

[0058] If the answer is Yes in step S45b, the ECU 100 determines that the TA system load factor is abnormal (step S46b). If the answer is No in step S45b, the ECU 100 determines that the TA system load factor is normal (step S47b). Also, if the answer is No in step S42b, the ECU 100 clears the time counter to zero (step S48b) and determines that the TA system load factor is normal (step S47b). That is, when the MBT difference is equal to or greater than the torque threshold and the time counter is equal to or greater than the time threshold, it is determined that the TA system load factor is abnormal.

[0059] As described above, to determine whether the TA system load factor is normal or abnormal, the MBT difference, which is the absolute value of the difference between the TA system MBT torque and the required system MBT torque, is used. For example, it is also conceivable to calculate the load factor (hereinafter referred to as the required system MBT torque) based on the required system MBT torque and determine the TA system load factor based on the difference between the TA system load factor and the required system load factor. However, in this case, torque cannot be used as the threshold for determining whether the difference in the load factor is normal or abnormal. As will be described in detail later, the torque threshold used for comparison with the MBT difference is also used during the TA system preliminary determination and the required system preliminary determination. By using a common torque threshold for the load factor determination, the TA system preliminary determination, and the required system preliminary determination in this way, the calculation load on the ECU 100 can be reduced.

[0060] Next, the TA system preliminary determination control will be described. FIG. 10 is a flowchart showing an example of the TA system preliminary determination control. The ECU 100 determines whether the TA system load factor is determined to be normal and whether the TA system difference is equal to or greater than the torque threshold (step S62b). The torque threshold here uses the threshold set in step S41b. If the answer is Yes in step S62b, the ECU 100 increments the time counter (step S63b). The time counter is a time counter for the TA system preliminary determination, which is different from the time counter in step S43b. Next, the ECU 100 determines whether this time counter is equal to or greater than the time threshold (step S65b). The time threshold here uses the threshold set in step S44b.

[0061] When the answer is Yes in step S65b, the ECU 100 tentatively determines that the Ga-axis torque is in an abnormal state where it is too small compared to the TA-axis torque (step S66b). When the answer is No in step S65b, the ECU 100 tentatively determines that the Ga-axis torque is normal (step S67b). Also, when the answer is No in step S62b, the ECU 100 clears the time counter to zero (step S68b) and tentatively determines that the Ga-axis torque is normal (step S67b). That is, when the state where the TA-axis load factor is normal and the TA-axis difference is equal to or greater than the torque threshold continues for a time threshold or more, the Ga-axis torque is tentatively determined to be in an abnormal state.

[0062] Next, the requested system tentative determination control will be described. FIG. 11 is a flowchart showing an example of the requested system tentative determination control. The ECU 100 determines whether the TA-axis load factor is determined to be abnormal and whether the requested system difference is equal to or greater than the torque threshold (step S72b). The torque threshold here uses the threshold set in step S41b. When the answer is Yes in step S72b, the ECU 100 increments the time counter (step S73b). The time counter here is a time counter for requested system tentative determination, which is different from the time counters in steps S43b and S63b. Next, the ECU 100 determines whether this time counter is equal to or greater than the time threshold (step S75b). The time threshold here uses the threshold set in step S44b.

[0063] When the answer is Yes in step S75b, the ECU 100 tentatively determines that the Ga-axis torque is in an abnormal state where it is too small compared to the requested system axis torque (step S76b). When the answer is No in step S75b, the ECU 100 tentatively determines that the Ga-axis torque is normal (step S77b). Also, when the answer is No in step S72b, the ECU 100 clears the time counter to zero (step S78b) and tentatively determines that the Ga-axis torque is normal (step S77b). That is, when the state where the TA-axis load factor is abnormal and the requested system difference is equal to or greater than the torque threshold continues for a time threshold or more, the Ga-axis torque is tentatively determined to be abnormal.

