JP2014189252A - Vehicle controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress waste operation of an engine.SOLUTION: A vehicle comprises: a first motor generator; an engine whose output shaft is rotated by the first motor generator; and a second motor generator. The vehicle can travel by an EV travel mode in which only the second motor generator is used as a drive source. An ECU increases output torque of the first motor generator by a predetermined first mode and then lowers the output torque of the first motor generator by a predetermined second mode when starting the engine. The ECU increases the output torque of the first motor generator by the first mode and then lowers the output torque of the first motor generator by a third mode different from the second mode while stopping jetting of fuel when rotating the output shaft of the engine while stopping jetting of the fuel in the engine during traveling by the EV travel mode.

Description

  The present invention relates to a vehicle control device, and more particularly to a technique for rotating an output shaft of an engine with another electric motor in a vehicle capable of traveling in an EV traveling mode using only an electric motor as a drive source.

  There are hybrid vehicles and electric vehicles that can run using an electric motor as a drive source. Some of these vehicles generate electricity using an engine and charge a battery. Normally, an engine is operated while consuming fuel. However, in some cases, as described in Japanese Patent Application Laid-Open No. 2007-99165 (Patent Document 1), the engine is cut (fuel injection is stopped). May be motored.

JP 2007-99165 A

  By the way, in general, since fuel injection is resumed after the fuel is cut, the fuel is cut after the warm-up of the catalyst and the engine is completed in preparation for the restart of the fuel injection. Therefore, once the engine is started in the process of motoring the stopped engine, it may not be possible to stop the engine until the warm-up is completed. Therefore, even when it is not necessary to operate the engine later, the warm-up process can be performed wastefully.

  The present invention has been made to solve the above-described problems, and an object thereof is to suppress useless operation of the engine.

  In one embodiment, a vehicle includes a first electric motor, an engine whose output shaft is rotated by the first electric motor, and a second electric motor. This vehicle can travel in the EV travel mode using only the second electric motor as a drive source. When starting the engine, the control device increases the output torque of the first electric motor in the predetermined first mode and then decreases the output torque of the first electric motor in the predetermined second mode. Let In addition, when the control device rotates the engine output shaft while the fuel injection is stopped in the engine while traveling in the EV travel mode, the first mode is used in the first mode while the fuel injection is stopped. After increasing the output torque of the electric motor, the output torque of the first electric motor is reduced in a predetermined third mode different from the second mode.

  As a result, when the engine is motored, the output shaft rotational speed of the engine can be increased in the same manner as when the engine is started. Also, when starting the engine, the engine itself maintains the output shaft speed after the complete explosion, while when motoring the engine, the first electric motor must maintain the engine output shaft speed. Therefore, the output torque of the electric motor after the output shaft rotation speed of the engine is increased is reduced in a different manner between when the engine is started and when the motoring is performed. In this way, motoring of the engine can be realized without starting the engine. Therefore, useless operation of the engine can be suppressed.

  In another embodiment, when the engine is started, the output torque of the first electric motor is reduced faster than when the engine is motored. Thereby, it is possible to suppress an excessive increase in the output shaft rotational speed of the engine due to the output torque of the first electric motor after the complete explosion of the engine. Further, when the engine is motored, it is possible to suppress a decrease in the output shaft rotational speed of the engine by the output torque of the first electric motor.

  In yet another embodiment, when the engine output shaft is rotated by the first electric motor while ignition is stopped in the engine while traveling in the EV traveling mode, that is, when the engine is motored, No determination is made as to whether the engine has started.

  Thereby, it can suppress determining with the mistake that the engine has not started.

