JP2009023378A - Control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a vehicle enabling slow speed backing as intended by a driver. <P>SOLUTION: The control device of a vehicle is provided with: an accelerator opening detection means; a tilt angle detection means; a speed detection means; a request driving force calculation means; a running resistance calculation means; and a control means. The request driving force calculation means calculates the request driving force of the driver from the accelerator opening. The running resistance calculation means calculates a running resistance from the tilt angle of a road surface. When the speed of a vehicle is within a prescribed range, and the request driving force is a running resistance obtained by the traveling resistance calculation means or less, the control means causes a vehicle to generate a braking force by a brake and a driving force by a motor based on the request driving force and the running resistance. Thus, it is possible to prevent the specific switching element of an invertor from thermally breaking down, and to smoothly perform slow speed backing as intended by the driver. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle control apparatus that controls braking force and driving force generated in a vehicle.

  In an electric vehicle or a hybrid vehicle, there is a possibility that the electric motor may be locked due to insufficient depression of the accelerator pedal when climbing up. When the electric motor is in a locked state, current concentrates on a specific switching element of the inverter that drives the electric motor, and a rapid temperature increase may occur, which may cause thermal destruction of the switching element. In order to prevent such thermal destruction of the switching element, for example, in Patent Document 1, it is determined that the actual vehicle traveling state is a traveling state unintended by the driver, and the command value of the required torque is equal to or less than the uphill torque In this case, a technique for releasing the lock state by operating the brake and setting the drive output to the electric motor to zero is described.

  Patent Document 2 describes a technique for reducing torque so as to change the phase region of a motor in order to release a lock state when an electric vehicle is climbing uphill. Further, in Patent Document 3, when the vehicle is stopped on a slope with the driving torque being equal to or greater than a predetermined value, the driving torque output to the electric motor is calculated using the hydraulic braking force. There is described a technique for reducing the electric power consumption of an electric motor by lowering the driving torque from a normal driving torque controlled according to an operating state. Furthermore, Patent Document 4 describes a technique for generating a braking force having a value corresponding to a vehicle speed when the vehicle speed is equal to or lower than a predetermined value in a vehicle traveling on a congested road.

JP 2004-180437 A JP 11-215687 A JP 2003-182404 A Japanese Patent Laid-Open No. 10-329684

  However, in the technique described in Patent Document 1, since the drive output to the electric motor is set to zero, it is possible to perform slow speed travel according to the driver's intention during reverse, that is, slow speed travel according to the driver's intention. Can not. This point is not studied at all in Patent Documents 2 to 4.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a vehicle control device capable of performing a slow reverse according to the driver's intention.

  In one aspect of the present invention, a vehicle control device includes an accelerator opening detecting unit that detects an accelerator opening, an inclination angle detecting unit that detects an inclination angle of a road surface, and a speed detecting unit that detects a vehicle speed. From the accelerator opening obtained from the accelerator opening detecting means, the required driving force calculating means for calculating the driver's required driving force and the road resistance obtained from the inclination angle of the road surface obtained by the inclination angle detecting means. The running resistance calculating means for calculating and the vehicle speed obtained by the speed detecting means are within a predetermined range, and the required driving force obtained by the required driving force calculating means is obtained by the running resistance calculating means. Control means for causing the vehicle to generate a braking force by a brake and a driving force by an electric motor based on the required driving force and the traveling resistance when the driving resistance is less than or equal to the traveling resistance.

  The vehicle control apparatus includes an accelerator opening degree detecting means, an inclination angle detecting means, a speed detecting means, a required driving force calculating means, a running resistance calculating means, and a control means. The accelerator opening detection means is, for example, an accelerator opening sensor, and detects the accelerator opening. The inclination angle detection means is, for example, an inclination angle sensor, and detects the inclination angle of the road surface. The required driving force calculation means, the running resistance calculation means, and the control means are, for example, an ECU (Electronic Control Unit). The required driving force calculating means calculates a driver's required driving force from the accelerator opening obtained by the accelerator opening detecting means. The travel resistance calculating means calculates a travel resistance from the road surface inclination angle obtained by the inclination angle detecting means. The control means is such that the vehicle speed obtained by the speed detection means is within a predetermined range, and the required driving force obtained by the required driving force calculation means is equal to or less than the running resistance obtained by the running resistance calculation means. In this case, the braking force generated by the brake and the driving force generated by the electric motor are generated in the vehicle based on the required driving force and the running resistance. By doing so, it is possible to prevent current from concentrating on a specific switching element of the inverter, to prevent the switching element from being thermally destroyed, and to smoothly perform a slow reverse according to the driver's intention. It can be carried out.

