JP2005341778A - Control unit of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control unit of hybrid vehicle adapted to suppress torque shocks in a drive system, when starting the engine of a hybrid car using a starter. <P>SOLUTION: A control unit of a hybrid vehicle 30, when starting an engine 12 using a starter 32, computes angular accelerations dωg/dt of a generator 19 based on angular velocities ωg of the generator 19 detected by a rotary sensor 31, and computes generator torque command values Tg (values equivalent to torques by the inertia Jg of the generator 19 acting on the drive system) multiplying the angular accelerations dωg/dt of the generator 19 by the inertia Jg of the genertaor 19. The signals of the generator torque command values Tg are transmitted from a hybrid vehicle control unit 30 to a generator ECU26 and the generated torques of the generator 19 are controlled so as to cancel the torques by the inertia of the generator 19 acting on the drive system, thereby suppressing torque shocks of the drive system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hybrid vehicle control apparatus in which a control method at the start of the internal combustion engine is improved in a hybrid vehicle using an internal combustion engine and a motor as drive sources.

  In recent years, demand for hybrid vehicles has been rapidly expanding due to social demands for low fuel consumption and low emissions. Many hybrid vehicles currently on the market adopt a drive system (so-called split type) described in Patent Document 1 (Japanese Patent Laid-Open No. 11-22501), and are low speed and light in which the internal combustion engine has poor fuel efficiency. In the load range, the internal combustion engine is stopped and the vehicle is driven only by the power of the motor to improve fuel efficiency. Further, when the capacity of the high voltage battery is reduced or the load is high, the internal combustion engine is started and the vehicle is driven using the power of the internal combustion engine. Further, when the hybrid vehicle is started and accelerated from a stopped state, the hybrid vehicle is started with the power of the motor, and the internal combustion engine is started using a generator during the start and acceleration.

  Also, when starting an internal combustion engine with a generator, power is supplied to the generator from a high-voltage battery to motor the internal combustion engine, or when starting, some of the engine's friction and inertia split into the wheel drive shaft. Therefore, if nothing is done, the driving torque of the vehicle will change, causing the driver to feel a torque shock. As a countermeasure, a system has been developed in which the generator torque transmitted to the wheel drive shaft is canceled by the motor torque to prevent changes in the vehicle drive torque. In such a system, when the internal combustion engine is started with a generator, if the startability of the internal combustion engine is poor, the time for executing motoring by the generator and torque cancellation by the motor increases, and the high voltage battery This will increase the amount of electricity taken out. On the other hand, during startup, the driving power of only the motor is supplied by only the energy of the high-voltage battery, so that the carry-out of power from the high-voltage battery further increases. It becomes necessary to limit the power, which makes the driver feel insufficient power. This problem becomes more prominent as the mounting capacity of the high voltage battery is reduced from the viewpoint of reducing the battery cost and reducing the vehicle weight and weight.

Therefore, as described in Patent Document 2 (Japanese Patent Laid-Open No. 9-170533), a starter motor (so-called starter) that is driven by an auxiliary battery is provided, and the crankshaft of the internal combustion engine is driven by this starter. There is one that starts an internal combustion engine without taking out electric power from a high-voltage battery by rotationally driving.
Japanese Patent Laid-Open No. 11-22501 (pages 6 to 7 etc.) JP-A-9-170533 (page 8, FIG. 10 etc.)

  However, in the split type hybrid vehicle, when the internal combustion engine is started with a starter as in the technique of Patent Document 2, the following problem occurs. Generally, in a split type hybrid vehicle, the crankshaft of the internal combustion engine and the generator are connected by a planetary gear mechanism or the like. Therefore, when the internal combustion engine is started by rotating the crankshaft with a starter, The generator rotates according to the rotation of the shaft (see FIG. 4). For this reason, the rotational speed of the generator changes according to the crank shaft rotation fluctuation at the time of starting the internal combustion engine, and the torque generated by the inertia of the generator acts on the drive system. You will feel a torque shock.

  The present invention has been made in consideration of such circumstances. Accordingly, an object of the present invention is to suppress a torque shock of the drive system when starting the internal combustion engine, and to improve the drivability when starting the internal combustion engine. An object of the present invention is to provide a control device for a hybrid vehicle that can improve the performance.