It is a schematic block diagram which shows a hybrid vehicle. It is a figure which shows the alignment chart of a power split device. It is a figure which shows the electric system of a hybrid vehicle. It is a figure which shows the period which an engine drives, and the period which stops. It is a figure which shows an engine operating line and an equal power line. It is a figure which shows torque profile PC of the 1st motor generator when starting an engine. It is a figure which shows torque profile PM of the 1st motor generator when motoring. It is a figure which shows two torque profiles in piles. It is a flowchart which shows the process which ECU performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  Referring to FIG. 1, engine 100, first motor generator 110, second motor generator 120, power split mechanism 130, reduction gear 140, and battery 150 are mounted on the hybrid vehicle. In the following description, a hybrid vehicle not having a charging function from an external power source will be described as an example, but a plug-in hybrid vehicle having a charging function from an external power source may be used. Moreover, you may use the electric vehicle with the range extender (cruising range expansion device) which uses the engine 100 mainly for electric power generation.

  Engine 100, first motor generator 110, second motor generator 120, and battery 150 are controlled by an ECU (Electronic Control Unit) 170. ECU 170 may be divided into a plurality of ECUs.

  The hybrid vehicle travels by driving force from at least one of engine 100 and second motor generator 120. That is, either one or both of engine 100 and second motor generator 120 is automatically selected as a drive source according to the operating state.

  For example, engine 100 and second motor generator 120 are controlled according to the result of the driver operating accelerator pedal 172. The operation amount (accelerator opening) of the accelerator pedal 172 is detected by an accelerator opening sensor (not shown).

  When the accelerator opening is small and the vehicle speed is low, the hybrid vehicle runs using only the second motor generator 120 as a drive source. In this case, engine 100 is stopped. However, the engine 100 may be driven for power generation or the like.

Further, when the accelerator opening is large, when the vehicle speed is high, the remaining capacity of the battery 150 (SO
When the C (State Of Charge) is small, the engine 100 is driven. In this case, the hybrid vehicle runs using only engine 100 or both engine 100 and second motor generator 120 as drive sources.

  The engine 100 is an internal combustion engine. The temperature of the air taken into engine 100 is detected by temperature sensor 102 and input to ECU 170. Engine 100, first motor generator 110, and second motor generator 120 are coupled to an output shaft (crankshaft) 108 of engine 100 via power split mechanism 130. The power generated by the engine 100 is divided into two paths by the power split mechanism 130. One is a path for driving the front wheels 160 via the speed reducer 140. The other is a path for driving the first motor generator 110 to generate power.

  First motor generator 110 is a three-phase AC rotating electric machine including a U-phase coil, a V-phase coil, and a W-phase coil. First motor generator 110 generates power using the power of engine 100 divided by power split mechanism 130. The electric power generated by the first motor generator 110 is selectively used according to the running state of the vehicle and the remaining capacity of the battery 150. For example, during normal traveling, the electric power generated by first motor generator 110 becomes electric power for driving second motor generator 120 as it is. On the other hand, when the SOC of battery 150 is lower than a predetermined value, the electric power generated by first motor generator 110 is converted from AC to DC by an inverter described later. Thereafter, the voltage is adjusted by a converter described later and stored in the battery 150.

  When first motor generator 110 is acting as a generator, first motor generator 110 generates negative torque. Here, the negative torque means a torque that becomes a load on engine 100. When first motor generator 110 is supplied with electric power and acts as a motor, first motor generator 110 generates positive torque. Here, the positive torque means a torque that does not become a load on the engine 100, that is, a torque that assists the rotation of the engine 100. The same applies to the second motor generator 120.

  Second motor generator 120 is a three-phase AC rotating electric machine including a U-phase coil, a V-phase coil, and a W-phase coil. Second motor generator 120 is driven by at least one of the electric power stored in battery 150 and the electric power generated by first motor generator 110.

  The driving force of the second motor generator 120 is transmitted to the front wheels 160 via the speed reducer 140. As a result, the second motor generator 120 assists the engine 100 or causes the vehicle to travel by the driving force from the second motor generator 120. The rear wheels may be driven instead of or in addition to the front wheels 160.

  During regenerative braking of the hybrid vehicle, the second motor generator 120 is driven by the front wheels 160 via the speed reducer 140, and the second motor generator 120 operates as a generator. Accordingly, second motor generator 120 operates as a regenerative brake that converts braking energy into electric power. The electric power generated by second motor generator 120 is stored in battery 150.

