JP2009190564A - Control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce deterioration in driveability by reducing shock which may be generated when the driving power of a vehicle is limited. <P>SOLUTION: When a predicted value f(t+tsk) of a first request driving force f(t) of a driver becomes larger than a predicted value H(t+tsk) of an upper limit value H(t) of the driving force, a second request driving force F(t) is calculated so that a difference between an upper limit value H(t) and a second request driving force F(t) can be reduced as time elapses. Furthermore, a power train is controlled so that the actual driving force of a hybrid car can be set to the second request driving force F(t). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle control device, and more particularly to a technique for changing a difference between an upper limit value of a driving force of a vehicle and a required driving force required for the vehicle in a predetermined manner.

  Conventionally, a hybrid vehicle that travels using the driving force of a motor in addition to or instead of an engine is known. In hybrid vehicles, the driving force of a motor that does not have a throttle opening is used. Therefore, even if the slot opening is determined from the accelerator opening as in the case of a vehicle with only an engine, driving in accordance with the driver's request The power cannot be realized.

  Therefore, in a hybrid vehicle, for example, the required driving force requested by the driver to the vehicle is determined based on the accelerator opening, etc., and the engine and motor are controlled so that the actual driving force of the vehicle matches the required driving force. Is done. That is, control is performed so that the required driving force of the driver is shared by the driving force from the engine and the driving force from the motor.

JP-T-2004-538197 (Patent Document 1) includes a driver input, a control actuator, and a control processor. The control processor processes the driver input to derive an actual driver request. A control system is disclosed that is configured to control a vehicle via a control actuator according to requirements.
JP-T-2004-538197

  However, when the driver's required driving force is calculated, the upper limit value of the driving force that can be achieved by the vehicle may be exceeded. When the required driving force of the driver exceeds the upper limit value of the driving force, the driving force that meets the driver's request cannot be realized. Therefore, the driving force of the vehicle is suddenly limited, and a shock can occur. As a result, drivability can deteriorate.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle control device that can reduce deterioration in drivability.

  A vehicle control device according to a first aspect of the present invention is a vehicle control device provided with a power train. The control device includes means for calculating an upper limit value of the driving force of the vehicle, calculation means for calculating a first required driving force requested by the driver to the vehicle, and a first required driving force. The determination means for determining whether or not the upper limit value is exceeded and the second required driving force required for the vehicle when the first required driving force is determined to exceed the upper limit value, And a calculating means for calculating the difference between the second required driving force and the second required driving force so as to change in a predetermined manner, and when it is determined that the first required driving force exceeds the upper limit value, the actual driving of the vehicle Means for controlling the power train such that the force is a second required driving force.

  According to this configuration, when it is determined that the first required driving force that the driver requests for the vehicle exceeds the upper limit value of the driving force of the vehicle, the second required driving force that is required for the vehicle is calculated. Is done. The second driving force is calculated so that the difference between the upper limit value and the second required driving force changes in a predetermined manner. For example, the second driving force is calculated so that the difference between the upper limit value and the second required driving force becomes smaller as time elapses. The power train is controlled so that the actual driving force of the vehicle becomes the second required driving force. Thereby, the actual driving force of the vehicle can gradually approach the upper limit value of the driving force. That is, the actual driving force of the vehicle can be gradually limited. Therefore, it is possible to reduce a shock that may occur when the driving force is limited. As a result, it is possible to provide a vehicle control device that can reduce deterioration in drivability.

  In the vehicle control apparatus according to the second invention, in addition to the configuration of the first invention, the predetermined mode is a mode in which the difference between the upper limit value and the second required driving force becomes smaller as time elapses. It is.

  According to this configuration, the actual driving force of the vehicle can be gradually limited. Therefore, it is possible to reduce a shock that may occur when the driving force is limited.

