JP3974091B2 - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of a hybrid car in which a vehicle is prevented from retracting on an upward slope and dragging of a brake does not occur when the vehicle is started. <P>SOLUTION: The controller of a hybrid vehicle equipped with an engine E and a motor M1 as a drive source for the vehicle comprises a brake pedal sensor S7 for detecting operation of a brake pedal, a G sensor S9 for detecting the slope of road surface, and a motor ECU4 for generating a drive torque from the motor when a decision is made that the vehicle is stopping on an upward slope based on the detection results from the brake pedal sensor S7 and the G sensor S9 and release of the brake medal is detected. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device in a hybrid vehicle, for example.
[0002]
[Prior art]
In order to improve fuel efficiency in hybrid vehicles, idling stops are generally performed when predetermined conditions are satisfied when the vehicle is stopped or the vehicle is decelerated. Here, when the vehicle stops on an inclined road surface such as an uphill road, creep torque is not generated when the vehicle stops idling. Therefore, it is necessary to prevent the vehicle from moving backward after the brake is released. For this reason, there is a vehicle in which the braking torque of the hydraulic brake corresponding to the depressing force of the brake pedal is continuously applied until the vehicle is prevented from moving backward until the brake pedal is released and the accelerator pedal is depressed (for example, patent Reference 1).
[0003]
[Patent Document 1]
JP 2001-47987 A
[0004]
[Problems to be solved by the invention]
However, in the above prior art, since it takes time to depressurize the hydraulic brake after the brake pedal is released, the braking torque of the brake continues even when the vehicle starts to move forward by depressing the accelerator pedal. May be dragged. For this reason, there is a problem that the brake pad wear is accelerated and the driving force is lost and the improvement of fuel consumption is hindered.
Accordingly, the present invention provides a hybrid vehicle control device that prevents a vehicle from retreating on an uphill road and that does not cause brake dragging when the vehicle starts.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the invention described in claim 1 is a hybrid vehicle including an engine (for example, engine E in the embodiment) and a motor (for example, motor M1 in the embodiment) as a vehicle drive source. In the control device, an operation detection means for detecting the operation of the brake pedal (for example, the brake pedal sensor S7 in the embodiment), a gradient detection means for detecting the road surface gradient (for example, the G sensor S9 in the embodiment), When it is detected that the road surface where the vehicle has stopped is an uphill road and the brake pedal is released based on the detection results of the operation detection means and the gradient detection means, the motor is The first command torque Motor control means (for example, the motor ECU 4 in the embodiment) that generates torque in the forward direction and rotation speed detection means (for example, the motor rotation speed sensor S2 in the embodiment) for detecting the rotation speed of the motor are provided. The motor control means is controlled by the motor. Second command torque When the forward rotation direction torque is applied and the rotational speed of the motor detected by the rotational speed detection means falls below a lower limit rotational speed (for example, the reference rotational speed_1 in the embodiment), the motor Forward direction of The second command torque is the forward direction Reduce the torque gradually, The second command torque is the forward direction When the torque is gradually reduced, when the rotation speed of the motor detected by the rotation speed detection unit exceeds an upper limit rotation speed (for example, the reference rotation speed_2 in the embodiment), Second command torque It is characterized by increasing the forward torque
[0006]
Also, With this configuration, the motor torque can be gradually reduced as the vehicle stops due to the motor torque.
[0007]
further, With this configuration, the motor torque is insufficient, so that the motor torque can be increased when the rotational speed of the motor increases and the vehicle tries to move backward.
[0008]
The invention described in claim 2 Generated when it is detected that the brake pedal is released The torque in the forward direction of the motor is , It is the first command torque (for example, torque_1 in the embodiment) set according to the road surface gradient of the uphill road.
By comprising in this way, the appropriate motor torque according to a road surface gradient can be provided.
[0009]
The invention described in claim 3 Generated when it is detected that the brake pedal is released The forward torque of the motor is a first command torque set to a torque equivalent to a braking force generated by a brake mechanism by a brake pedal operation when the vehicle is stopped.