  Power split device 130 includes a planetary gear including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear engages with the sun gear and the ring gear. The carrier supports the pinion gear so that it can rotate. The sun gear is connected to the rotation shaft of first motor generator 110. The carrier is connected to the crankshaft of engine 100. The ring gear is connected to the rotation shaft of second motor generator 120 and speed reducer 140.

  The engine 100, the first motor generator 110, and the second motor generator 120 are connected via a power split mechanism 130 that is a planetary gear, so that the rotational speeds of the engine 100, the first motor generator 110, and the second motor generator 120 are increased. As shown in FIG. 2, the relationship is connected by a straight line in the alignment chart.

  As can be understood from the alignment chart, in the present embodiment, even when fuel injection and ignition are stopped in engine 100, first motor generator 110 increases and maintains the output shaft rotational speed of engine 100. Can do. In other words, the motor shaft using the first motor generator 110 can set the output shaft rotational speed of the engine 100 to a desired rotational speed.

  As an example, since the battery 150 is nearly fully charged, the first motor generator 110 is used when the remaining capacity of the battery 150 is to be lowered to the target value, that is, when the remaining capacity of the battery 150 is higher than the threshold value. The motoring of the engine 100 is performed. Note that motoring may be performed under other conditions. For example, when the vehicle speed is equal to or higher than the threshold value, motoring of the engine 100 by the first motor generator 110 is performed in order to prevent the output shaft rotational speed of the first motor generator 110 from becoming excessive. May be.

  Returning to FIG. 1, the battery 150 is an assembled battery configured by further connecting a plurality of battery modules in which a plurality of battery cells are integrated in series. The voltage of the battery 150 is about 200V, for example. The battery 150 is charged with electric power supplied from a power source external to the vehicle in addition to the first motor generator 110 and the second motor generator 120. A capacitor may be used instead of or in addition to the battery 150.

  With reference to FIG. 3, the electric system of the hybrid vehicle will be further described. The hybrid vehicle is provided with a converter 200, a first inverter 210, a second inverter 220, and a system main relay 230.

  Converter 200 includes a reactor, two npn transistors, and two diodes. One end of the reactor is connected to the positive electrode side of each battery, and the other end is connected to the connection point of the two npn transistors.

  Two npn-type transistors are connected in series. The npn transistor is controlled by the ECU 170. A diode is connected between the collector and emitter of each npn transistor so that a current flows from the emitter side to the collector side.

  For example, an IGBT (Insulated Gate Bipolar Transistor) can be used as the npn transistor. Instead of the npn type transistor, a power switching element such as a power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) can be used.

  When the electric power discharged from the battery 150 is supplied to the first motor generator 110 or the second motor generator 120, the voltage is boosted by the converter 200. Conversely, when charging the battery 150 with the electric power generated by the first motor generator 110 or the second motor generator 120, the voltage is stepped down by the converter 200.

  System voltage VH between converter 200 and each inverter is detected by voltage sensor 180. The detection result of voltage sensor 180 is transmitted to ECU 170.

  First inverter 210 includes a U-phase arm, a V-phase arm, and a W-phase arm. The U-phase arm, V-phase arm and W-phase arm are connected in parallel. Each of the U-phase arm, the V-phase arm, and the W-phase arm has two npn transistors connected in series. Between the collector and emitter of each npn-type transistor, a diode for passing a current from the emitter side to the collector side is connected. A connection point of each npn transistor in each arm is connected to an end portion different from neutral point 112 of each coil of first motor generator 110.

  First inverter 210 converts a direct current supplied from battery 150 into an alternating current and supplies the alternating current to first motor generator 110. The first inverter 210 converts the alternating current generated by the first motor generator 110 into a direct current.

  Second inverter 220 includes a U-phase arm, a V-phase arm, and a W-phase arm. The U-phase arm, V-phase arm and W-phase arm are connected in parallel. Each of the U-phase arm, the V-phase arm, and the W-phase arm has two npn transistors connected in series. Between the collector and emitter of each npn-type transistor, a diode for passing a current from the emitter side to the collector side is connected. A connection point of each npn transistor in each arm is connected to an end portion different from neutral point 122 of each coil of second motor generator 120.

