Control device

Abstract

To provide a control device that can execute backlash-reduction control at an appropriate timing.SOLUTION: A control device, which is mounted on a vehicle that is provided with a gear mechanism that transmits each power of an internal combustion engine and an electric motor to driving wheels, comprises: a determining part that determines success or failure of a stable state of operation of the internal combustion engine that is started, on the basis of rotation speed, an ignition time and an air-intake quantity of the internal combustion engine; and a control part that when the determining part determines that the stable state is established, starts backlash-reduction control of the gear mechanism using output torque of the electric motor.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device. [Background technology]

[0002] In a hybrid vehicle, while the engine is idling, rattle noise caused by collision between gears can be suppressed by controlling the output torque of the electric motor to eliminate backlash between the gears (see, for example, Patent Document 1). For example, backlash elimination control is initiated when the engine is started, after a certain waiting time has elapsed until the engine's operation has stabilized. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-159722 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the time required for engine operation to stabilize varies depending on the type of engine, its state (such as warm-up and degree of deterioration), and the operating environment (such as outside air pressure and intake air temperature).For this reason, if the waiting time before starting backlash elimination control is shorter than the actual required time, there is a risk of an increase in engine load or a decrease in NV (Noise Vibration) performance, and if it is longer, there will be wasted time during idling.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a control device that can execute backlash elimination control at appropriate timing. [Means for solving the problem]

[0006] The control device of the present invention is a control device for a vehicle equipped with a gear mechanism that transmits the power of an internal combustion engine and an electric motor to drive wheels, and includes a judgment unit that judges whether a stable state of operation has been achieved when the internal combustion engine is started based on the rotation speed, ignition timing, and intake volume of the internal combustion engine, and a control unit that starts backlash-eliminating control of the gear mechanism using the output torque of the electric motor when the judgment unit determines that the stable state has been achieved. [Effects of the Invention]

[0007] According to the present invention, backlash elimination control can be executed at an appropriate timing. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram showing an example of a vehicle system. [Figure 2] FIG. 2 is a diagram showing an example of time-dependent changes in engine speed, intake air amount, ignition timing, and stable state determination signal. [Figure 3] FIG. 3 is a flowchart showing an example of the backlash eliminating process. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Vehicle system configuration) 1 is a configuration diagram showing an example of a system of a vehicle 9. The vehicle 9 is, for example, a hybrid vehicle, and includes an ECU (Electronic Control Unit) 1, an engine (ENG) 2, a damper 3, a gear mechanism 4, motor generators (MG) 51, 52, a differential gear 62, a battery 54, an inverter 53, a final gear 61, a drive shaft 60, and a pair of drive wheels 63. The vehicle 9 also includes an ignition switch (IG-SW) 90, a crank angle sensor 91, an air flow sensor 92, and a resolver 93.

[0010] The engine 2 and the MGs 51 and 52 are sources of driving force for the vehicle 9. The engine 2 is an example of an internal combustion engine. In this example, the engine 2 is a gasoline engine, but is not limited to this and a diesel engine may also be used.

[0011] The MGs 51 and 52 have a stator and a rotor, and output shafts 50 and 55 are respectively integrally provided at the center of each rotor. An inverter 53 is electrically connected to the MGs 51 and 52. The inverter 53 is connected to a battery 54 such as a lithium-ion battery. A resolver 93 detects the rotation angle of the output shaft 50 and outputs it to the ECU 1. The MGs 51 and 52 can operate as either a motor or a generator. The MG 51 is an example of an electric motor.

[0012] An airflow sensor 92 detects the amount of intake air that the engine 2 takes into the combustion chamber from the outside and outputs the result to the ECU 1. A crank angle sensor 91 detects the angle of the crankshaft 20 of the engine 2 and outputs the result to the ECU 1. The torque of the engine 2 is input from the crankshaft 20 to the damper 3. The output shaft of the damper 3 is connected to the input shaft 40 of the gear mechanism 4.

