Drive unit

Abstract

To improve the accuracy in diagnosing variations in air-fuel ratio among cylinders of a multi-cylinder engine.SOLUTION: A first control device for controlling an engine transmits a counter, which switches every time an engine crank angle rotates a predetermined angle, to a second control device, and each time the counter switches, calculates a rotational angular velocity based on the engine crank angle and calculates engine inertia torque based on the rotational angular velocity. The second control device, which controls a motor connected to the engine via a torsion element, calculates the rotational angular velocity based on a rotational position of a rotor of the motor each time the counter switches, calculates resonance influence torque on an output side of the torsion element based on the rotational angular velocity and transmits the calculated resonance influence torque to the first control device. The first control device calculates, as an output torque of the engine, a sum of the inertia torque and the resonance influence torque when the counters have the same value, and performs a diagnosis process for variations in air-fuel ratios among cylinders based on amounts of changes in the output torque.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a drive device. [Background technology]

[0002] Conventionally, as this type of drive device, one that executes a diagnostic process for the variation in the air-fuel ratio between cylinders based on a change in the rotation speed of a multi-cylinder engine has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5136718 Summary of the Invention [Problem to be solved by the invention]

[0004] When an engine crankshaft is connected to a motor via a torsion element, the resonance-affected torque on the output side of the torsion element due to torsional resonance of the torsion element can affect fluctuations in engine speed and torque, so it is necessary to calculate engine speed and torque while eliminating the effects of torsion resonance.When a first control device that controls the engine receives information on the torsion angle of the torsion element from a motor control device via communication and calculates the torsional resonance component, the effects of communication delays can reduce the accuracy of calculating the torsional resonance component, reducing the accuracy of calculating engine speed and torque and potentially reducing the accuracy of diagnosing variations in air-fuel ratio between cylinders.

[0005] The main object of the drive device of the present disclosure is to improve the accuracy of diagnosing variations in air-fuel ratio between cylinders of a multi-cylinder engine. [Means for solving the problem]

[0006] The driving device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The drive device of the present disclosure comprises: A drive device comprising: a multi-cylinder engine; a motor; a torsion element having an input side connected to a crankshaft of the engine and an output side connected to a rotor of the motor; a first sensor that detects a crank angle of the crankshaft; a second sensor that detects a rotational position of the rotor; a first control device that controls the engine based on the crank angle; and a second control device that controls the motor based on the rotational position, the first control device transmits to the second control device a counter that is switched every time the crank angle rotates by a predetermined angle, and calculates a rotational angular velocity of the engine based on the crank angle and calculates an inertia torque of the engine based on the rotational angular velocity of the engine every time the counter is switched; the second control device calculates a rotational angular velocity of the motor based on the rotational position and a resonance-affected torque on the output side of the torsion element based on torsional resonance of the torsion element based on the rotational angular velocity of the motor each time the counter is switched, and transmits the calculated torque to the first control device; the first control device calculates the sum of the inertia torque and the resonance influence torque when the counters have the same value as each other as the output torque of the engine, and performs a diagnosis process for the variation in the air-fuel ratio between the cylinders based on the amount of change in the output torque. The gist of this is as follows.

[0008] In the drive system of the present disclosure, the first control device transmits a counter that switches every time the crank angle rotates by a predetermined angle to the second control device, and calculates the engine rotational angular velocity based on the crank angle and the engine inertia torque based on the engine rotational angular velocity each time the counter switches. The second control device calculates the motor rotational angular velocity based on the rotational position each time the counter switches, and calculates the resonance-affected torque on the output side of the torsion element based on the torsional resonance of the torsion element based on the motor rotational angular velocity, and transmits the calculated value to the first control device. The first control device calculates the sum of the inertia torque and the resonance-affected torque when the counters have the same value as each other as the engine output torque, and performs a diagnostic process for the air-fuel ratio variation between cylinders based on the change in the output torque. Therefore, since the engine output torque is calculated using the synchronized inertia torque and the resonance-affected torque, the accuracy of calculating the engine output torque can be improved. Then, by performing a diagnostic process for the air-fuel ratio variation between cylinders based on the change in the engine output torque, the accuracy of diagnosing the air-fuel ratio variation between cylinders can be improved. Here, in the case of a four-cylinder engine, the amount of change in engine output torque may be calculated as the amount of change in output torque when the crankshaft rotates by 180 degrees or 360 degrees.