  Second inverter 220 converts a direct current supplied from battery 150 into an alternating current, and supplies the alternating current to second motor generator 120. Second inverter 220 converts the alternating current generated by second motor generator 120 into a direct current.

  Converter 200, first inverter 210, and second inverter 220 are controlled by ECU 170.

  System main relay 230 is provided between battery 150 and converter 200. The system main relay 230 is a relay that switches between a state where the battery 150 and the electric system are connected and a state where the battery 150 is disconnected. When system main relay 230 is in an open state, battery 150 is disconnected from the electrical system. When system main relay 230 is in a closed state, battery 150 is connected to the electrical system.

  The state of system main relay 230 is controlled by ECU 170. For example, when ECU 170 is activated, system main relay 230 is closed. When ECU 170 stops, system main relay 230 is opened.

  With reference to FIG. 4, the control mode of engine 100 will be further described. As shown in FIG. 4, when the output power of the hybrid vehicle is smaller than the engine start threshold value, the hybrid vehicle runs using only the driving force of second motor generator 120. In the present embodiment, a travel mode using only the driving force of second motor generator 120 is also referred to as an EV travel mode. Even in the EV traveling mode, engine 100 may be driven for power generation or the like.

  The output power is set as power used for running the hybrid vehicle. The output power is calculated by ECU 170 according to a map having, for example, the accelerator opening and the vehicle speed as parameters. The method for calculating the output power is not limited to this. Note that torque, acceleration, driving force, accelerator opening, and the like may be used instead of output power.

  When the output power of the hybrid vehicle exceeds the engine start threshold value, engine 100 is driven. Thus, the hybrid vehicle travels using the driving force of engine 100 in addition to or instead of the driving force of second motor generator 120. Further, the electric power generated by first motor generator 110 using the driving force of engine 100 is directly supplied to second motor generator 120.

  As shown in FIG. 5, the operating point of engine 100, that is, engine speed NE and output torque TE are determined by the intersection of the output power and the operating line.

  The output power is indicated by an isopower line. The operating line is predetermined by the developer based on the results of experiments and simulations. The operation line is set so that the engine 100 can be driven so that the fuel consumption becomes optimum (minimum). That is, when the engine 100 is driven along the operation line, optimal fuel consumption is realized. However, in the section from the predetermined torque TE1 to the predetermined torque TE2, the operation line is set so that vibration and noise are reduced. The operation line setting method is not limited to these.

  In the present embodiment, when engine 100 is started, engine 100 is cranked by driving first motor generator 110. As shown in FIG. 6, at time T1, output torque TMG of first motor generator 110 is increased to a predetermined torque TMG1. Thereafter, when fuel injection and ignition in engine 100 are started and the start of engine 100 is completed, output torque TMG of first motor generator 110 is reduced at time T2.

  The first mode when increasing the output torque TMG of the first motor generator 110 and the second mode when decreasing the output torque TMG are predetermined by the developer in consideration of the results of experiments and simulations.

  In the process of starting engine 100, it is determined whether or not engine 100 cannot be started. As an example, it is determined whether the output shaft rotational speed NE of the engine 100 has increased to a predetermined rotational speed. If the output shaft rotational speed NE of the engine 100 does not increase to a predetermined rotational speed during the period when the engine 100 is being started, it is determined that the engine 100 cannot be started.

  On the other hand, when the engine 100 is motored by the first motor generator 110 during traveling in the EV traveling mode, the output torque TMG of the first motor generator 110 is a predetermined torque TMG1 at time T3 as shown in FIG. Is increased. Thereafter, at time T4, output torque TMG of first motor generator 110 is reduced.

  Also when motoring engine 100 by first motor generator 110, output torque TMG of first motor generator 110 is increased in the same first manner as when engine 100 is started. On the other hand, when motoring engine 100 with first motor generator 110, output torque TMG of first motor generator 110 is reduced in a third mode different from when engine 100 is started. The third mode for reducing the output torque TMG is predetermined by the developer in consideration of the results of experiments and simulations.