[0013] The gear mechanism 4 transmits the power of the engine 2 and the MG51 to the drive wheels 63. The gear mechanism 4 includes an input shaft 40, a sun gear S, a ring gear R, a pinion gear P, a carrier CA, and a counter drive gear 41. The sun gear S, the ring gear R, the pinion gear P, and the carrier CA form a single-pinion planetary gear mechanism. The sun gear S is integrally connected to the output shaft 50 of the MG51, and the carrier CA is integrally connected to the input shaft 40. The pinion gear P meshes with the sun gear S and the ring gear R between them. The ring gear R and the counter drive gear 41 are integrally provided on the inner and outer circumferential surfaces, respectively, of a cylindrical member.

[0014] The gear mechanism 4 also includes a counter driven gear 42, a counter pinion gear 43, and a counter shaft 44. The counter driven gear 42, the counter pinion gear 43, and the counter shaft 44 form a counter gear mechanism. The counter driven gear 42 and the counter pinion gear 43 are integrally connected via the counter shaft 44. The counter driven gear 42 meshes with the counter drive gear 41, and also meshes with an output gear 56 provided integrally with the output shaft 55 at a different position. The counter pinion gear 43 meshes with a final gear 61.

[0015] The final gear 61 is connected to a differential gear 62 via a drive shaft 66. This transmits the driving force of the engine 2 and MGs 51, 52 to the differential gear 62. The differential gear 62 is connected to a drive shaft 60 of drive wheels 63. The differential gear 62 transmits the driving force transmitted from the gear mechanism 4 to the drive shaft 60 and drive wheels 63 so that a difference in rotation speed occurs among the drive wheels 63.

[0016] The ECU 1 is an example of a control device and includes a central processing unit (CPU), a read-only memory (ROM), and a random access memory (RAM), none of which are shown. In response to the IG-SW90 being turned on, the ECU 1 starts the engine 2 and puts it into an idling state, controls the output torque of the MG51, and eliminates backlash in the gear mechanism.

[0017] The ECU 1 has, as software functions that drive the CPU, a torque control unit 10, an operating state determination unit 11, and an engine control unit 12. Note that the torque control unit 10, the operating state determination unit 11, and the engine control unit 12 may be realized by hardware such as an integrated circuit (IC).

[0018] When starting the engine 2, the engine control unit 12 rotates the crankshaft using a motor (not shown) and controls the fuel injection amount and ignition timing of the engine 2 to perform idling operation. The operation state determination unit 11 determines whether the operation of the engine 2 is stable at this time based on the rotation speed, ignition timing, and intake air amount of the engine 2. Here, the operation state determination unit 11 calculates the rotation speed from the detection value of the crank angle sensor 91, obtains the intake air amount from the air flow sensor 92, and obtains the amount of retardation of the ignition timing as the ignition timing from the engine control unit 12.

[0019] The operation state determination unit 11 determines that the operation of the engine 2 is stable when the rotation speed, ignition timing, and intake amount have converged, respectively. The operation state determination unit 11 notifies the torque control unit 10 and the engine control unit 12 of the determination result of the stable state.

[0020] When a stable state of operation of the engine 2 is established, the torque control unit 10 and the engine control unit 12 eliminate backlash in the gear mechanism 4. When the operation state determination unit 11 determines that a stable state is established, the engine control unit 12 increases the output torque of the engine 2 by a predetermined value, and the torque control unit 10 controls the inverter 53 so that the MG 51 outputs an output torque in the opposite direction that cancels out the increase in the output torque. At this time, for example, the torque control unit 10 determines the output torque of the MG 51 based on the target value of the torque of the engine 2 input from the engine control unit 12 and the detection value of the resolver 93.

[0021] In this way, after the operation of the engine 2 has stabilized, the torque control unit 10 starts backlash elimination control of the gear mechanism 4 using the output torque of the MG 51. At this time, the vehicle 9 is stopped, so the counter driven gear 42 and the counter pinion gear 43 are maintained in a non-rotatable state. Therefore, the backlash elimination control reduces the gaps between the gears in the gear mechanism 4, making it possible to suppress rattle noise caused by collisions between the gears.