[0064] Next, the present determination control will be described. FIG. 12 is a flowchart showing an example of the present determination control. The ECU 100 determines whether or not the Ga-axis torque is tentatively determined to be in an abnormal state in step S66b or S76b (step S81). If Yes in step S81, the ECU 100 makes the determination that the Ga-axis torque is in an abnormal state (step S82). If No in step S81, the ECU 100 makes the determination that the Ga-axis torque is normal (step S83).

[0065] As described above, when the TA system load factor is normal, the abnormal state of the Ga-axis torque is determined based on the TA system difference, and when the TA system load factor is abnormal, the abnormal state of the Ga-axis torque is determined based on the required system difference. Therefore, even when the TA system load factor is abnormal and the reliability of the TA system difference is impaired, the abnormal state of the Ga-axis torque can be accurately determined based on the required system difference.

[0066] Also, as shown in FIG. 8, the required axis torque is calculated (step S50b) before the TA system tentative determination (step S60b) is executed. Therefore, even when the TA system load factor is abnormal, the required system difference can be immediately calculated (step S70a), and the required system tentative determination can be executed based on this (steps S70b, S72b). Thereby, even when the TA system load factor is abnormal, it is possible to suppress the lengthening of the period until the present determination is executed.

[0067] Next, the required system MBT torque calculation control will be described. FIG. 13A is a flowchart showing an example of the required system MBT torque calculation control. The ECU 100 calculates the required engine torque (step S31b). The required engine torque is calculated by adding the pump loss torque and the friction / auxiliary load torque to the required axis torque to the engine 10. The required axis torque is calculated by the ECU 100 based on the accelerator opening. The calculation of the pump loss torque and the friction / auxiliary load torque is the same as the calculation method in step S36 in the present embodiment described above.

[0068] Next, the ECU 100 calculates the required system MBT torque based on the required engine torque (step S32b). Specifically, the required MBT torque is calculated by multiplying the post-idle required MBT torque by the injection cylinder ratio. The injection cylinder ratio is calculated by the same method as in step S32 of the present embodiment described above. The post-idle required MBT torque is calculated by performing an idle process based on the idle time and the temporary delay time constant on the value obtained by dividing the required engine torque by the required efficiency.

[0069] Next, the required system shaft torque calculation control will be described. FIG. 13B is a flowchart showing an example of the required system shaft torque calculation control. The ECU 100 calculates a load ratio based on the required system MBT torque (hereinafter referred to as the required system load ratio) (step S53b). Here, since the required system MBT torque is calculated based on the required shaft torque as described above, it can be said that the required system shaft torque is calculated based on the required shaft torque. The required system load ratio is calculated by referring to a map that defines the required system MBT torque, the engine speed, and the required system load ratio. This map is stored in the ROM of the ECU 100 in advance. The required system load ratio is an example of the second load ratio.

[0070] Next, the ECU 100 calculates a torque efficiency based on the required system load ratio (hereinafter referred to as the required system torque efficiency) (step S54b). The required system torque efficiency is calculated by referring to a map that defines the ignition timing retard amount, the required system load ratio, the engine speed, and the required system torque efficiency. This map is stored in the ROM of the ECU 100 in advance. The ignition timing retard amount is calculated by subtracting the required system MBT ignition timing from the required ignition timing. The required system MBT ignition timing is calculated by referring to a map that defines the required system load ratio, the engine speed, and the base MBT ignition timing to calculate the base MBT ignition timing, and adding various ignition timing correction amounts to the base MBT ignition timing. This map is stored in the ROM of the ECU 100 in advance. The various ignition timing correction amounts are the same as the processing in step S34 of the present embodiment described above.

[0071] Next, the ECU 100 calculates a target indicated torque (hereinafter referred to as the target indicated torque for the demand system) based on the demand system MBT torque and the demand system torque efficiency (step S55b). The TA system indicated torque is calculated by multiplying the demand system MBT torque by the demand system torque efficiency.