By comprising in this way, the motor torque equivalent to the braking force which stops a vehicle can be provided.
[0010]
The invention described in claim 4 The forward torque generated when it is detected that the brake pedal is released is Said first indicated torque The Decrease gradually over time after releasing the brake It was When the second command torque (for example, torque_2 in the embodiment) is reached, the second command torque is maintained.
With this configuration, the first command torque applied when the brake is released causes the torque for stopping the vehicle to smoothly shift from the brake device to the motor, and then the second command torque. It becomes possible to make this act continuously.
[0011]
Claim 5 The second described torque is characterized in that the second command torque is set based on the presence or absence of the creep torque of the engine and the presence or absence of connection of a starting clutch that transmits driving force to the wheels.
With this configuration, when there is creep torque and the start clutch is connected, the second command torque can be reduced, and when there is no creep torque and the start clutch is disconnected, the second instruction torque can be reduced. The creep torque can be secured by the indicated torque.
[0012]
Claim 6 The invention described in (2) is characterized in that the second command torque is set to be equal to or less than a creep torque of the engine.
By comprising in this way, the torque more than a creep torque can be ensured and it can prevent giving a sense of incongruity.
[0013]
The invention described in claim 7 is a four-wheel drive in which one of the front and rear wheels is driven by an engine and the other is driven by a motor.
By comprising in this way, a creep torque can always be provided with respect to one wheel with a motor independent.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the hybrid vehicle according to the embodiment of the present invention is a four-wheel drive, and includes an engine E and a motor (MOTOR) M2 directly connected as a drive source on the front (FR) side of the vehicle. On the side, for example, a motor M1 connected to the input side of a differential gear (DIFF) D is provided.
Here, the motor M2 is disposed between the engine E and a transmission T (may be an automatic transmission) such as a CVT (transmission ratio continuously variable transmission). Further, a start clutch 14 that mechanically disconnects and connects the driving force output from the engine E and the motor M2 is provided at the motor side end in the transmission T.
Therefore, the outputs of the front-side engine E and the motor M2 are transmitted to the front wheels Wf via the transmission T and the starting clutch 14, and the output of the rear-side motor M1 is transmitted to the rear wheels Wr via the differential gear D. Communicated.
[0015]
The motor M1 is controlled by a power drive unit (PDU) 1 in response to a control command from a motor ECU (MOTECU) 4 serving as motor control means. Similarly, the motor M2 receives a control command from the motor ECU 4. It is controlled by a power drive unit (PDU) 2.
Here, the motor ECU 4 receives road surface inclination angle information from a brake ECU 5 to be described later, determines an instruction motor torque (see FIGS. 2A and 2B) to be described later corresponding to the road surface inclination angle, Control is performed via the power drive unit 1 so that the torque of the motor M1 becomes the indicated motor torque.
[0016]
The power drive unit 1 and the power drive unit 2 are connected to a high-voltage nickel-hydrogen battery (power storage device) 7 that exchanges power with the motor M1 and the motor M2. Reference numeral 8 denotes a 12-volt auxiliary battery for driving various auxiliary machines. The auxiliary battery 8 is connected to the battery 7 via a downverter 9 which is a DC-DC converter.
A battery ECU (BATT ECU) 6 that controls the downverter 9 and protects the battery 7 includes a battery current sensor S3 and a battery voltage sensor S4 that detect currents and voltages input to and output from the battery 7. In addition, a battery temperature sensor S5 for detecting the temperature of the battery 7 is connected.
[0017]
Here, the downverter 9 steps down the voltage of the battery 7 to charge the auxiliary battery 8, and the battery ECU 6 determines the remaining capacity of the battery 7 based on the signals from the sensors connected to the battery ECU 6. Perform the calculation.
[0018]
The motor ECU 4 that monitors the operation of the motor M1 and the motor M2 includes a motor rotation sensor S1 (S1a, S1b) serving as a rotational speed detection unit that monitors the rotation of the motors M1 and M2, and the motor M1 and the motor. A motor system temperature sensor S2 (S2a, S2b) that monitors the temperature state of M2 is connected.