  In another aspect of the vehicle control device, the regenerative unit that supplies battery power from the rotational energy of the generator, and the vehicle speed obtained by the speed detection unit is smaller than a lower limit value of the predetermined range. A regenerative braking means for causing the vehicle to generate a regenerative braking force from the regenerative means. The regeneration means is, for example, a motor, and the regeneration control means is, for example, an ECU. In this way, power can be recovered.

  Another aspect of the vehicle control apparatus includes inverter temperature prediction means for predicting an inverter temperature after a predetermined time of the electric motor, and the control means has a temperature predicted by the inverter prediction means having a predetermined value. In the above case, the braking force by the brake is generated in the vehicle. The inverter temperature predicting means is, for example, an ECU. By doing in this way, the frequency | count of operating a brake can be reduced and the discomfort which a driver | operator feels can be reduced.

  Another aspect of the vehicle control device includes a temperature detection unit configured to detect a temperature of the inverter, and the inverter temperature prediction unit is configured to perform the predetermined time based on the inverter temperature and the inverter current. The temperature of the inverter after the lapse is predicted. The temperature detection means is, for example, a temperature sensor. As a result, the temperature of the inverter can be reliably predicted.

  Another aspect of the vehicle control device includes an internal combustion engine, internal combustion engine starting means for supplying electric power from the battery to a generator, and starting the internal combustion engine by the generator, the required driving force, Output predicting means for predicting the output of the vehicle when a predetermined time elapses based on the running resistance, and internal combustion engine control for starting the internal combustion engine by the internal combustion engine starting means when the output is greater than or equal to a predetermined value The internal combustion engine control means starts the internal combustion engine by the internal combustion engine start means while the control means is generating braking force by the brake in the vehicle. The internal combustion engine starting means, output predicting means, internal combustion engine control means, and braking force generating means are, for example, ECUs. By doing so, the reaction force of the starting torque of the internal combustion engine can be canceled by the braking force of the brake, so that the driving force of the electric motor can be reduced and the battery output at the time of starting the internal combustion engine can be reduced. Can be reduced.

  In another aspect of the present invention, a control device for a vehicle detects an accelerator opening, an internal combustion engine, internal combustion engine starting means for supplying power from a battery to a generator, and starting the internal combustion engine by the generator. An accelerator opening detecting means; a required driving force calculating means for calculating a driver's required driving force from an accelerator opening obtained by the accelerator opening detecting means; a running resistance calculating means for calculating a running resistance; Output predicting means for predicting the output of the vehicle when a predetermined time elapses based on the required driving force and the running resistance; and when the output exceeds a predetermined value, the internal combustion engine starting means Internal combustion engine control means for starting, and braking force generation means for generating braking force by the brake on the vehicle, while the braking force generation means is generating braking force by the brake on the vehicle The internal combustion engine control means starts the internal combustion engine by said engine starting means. By doing so, the reaction force of the starting torque of the internal combustion engine can be offset by the braking force of the brake, not only when the vehicle is climbing uphill, thereby reducing the driving force of the electric motor. The battery output at the time of starting the internal combustion engine can be reduced.

  According to the vehicle control apparatus of the present invention, the control means has the vehicle speed obtained by the speed detecting means within a predetermined range, and the required driving force obtained from the required driving force calculating means is the running resistance calculating means. When the travel resistance is less than or equal to the obtained travel resistance, the braking force generated by the brake and the drive force generated by the electric motor are generated in the vehicle based on the required drive force and the travel resistance. By doing so, it is possible to prevent current from concentrating on a specific switching element of the inverter, to prevent the switching element from being thermally destroyed, and to smoothly perform a slow reverse according to the driver's intention. It can be carried out.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Vehicle configuration]
First, a hybrid vehicle to which the vehicle control device of the present invention is applied will be described with reference to FIG.

  FIG. 1 is a diagram showing a schematic configuration of the hybrid vehicle 100. The hybrid vehicle 100 mainly includes an engine (internal combustion engine) 1, an axle 2, wheels 3, motors (motor generators) MG 1 and MG 2, a planetary gear 4, an inverter 5, a battery 6, and an ECU (Electronic Control). Unit) 10.