  In order to achieve the above object, an invention according to claim 1 divides an internal combustion engine and a motor provided as a power source for driving wheels of a vehicle and a crankshaft power of the internal combustion engine into two systems, A power splitting means for driving the wheels of the vehicle in the system, and a generator connected to the other system of the power splitting means, and during the driving of the motor, the torque of the motor is applied to one system of the power splitting means. In a hybrid vehicle that is actuated to drive the wheels of a vehicle, a starting means for rotationally driving a crankshaft is provided to start the internal combustion engine. When the internal combustion engine is started by the starting means, The generated torque of the generator is controlled so as to suppress the torque shock of the drive system by the machine torque control means.

  In this configuration, when the crankshaft of the internal combustion engine is rotationally driven by the starting means, the torque acting on the drive system in accordance with the crankshaft rotational fluctuation (for example, torque generated by the inertia of the generator or power split means, etc. ) Can be controlled by the generated torque of the generator to suppress the torque shock of the drive system by controlling the generated torque of the generator, and the drivability at the start of the internal combustion engine can be improved.

  In this case, as described in claim 2, it is preferable to suppress the torque shock of the drive system by controlling the generated torque of the generator so as to cancel the torque caused by the inertia of the generator. The torque shock of the drive system generated at the start of the internal combustion engine is mainly caused by the torque generated by the inertia of the generator. The torque shock of the drive system can be effectively suppressed at the time of starting.

  Further, the starting means of the internal combustion engine is configured such that the crankshaft of the internal combustion engine is rotationally driven by the starter dedicated motor driven by the auxiliary battery without using the power split means as in the third aspect. Also good. Alternatively, the crankshaft of the internal combustion engine may be driven to rotate by the combustion energy of the fuel confined in the cylinder when the internal combustion engine is stopped. In any of these cases, the internal combustion engine can be started without taking out electric power from the high-voltage battery that drives the motor that is the power source of the wheels, so that the requirement for reducing the mounting capacity of the high-voltage battery can be satisfied.

  As a specific method for controlling the generator generated torque at the time of starting the internal combustion engine, as in claim 5, a torque command value to the generator is calculated based on the rotational speed of the generator, and based on the torque command value. Then, the torque shock of the drive system may be suppressed by controlling the generated torque of the generator. The torque generated by the inertia of the generator acting on the drive system based on the rotation speed of the generator, because the rotation speed of the generator changes according to the rotation fluctuation of the crankshaft and the torque generated by the generator inertia acts on the drive system. Can be calculated. From this relationship, based on the rotational speed of the generator, the torque command value for the generator is set to a value corresponding to the torque generated by the generator inertia so as to cancel the torque generated by the generator inertia acting on the drive system. The torque generated by the generator can be controlled, and the torque shock of the drive system can be suppressed.

  Further, when the internal combustion engine is started by rotationally driving the crankshaft with the start dedicated motor (in the case of the invention according to claim 3), the generator is generated based on the energization current of the start dedicated motor as in claim 6. The torque command value of the drive system may be calculated, and the torque shock of the drive system may be suppressed by controlling the torque generated by the generator based on the torque command value.

  Since the energizing current of the start-only motor is a parameter that reflects the rotation speed of the crankshaft and hence the generator, the torque generated by the generator inertia acting on the drive system is calculated based on the energizing current of the start-only motor. be able to. Therefore, based on the energization current of the start-up motor, the torque command value for the generator is set to a value corresponding to the torque generated by the generator inertia so that the torque generated by the generator inertia acting on the drive system is canceled out. The torque generated by the machine can be controlled.

  On the other hand, when the internal combustion engine is started by rotationally driving the crankshaft with the combustion energy of the fuel confined in the cylinder (in the case of the invention according to claim 4), the crank of the internal combustion engine is as in claim 7. The torque command value for the generator is calculated based on the shaft stop position and the fuel temperature in the cylinder, and the torque generated in the generator is controlled based on the torque command value to suppress the torque shock of the drive system. You may do it.