[0009] In the drive system of the present disclosure, the first control device may execute a process for diagnosing a lean imbalance in the air-fuel ratio between the cylinders based on an amount of change in the output torque.

[0010] In the drive device of the present disclosure, the counter may be transmitted from the first control device to the second control device via a dedicated communication line. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a hybrid vehicle 20 equipped with a drive device according to the present embodiment. [Figure 2] 4 is an explanatory diagram for explaining the calculation process of the output torque Te of the engine 22. FIG. [Figure 3] 4 is a flowchart showing an example of a lean imbalance diagnosis process executed by an engine ECU 24. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram of a hybrid vehicle 20 equipped with a drive system according to the present embodiment. As shown in the figure, the hybrid vehicle 20 according to the present embodiment includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 24, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a motor electronic control unit (hereinafter referred to as "motor ECU") 40, a battery 50, a battery electronic control unit (hereinafter referred to as "battery ECU") 52, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70. The engine ECU 24, the motor ECU 40, the battery ECU 52, and the HVECU 70 are capable of communicating with each other via a shared communication line (CAN bus) 90, and further, the engine ECU 24 and the motor ECU 40 are capable of communicating with each other via a dedicated communication line (local bus) 92. It should be noted that communication delays in communication via the dedicated communication line 92 are sufficiently suppressed compared to communication via the shared communication line 90 .

[0013] The engine 22 is configured as a four-cylinder internal combustion engine that outputs power using fuel such as gasoline or diesel, and its operation is controlled by the engine ECU 24. The crankshaft 23 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28 and a carrier shaft 32. The damper 28 has an input element connected to the crankshaft 23, an output element connected to the carrier shaft 32, and a plurality of elastic bodies (springs) arranged between the input element and the output element.

[0014] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The engine ECU 24 receives signals from various sensors required for controlling the operation of the engine 22 via an input port. For example, the engine ECU 24 receives a crank angle θcr of the engine 22 from a crank position sensor 23a that detects the rotational position of a crankshaft 23 of the engine 22. The engine ECU 24 outputs various control signals for controlling the operation of the engine 22 via an output port. For example, the engine ECU 24 outputs control signals to a throttle valve, a fuel injection valve, a spark plug, and the like. The engine ECU 24 calculates the rotation speed Ne and rotational angular velocity ωe of the engine 22 (crankshaft 23) based on the crank angle θcr of the engine 22.

[0015] The planetary gear 30 is configured as a single-pinion planetary gear mechanism and includes a sun gear (externally toothed gear), a ring gear (internal toothed gear), multiple pinion gears meshing with the sun gear and the ring gear, and a carrier supporting the multiple pinion gears so that they can rotate and revolve. The sun gear is connected to the rotor of the motor MG1 via a sun gear shaft 31. The ring gear is connected to a drive shaft 37 that is connected to drive wheels 39a, 39b via a differential gear 38. As described above, the carrier is connected to the crankshaft 23 of the engine 22 via the carrier shaft 32 and the damper 28.

[0016] The motor MG1 is configured as, for example, a synchronous generator motor, and the rotor of the motor MG1 is connected to the sun gear of the planetary gear 30 via the sun gear shaft 31 as described above. The motor MG2 is configured as, for example, a synchronous generator motor, and the rotor of the motor MG2 is connected to the drive shaft 37. The inverters 41 and 42 are used to drive the motors MG1 and MG2, and are connected to the battery 50 via a power line 54. The motors MG1 and MG2 are rotationally driven by the motor ECU 40 controlling the switching of multiple switching elements of the inverters 41 and 42.

[0017] The motor ECU 40 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The motor ECU 40 receives signals from various sensors required for driving and controlling the motors MG1 and MG2 via input ports. For example, the motor ECU 40 receives rotational positions θm1 and θm2 from rotational position sensors 43a and 44a, which detect the rotational positions of the rotors of the motors MG1 and MG2, and phase currents Iu, 1v1, Iu2, and Iv2 from current sensors 43u, 43v, 44u, and 44v, which detect the phase currents of the respective phases of the motors MG1 and MG2. The motor ECU 40 outputs control signals to the inverters 41 and 42 via output ports. The motor ECU 40 calculates the rotational speeds Nm1 and Nm2 and rotational angular velocities ωm1 and ωm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2.