[0019]
Here, the motor system temperature sensors S2a and S2b monitor the temperatures of the power drive units 1 and 2 that drive the motors M1 and M2 as well as the motors M1 and M2. Further, when the motor system temperature sensor S2a or the motor system temperature sensor S2b exceeds a predetermined allowable temperature, the motor ECU 4 stops the output of the motor M1 or the motor M2 corresponding thereto, and the motors M1, M2 Is not subjected to thermal load. The predetermined allowable temperature indicates the maximum operating temperature unique to the motor.
[0020]
The front wheel Wf driven by the engine E and the motor M2 has a front wheel brake Bf. Similarly, the rear wheel Wr driven by the motor M1 has a rear wheel brake Br. The front wheel brake Bf and the rear wheel brake Br include a braking device 10 that generates a braking torque by hydraulic pressure. The braking device 10 receives a control command from a brake ECU (BRKECU) 5 and controls the hydraulic pressure of the brake. The actuator 11 is connected. The rear wheel brake Br and the front wheel brake Bf constitute a brake device (hereinafter also referred to as a hydraulic brake).
[0021]
The brake ECU 5 includes a brake hydraulic pressure sensor S6 for detecting the hydraulic pressure of the brake, a brake pedal sensor S7 for detecting an operation of a brake pedal (not shown), a wheel speed sensor S8 for detecting the speed of the vehicle, and a gradient detection. A G sensor S9 for detecting acceleration is connected as means.
[0022]
Here, the brake ECU 5 calculates the inclination angle of the road surface from the signals of the wheel speed sensor S8 and the G sensor S9, and outputs the calculated result to the motor ECU 4. That is, the road surface gradient is detected when the vehicle speed zero is detected by the wheel speed sensor S8 and the acceleration is detected by the G sensor S9. If the acceleration detected at this time is a negative value, it is determined that the traveling road is an uphill road. Here, this determination is made by the motor ECU 4 or the engine ECU 3. In this way, it may be determined whether or not the road is uphill by using an inclination sensor or the like without using the wheel speed sensor S8 and the G sensor S9.
[0023]
The engine E is a so-called in-line four-cylinder engine, and an intake pipe 13 of the engine E is provided with an electronically controlled throttle 12 that is controlled by an engine ECU (FIECU) 3. An accelerator opening sensor S10 that detects an operation amount of an accelerator pedal (AP) (not shown) is connected to the engine ECU 3.
Here, the engine ECU 3 calculates the fuel injection amount from the operation amount of the accelerator pedal and the like, and outputs a control signal for the fuel injection amount to the electronic control throttle 12.
[0024]
Next, the braking process using the motor M1 when the vehicle is idled on the uphill road will be described based on the flowchart of FIG. In the flowchart of FIG. 3 (same as in FIGS. 4 to 7 in the following embodiments), ENG indicates the engine E, and the motor indicates the motor M1. Further, the gradient indicates an upward gradient.
First, at step S300, the engine E is idled and the starting clutch is disengaged. When the brake pedal is depressed at step S301, brake torque is generated at step S302, and the vehicle is stopped at step S303.
[0025]
Next, in step S304, it is determined whether or not the brake pedal is released by removing the foot from the brake pedal in order to start. If the determination result is “YES” (released), the process proceeds to step S305. If the determination result is “NO” (not released), the process returns to step S302 and the above-described processing is repeated. In step S305, the brake torque is released, that is, the brake hydraulic pressure is released, and the process proceeds to step S306.
[0026]
In step S306, it is determined whether or not there is a slope on the road surface. If the determination result is “YES” (with a gradient), the process proceeds to step S307, and if the determination result is “NO” (without a gradient), the process ends.
Next, in step S307, the motor torque corresponding to the road gradient is instructed to the motor, and the process proceeds to step S308.
Here, the motor torque set in accordance with the road surface gradient in step S307 indicates torque_1 in FIG. The same applies to step S407, step S507, step S607, and step S707 in the embodiment described later.