  Further, in the process of shifting from a state where the engine 100 is stopped to a motored state, fuel injection and ignition are kept stopped. That is, the engine 100 is motored without being started. Since the engine 100 is not started, it is not determined whether the engine 100 cannot be started.

  For explanation, FIG. 8 shows the torque profile PC of the output torque TMG of the first motor generator 110 when starting the engine 100 and the first motor generator when motoring the engine 100 during traveling in the EV traveling mode. 110 shows a torque profile PM of 110 output torque TMG. As shown in FIG. 8, the manner in which the output torque TMG of the first motor generator 110 increases is the same for the torque profile PC and the torque profile PM.

  On the other hand, the torque profile PC decreases faster than the torque profile PM. That is, when engine 100 is started, output torque TMG of first motor generator 110 is quickly reduced after complete explosion of engine 100, while when motor 100 is motored, output shaft of engine 100 is output. The torque necessary to maintain the rotational speed NE is maintained.

  With reference to FIG. 9, a process executed by ECU 170 in the present embodiment will be described. The processing described below is repeatedly executed at a predetermined cycle. The processing described below may be realized by software, may be realized by hardware, or may be realized by cooperation of software and hardware.

  In step (hereinafter, step is abbreviated as S) 100, it is determined whether or not motoring of engine 100 is to be performed. When the engine 100 is started instead of motoring (NO in S100), the correction amount TGMMOT of the output torque TMG of the first motor generator 110 is made zero in S102.

  In S104, the output torque TMG of the first motor generator 110 is determined by adding the correction amount TGMMOT to the standard value TMGBASE of the output torque TMG of the first motor generator 110. The standard value TMGBASE is the same as the torque profile PC shown in FIG.

  When output torque TMG of first motor generator 110 is determined, first motor generator 110 is controlled to output the determined torque in S106.

  On the other hand, when motoring engine 100 (YES in S100), the determination of whether engine 100 cannot be started is stopped in S108.

  In S110, the state of engine 100 is determined. If engine 100 is stopped in the previous determination (YES in S112), the counter is reset (the count value is made zero) in S114. If engine 100 is not stopped in the previous determination (NO in S112), the count value is incremented in S116.

  Further, in S118, correction amount TGMMOT of output torque TMG of first motor generator 110 is determined according to the count value. As an example, when the count value is zero, the correction amount TMGMOT is zero. The correction amount TMGMOT determined in S118 corresponds to the difference between the torque profile PM shown in FIG. 7 and the torque profile PC shown in FIG. Therefore, in S104, the output torque TMG corresponding to the torque profile PM shown in FIG. 7 is determined by adding the correction amount TMGMOT to the standard value TMGBASE of the output torque TMG of the first motor generator 110.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100 engine, 110 first motor generator, 120 second motor generator, 150 battery, 170 ECU.

Claims (3)

Traveling in an EV travel mode equipped with a first electric motor, an engine whose output shaft is rotated by the first electric motor, and a second electric motor, and using only the second electric motor as a drive source A possible vehicle control device,
When starting the engine, the output torque of the first electric motor is increased in the predetermined first mode, and then the output torque of the first electric motor is decreased in the predetermined second mode. ,
When the output shaft of the engine is rotated while the fuel injection is stopped in the engine while traveling in the EV travel mode, the first electric motor is operated in the first mode while the fuel injection is stopped. A control apparatus for a vehicle, which increases the output torque of the motor and then reduces the output torque of the first electric motor in a predetermined third mode different from the second mode.   2. The vehicle control device according to claim 1, wherein in the second aspect, the output torque of the first electric motor is rapidly reduced as compared with the third aspect.   When the output shaft of the engine is rotated by the first electric motor while ignition is stopped in the engine while traveling in the EV traveling mode, it is not determined whether or not the engine is started. Item 2. The vehicle control device according to Item 1.

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