[0018] The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery, and as described above, is connected to the inverters 41, 42 via the power line 54. The battery 50 is managed by the battery ECU 52.

[0019] The battery ECU 52 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The battery ECU 52 receives signals from various sensors required for managing the battery 50 via the input port. For example, the battery ECU 52 receives a voltage Vb from a voltage sensor attached between the terminals of the battery 50, a current Ib from a current sensor attached to the output terminals of the battery 50, and a temperature Tb from a temperature sensor attached to the battery 50. The battery ECU 52 calculates the state of charge (SOC) of the battery 50 based on the integrated value of the current Ib of the battery 50.

[0020] The HVECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The HVECU 70 receives signals from various sensors via the input ports. For example, the HVECU 70 receives a start signal from a start switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the depression amount of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the depression amount of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87.

[0021] In the embodiment, the engine 22, the motor MG1, the damper 28, the crank position sensor 23a, the rotational position sensor 43a, the engine ECU 24, and the motor ECU 40 mainly correspond to the "drive device."

[0022] In the hybrid vehicle 20 of this embodiment, the engine 22 and the motors MG1 and MG2 are controlled to travel in a hybrid driving mode (HV driving mode) or an electric driving mode (EV driving mode) through cooperative control between the HVECU 70, the engine ECU 24, and the motor ECU 40. The HV driving mode is a mode in which the vehicle travels with the engine 22 operating, and the EV driving mode is a mode in which the vehicle travels with the engine 22 stopped.

[0023] In the HV traveling mode, the HVECU 70 first sets the required torque Tr* required for traveling (required of the drive shaft 37) based on the accelerator pedal position Acc and the vehicle speed V, and then calculates the required power Pr* required for traveling by multiplying the set required torque Tr* by the drive shaft rotation speed Nd (motor MG2 rotation speed Nm2). Next, the HVECU 70 calculates the target power Pe* for the engine 22 by subtracting the battery 50's required charging / discharging power Pb* (a positive value when discharging from the battery 50) from the required power Pr*. Then, the HVECU 70 sets the target rotation speed Ne* and target torque Te* for the engine 22 and the torque commands Tm1* and Tm2* for the motors MG1 and MG2 so that the calculated target power Pe* is output from the engine 22 and the required torque Tr* is output to the drive shaft 37. The HVECU 70 then transmits the target rotation speed Ne* and target torque Te* for the engine 22 to the engine ECU 24, and transmits the torque commands Tm1* and Tm2* for the motors MG1 and MG2 to the motor ECU 40. The engine ECU 24 performs operation control (intake air amount control, fuel injection control, ignition control, etc.) of the engine 22 so that the engine 22 operates based on the target rotation speed Ne* and the target torque Te*. The motor ECU 40 performs switching control of multiple switching elements of the inverters 41, 42 so that the motors MG1, MG2 are driven by the torque commands Tm1*, Tm2*.

[0024] In the EV driving mode, the HVECU 70 sets the required torque Tr* in the same manner as in the HV driving mode, sets the torque command Tm1* of the motor MG1 to the value 0, and sets the torque command Tm2* of the motor MG2 so that the required torque Tr* is output to the drive shaft 37. The torque commands Tm1* and Tm2* of the motors MG1 and MG2 are sent to the motor ECU 40. The control of the inverters 41 and 42 by the motor ECU 40 has been described above.

[0025] Next, we will explain the operation of the hybrid vehicle 20 of this embodiment, particularly the calculation process of the output torque Te of the engine 22 and the diagnosis process of lean imbalance of the engine 22. Lean imbalance means that the fuel injection amount of some cylinders of the engine 22 is less than the fuel injection amount of other cylinders (the air-fuel ratio of some cylinders is leaner than the air-fuel ratio of other cylinders).

[0026] The following describes the calculation process of the output torque Te of the engine 22. Fig. 2 is an explanatory diagram for explaining the calculation process of the output torque Te of the engine 22. The engine ECU 24 and the motor ECU 40 are capable of communicating with each other via a shared communication line 90 and a dedicated communication line 92.