  The axle 2 is a part of a power transmission system that transmits the power of the engine 1 and the motor MG2 to the wheels 3. The wheels 3 are wheels of the hybrid vehicle 100, and only the left and right front wheels are particularly shown in FIG. The engine 1 is constituted by a gasoline engine or the like, and functions as a power source that outputs the main driving force of the hybrid vehicle 100. The engine 1 is controlled variously by the ECU 10. Specifically, the ECU 10 controls the number of engine revolutions, or controls the opening (throttle opening) of a throttle valve (not shown).

  Motor MG1 is configured to function mainly as a generator for charging battery 6 or a generator for supplying electric power to motor MG2. The motor MG1 is configured to function as a generator for starting the engine 1. The motor MG2 is mainly configured to function as an electric motor that assists (assists) the output of the engine 1. These motors MG1 and MG2 are configured as, for example, synchronous motor generators, and include a rotor having a plurality of permanent magnets on the outer peripheral surface, and a stator wound with a three-phase coil that forms a rotating magnetic field. The planetary gear (planetary gear mechanism) 4 is configured to be able to distribute the output of the engine 1 to the motor MG1 and the axle 2 and functions as a power split mechanism.

  The inverter 5 is a DC / AC converter that controls power input / output between the battery 6 and the motors MG1 and MG2. For example, the inverter 5 converts the DC power taken out from the battery 6 into AC power, or supplies AC power generated by the motor MG1 to the motor MG2 and converts the AC power generated by the motor MG1 into DC power. It can be converted to and supplied to the battery 6. The battery 6 is a rechargeable storage battery configured to be able to function as a power source for driving the motor MG1 and the motor MG2.

  The ECU 10 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). The ECU 10 controls the entire operation of the hybrid vehicle 100 and controls the driving force by the motor MG2 and the braking force by the brake, as will be described later.

  FIG. 2 is a schematic diagram illustrating a vehicle control device. 2 is a view of the hybrid vehicle 100 observed from above, with the left showing the front of the hybrid vehicle 100 and the right showing the rear of the hybrid vehicle 100. FIG. In addition, broken line arrows in the figure indicate signal input / output. Further, the wheels 3FR and 3FL indicate the front wheels of the wheel 3, and the wheels 3RR and 3RL indicate the rear wheels of the wheel 3.

  The vehicle control device mainly includes wheel speed sensors 13FR, 13FL, 13RR, 13RL, a brake system 14, an oil passage 14a, brakes 15FR, 15FL, 15RR, 15RL, an inclination angle sensor 17, and an accelerator opening. The sensor 18 and the ECU 10 are provided.

  As described above, the motor MG2 is mainly configured to function as an electric motor that assists (assides) the output of the engine 1. Motor MG2 is controlled in its driving force and the like by a control signal supplied from ECU 10.

  The wheel speed sensors 13FR, 13FL, 13RR, and 13RL are sensors that detect rotational speeds (hereinafter also referred to as “wheel speed”) of the wheels 3FR, 3FL, 3RR, and 3RL, respectively. The wheel speed sensors 13FR, 13FL, 13RR, and 13RL supply the ECU 10 with detection signals corresponding to the wheel speed. The inclination angle sensor 17 is a sensor that detects the inclination angle of the road surface. The inclination angle sensor 17 supplies a detection signal corresponding to the detected value to the ECU 10. Further, the accelerator opening sensor 18 is a sensor that detects the accelerator opening of the driver. The accelerator opening sensor 18 supplies a detection signal corresponding to the detected value to the ECU 10.

  The brake system 14 is configured by a hydraulic system. The brake system 14 includes a master cylinder and a hydro unit (not shown), and is connected to brakes 15FR, 15FL, 15RR, and 15RL through an oil passage 14a. The brake system 14 is controlled by a control signal supplied from the ECU 10. The brakes 15FR, 15FL, 15RR, and 15RL are constituted by friction brakes such as a drum brake and a disc brake. The brakes 15FR, 15FL, 15RR, 15RL are driven by the hydraulic pressure supplied from the brake system 14 via the oil passage 14a, and generate braking forces for the wheels 3FR, 3FL, 3RR, 3RL. In this case, the brakes 15FR, 15FL, 15RR, 15RL generate a braking force according to the value of the hydraulic pressure supplied from the brake system 14. Here, in the brakes 15FR, 15FL, 15RR, and 15RL, when there is no distinction between front and rear, right and left, they are simply used as “brake 15”. Note that the mechanism for generating the braking force for the hybrid vehicle 100 is not limited to being configured by the hydraulic brake system 14 or the like.