  In the vehicle control apparatus according to the third aspect of the invention, in addition to the configuration of the first aspect, the judging means includes a means for predicting an expected value of the upper limit value after a predetermined time, and a predetermined means. Means for predicting the predicted value of the first required driving force after time, and if the predicted value of the first required driving force is greater than the expected value of the upper limit value, the first required driving force exceeds the upper limit value And means for judging.

  According to this configuration, the actual driving force of the vehicle can be gradually limited before the required driving force of the driver exceeds the upper limit value of the driving force. Therefore, it is possible to further reduce the shock that may occur when the driving force is limited.

  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.

  A hybrid vehicle equipped with a control device according to an embodiment of the present invention will be described with reference to FIG. This vehicle includes an engine 100, a first MG (Motor Generator) 110, a second MG 120, a power split mechanism 130, a speed reducer 140, and a battery 150.

  This vehicle travels by driving force from at least one of engine 100 and second MG 120. Instead of the hybrid vehicle, an electric vehicle or a fuel cell vehicle that travels only by the driving force from the motor may be used. Moreover, the vehicle provided only with an engine may be sufficient.

  Engine 100, first MG 110, and second MG 120 are connected 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 MG 110 to generate power.

  First MG 110 is a three-phase AC rotating electric machine including a U-phase coil, a V-phase coil, and a W-phase coil. First MG 110 generates power using the power of engine 100 divided by power split mechanism 130. The electric power generated by first MG 110 is selectively used according to the running state of the vehicle and the state of charge (SOC) of battery 150. For example, during normal traveling, the electric power generated by first MG 110 becomes electric power for driving second MG 120 as it is. On the other hand, when the SOC of battery 150 is lower than a predetermined value, the power generated by first MG 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 MG 110 acts as a generator, first MG 110 generates a negative torque. Here, the negative torque means a torque that becomes a load on engine 100. When first MG 110 is supplied with electric power and acts as a motor, first MG 110 generates a 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 MG 120.

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

  The driving force of second MG 120 is transmitted to front wheel 160 via reduction gear 140. Thereby, second MG 120 assists engine 100 or causes the vehicle to travel by the driving force from second MG 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 MG 120 is driven by the front wheels 160 via the speed reducer 140, and the second MG 120 operates as a generator. Thus, second MG 120 operates as a regenerative brake that converts braking energy into electric power. The electric power generated by second MG 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 MG 110. The carrier is connected to the crankshaft of engine 100. The ring gear is connected to the rotation shaft of second MG 120 and speed reducer 140.

  Engine 100, first MG 110 and second MG 120 are connected via power split mechanism 130 formed of a planetary gear, so that the rotational speeds of engine 100, first MG 110 and second MG 120 are collinear as shown in FIG. The relationship is connected by a straight line.

  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. Battery 150 is charged with power supplied from first MG 110 and second MG 120.

  The engine 100, the first MG 110, and the second MG 120 that constitute a part of the power train of the hybrid vehicle are controlled by an ECU (Electronic Control Unit) 170. ECU 170 may be divided into a plurality of ECUs.

  As shown in FIG. 3, ECU 170 receives a signal representing the accelerator opening from accelerator opening sensor 172 and a signal representing the vehicle speed from vehicle speed sensor 174. ECU 170 controls engine 100, first MG 110, and second MG 120 based on vehicle speed, accelerator opening, and the like.

  The hybrid vehicle is further provided with a converter 200, a first inverter 210, a second inverter 220, a DC / DC converter 230, an auxiliary battery 240, and an SMR (System Main Relay) 250.

  Converter 200 includes a reactor, two npn transistors, and two diodes. Reactor has one end connected to the positive electrode side of battery 150 and the other end connected to a connection point of 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 MG 110 or the second MG 120, the voltage is boosted by the converter 200. Conversely, when charging the battery 150 with the power generated by the first MG 110 or the second MG 120, the voltage is stepped down by the converter 200.