[0027] The processing of the motor ECU 40 will now be described. The motor ECU 40 executes a motor torque calculation process M21, a motor rotation speed calculation process M22, a motor rotation angular velocity calculation process M23, a carrier shaft rotation angular velocity calculation process M24, and a resonance influence torque calculation process M25. In this embodiment, each of the processes M21 to M25 is executed each time the crank counter Ccr is switched. The crank counter Ccr, as will be described in detail later, is set by the engine ECU 24 and transmitted to the motor ECU 40 via the dedicated communication line 92. In the following description, [Ccr] means a value corresponding to the crank counter Ccr. Note that [Ccr] is not shown in FIG. 2.

[0028] The motor torque calculation process M21 is a process for calculating the output torque Tm1 [Ccr] of the motor MG1. The motor ECU 40 uses the rotational position θm1 of the rotor of the motor MG1 from the rotational position sensor 43a to perform coordinate transformation (three-phase to two-phase transformation) on the U-phase and V-phase currents Iu and Iv of the motor MG1 from the current sensors 43u and 43v into d-axis and q-axis currents Id and Iq, and calculates the output torque Tm1 [Ccr] of the motor MG1 based on the obtained d-axis and q-axis currents Id and Iq.

[0029] The motor rotation speed calculation process M22 is a process for calculating the rotation speeds Nm1 [Ccr] and Nm2 [Ccr] of the motors MG1 and MG2. The motor ECU 40 calculates the rotation speeds Nm1 [Ccr] and Nm2 [Ccr] of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position sensors 43a and 44a.

[0030] The motor rotational angular velocity calculation process M23 is a process for calculating the rotational angular velocity ωm1 [Ccr] of the motor MG1. The motor ECU 40 converts the rotational speed Nm1 [Ccr] of the motor MG1 calculated in the motor rotational speed calculation process M22 into the rotational angular velocity ωm1 [Ccr] of the motor MG1.

[0031] Carrier shaft rotational angular velocity calculation process M24 is a process for calculating the rotational angular velocity ωm1 [Ccr] of the carrier shaft 32. The motor ECU 40 calculates the rotational speed Nc [Ccr] of the carrier shaft 32 according to equation (1) using the rotational speeds Nm1 [Ccr] and Nm2 [Ccr] of the motors MG1 and MG2 calculated in the motor rotational speed calculation process M22, and converts the calculated rotational speed Nc [Ccr] into the rotational angular velocity ωc [Ccr]. In equation (1), "ρ" is the gear ratio of the planetary gear 30 (number of teeth of the sun gear / number of teeth of the ring gear).

[0032] Nc[Ccr]=(ρ·Nm1[Ccr]+Nm2[Ccr]) / (1+ρ) (1)

[0033] The resonance influence torque calculation process M25 calculates the resonance influence torque Tdmp [Ccr], which is the torque of the carrier shaft 32 based on the torsional resonance of the damper 28, and transmits it to the engine ECU 24. In the hybrid vehicle 20, the crankshaft 23 of the engine 22 is connected to the carrier shaft 32 via the damper 28. Therefore, the torque of the carrier shaft 32 based on the torsional resonance of the damper 28 (resonance influence torque Tdmp) can affect fluctuations in the rotation speed and torque of the engine 22. The motor ECU 40 calculates the resonance influence torque Tdmp[Ccr] according to equation (2) using the output torque Tm1[Ccr] of the motor MG1 calculated in the motor torque calculation process M21, the rotational angular velocity ωm1[Ccr] of the motor MG1 calculated in the motor rotational angular velocity calculation process M23, and the rotational angular velocity ωc[Ccr] of the carrier shaft 32 calculated in the carrier shaft rotational angular velocity calculation process M24, and transmits the calculated resonance influence torque Tdmp[Ccr] to the engine ECU 24 via the shared communication line 90. In equation (2), "Ic" is the moment of inertia of the carrier shaft 32, and "Im1" is the moment of inertia of the motor MG1. Equation (2) can be derived from equation (3), which shows the torque relationship of the sun gear shaft 31.

[0034] Tdmp[Ccr]=Ic·dωc[Ccr] / dt+(1+ρ) / ρ·(Im1·dωm1[Ccr] / dt-Tm1[Ccr]) (2) ρ / (1+ρ)·Ic·dωc+Im1·dωm1 / dt=Tm1+ρ / (1+ρ)·Tdmp (3)

[0035] Next, a description will be given of the processing of the engine ECU 24. The engine ECU 24 executes crank counter update processing M11, engine rotation angular velocity calculation processing M12, inertia torque calculation processing M13, and engine torque calculation processing M14. In this embodiment, each of the processing M12 to M13 is executed every time the crank counter Ccr is switched.