[0027]
In step S308, it is determined whether the rotation speed of the motor is lower than the reference rotation speed_1. When the determination result is “YES” (lower than the reference rotation speed_1), the process proceeds to step S309, and when the determination result is “NO” (reference rotation speed_1 or more), the process proceeds to step S310. In step S309, the instruction motor torque is gradually decreased, for example, and the process proceeds to step S310. Here, the rotation number of the motor is detected by moving average calculation within a set time. Further, the reference rotational speed_1 is a lower limit rotational speed (for example, 15 rpm) for preventing the motor from generating heat (the same applies to the following embodiments).
[0028]
In step S309, when the motor has a rotational speed lower than the reference rotational speed_1, the torque of the motor is gradually increased in order to prevent the motor from generating heat due to the change in polarity while generating torque. This is a process of ensuring the minimum number of rotations of the motor while decreasing and allowing the vehicle to gradually move backward. The same applies to step S409, step S509, step S609, and step S709 in the embodiments described later.
[0029]
In step S310, it is determined whether or not the motor rotational speed is larger than the reference rotational speed_2. If the determination result is “YES” (greater than the reference rotation speed_2), the process proceeds to step S311. If the determination result is “NO” (reference rotation speed_2 or less), the process proceeds to step S314.
In step S311, the instruction motor torque is increased and the process proceeds to step S312. In step S312, it is determined whether the motor torque is lower than the maximum value that can be indicated. When the determination result is “YES” (lower than the instructable maximum value), the process proceeds to step S313, and when the determination result is “NO” (greater than the instructable maximum value), the process proceeds to step S314. In step S313, the maximum value of the instruction motor torque is instructed, and the process proceeds to step S314.
Here, the reference rotational speed_2 (for example, 88 rpm) indicates the upper limit rotational speed of the motor due to the reverse of the vehicle (the motor is reverse) (the same applies to the following embodiments).
[0030]
In step S314, it is determined whether or not the accelerator pedal is depressed. If the determination result is “YES” (with depression), the process proceeds to step S315. If the determination result is “NO” (without depression), the process returns to step S308 and the above-described processing is repeated. By this determination, it is determined that the driver is going forward.
In step S315, the motor torque is increased, the process proceeds to step S315A, the engine is started, and the process proceeds to step S315B. In step S315B, the starting clutch is connected, and in step S316, driving force is generated by the engine and the motor. In step S317, the forward movement of the vehicle is confirmed, and the process is terminated.
[0031]
Here, the motor command torque in the flowchart of the first embodiment will be described with reference to FIGS.
First, FIG. 2A shows changes in the brake pedal depression amount when the vertical axis represents the brake pedal depression amount and the horizontal axis represents the time. For example, in step S301, the brake pedal was depressed with the depression amount L. However, the stepping amount is zero at step S305 (at the time t), that is, the stepping is released.
[0032]
Next, FIG. 2B shows the motor torque that changes with time when the vertical axis is the axle torque and the horizontal axis is the time (corresponding to FIG. 2A). In this embodiment (the same applies to the following embodiments), since the hybrid vehicle is four-wheel drive, the motor torque is the axle torque as shown in FIG. Here, in FIG. 2B, three types of torque indicated by a solid line, a one-dot chain line, and a two-dot chain line are shown together as the motor torque, and in the engine stop state according to the first embodiment, and creep The torque when there is no torque is indicated by the solid line. In addition, since a dashed-dotted line and a dashed-two dotted line apply to the 2nd-5th embodiment mentioned later, description here is abbreviate | omitted.
[0033]
In FIG. 2B, the torque_1 indicated on the vertical axis is the command motor torque (first command torque) set according to the road surface gradient used in step S307, while the torque _2 is the instruction motor torque (second instruction torque) in step S309 and step S311.
Therefore, when the G sensor S9 detects the uphill slope in step S306, the motor torque is instructed as torque_1 in step S307 at the same time when the brake pedal is released, and then the torque is increased with time. The torque instruction is held when the instruction value is reduced to reach the instruction torque of torque_2.