  As described above, the ECU 10 includes a CPU, ROM, and RAM (not shown). In each embodiment, the ECU 10 mainly controls the driving force by the motor MG2 and the braking force by the brake 15 when the hybrid vehicle 100 is climbing up. Specifically, the ECU 10 calculates the running resistance of the hybrid vehicle 100 based on the road surface inclination angle obtained from the inclination angle sensor 17, and based on the accelerator opening obtained from the accelerator opening sensor 18, The driver's required driving force is calculated, and the speed of the hybrid vehicle 100 is calculated based on the wheel speed acquired from the wheel speed sensor 13. When the ECU 10 determines that the speed of the hybrid vehicle 100 is within the predetermined range, the ECU 10 controls the driving force by the motor MG2 and the braking force by the brake 15 based on the calculated running resistance and the required driving force. To do.

[First Embodiment]
Next, a vehicle control method according to the first embodiment will be described. In FIG. 3, a graph 31 shows the relationship between the speed V of the hybrid vehicle 100 on the uphill road and the required driving force, and a graph 32 shows the speed V of the hybrid vehicle 100 on the uphill road and the magnitude of the braking force by the brake 15. Show. That is, in FIG. 3, the hatched portion surrounded by the graph 32 indicates the ratio of the braking force by the brake 15 to the required driving force.

  In FIG. 3, when the speed V is 0, it indicates that the hybrid vehicle 100 is stopped on the uphill road. Further, when the speed V is larger than 0, it indicates that the hybrid vehicle 100 is moving forward on the uphill road, and when the speed V is lower than 0, the hybrid vehicle 100 descends on the uphill road. It shows that it is retreating in the direction.

  In a typical hybrid vehicle, on the uphill road, all of the required driving force is carried by the driving force of the motor, which is an electric motor, regardless of the speed of the hybrid vehicle. For this reason, when the hybrid vehicle is stopped or retreating at a slow speed on the uphill road, the current concentrates on the specific switching element of the inverter that drives the motor as the electric motor, and a rapid temperature rise occurs. The specific switching element may be thermally destroyed. On the other hand, if the hybrid vehicle is stopped on the uphill only by generating the braking force of the brake on the hybrid vehicle, it is possible to prevent the current from concentrating on a specific switching element of the inverter, but the driver's intention Depending on the situation, it will not be possible to perform a slow reverse.

  Therefore, in the first embodiment, the ECU 10 determines that the driver is in a state where the hybrid vehicle 100 is stopped or retreats at a slow speed on the uphill road, that is, when the speed of the hybrid vehicle 100 is within a predetermined range. When the requested driving force is equal to or less than the running resistance, the hybrid vehicle 100 generates the driving force by the motor MG2 and the braking force by the brake 15 based on the running resistance and the requested driving force.

  Specifically, the ECU 10 determines that the speed V of the hybrid vehicle 100 is within a predetermined range (Va ≦ V ≦ 0), that is, the hybrid vehicle 100 is stopped on the uphill road or retreats at a slow speed. If it is determined that the vehicle is in a state, as shown in FIG. 3, a certain proportion X1 of the required driving force is carried by the braking force by the brake 15, and the remaining proportion X2 is driven by the driving force by the motor MG2. I will bear it. By doing in this way, it can prevent that an electric current concentrates on the specific switching element of the inverter 5, and can prevent the said switching element being thermally destroyed. In addition, the required driving force is not only caused by the braking force by the brake 15 but also by the driving force by the motor MG2, so that the slow reverse according to the driver's intention can be smoothly performed. The magnitude of the speed Va is a value obtained by experiment or the like based on the amount of heat generated by the inverter per unit time in the inverter 5 based on the amount of heat generated by the inverter per unit time. Etc. are recorded.

  When the ECU 10 determines that the speed V is higher than the speed 0, that is, when the hybrid vehicle 100 determines that the hybrid vehicle 100 is moving forward on the uphill road, it is shown in FIG. As described above, the braking by the brake 15 is stopped, and all the required driving force is assumed to be borne by the driving force of the motor MG2. This is because in this case, the hybrid vehicle 100 does not retreat on the uphill road (V> 0), and it is not necessary to cause the hybrid vehicle 100 to generate a braking force by the brake 15.