[0036] The crank counter update process M11 is a process for updating the crank counter Ccr. The engine ECU 24 counts up the crank counter Ccr every time the crank angle θcr of the crankshaft 23 of the engine 22, which is detected by the crank position sensor 23a, rotates by a predetermined angle (e.g., 30 degrees, 45 degrees, etc.), and resets the crank counter Ccr to a value of 0 every time the engine 22 completes one cycle (two rotations).

[0037] The engine rotational angular velocity calculation process M12 is a process for calculating the rotational angular velocity ωe[Ccr] of the engine 22. The engine ECU 24 calculates the rotational speed Ne[Ccr] of the engine 22 based on the crank angle θcr of the crankshaft 23 of the engine 22 from the crank position sensor 23a, and converts the calculated rotational speed Ne[Ccr] into the rotational angular velocity ωe[Ccr] of the engine 22.

[0038] The inertia torque calculation process M13 is a process for calculating the inertia torque Tei [Ccr] of the engine 22. The engine ECU 24 calculates the inertia torque Tei [Ccr] of the engine 22 according to equation (4) using the rotational angular velocity ωe [Ccr] of the engine 22 calculated in the engine rotational angular velocity calculation process M12. In equation (4), "Ie" is the moment of inertia of the engine 22. Equation (4) can be derived from equation (5) which shows the relationship of the torque of the crankshaft 23.

[0039] Tei=Ie·dωe / dt (4) Ie·dωe / dt=Te-Tdmp=Tei (5)

[0040] The engine torque calculation process M14 is a process for calculating the output torque Te[Ccr] of the engine 22. The engine ECU 24 selects the inertia torque Tei[Ccr] and the resonance influence torque Tdmp[Ccr] when the crank counter Ccr has the same value (for example, the latest value) from the inertia torque Tei[Ccr] of the engine 22 for each crank counter Ccr calculated in the inertia torque calculation process M13 and the resonance influence torque Tdmp[Ccr] for each crank counter Ccr received from the motor ECU 40, and calculates the sum of the two as the output torque Te[Ccr] of the engine 22.

[0041] In this way, by calculating the sum of the inertia torque Tei of the synchronized engine 22 and the resonance influence torque Tdmp as the output torque Te of the engine 22, the calculation accuracy of the output torque Te of the engine 22 can be improved.

[0042] Furthermore, since the crank counter Ccr is transmitted from the engine ECU 24 to the motor ECU 40 via the dedicated communication line 92, the discrepancy between the execution timing of each process M12 to M13 by the engine ECU 24 (the timing of obtaining the crank angle θcr) and the execution timing of each process M21 to M25 by the motor ECU 40 (the timing of obtaining the phase currents Iu1, Iv1 of motor MG1 and the rotational positions θm1, θm2 of the rotors of motors MG1, MG2) can be reduced compared to when the crank counter Ccr is transmitted via the shared communication line 90.

[0043] Furthermore, the resonance influence torque Tdmp is calculated by the motor ECU 40, and this resonance influence torque Tdmp is used to calculate the output torque Te of the engine 22, so that the influence of the tolerance of the damper 28 can be appropriately eliminated.

[0044] Next, a description will be given of the lean imbalance diagnosis process for the engine 22. Fig. 3 is a flowchart showing an example of the lean imbalance diagnosis process executed by the engine ECU 24. This routine is executed repeatedly.

[0045] When the lean imbalance diagnosis process of FIG. 3 is executed, the engine ECU 24 first inputs the latest output torque Te0, which is the output torque Te of the engine 22 most recently calculated, and the 180 degree previous output torque Te1, which is the output torque Te of the engine 22 calculated 180 degrees prior in terms of the rotation angle of the crankshaft 23 (step S100).