  Because the combustion energy of the fuel confined in the cylinder changes depending on the stop position of the crankshaft (that is, the piston stop position) and the fuel temperature in the cylinder, the drive torque of the crankshaft changes. The stop position and the fuel temperature in the cylinder are parameters that reflect the rotation speed of the crankshaft and thus the rotation speed of the generator, and the inertia of the generator acting on the drive system based on the stop position of the crankshaft and the fuel temperature in the cylinder. The torque due to can be calculated. Therefore, based on the stop position of the crankshaft and the temperature of the fuel in the cylinder, the torque command value for the generator is set to a value corresponding to the torque generated by the generator inertia and the torque generated by the generator inertia acting on the drive system The generated torque of the generator can be controlled so as to cancel out.

  Hereinafter, three Examples 1 to 3 embodying the best mode for carrying out the present invention will be described.

  A first embodiment of the present invention will be described with reference to FIGS.

  First, a drive system for a split type hybrid vehicle will be described with reference to FIG. An engine 12 (internal combustion engine) and a motor 13 (motor generator) are mounted as power sources for driving the wheels 11 of the hybrid vehicle. The power of the crankshaft 14 of the engine 12 is divided into two systems by a planetary gear mechanism 15 that is power split means. The planetary gear mechanism 15 includes a sun gear 16 that rotates at the center, a planetary gear 17 that revolves while rotating on the outer periphery of the sun gear 16, and a ring gear 18 that rotates on the outer periphery of the planetary gear 17. The crankshaft 14 of the engine 12 is connected through a carrier that is not connected, the rotating shaft of the motor 13 is connected to the ring gear 18, and the generator 19 (motor generator) is connected to the sun gear 16. The generator 19 is provided with a rotation sensor 31 that detects the angular velocity of the generator 19.

  The motor 13 and the generator 19 exchange power with the battery 27 via inverters 28 and 29, respectively. On the other hand, a starter 32 (starting means) for starting the engine 12 is constituted by a starter motor driven by an auxiliary battery (not shown), and the starter 32 does not pass through the planetary gear mechanism 15. The crankshaft 14 of the engine 12 is driven to rotate.

  When starting or running at low and medium speeds (region where the fuel efficiency of the engine 12 is poor), the engine 12 is kept stopped and the vehicle runs only with the power of the motor 13 (motor running mode). In this motor travel mode, the drive shaft 20 is driven only by the power of the motor 13 to drive the wheels 11. At this time, a part of the rotational force of the motor 13 is transmitted to the ring gear 18 of the planetary gear mechanism 15, whereby the ring gear 18 rotates, the planetary gear 17 rotates, and the sun gear 16 rotates. 19 is driven to rotate. Further, when the engine 12 is started during the motor travel mode, the starter 32 is driven by a battery for auxiliary equipment, and the crankshaft 14 of the engine 12 is rotationally driven.

  During normal running, the power of the crankshaft 14 of the engine 12 is crushed by the planetary gear mechanism 15 on the generator 19 side and the drive shaft 20 side (rotation shaft side of the motor 13) so that the fuel efficiency of the engine 12 is maximized. The system is divided into systems, and the drive shaft 20 is driven via the rotating shaft of the motor 13 by the output of one system to drive the wheels 11, and the generator 19 is driven by the output of the other system. The supplied electric power is supplied to the motor 13, and the wheels 11 are driven by the power of the motor 13.

  At the time of sudden acceleration, the most torque is required. Therefore, in addition to the power generated during normal driving, the DC power of the battery 27 is also added to the inverter 28 to be converted into AC power and supplied to the motor 13 to operate the motor 13. To do. Thereby, the drive shaft 20 is driven by the power of both the engine 12 and the battery 27 to drive the wheels 11, thereby improving the acceleration performance.

  During deceleration or braking, the wheel 11 drives the motor 13 to operate as a generator, converts the braking energy of the vehicle into electric power, and charges the battery 27.

  Next, the configuration of the control system will be described. The hybrid vehicle control device 30 is a computer that comprehensively controls the entire hybrid vehicle, and includes an accelerator sensor 21 that detects an accelerator opening, a shift switch 22 that detects a shift range of an automatic transmission, and a brake switch that detects a brake operation. The output signals of various sensors such as 23 and switches are read to detect the driving state of the vehicle and determine the requested travel mode. The hybrid vehicle control device 30 transmits and receives control signals between an engine ECU 24 that controls the operation of the engine 12, a motor ECU 25 that controls the operation of the motor 13, and a generator ECU 26 that controls the operation of the generator 19. Each of the ECUs 24 to 26 controls the operation of the engine 12, the motor 13, and the generator 19 in accordance with the required travel mode.