  In the present embodiment, when eco switch 176 is turned on, an economy mode that prohibits boosting of converter 200 is selected. The economy mode is a travel mode that emphasizes fuel efficiency. When boosting of converter 200 is prohibited in the economy mode, power consumption is limited. As a result, the upper limit value of the driving force of the hybrid vehicle is reduced. In the present embodiment, the economy mode can be automatically ended.

  System voltage VH between converter 200 and first inverter 210 and second inverter 220 is detected by voltmeter 180. The detection result of the voltmeter 180 is transmitted to the 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 the neutral point 112 of each coil of the first MG 110.

  First inverter 210 converts a direct current supplied from battery 150 into an alternating current, and supplies the alternating current to first MG 110. In addition, first inverter 210 converts the alternating current generated by first MG 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 the neutral point 122 of each coil of the second MG 120.

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

  DC / DC converter 230 is connected in parallel with converter 200 between battery 150 and converter 200. The DC / DC converter 230 steps down the direct current voltage. The electric power output from the DC / DC converter 230 is charged in the auxiliary battery 240. The electric power charged in the auxiliary battery 240 is supplied to the auxiliary machine 242 such as an electric oil pump and the ECU 170.

  An SMR (System Main Relay) 250 is provided between the battery 150 and the DC / DC converter 230. The SMR 250 is a relay that switches between a state where the battery 150 and the electrical system are connected and a state where the battery 150 is disconnected. When SMR 250 is open, battery 150 is disconnected from the electrical system. When SMR 250 is closed, battery 150 is connected to the electrical system. The state of SMR 250 is controlled by ECU 170. For example, when the ECU 170 is activated, the SMR 250 is closed. When ECU 170 pauses, SMR 250 is opened.

  The function of ECU 170 will be described with reference to FIG. Note that the functions described below may be realized by software, or may be realized by hardware.

  ECU 170 includes an upper limit calculation unit 700, a first required driving force calculation unit 710, a determination unit 720, a second required driving force calculation unit 730, and a control unit 740.

  Upper limit calculation unit 700 calculates upper limit value H (t) of the driving force of the hybrid vehicle. In the present embodiment, the driving force is represented by “N (Newton)”. The power represented by “W (Watt)” and the torque represented by “N · m (Newton meter)” may be interpreted as being included in the driving force.

  The upper limit value H (t) of the driving force is calculated according to a predetermined map based on various parameters such as the vehicle speed, the SOC of the battery 150, the temperature of the battery 150, and whether or not the economy mode is selected. . The calculation method of the upper limit value H (t) of the driving force may be appropriately determined according to the vehicle specifications and the like.

  The first required driving force calculation unit 710 calculates a first required driving force f (t) requested by the driver from the vehicle according to a predetermined map, for example, based on the vehicle speed, the accelerator opening, and the like.

  The determination unit 720 determines whether or not the first required driving force f (t) of the driver exceeds the upper limit value H (t) of the driving force. The determination unit 720 determines the expected value f (t + tsk) of the first required driving force f (t) and the predicted value H (t + tsk) of the upper limit value H (t) of the driving force after a predetermined skip time tsk. ) And the predicted value f (t + tsk) of the first required driving force f (t) is larger than the predicted value H (t + tsk) of the upper limit value H (t) of the driving force, the first required driving force It is determined that the force f (t) exceeds the upper limit value H (t).

  The predicted value f (t + tsk) of the first required driving force f (t) is, for example, the predicted value of the vehicle speed expected from the acceleration and the rate of change of the accelerator opening, instead of the current value of the vehicle speed and the accelerator opening. It is calculated using the predicted value of the accelerator opening estimated from Similarly, the predicted value H (t + tsk) of the upper limit value H (t) of the driving force is calculated using the predicted value of the vehicle speed, the predicted value of the SCO of the battery 150, the predicted value of the temperature of the battery 150, and the like. .