Moreover, the broken line shown in FIG.2 (b) is a hydraulic brake torque at the time of using the brake force holding | maintenance apparatus in a prior art. Here, the prior art refers to a brake system for a hybrid vehicle for preventing the vehicle from moving backward until the accelerator pedal is depressed by continuing to gradually decrease the brake torque after releasing the brake pedal. is there.
[0034]
Therefore, according to the first embodiment, when it is determined that the road surface on which the vehicle has stopped is an uphill road based on the wheel speed sensor S8 and the G sensor S9, the road surface gradient is determined when the brake is released. Torque, i.e., torque that does not cause the vehicle to move backward, can be generated in the motor M1 as driving torque in the forward direction.
Therefore, it is possible to avoid the problem of dragging of the hydraulic brake, and it is possible to reliably prevent the vehicle from retreating on the uphill road by effectively using the motor M1 for four-wheel drive traveling.
[0035]
Further, when the motor M1 applies a forward torque_2 in order to prevent the vehicle from moving backward on the uphill road, the motor M1 is rotated when the rotational speed of the motor M1 falls below the reference rotational speed_1. Gradually reduce the forward torque_2 Toga it can. Therefore, it is possible to prevent the rotation of the motor M1 that is thermally disadvantageous and to protect the motor M1 from a thermal load.
Further, when the torque_2 of the motor M1 is gradually reduced, the torque in the forward direction of the motor M1 can be increased when the rotational speed of the motor M1 exceeds the reference rotational speed_2. Therefore, the backward movement of the vehicle can be reliably prevented.
[0036]
Here, since the torque in the forward direction of the motor M1 is the torque_1 set according to the road surface gradient of the uphill road, an appropriate motor torque according to the road surface gradient can be applied, and the road surface gradient is smooth. It is possible to reliably prevent the vehicle from moving backward.
The torque_1 described above is gradually reduced as time elapses after the brake is released, and when the torque_2 is reached, the torque for stopping the vehicle is changed from that by the hydraulic brake to the motor M1. It is possible to make a smooth transition to the above, and then to act continuously with torque_2. Therefore, the sense of discomfort with the normal vehicle is eliminated and the merchantability can be improved.
[0037]
Further, since the torque_2 is set to be equal to or lower than the creep torque of the engine E, it is possible to prevent the driver from feeling uncomfortable as compared with the case where the torque_2 is set to be higher than the creep torque. Therefore, merchantability can be improved.
In the first embodiment, the torque corresponding to the road surface gradient is calculated and applied to the motor M1. For example, the brake hydraulic pressure by the brake pedal operation when the vehicle is stopped is detected by the brake hydraulic pressure sensor S6. Torque based on the detection result may be applied to the motor M1 (hereinafter, the same applies to the second to fifth embodiments).
[0038]
Next, a second embodiment of the present invention will be described based on the flowchart of FIG. 4 with reference to FIGS. Since this embodiment is different only in the flowchart of FIG. 3 of the first embodiment described above, other description is omitted. This process also shows the braking process using the motor M1 when the vehicle is idled on the uphill road as in the previous embodiment, but the engine start process in step S315A of the previous embodiment is performed in step S305. This was performed immediately before releasing the brake torque. In the following, description will be given in order.
[0039]
First, at step S400, the engine E is idled and the starting clutch is disconnected. When the brake pedal is depressed at step S401, brake torque is generated at step S402, and the vehicle is stopped at step S403.
[0040]
Next, in step S404, it is determined whether the brake pedal is released by removing the foot from the brake pedal in order to start. If the determination result is “YES” (released), the process proceeds to step S404A. If the determination result is “NO” (not released), the process returns to step S402 and the above-described processing is repeated. In step S404A, the engine is started, and in the next step S405, the brake torque is released, that is, the brake hydraulic pressure is released, and the process proceeds to step S406.
In step S406, it is determined whether or not there is a slope on the road surface. If the determination result is “YES” (with a gradient), the process proceeds to step S407, and if the determination result is “NO” (no gradient), the process ends.