  The hybrid vehicle control device 30 outputs an engine start command to the engine ECU 24 when an engine start request is generated. As a result, the engine ECU 24 drives the starter 32 with the battery for auxiliary equipment to rotationally drive the crankshaft 14 of the engine 12. At the time of this cranking, the cam angle sensor (not shown) and the crank angle sensor 33 are driven. Cylinder discrimination is performed based on the output signal, fuel injection / ignition is executed, and the engine 12 is started.

  In the split type hybrid vehicle, the crankshaft 14 and the generator 19 are connected by the planetary gear mechanism 15. Therefore, when the crankshaft 14 is rotationally driven by the starter 32 and the engine 12 is started, the crankshaft The generator 19 rotates according to the rotation of 14 (see FIG. 4). For this reason, the rotational speed of the generator 19 changes according to the rotational fluctuation of the crankshaft 14 at the time of starting the engine, and the torque due to the inertia of the generator 19 acts on the drive system.

  Accordingly, the hybrid vehicle control device 30 executes each of the generator torque control routines shown in FIGS. 2 and 3 to be described later, and changes the angular acceleration dωg / dt (angular velocity ωg of the generator 19 over time) when starting the engine. ) To calculate the generator torque command value Tg so as to cancel the torque due to the inertia of the generator 19 acting on the drive system, and the generator torque command value Tg A signal is output to the generator ECU 26. As a result, the generator ECU 26 converts the DC power of the battery 27 into AC power by the inverter 29 based on the generator torque command value Tg and supplies it to the generator 19, as shown in FIG. The generated torque of the generator 19 is controlled so as to cancel the torque caused by the inertia of the generator 19 that acts.

Hereinafter, the processing content of each routine for generator torque control shown in FIG.2 and FIG.3 is demonstrated.
The generator torque control main routine shown in FIG. 2 is executed at a predetermined cycle while the hybrid vehicle control device 30 is powered on. When this routine is started, first, at step 101, it is determined whether or not there is an engine start request.

  As a result, if it is determined that there is an engine start request, the routine proceeds to step 102, where an engine start-time generator torque control routine of FIG. Calculate.

  On the other hand, if it is determined in step 101 that there is no engine start request, the routine proceeds to step 103, where a normal generator torque control routine (not shown) is executed to calculate a normal generator torque command value Tg. To do.

  The engine starting generator torque control routine of FIG. 3 executed in step 102 of FIG. 2 serves as the starting generator torque control means in the claims. When this routine is started, first, in step 201, the angular velocity ωg of the generator 19 detected by the rotation sensor 31 is read. In a system that does not have the rotation sensor 31, the angular velocity ωg of the generator 19 may be estimated based on the operating state.

Thereafter, the process proceeds to step 202, and after calculating the angular acceleration dωg / dt, which is the time change of the angular velocity ωg of the generator 19, the process proceeds to step 203, where the inertia Jg of the generator 19 is multiplied by the angular acceleration dωg / dt. A generator torque command value Tg is calculated.
Tg = Jg × dωg / dt

  The generator torque command value Tg is a value corresponding to the torque generated by the inertia Jg of the generator 19 acting on the drive system. Note that the inertia Jg of the generator 19 is stored in the ROM of the hybrid vehicle control device 30 in advance based on design data, experimental data, and the like.

  The generator torque command value Tg calculated in this way is transmitted from the hybrid vehicle control device 21 to the generator ECU 26, and the generator ECU 26 cancels the torque generated by the inertia Jg of the generator 19 acting on the drive system. The generated torque of the generator 19 is controlled.

  In the first embodiment described above, the generator torque command value Tg is calculated based on the angular acceleration dωg / dt of the generator 19 when the engine 12 is started by rotating the crankshaft 14 with the starter 32. Since the generated torque of the generator 19 is controlled so as to cancel the torque due to the inertia Jg of the generator 19 acting on the drive system, the torque shock of the drive system can be effectively suppressed when starting the engine. It is possible to improve drivability when starting the engine.