[0022] (Example of determining a stable state) FIG. 2 is a diagram showing an example of the time change of the rotational speed, intake air amount, ignition timing, and determination signal in the steady state of the engine 2. Since the pressure in the combustion chamber of the engine 2 during stoppage is substantially equal to the atmospheric pressure, the intake air amount immediately after the start of the engine 2 is large, but it decreases as the pressure in the combustion chamber increases and converges to a substantially constant value at time t2. Further, the rotational speed of the engine 2 rapidly increases immediately after the start of the engine 2, but then decreases according to the control of the engine control unit 12 and converges to a predetermined target value at time t5.

[0023] Also, the ignition timing of the engine 2 is controlled, for example, as a retard amount (negative value). The retard amount is controlled to a predetermined value according to the fuel consumption and exhaust gas performance near the time t1 when the first explosion occurs at the start of the engine 2, but then increases as the rotational speed converges from time t3, and converges to a substantially constant value at time t4. Note that during the period from time t1 to t5, the magnitude relationship of t1 < t2 < t3 < t4 < t5 holds.

[0024] For the convenience of control of the engine control unit 12, the times t5, t2, and t4 at which the rotational speed, intake air amount, and ignition timing converge are different. However, the operation state determination unit 11 determines that the idling operation of the engine 2 has stabilized at time t5 when all of the rotational speed, intake air amount, and ignition timing have converged. At this time, the operation state determination unit 11 changes the determination signal from "0" (non-establishment of the steady state) to "1" (establishment of the steady state). The engine control unit 12 and the torque control unit 10 start backlash elimination契机にして契機として when the determination signal changes to "1".

[0025] In this way, the operating state determination unit 11 determines whether the engine 2 has reached a stable state of operation at startup based on the engine speed, ignition timing, and intake air volume of the engine 2. As described above, the engine speed, ignition timing, and intake air volume are parameters that clearly indicate the state of the engine 2 during startup. Therefore, the torque control unit 10 can determine with high accuracy whether a stable state has been established, compared to when backlash elimination control is performed after a predetermined waiting time has elapsed, and can therefore perform backlash elimination control at an appropriate timing. Note that the operating state determination unit 11 can detect the convergence of each of the engine speed, ignition timing, and intake air volume based on the amount of change per unit time in accordance with, for example, the control processing sequence of the engine control unit 12.

[0026] (Reducing backlash) 3 is a flowchart showing an example of the backlash reduction process. This process is executed after the ECU 1 is started. First, the engine control unit 12 determines whether the IG-SW 90 is on or not (step St1). If the IG-SW 90 is off (No in step St1), step St1 is executed again.

[0027] If the IG-SW 90 is on (Yes in step St1), the engine control unit 12 starts the engine 2 in idling operation (step St2). Next, the operation state determination unit 11 acquires the rotation speed, ignition timing, and intake amount of the engine 2 (step St3).

[0028] Next, the operation state determination unit 11 determines whether the rotation speed, ignition timing, and intake air amount have converged (step St4). If at least one of the rotation speed, ignition timing, and intake air amount has not converged (No in step St4), the processes from step St3 onward are executed again. If all of the rotation speed, ignition timing, and intake air amount have converged (Yes in step St4), the operation state determination unit 11 determines that a stable state of operation of the engine 2 has been established, and determines whether other conditions necessary for backlash elimination control are met (step St5). Examples of such conditions include, but are not limited to, the charging rate and voltage of the battery 54.

[0029] If the other conditions are not met (No in step St5), the process of step St5 is executed again. On the other hand, if the other conditions are met (Yes in step St5), the engine control unit 12 and the torque control unit 10 execute backlash elimination control (step St6). In this manner, the backlash elimination process is executed.

[0030] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this and can be modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0031] 1 ECU (control unit), 2 engine, 4 gear mechanism, 9 vehicle, 10 torque control unit, 11 operation state determination unit, 12 engine control unit, 51 motor generator (electric motor), 63 drive wheel

Claims

[Claim 1] A control device for a vehicle equipped with a gear mechanism that transmits the power of an internal combustion engine and an electric motor to drive wheels, a determination unit that determines whether the internal combustion engine has reached a stable state of operation at the time of startup based on the rotation speed, ignition timing, and intake amount of the internal combustion engine; a control unit that starts a backlash elimination control of the gear mechanism using an output torque of the electric motor when the determination unit determines that the stable state is established. Control device.

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