[0072] Next, the ECU 100 calculates the demand system shaft torque (step S56b). The demand system shaft torque is calculated by subtracting the pump loss torque and the friction / accessory load torque from the demand system indicated torque. The pump loss torque and the friction / accessory load torque are calculated by the same method as in step S36 described above.

[0073] In the above-described embodiments and modifications, the shaft torque has been described as an example of the first to third estimated values, but the present invention is not limited thereto. For example, the first to third estimated values may be indicated torque or MBT torque.

[0074] In the above-described embodiments and modifications, the engine 10 not provided with a supercharger has been described as an example, but the present invention is not limited thereto, and an engine provided with a supercharger may be used. In this case, the intake air pressure described in the above embodiment is the pressure in the intake passage on the downstream side of the compressor of the supercharger and on the upstream side of the throttle valve, which corresponds to the so-called supercharged pressure.

[0075] In the above-described embodiments and modifications, the case where a hybrid vehicle is controlled by a single ECU 100 has been illustrated, but the present invention is not limited thereto. For example, when a plurality of ECUs such as an engine ECU that controls the engine 10 and a motor ECU that controls the motor 15 are provided, the above-described control may be executed by the engine ECU.

[0076] In the above-described embodiments and modified examples, the hybrid vehicle 1 has been described as an example, but the present invention is not limited thereto. For example, an engine vehicle provided only with an engine as a driving power source may be used. Further, a device equipped with an engine other than a vehicle may be used. This is because, even in the case of a device other than a vehicle, if the Ga system shaft torque becomes too small exceeding the allowable error with respect to the actual engine shaft torque, it may affect the control based on the Ga system shaft torque.

[0077] As described above in detail with respect to the embodiments of the present invention, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0078] 1 Hybrid vehicle (vehicle) 10 Engine 40 Throttle valve 100 ECU (Torque abnormality determination device, First calculation unit, Second calculation unit, Third calculation unit, Torque determination unit, Load factor determination unit)

Claims

1. a first calculation unit that calculates a first estimated value of the torque of the engine; a second calculation unit that calculates a second estimated value of the torque by a method different from the method for calculating the first estimated value; a torque determination unit that determines whether the first estimated value is normal or in an abnormal state where the first estimated value is too small with respect to the second estimated value based on a difference between the first estimated value and the second estimated value; the first calculation unit calculates the first estimated value based on an intake air amount of the engine; the second calculation unit calculates the second estimated value based on a throttle opening degree of the engine; the second calculation unit calculates a first load factor of the engine based on the throttle opening degree, and calculates the second estimated value based on the first load factor, a torque abnormality determination device.

2. comprising a load factor determination unit that determines whether the first load factor calculated based on the throttle opening degree is normal or abnormal; when the first load factor is determined to be normal by the load factor determination unit, the torque determination unit determines whether the first estimated value is normal or in an abnormal state where the first estimated value is too small with respect to the second estimated value based on a difference between the first estimated value and the second estimated value, the torque abnormality determination device according to Claim 1.

3. comprising a third calculation unit that calculates a third estimated value of the torque by a method different from the first and second estimated values; when the first load factor is determined to be abnormal by the load factor determination unit, the torque determination unit determines whether the first estimated value is normal or in an abnormal state where the first estimated value is too small with respect to the third estimated value based on a difference between the first estimated value and the third estimated value, the torque abnormality determination device according to Claim 2.

4. the third calculation unit calculates a second load factor of the engine based on a required shaft torque to the engine, and calculates the third estimated value based on the second load factor; the load factor determination unit determines whether the first load factor is normal or abnormal based on a difference between the torque calculated based on the first load factor and the torque calculated based on the second load factor, the torque abnormality determination device according to Claim 3.

5. A torque abnormality determination device according to any one of Claims 1 to 4, and a hybrid vehicle comprising a motor that outputs an assist torque for assisting the torque of the engine based on the first estimated value.

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