[0046] Next, the output torque change amount ΔTe is calculated by subtracting the 180-degree-previous output torque Te1 from the latest output torque Te0 (step S110), and the calculated output torque change amount ΔTe is compared with a negative threshold ΔTeref (step S120). Here, the threshold ΔTeref is a threshold used to determine whether a lean imbalance occurs in the engine 22, specifically, whether the fuel injection amount of the target cylinder (the cylinder experiencing explosive combustion at that time) corresponding to the latest output torque Te0 is smaller than the fuel injection amount of the other cylinder (the cylinder experiencing explosive combustion one cylinder before that) (i.e., whether the air-fuel ratio of the target cylinder is leaner than the air-fuel ratio of the other cylinder). The process of step S120 takes into account the fact that the latest output torque Te0 becomes somewhat smaller than the 180-degree-previous output torque Te1 when the fuel injection amount of the target cylinder is smaller than the fuel injection amounts of the other cylinders.

[0047] If the output torque change amount ΔTe is equal to or greater than the threshold value ΔTeref in step S120, it is determined that the fuel injection amount of the target cylinder is not smaller than the fuel injection amount of the other cylinder (the cylinder that experienced explosive combustion immediately before), and this routine is terminated.

[0048] If the output torque change amount ΔTe is less than the threshold value ΔTeref in step S120, it is determined that the fuel injection amount of the target cylinder is less than the fuel injection amount of the other cylinder (the cylinder that experienced explosive combustion immediately before), and it is determined that a lean imbalance has occurred in the engine 22 (step S130), and this routine is terminated.

[0049] As described above, the accuracy of calculating the output torque Te of the engine 22 can be improved, and by using this output torque Te, the accuracy of diagnosing the lean imbalance of the engine 22 can be improved.

[0050] In the drive device mounted on the hybrid vehicle 20 of this embodiment described above, the engine ECU 24 transmits the crank counter Ccr, which changes every time the crank angle θcr rotates by a predetermined angle, from the crank position sensor 23a to the motor ECU 40, and calculates the rotational angular velocity ωe[Ccr] of the engine 22 based on the crank angle θcr every time the crank counter Ccr changes, and calculates the inertia torque Te[Ccr] of the engine 22 based on the calculated rotational angular velocity ωe[Ccr]. Each time the crank counter Ccr from the engine ECU 24 switches, the motor ECU 40 calculates the output torque Tm1[Ccr] of the motor MG1 based on the phase currents Iu1, Iv1 of the U phase and V phase of the motor MG1 from the current sensors 43u, 43v and the rotational position θm1 of the rotor of the motor MG1 from the rotational position sensor 43a, and also calculates the rotational angular velocity ωm1[Ccr] of the motor MG1 based on the rotational position θm1, and calculates the resonance influence torque Tdmp[Ccr] based on the calculated output torque Tm1[Ccr] and rotational angular velocity ωm1[Ccr] and transmits it to the engine ECU 24. The engine ECU 24 selects the inertia torque Tei [Ccr] and the resonance influence torque Tdmp [Ccr] when the crank counter Ccr has the same value from the inertia torque Tei [Ccr] of the engine 22 for each crank counter Ccr and the resonance influence torque Tdmp [Ccr] for each crank counter Ccr, and calculates the sum of the two as the output torque Te [Ccr] of the engine 22. In this way, by calculating the sum of the inertia torque Tei and the resonance influence torque Tdmp of the synchronized engine 22 as the output torque Te of the engine 22, the calculation accuracy of the output torque Te of the engine 22 can be improved.

[0051] Then, the drive device calculates the output torque change amount ΔTe by subtracting the 180-degree-before output torque Te1 from the latest output torque Te0, and uses the calculated output torque change amount ΔTe to execute the process of diagnosing the lean imbalance of the engine 22. This makes it possible to improve the accuracy of diagnosing the lean imbalance of the engine 22.

[0052] In the above-described embodiment, the motor ECU 40 calculates the resonance-influencing torque Tdmp[Ccr] according to the above-described equation (2) using the output torque Tm1[Ccr] of the motor MG1, the rotational angular velocity ωm1[Ccr] of the motor MG1, and the rotational angular velocity ωc[Ccr] of the carrier shaft 32. However, the resonance-influencing torque Tdmp[Ccr] may be calculated without using the rotational angular velocity ωc[Ccr] of the carrier shaft 32, that is, without using the first term on the right-hand side of equation (2).

[0053] In the above-described embodiment, the engine ECU 24 calculates the output torque change amount ΔTe by subtracting the 180-degree-ago output torque Te1 from the latest output torque Te0. However, this is not limited to this, and for example, the engine ECU 24 may calculate the output torque change amount ΔTe by subtracting the 360-degree-ago output torque Te2, which is the output torque Te of the engine 22 calculated 360 degrees ago in terms of the rotation angle of the crankshaft 23, from the latest output torque Te0.