  When the ECU 10 determines that the speed V is smaller than the lower limit value Va of the predetermined range, that is, the ECU 10 determines that the hybrid vehicle 100 is moving backward on the uphill road at a certain speed. In this case, the braking by the brake 15 is stopped as shown in FIG. At this time, the ECU 10 causes the motor MG1 or the motor MG2 to function as a regenerative brake so that the required driving force is all borne by the regenerative braking force by the motor MG1 or the motor MG2. At this time, the motor MG1 or the motor MG2 converts the rotational energy generated in the motor shaft into electric energy and supplies it to the battery 6. That is, when the speed V is smaller than the speed Va (V <Va), the reverse speed of the hybrid vehicle 100 is such that current does not concentrate on a specific switching element of the inverter 5. Since it is sufficiently large, the ECU 10 stops the braking by the brake 15 and operates the regenerative brake. By doing in this way, electric power can be collect | recovered from motor MG1 or motor MG2.

  4A to 4D are examples of graphs showing the relationship between the accelerator opening, the required driving force, the speed, and the driving force ratio of the hybrid vehicle 100 on the uphill road, and time. A graph 41 in FIG. 4A shows the accelerator opening with respect to the time of the hybrid vehicle 100 on the uphill road. A graph 42 in FIG. 4B shows the required driving force with respect to time of the hybrid vehicle 100 on the uphill road. A graph 43 in FIG. 4C shows the speed V with respect to time of the hybrid vehicle 100 on the uphill road. The graph 44a in FIG. 4D shows the ratio of the driving force by the motor MG2 to the required driving force, and the graph 44b shown by the alternate long and short dash line shows the ratio of the braking force by the brake 15 to the required driving force. Since the required driving force is obtained based on the accelerator opening, the graph 41 in FIG. 4A and the graph 42 in FIG. 4B are both qualitatively the same tendency. Yes.

  From time 0 to time T1, the required driving force obtained based on the accelerator opening is larger than the running resistance as shown in the graph 42 of FIG. 4B, and thus the hybrid vehicle 100 is accelerated. The speed V increases with time as shown in the graph 43 of FIG. At this time, the ratio of the driving force by the motor MG2 to the required driving force is 100% as shown in the graph 44a of FIG. This is because, at this time, the required driving force is larger than the running resistance, so the ECU 10 can consider that the driver has an intention to accelerate, and it is not necessary to cause the hybrid vehicle 100 to generate the braking force by the brake 15. .

  From time T1 to time T2, as shown in the graph 42 of FIG. 4B, the required driving force is smaller than the running resistance, so the hybrid vehicle 100 is decelerated and its speed V is as shown in FIG. As shown in the graph 43 of c), it decreases with the passage of time. At this time, the ratio of the driving force by the motor MG2 to the required driving force is 100% as shown in the graph 44a of FIG. This is because in this case, the hybrid vehicle 100 is in a state where the vehicle is climbing forward on an uphill road while reducing the speed (V> 0), the ECU 10 applies the braking force by the brake 15 to the hybrid vehicle. This is because there is no need to generate it in 100.

  From time T2 to time T3, the speed V of the hybrid vehicle 100 is smaller than the speed 0 (V <0) as shown in the graph 43 of FIG. That is, at this time, the hybrid vehicle 100 is moving backward on the uphill road. Accordingly, the ECU 10 causes the hybrid vehicle 100 to generate a braking force by the brake 15 as shown in the graphs 44a and 44b in FIG. At this time, the ECU 10 controls the braking force by the brake 15 and the driving force by the motor MG2 so that the sum of the braking force by the brake 15 and the driving force by the motor MG2 is always the required driving force.

  From time T3 to time T4, as shown in the graph 42 of FIG. 4B, the required driving force is substantially the same as the running resistance. Therefore, the speed V of the hybrid vehicle 100 is as shown in FIG. As shown in the graph 43 of (), the speed Vb is smaller than the speed 0 and is constant. That is, at this time, the hybrid vehicle 100 moves backward at a constant speed (the magnitude of the speed Vb) on the uphill road. Here, the speed Vb satisfies the relationship Va ≦ Vb ≦ 0. Therefore, as shown in the graphs 44a and 44b in FIG. 4D, the ECU 10 causes the hybrid vehicle 100 to generate the braking force by the brake 15 and also causes the hybrid vehicle 100 to generate the driving force by the motor MG2. Also at this time, the ECU 10 controls the braking force by the brake 15 and the driving force by the motor MG2 so that the sum of the braking force by the brake 15 and the driving force by the motor MG2 is always the required driving force. As described above, from time T2 to time T4, the driving force generated by the motor MG2 and the braking force generated by the brake 15 are generated in the hybrid vehicle 100, thereby preventing current from concentrating on a specific switching element of the inverter 5. It is possible to prevent the specific switching element from being thermally destroyed and to smoothly perform the slow reverse according to the driver's intention.