[0041]
Here, after the engine is started in step S404A, the starting clutch 14 performs invalid stroke reduction. This invalid stroke filling means that when the start clutch is disconnected from the start clutch disengaged state to the connected (engaged) state, the transmission side receives force without delay with respect to the engine torque input by the accelerator pedal operation, This refers to the operation (operation) to close the clearance (between the piston and the end plate) generated in this clutch. By generating the load necessary to contract the piston return spring so that the piston moves by this clearance, is there. Therefore, it is necessary to complete the invalid stroke filling before the accelerator pedal is depressed. However, since some friction is involved, it is desirable to complete the idle stroke just before the accelerator pedal operation.
Therefore, in the processing from step S404A to step S415B, a weak creep torque acts on the front wheel Wf due to the invalid stroke reduction.
[0042]
Next, in step S407, the motor torque corresponding to the road gradient is instructed to the motor, and the process proceeds to step S408.
Here, the motor torque set in accordance with the road surface gradient in step S407 indicates the torque_1 in FIG.
[0043]
In step S408, it is determined whether the rotational speed of the motor is lower than the reference rotational speed_1. When the determination result is “YES” (lower than the reference rotation speed_1), the process proceeds to step S409, and when the determination result is “NO” (reference rotation speed_1 or more), the process proceeds to step S410. In step S409, the instruction motor torque is gradually decreased, for example, and the process proceeds to step S410.
Here, the instruction motor torque in step S409 indicates, for example, a one-dot chain line torque_2 in FIG. 2B, and this torque_2 includes a case where the engine is started and the starting clutch is OFF (weak creep torque is generated). A value (smaller than the first embodiment) is applied.
[0044]
In step S410, it is determined whether the motor rotation speed is larger than the reference rotation speed_2. If the determination result is “YES” (greater than the reference rotation speed_2), the process proceeds to step S411, and if the determination result is “NO” (reference rotation speed_2 or less), the process proceeds to step S414.
In step S411, the instruction motor torque (torque_2) is increased, and the process proceeds to step S412. In step S412, it is determined whether the motor torque is lower than the maximum value that can be indicated. When the determination result is “YES” (lower than the instructable maximum value), the process proceeds to step S413, and when the determination result is “NO” (greater than the instructable maximum value), the process proceeds to step S414. In step S413, the maximum value of the instruction motor torque is instructed and the process proceeds to step S414.
[0045]
In step S414, it is determined whether or not the accelerator pedal is depressed. If the determination result is “YES” (with depression), the process proceeds to step S415. If the determination result is “NO” (without depression), the process returns to step S408 and the above-described processing is repeated. By this determination, it is determined that the driver is going forward.
In step S415, the motor torque is increased, and the process proceeds to step S415B. In step S415B, the starting clutch is connected, and in step S416, driving force is generated by the engine and the motor. In step S417, the forward movement of the vehicle is confirmed, and the process ends.
[0046]
Therefore, according to the second embodiment, in addition to the effects of the first embodiment, the engine is stabilized when the starting clutch is connected in step S415B by the amount that the engine is started earlier in step S404A. This is advantageous in that
[0047]
Next, a third embodiment of the present invention will be described based on the flowchart of FIG. 5 with reference to FIGS. Since this embodiment is different only in the flowchart of FIG. 3 of the first embodiment described above, other description is omitted. This process also shows the braking process using the motor M1 when the vehicle is idled on the uphill road as in the above-described embodiments, but the starting clutch connection in step S415B of the above-described second embodiment. The process is performed immediately before releasing the brake torque in step S405. In the following, description will be given in order.
[0048]
First, at step S500, the engine E is idled and the starting clutch is disengaged. When the brake pedal is depressed at step S501, brake torque is generated at step S502, and the vehicle is stopped at step S503.