  When the predicted value f (t + tsk) of the first required driving force f (t) is larger than the predicted value H (t + tsk) of the upper limit value H (t) of the driving force, the second required driving force calculation unit 730 Then, the second required driving force F (t) required for the vehicle is calculated. The second required driving force F (t) is calculated so that the difference between the upper limit value H (t) and the second required driving force F (t) becomes smaller as time elapses.

  More specifically, the difference d (t) between the upper limit value H (t) of the driving force and the second required driving force F (t) changes along the ideal curve D (t) shown in FIG. The second required driving force F (t) is calculated by performing filtering using PID (Proportion, Integration, Differential) control.

  In the filtering, the second required driving force F (t) is calculated by the following formula 1. In Equation 1, F (t + 1) represents the next value of the second required driving force F (t). “Gp”, “Gi”, and “Gd” are the gains of the proportional term, integral term, and derivative term, respectively.

F (t + 1) = F (t) + Gp × (d (t) -D (t)) + Gi × ∫ (d (t) -D (t)) dt + Gd × d (d (t)- D (t)) / dt… (1)
When the calculation of the second required driving force F (t) is started at time A in FIG. 5, the difference d (t) between the upper limit value H (t) of the driving force and the second required driving force F (t) gradually becomes ideal. Approach curve D (t). Note that the second required driving force F (t) may be calculated without using any of P control, I control, and D control.

  When the predicted value f (t + tsk) of the first required driving force f (t) becomes larger than the predicted value H (t + tsk) of the upper limit value H (t) of the driving force, the control unit 740 The power train, that is, the engine 100, the first MG 110, and the second MG 120 are controlled such that the driving force becomes the second required driving force F (t).

  While the predicted value f (t + tsk) of the first required driving force f (t) is less than or equal to the predicted value H (t + tsk) of the upper limit value H (t) of the driving force, the actual driving force of the hybrid vehicle However, the power train is controlled to be the first required driving force f (t).

  A control structure of a program executed by ECU 170 will be described with reference to FIG. The program executed by the ECU 170 may be recorded on a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc) and distributed to the market.

  In step (hereinafter, step is abbreviated as S) 100, ECU 170 calculates upper limit value H (t) of hybrid vehicle driving force and expected value H (t + tsk) of upper limit value H (t).

  In S102, ECU 170 calculates first required driving force f (t) requested by the driver to the vehicle and predicted value f (t + tsk) of first required driving force f (t).

  In S104, ECU 170 determines whether or not expected value f (t + tsk) of first required driving force f (t) is larger than expected value H (t + tsk) of upper limit value H (t) of driving force. to decide. If predicted value f (t + tsk) of first required driving force f (t) is larger than expected value H (t + tsk) of upper limit value H (t) of driving force (YES in S104), the process is S106. Moved to. If the predicted value f (t + tsk) of the first required driving force f (t) is equal to or less than the predicted value H (t + tsk) of the upper limit value H (t) of the driving force (NO in S104), the process is Moved to S110.

  In S106, ECU 170 starts calculating the second required driving force F (t) required for the vehicle.

  In S108, ECU 170 controls the power train so that the actual driving force of the hybrid vehicle becomes the second required driving force F (t). In S110, ECU 170 controls the power train so that the actual driving force of the hybrid vehicle becomes the first required driving force f (t).

  An operation of the control device according to the present embodiment based on the above-described structure and flowchart will be described.

  While the hybrid vehicle is traveling, an upper limit value H (t) and an expected value H (t + tsk) of the upper limit value H (t) are calculated (S100). Further, the first required driving force f (t) requested by the driver to the vehicle and the expected value f (t + tsk) of the first required driving force f (t) are calculated (S102).

  If the predicted value f (t + tsk) of the first required driving force f (t) is equal to or less than the predicted value H (t + tsk) of the upper limit value H (t) of the driving force (NO in S104), the hybrid vehicle The power train is controlled so that the actual driving force becomes the first required driving force f (t) (S110). Thus, the driver's request can be satisfied.