  After time T4, as shown in the graph 42 of FIG. 4B, the required driving force is greater than the running resistance, so that the hybrid vehicle 100 is accelerated and its speed V is as shown in FIG. 4C. As shown in the graph 43, the value increases with the passage of time, and at time T5, becomes greater than the speed 0. That is, at this time, the hybrid vehicle 100 gradually slows down on the uphill road from time T4 to time T5, and moves forward on the uphill road after time T5. If the ECU 10 determines that the required driving force is greater than the running resistance, the driver 10 intends to accelerate and stops braking by the brake 15 as shown in the graphs 44a and 44b in FIG. Suppose that the required driving force is carried only by the driving force by the motor MG2. Thereby, the hybrid vehicle 100 can be accelerated smoothly.

  As can be seen from the above, in the vehicle control method according to the first embodiment, the ECU 10 performs the requested drive when the hybrid vehicle 100 determines that the hybrid vehicle 100 is stopped or retreats at a slow speed on the uphill road. When the force is equal to or less than the running resistance, the hybrid vehicle 100 generates the driving force by the motor MG2 and the braking force by the brake 15 based on the calculated running resistance and the required driving force. At this time, the ECU 10 controls the braking force by the brake 15 and the driving force by the motor MG2 so that the sum of the braking force by the brake 15 and the driving force by the motor MG2 is always the required driving force. As a result, it is possible to prevent current from concentrating on a specific switching element of the inverter 5, to prevent the specific switching element from being thermally destroyed, and to smoothly perform a slow reverse according to the driver's intention. be able to.

(Modification of the first embodiment)
Next, a modification of the first embodiment will be described. In the above-described first embodiment, when the ECU 10 determines that the hybrid vehicle 100 is in a state of being stopped or retreating at a slow speed on the uphill road, The braking force generated by the brake 15 is generated in the hybrid vehicle 100. On the other hand, in the modified example of the first embodiment, as a further limiting condition, the hybrid vehicle 100 generates the braking force by the brake 15 only when the inverter temperature of the inverter 5 after a predetermined time elapses exceeds a predetermined value. I will do it. Thereby, the frequency | count of operating the brake 15 can be reduced, and the discomfort which a driver | operator feels can be reduced. This predetermined time is set in advance and recorded in a ROM or the like. The details will be described below.

  First, the ECU 10 predicts the temperature of the inverter 5 after a predetermined time has elapsed based on the temperature of the inverter 5 and the inverter current. Specifically, a temperature sensor for detecting the inverter temperature is attached to the inverter 5, and the ECU 10 obtains the inverter temperature based on the detection signal from the temperature sensor. Further, the ECU 10 predicts the rising temperature of the inverter temperature after a predetermined time has elapsed based on the inverter current.

  A method for predicting the rising temperature of the inverter temperature after a predetermined time has elapsed will be described based on the inverter current. Since the inverter heat generation amount per unit time in the inverter 5 is considered to be proportional to the square of the inverter current flowing through the inverter 5, the ECU 10 can estimate the inverter heat generation amount per unit time based on the inverter current. . Then, the ECU 10 can predict the rising temperature of the inverter temperature after a predetermined time has elapsed based on the estimated inverter heat generation amount per unit time. For example, the ECU 10 can obtain the rising temperature of the inverter temperature after a predetermined time has elapsed, using a map showing the relationship between the rising temperature of the inverter temperature and the amount of heat generated by the inverter. In this way, the ECU 10 can predict the rising temperature of the inverter temperature after a predetermined time has elapsed based on the inverter current.

  The ECU 10 predicts, as the inverter temperature after the lapse of the predetermined time, a value obtained by adding the rising temperature of the inverter temperature after the lapse of the predetermined time to the inverter temperature obtained based on the detection signal from the temperature sensor. By doing in this way, the inverter temperature of the inverter 5 after predetermined time progress can be estimated reliably. Needless to say, the method of predicting the inverter temperature after the elapse of the predetermined time is not limited to this. For example, the ECU 10 estimates the inverter heat generation amount per unit time based on the inverter current, and based on only the estimated inverter heat generation amount per unit time, using a map or the like, the inverter temperature after a predetermined time has elapsed. May be predicted.