[0049]
Next, in step S504, it is determined whether or not the brake pedal is released by removing the foot from the brake pedal in order to start. If the determination result is “YES” (released), the process proceeds to step S504A. If the determination result is “NO” (not released), the process returns to step S502 and the above-described processing is repeated. In step S504A, the engine is started, and in step S504B, the starting clutch is connected. In step S505, the brake torque is released, that is, the brake hydraulic pressure is released, and the process proceeds to step S506.
In step S506, it is determined whether or not there is a slope on the road surface. When the determination result is “YES” (with a gradient), the process proceeds to step S507, and when the determination result is “NO” (without a gradient), the process ends.
[0050]
Next, in step S507, the motor torque corresponding to the road gradient is instructed to the motor, and the process proceeds to step S508.
Here, the motor torque set in accordance with the road surface gradient in step S507 indicates the torque_1 in FIG. 2B. This torque_1 is obtained by a search using a road surface gradient and motor torque map (not shown). Desired.
[0051]
In step S508, it is determined whether the rotation speed of the motor is lower than the reference rotation speed_1. When the determination result is “YES” (lower than the reference rotation speed_1), the process proceeds to step S509, and when the determination result is “NO” (reference rotation speed_1 or more), the process proceeds to step S510. In step S509, the instruction motor torque is gradually reduced, for example, and the process proceeds to step S510.
Here, the instruction motor torque in step S509 indicates, for example, a two-dot chain line torque_2 in FIG. 2 (b), and this torque_2 is a value when the engine is started and the start clutch is ON (the second value) Smaller than the embodiment) is applied.
[0052]
In step S510, it is determined whether or not the motor rotational speed is larger than the reference rotational speed_2. If the determination result is “YES” (greater than the reference rotation speed_2), the process proceeds to step S511, and if the determination result is “NO” (reference rotation speed_2 or less), the process proceeds to step S514.
In step S511, the instruction motor torque (torque_2) is increased and the process proceeds to step S512. In step S512, it is determined whether the motor torque is lower than the maximum value that can be indicated. When the determination result is “YES” (lower than the instructable maximum value), the process proceeds to step S513, and when the determination result is “NO” (greater than the instructable maximum value), the process proceeds to step S514. In step S513, the maximum value of the instruction motor torque is instructed, and the process proceeds to step S514.
[0053]
In step S514, it is determined whether or not the accelerator pedal is depressed. If the determination result is “YES” (with depression), the process proceeds to step S515, and if the determination result is “NO” (without depression), the process returns to step S508 and the above-described processing is repeated. By this determination, it is determined that the driver is going forward.
In step S515, the torque of the motor is increased. In step S516, the driving force generated by the engine and the motor is generated. In step S517, the advance of the vehicle is confirmed, and the process is terminated.
[0054]
Therefore, according to the third embodiment, in addition to the effect of the second embodiment, the start clutch connection is performed early in step S504B, so that the vehicle is quickly advanced when the accelerator pedal is depressed in step S514. It is possible to speed up the responsiveness.
[0055]
Next, a fourth embodiment of the present invention will be described based on the flowchart of FIG. 6 with reference to FIGS. Since this embodiment is different only in the flowchart of FIG. 3 of the first embodiment described above, other description is omitted. This process is different from the above-described embodiments, and shows a braking process using the motor M1 when the vehicle is stopped in a state where the engine is not stopped on the uphill road, and in step S500 of the above-described third embodiment. The engine stop and start clutch disconnection process, the engine start process in step S504A, and the start clutch connection process in step S504B are omitted. In the following, description will be given in order.
[0056]
First, when the brake pedal is depressed in step S601, brake torque is generated in step S602, and the vehicle is stopped in step S603. Next, in step S604, it is determined whether or not the brake pedal is released by removing the foot from the brake pedal in order to start. If the determination result is “YES” (released), the process proceeds to step S605. If the determination result is “NO” (not released), the process returns to step S602 and the above-described processing is repeated.
[0057]
In step S605, the brake torque is released, that is, the brake hydraulic pressure is released, and the process proceeds to step S606. Next, in step S606, it is determined whether or not there is a gradient on the road surface. If the determination result is “YES” (with a gradient), the process proceeds to step S607, and if the determination result is “NO” (no gradient), the process ends.