  On the other hand, as shown in FIG. 7, at time t0, the expected value f (t + tsk) of the first required driving force f (t) is the expected value H (t + tsk) of the upper limit value H (t) of the driving force. When it becomes larger (YES in S104), calculation of the second required driving force F (t) is started (S106). As shown by the alternate long and short dash line in FIG. 7, the second required driving force F (t) is calculated so as to gradually approach the upper limit value H (t) of the driving force.

  The power train is controlled so that the actual driving force of the hybrid vehicle becomes the second required driving force F (t) (S108). Thereby, the actual driving force of the vehicle can be gradually brought close to the upper limit value H (t) of the driving force. Therefore, when the driving force of the vehicle controlled to become the first required driving force f (t) of the driver as shown by a two-dot chain line in FIG. 7 is limited to the upper limit value H (t) at time t1. As compared with the above, the actual driving force of the vehicle can be gradually limited.

  In FIG. 7, the upper limit value H (t) of the driving force is increased because the expected value f (t + tsk) of the first required driving force f (t) is the upper limit value H (t This is because the economy mode was automatically terminated as a result of the increase in the expected value H (t + tsk) of).

  As described above, according to the control device according to the present embodiment, the predicted value f (t + tsk) of the first required driving force f (t) of the driver is the predicted value of the upper limit value H (t) of the driving force. When it becomes larger than H (t + tsk), the second required driving force F (t) becomes smaller so that the difference between the upper limit value H (t) and the second required driving force F (t) becomes smaller as time elapses. Calculated. Further, the power train is controlled so that the actual driving force of the hybrid vehicle becomes the second required driving force F (t). Thereby, the actual driving force of the vehicle can be gradually brought close to the upper limit value H (t) of the driving force. That is, the actual driving force of the vehicle can be gradually limited. Therefore, it is possible to reduce a shock that may occur when the driving force is limited. As a result, the deterioration of drivability can be reduced.

  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.

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 functional block diagram of ECU. It is a figure which shows the ideal curve D (t). It is a flowchart which shows the control structure of the program which ECU performs. 4 is a timing chart showing a first required driving force f (t), a second required driving force F (t), and the like.

Explanation of symbols

  100 Engine, 110 1st MG, 120 2nd MG, 130 Power split mechanism, 140 Reducer, 150 Battery, 160 Front wheel, 170 ECU, 176 Eco switch, 180 Voltmeter, 200 Converter, 210 1st inverter, 220 2nd inverter, 230 DC / DC converter, 240 Auxiliary battery, 242 Auxiliary machine, 700 Upper limit value calculation unit, 710 Required driving force calculation unit, 720 Judgment unit, 730 Required driving force calculation unit, 740 Control unit.

Claims (3)

A vehicle control device provided with a power train,
Means for calculating an upper limit value of the driving force of the vehicle;
Calculating means for calculating a first required driving force requested by the driver to the vehicle;
Determining means for determining whether or not the first required driving force exceeds the upper limit;
When it is determined that the first required driving force exceeds the upper limit value, a second required driving force required for the vehicle is determined in advance by a difference between the upper limit value and the second required driving force. Calculating means for calculating to change in a predetermined manner;
And means for controlling the power train so that the actual driving force of the vehicle becomes the second required driving force when it is determined that the first required driving force exceeds the upper limit value. Vehicle control device.   2. The vehicle control device according to claim 1, wherein the predetermined mode is a mode in which a difference between the upper limit value and the second required driving force becomes smaller as time elapses. The determination means includes
Means for predicting an expected value of the upper limit value after a predetermined time;
Means for predicting an expected value of the first required driving force after the predetermined time;
2. The apparatus according to claim 1, further comprising means for determining that the first required driving force exceeds the upper limit value when an expected value of the first required driving force is greater than an expected value of the upper limit value. Vehicle control device.

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