  When the ECU 10 determines that the inverter temperature after a predetermined time has elapsed becomes equal to or higher than a predetermined value, the ECU 10 causes the hybrid vehicle 100 to generate a braking force by the brake 15. The predetermined value here is a value of an inverter temperature at which a specific switching element can be thermally destroyed.

  That is, in the second embodiment, the ECU 10 determines that the required driving force is equal to or less than the running resistance when the hybrid vehicle 100 determines that the hybrid vehicle 100 is stopped or retreats at a slow speed, and The hybrid vehicle 100 is caused to generate the braking force by the brake 15 only when the predicted inverter temperature after the elapse of the predetermined time exceeds a predetermined value. In this way, the brake 15 is operated only when the inverter temperature of the inverter 5 after a predetermined time is predicted to be equal to or higher than a predetermined value. Therefore, the brake 15 is compared with the above-described embodiment. The number of times of operating can be reduced, and the uncomfortable feeling felt by the driver can be reduced.

  In the above-described first embodiment and its modification, the vehicle control device of the present invention is applied to a hybrid vehicle. However, the present invention is not limited to this. Instead, the vehicle control device of the present invention is electrically connected. It goes without saying that the same effect can be obtained even if it is applied to an automobile.

[Second Embodiment]
Next, a vehicle control method according to the second embodiment will be described. In the vehicle control method according to the second embodiment, when the ECU 10 determines that the hybrid vehicle 100 is stopped or retreats at a slow speed on the uphill road, the engine needs to be started soon after the start of forward movement. If this is expected, the engine 1 is started while the brake 15 is being operated. Thereby, the torque of motor MG2 can be reduced. The details will be described below.

  First, when the ECU 10 determines that the hybrid vehicle 100 is stopped or retreats at a slow speed on an uphill road, the hybrid vehicle 100 when a predetermined time elapses based on the required driving force and the running resistance. Predict the output of. This predetermined time is set in advance and recorded in a ROM or the like. Here, the predicted output of the hybrid vehicle 100 when a predetermined time has elapsed can be predicted by the method described below. First, when the required driving force is F, the running resistance is R, and the mass and acceleration of the hybrid vehicle 100 are m and α, respectively, the following equation of motion (1) is established.

mα = F−R
→ α = (F−R) / m (1)
By integrating the above equation (1) over a predetermined time, the expected vehicle speed Vt of the hybrid vehicle 100 when the predetermined time elapses can be obtained. And the output P estimated when predetermined time passes can be calculated | required from the following formula | equation (2).

P = F · Vt (2)
That is, the ECU 10 obtains the predicted output P of the hybrid vehicle 100 when a predetermined time has elapsed by substituting the required driving force F and the running resistance R into the above formulas (1) and (2). it can.

  When the output P is equal to or greater than the predetermined value, the ECU 10 determines that the engine needs to be started soon after the start of forward movement, and the hybrid vehicle 100 generates the braking force by the brake 15 (time in FIG. 4). The engine 1 is started from the time T2 to the time T4. The predetermined value here is the magnitude of the output of the hybrid vehicle 100 when the engine 1 needs to be started, and is obtained in advance through experiments or the like and recorded in a ROM or the like.

  To summarize the above, when the ECU 10 determines that the hybrid vehicle 100 is in a state of being stopped or retreating at a slow speed on an uphill road, the ECU 10 determines when a predetermined time has elapsed based on the required driving force and the running resistance. When the output of the hybrid vehicle 100 is predicted and the output exceeds a predetermined value, the engine 1 is started while the braking force by the brake 15 is generated in the hybrid vehicle 100. Thus, by starting the engine 1 while the hybrid vehicle 100 is generating the braking force by the brake 15, the reaction force of the starting torque of the engine 1 by the motor MG 1 is canceled by the braking force of the brake 15. be able to. Therefore, in the second embodiment, the driving force of the motor MG2 can be reduced compared to the case of a general hybrid vehicle in which all the reaction force of the starting torque of the engine 1 is canceled by the driving force of the motor MG2. The battery output of the battery 6 when the engine 1 is started can be reduced.