  Moreover, in the first embodiment, the engine 12 is started by the starter 32 driven by the auxiliary battery, so that power is not taken out from the battery 27 that drives the motor 13 that is the power source of the wheels 11. The engine 11 can be started, the requirement for reducing the mounting capacity of the battery 27 can be satisfied, and the requirement for reducing the cost of the battery 27 and reducing the vehicle weight can be satisfied.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In the first embodiment, the generator torque command value Tg (value corresponding to the inertia Jg of the generator 19 acting on the drive system) is calculated based on the angular acceleration dωg / dt of the generator 19. In the second embodiment, considering that the energization current Is of the starter 32 is a parameter reflecting the rotation speed of the crankshaft 14 and thus the rotation speed of the generator 19, as shown in FIG. 7 is executed, an engine start-time generator torque control routine shown in FIG. 7 is executed, and a generator torque command value Tg (generator acting on the drive system) is determined based on the starter 32 energization current Is. 19) (value corresponding to 19 inertia Jg).

In the engine start-time generator torque control routine of FIG. 7 executed in the second embodiment, first, in step 301, the energization current Is of the starter 32 detected by the current sensor 34 is read.
Thereafter, the process proceeds to step 302, and the generator torque command value Tg corresponding to the energization current Is of the starter 32 is calculated using the generator torque command value Tg map shown in FIG. The generator torque command value Tg map shown in FIG. 8 is created in advance based on design data, experimental data, and the like, and is stored in the ROM of the hybrid vehicle control device 30.

  Even in the second embodiment described above, the torque generated by the generator 19 can be controlled so as to cancel the torque caused by the inertia of the generator 19 acting on the drive system at the time of starting the engine, thereby suppressing the torque shock of the drive system. This can improve drivability when starting the engine.

Next, Embodiment 3 of the present invention will be described with reference to FIGS.
In each of the first and second embodiments, the crankshaft 14 is rotationally driven by the starter 32 to start the engine 12. However, in the third embodiment, the fuel trapped in the cylinder when the engine is stopped is used when the engine is started. Combustion is performed, and the crankshaft 14 is rotationally driven by the combustion energy to start the engine 12.

  At that time, the combustion energy of the fuel confined in the cylinder changes depending on the stop position of the crankshaft 14 (that is, the stop position of the piston) and the fuel temperature in the cylinder, so that the drive torque of the crankshaft 14 changes. The stop position of 14 and the fuel temperature in the cylinder are parameters reflecting the rotation speed of the crankshaft 14 and the rotation speed of the generator 19.

  Therefore, in the third embodiment, as shown in FIG. 9, when the engine is stopped, the stop position Pos of the crankshaft 14 is detected based on the output signal of the crank angle sensor 33, and the temperature sensor 35 determines the fuel temperature Temp in the cylinder. The engine starting generator torque control routine shown in FIG. 10 is executed, and the generator torque command value Tg (in the drive system) is determined based on the stop position Pos of the crankshaft 14 and the fuel temperature Temp in the cylinder. The value corresponding to the inertia Jg of the working generator 19 is calculated.

  In the engine starting generator torque control routine of FIG. 10 executed in the third embodiment, first, in step 401, the stop position Pos of the crankshaft 14 detected by the crank angle sensor 33 when the engine is stopped is read.

  Thereafter, the process proceeds to step 402, and the fuel temperature Temp in the cylinder detected by the temperature sensor 35 is read. The fuel temperature Temp in the cylinder may be estimated from the coolant temperature detected by the coolant temperature sensor or the engine stop time.

  Thereafter, the process proceeds to step 403, and the generator torque command value Tg corresponding to the stop position Pos of the crankshaft 14 and the fuel temperature Temp in the cylinder is calculated using the map of the generator torque command value Tg shown in FIG. To do. The generator torque command value Tg map shown in FIG. 11 is created in advance based on design data, experimental data, and the like, and is stored in the ROM of the hybrid vehicle control device 30.

  Even in the third embodiment described above, the torque generated by the generator 19 can be controlled so as to cancel the torque caused by the inertia of the generator 19 acting on the drive system at the time of starting the engine, thereby suppressing the torque shock of the drive system. This can improve drivability when starting the engine.