[0054] In the above-described embodiment, the engine ECU 24 performs lean imbalance diagnosis processing by comparing the output torque change amount ΔTe with a negative threshold value ΔTeref to determine whether the fuel injection amount of the target cylinder is smaller than the fuel injection amount of the other cylinders (i.e., whether the air-fuel ratio of the target cylinder is leaner than the air-fuel ratios of the other cylinders). However, instead of or in addition to this, the engine ECU 24 may perform rich imbalance diagnosis processing by comparing the output torque change amount ΔTe with a positive threshold value ΔTeref2 to determine whether the fuel injection amount of the target cylinder is larger than the fuel injection amount of the other cylinders (i.e., whether the air-fuel ratio of the target cylinder is richer than the air-fuel ratios of the other cylinders).

[0055] In the above-described embodiment, a four-cylinder engine is used as the engine 22. However, a six-cylinder or eight-cylinder engine may also be used. When a six-cylinder engine is used, it is conceivable to perform the lean imbalance diagnostic process or the rich imbalance diagnostic process using the amount of change in the output torque Te of the engine 22 when the crankshaft 23 rotates 120 degrees, 240 degrees, or 360 degrees.

[0056] In the above-described embodiment, the drive device is mounted on the hybrid vehicle 20, and is configured such that the crankshaft 23 of the engine 22 and the carrier shaft 32 connected to the carrier of the planetary gear 30 are connected via the damper 28, and the rotor of the motor MG1 is connected to the sun gear shaft 31 connected to the sun gear of the planetary gear 30. However, the present invention is not limited to this, and any drive device configuration may be used as long as the crankshaft of the engine and the rotor of the motor are connected via a torsion element.

[0057] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the engine 22 corresponds to the "engine," the motor MG1 corresponds to the "motor," the damper 28 corresponds to the "torsion element," the crank position sensor 23a corresponds to the "first sensor," the rotational position sensor 43a corresponds to the "second sensor," the engine ECU 24 corresponds to the "first control device," and the motor ECU 40 corresponds to the "second control device."

[0058] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0059] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments and can, of course, be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0060] The present disclosure is applicable to industries such as the drive device manufacturing industry. [Explanation of symbols]

[0061] 20 hybrid vehicle, 22 engine, 23 crankshaft, 23a crank position sensor, 24 engine ECU, 28 damper, 30 planetary gear, 31 sun gear shaft, 32 carrier shaft, 37 drive shaft, 38 differential gear, 39a, 39b drive wheels, 40 motor ECU, 41, 42 inverter, 43a, 44a rotational position sensor, 43u, 43v, 44u, 44v current sensor, 50 battery, 52 battery ECU, 54 power line, 70 HVECU, 80 start switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 87 vehicle speed sensor, 90 shared communication line, 92 dedicated communication line.

Claims

1. A drive device comprising: a multi-cylinder engine; a motor; a torsion element having an input side connected to a crankshaft of the engine and an output side connected to a rotor of the motor; a first sensor that detects a crank angle of the crankshaft; a second sensor that detects a rotational position of the rotor; a first control device that controls the engine based on the crank angle; and a second control device that controls the motor based on the rotational position, the first control device transmits to the second control device a counter that is switched every time the crank angle rotates by a predetermined angle, and calculates a rotational angular velocity of the engine based on the crank angle and an inertia torque of the engine based on the rotational angular velocity of the engine every time the counter is switched; the second control device calculates a rotational angular velocity of the motor based on the rotational position and a resonance-affected torque on the output side of the torsion element based on torsional resonance of the torsion element based on the rotational angular velocity of the motor each time the counter is switched, and transmits the calculated torque to the first control device; the first control device calculates the sum of the inertia torque and the resonance influence torque when the counters have the same value as each other as an output torque of the engine, and performs a diagnosis process for a variation in air-fuel ratio between cylinders based on a change amount of the output torque; the first control device executes a diagnostic process for a lean imbalance in the air-fuel ratio among the cylinders based on the amount of change in the output torque. Drive unit.

2. 2. The drive device according to claim 1, The counter is transmitted from the first control device to the second control device via a dedicated communication line. Drive unit.

Images