  In the second embodiment described above, it is assumed that the hybrid vehicle 100 is in a state of being stopped or retreating at a slow speed on an uphill road. However, the present invention is not limited to this. It does not have to be on the street. In short, the ECU 10 calculates the required driving force and the running resistance, predicts the output of the hybrid vehicle 100 when a predetermined time has elapsed based on the required driving force and the running resistance, and the output is equal to or greater than a predetermined value. The engine 1 may be started while the hybrid vehicle 100 is generating the braking force by the brake 15. Thereby, even when the hybrid vehicle 100 is not on an uphill road, the driving force of the motor MG2 can be reduced, and the battery output of the battery 6 when the engine 1 is started can be reduced.

It is a schematic diagram which shows schematic structure of a hybrid vehicle. It is a schematic diagram which shows the control apparatus of the vehicle of this invention. It is a graph which shows the relationship between the speed and required drive force in the uphill road of a hybrid vehicle. It is an example of the graph which shows the relationship between each of the accelerator opening degree, request | requirement driving force, speed | velocity | rate, and driving force ratio in the uphill road of a hybrid vehicle, and time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 3 Wheel 4 Planetary gear 9 Fuel injection valve MG1, MG2 Motor 5 Inverter 6 Battery 13 Wheel speed sensor 15 Brake 17 Inclination angle sensor 18 Accelerator opening sensor 100 Hybrid vehicle

Claims (6)

An accelerator opening detecting means for detecting the accelerator opening;
An inclination angle detecting means for detecting an inclination angle of the road surface;
Speed detecting means for detecting the speed of the vehicle;
From the accelerator opening obtained by the accelerator opening detecting means, the required driving force calculating means for calculating the driver's required driving force;
A running resistance calculating means for calculating a running resistance from the inclination angle of the road surface obtained by the tilt angle detecting means;
When the vehicle speed obtained by the speed detecting means is within a predetermined range, and the required driving force obtained by the required driving force calculating means is less than or equal to the running resistance obtained by the running resistance calculating means, A control device for a vehicle, comprising: control means for causing the vehicle to generate a braking force by a brake and a driving force by an electric motor based on the required driving force and the running resistance. Regenerative means for supplying battery power from the rotational energy of the generator;
Regenerative braking means for generating regenerative braking force from the regenerative means to the vehicle when the vehicle speed obtained by the speed detection means is smaller than a lower limit value of the predetermined range. Item 2. The vehicle control device according to Item 1. Inverter temperature predicting means for predicting the temperature of the inverter of the electric motor after a predetermined time has elapsed,
3. The vehicle according to claim 1, wherein the control unit causes the vehicle to generate a braking force by the brake when the inverter temperature predicted by the inverter temperature prediction unit is equal to or higher than a predetermined value. 4. Control device. Temperature detecting means for detecting the temperature of the inverter,
The vehicle control device according to claim 3, wherein the inverter temperature predicting unit predicts a temperature of the inverter after the predetermined time has elapsed based on a temperature of the inverter and an inverter current. An internal combustion engine;
Internal combustion engine starting means for supplying electric power of the battery to a generator, and starting the internal combustion engine by the generator;
Output predicting means for predicting the output of the vehicle when a predetermined time elapses based on the required driving force and the running resistance;
An internal combustion engine control means for starting the internal combustion engine by the internal combustion engine start means when the output is greater than or equal to a predetermined value, while the control means is generating braking force by the brake in the vehicle, The vehicle control device according to any one of claims 1 to 4, wherein the internal combustion engine control means starts the internal combustion engine by the internal combustion engine start means. An internal combustion engine;
An internal combustion engine starting means for supplying battery power to a generator and starting the internal combustion engine with the generator;
An accelerator opening detecting means for detecting the accelerator opening;
From the accelerator opening obtained by the accelerator opening detecting means, the required driving force calculating means for calculating the driver's required driving force;
Running resistance calculating means for calculating running resistance;
Output predicting means for predicting the output of the vehicle when a predetermined time elapses based on the required driving force and the running resistance;
An internal combustion engine control means for starting the internal combustion engine by the internal combustion engine start means when the output is equal to or greater than a predetermined value;
Braking force generating means for generating braking force by the brake on the vehicle, and the internal combustion engine control means starts the internal combustion engine while the braking force generating means is generating braking force by the brake on the vehicle. A control apparatus for a vehicle, characterized in that the internal combustion engine is started by means.

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