  In each of the first to third embodiments, the torque generated by the generator 19 is controlled so as to cancel the torque generated by the inertia of the generator 19 when the engine is started. The torque generated by the generator 19 may be controlled so as to cancel the torque that takes into account the torque caused by the inertia of the gear mechanism 15. In short, at the start of the engine, the drive system is driven by the rotational fluctuation of the crankshaft 14. What is necessary is just to control the generated torque of the generator 19 so as to cancel the acting torque.

It is a schematic block diagram of the hybrid vehicle drive system in Example 1 of this invention. It is a flowchart which shows the flow of a process of a generator torque control main routine. 3 is a flowchart showing a flow of processing of an engine start-time generator torque control routine according to the first embodiment. It is a figure for demonstrating the relationship between the rotational speed of a generator, the rotational speed of an engine, and the rotational speed of a motor. It is a figure for demonstrating the relationship between the rotational speed of the generator at the time of engine starting by a starter, the rotational speed of an engine, and the rotational speed of a motor. It is a schematic block diagram of the hybrid vehicle drive system in Example 2. FIG. 7 is a flowchart showing a flow of processing of an engine start-time generator torque control routine according to a second embodiment. It is a figure which shows notionally the map of the generator torque command value according to a starter energization current. FIG. 6 is a schematic configuration diagram of a hybrid vehicle drive system in a third embodiment. 12 is a flowchart showing a flow of processing of an engine start-time generator torque control routine according to a third embodiment. It is a figure which shows notionally the map of the generator torque command value according to a crankshaft stop position and the fuel temperature in a cylinder.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Wheel, 12 ... Engine (internal combustion engine), 13 ... Motor, 14 ... Crankshaft, 15 ... Planetary gear mechanism (power split means), 16 ... Sun gear, 17 ... Planetary gear, 18 ... Ring gear, 19 ... Generator, 20 DESCRIPTION OF SYMBOLS ... Drive shaft, 24 ... Engine ECU, 25 ... Motor ECU, 26 ... Generator ECU, 27 ... Battery, 30 ... Hybrid vehicle control device (starting generator torque control means), 31 ... Rotation sensor, 32 ... Starter (start Means), 33 ... crank angle sensor, 34 ... current sensor, 35 ... temperature sensor

Claims (7)

An internal combustion engine and a motor provided as a power source for driving the wheels of the vehicle; a crankshaft power of the internal combustion engine is divided into two systems; And a generator connected to the other system of the dividing means, and during driving of the motor, a torque of the motor is applied to one system of the power dividing means to drive a vehicle wheel. In the car,
Starting means for rotationally driving a crankshaft to start the internal combustion engine;
And a starting-time generator torque control means for controlling a torque generated by the generator so as to suppress a torque shock of a drive system when the internal combustion engine is started by the starting means. Car control device.   2. The start-time generator torque control means controls torque generated by the generator so as to cancel torque due to inertia of the generator, thereby suppressing torque shock of the drive system. The hybrid vehicle control device described.   3. The hybrid according to claim 1, wherein the starting unit rotates and drives the crankshaft of the internal combustion engine without using the power dividing unit by a dedicated starter motor driven by an auxiliary battery. Car control device.   The control device for a hybrid vehicle according to claim 1 or 2, wherein the starting means rotationally drives the crankshaft of the internal combustion engine by the combustion energy of fuel confined in the cylinder when the internal combustion engine is stopped. .   The starting generator torque control means calculates a torque command value to the generator based on the rotational speed of the generator, and controls the generated torque of the generator based on the torque command value. The hybrid vehicle control device according to any one of claims 1 to 4, wherein a torque shock of the drive system is suppressed.   The starting generator torque control means calculates a torque command value to the generator based on the energization current of the start-only motor, and controls the generated torque of the generator based on the torque command value. The hybrid vehicle control device according to claim 3, wherein a torque shock of the drive system is suppressed.   The starting generator torque control means calculates a torque command value to the generator based on a stop position of a crankshaft of the internal combustion engine and a fuel temperature in a cylinder, and generates the power generation based on the torque command value. The hybrid vehicle control device according to claim 4, wherein a torque shock of the drive system is suppressed by controlling a torque generated by the machine.

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