[0058]
Next, in step S607, the motor torque corresponding to the road gradient is instructed to the motor, and the process proceeds to step S608.
Here, the motor torque set in accordance with the road surface gradient in step S607 indicates the torque_1 in FIG. 2B. This torque_1 is obtained by a search using a road surface gradient and motor torque map (not shown). Desired.
[0059]
In step S608, it is determined whether the rotation speed of the motor is lower than the reference rotation speed_1. If the determination result is “YES” (lower than the reference rotation speed_1), the process proceeds to step S609, and if the determination result is “NO” (reference rotation speed_1 or more), the process proceeds to step S610. In step S609, the instruction motor torque is gradually reduced, for example, and the process proceeds to step S610.
Here, the instruction motor torque in step S609 is, for example, the two-dot chain line torque_2 in FIG. 2B, as in the second embodiment, and this torque_2 includes the engine start and the start clutch ON. The value in the case of (which is smaller than the first embodiment) is applied.
[0060]
In step S610, it is determined whether the motor rotation speed is greater than the reference rotation speed_2. If the determination result is “YES” (greater than the reference rotation speed_2), the process proceeds to step S611, and if the determination result is “NO” (reference rotation speed_2 or less), the process proceeds to step S614.
[0061]
In step S611, the instruction motor torque (torque_2) is increased, and the process proceeds to step S612. In step S612, it is determined whether or not the motor torque is lower than the maximum value that can be indicated. If the determination result is “YES” (lower than the maximum value that can be indicated), the process proceeds to step S613, and if the determination result is “NO” (greater than the maximum value that can be specified), the process proceeds to step S614. In step S613, the maximum value of the instruction motor torque is instructed, and the process proceeds to step S614.
[0062]
In step S614, it is determined whether or not the accelerator pedal is depressed. If the determination result is “YES” (stepping on), the process proceeds to step S615. If the determination result is “NO” (no stepping), the process returns to step S608 and the above-described processing is repeated. By this determination, it is determined that the driver is going forward.
In step S615, the torque of the motor is increased. In step S616, the driving force generated by the engine and the motor is generated. In step S617, the forward movement of the vehicle is confirmed, and the process ends.
[0063]
Therefore, according to the fourth embodiment, in addition to the effects of the first embodiment, unlike the above-described embodiments, when the engine E does not stop, the start processing of the engine E and the start clutch 14 It is possible to promptly start on an uphill road without performing disconnection and connection processing.
[0064]
Next, a fifth embodiment of the present invention will be described based on the flowchart of FIG. 7 with reference to FIGS. Since this embodiment is different only in the flowchart of FIG. 3 of the first embodiment described above, other description is omitted. Similar to the fourth embodiment, this process shows a braking process using the motor M1 when the vehicle stops with the engine not stopped on the uphill road. The start clutch disconnection process is added immediately after the brake torque release process in step S605 of the embodiment, and the start clutch connection process is added immediately after the motor torque increase process in step S615 of the fourth embodiment described above. In the following, description will be given in order.
[0065]
First, when the brake pedal is depressed in step S701, brake torque is generated in step S702, and the vehicle stops in step S703.
Next, in step S704, it is determined whether or not the brake pedal is released by removing the foot from the brake pedal in order to start. If the determination result is “YES” (released), the process proceeds to step S705. If the determination result is “NO” (not released), the process returns to step S702 and the above process is repeated. In step S705, the brake torque is released, that is, the brake hydraulic pressure is released, and the process proceeds to step S705A. In step S705A, the starting clutch is disconnected and the process proceeds to step S706.
[0066]
Here, after the start clutch 14 is disengaged in step S705A, invalid stroke filling is performed in the same manner as in the second embodiment described above. This invalid stroke filling is an operation of closing the clutch clearance so that the transmission side can receive the engine torque without delay with respect to the operation of the accelerator pedal.
Therefore, a weak creep torque is generated from step S705A to step S715B due to the invalid stroke reduction.
In step S706, it is determined whether or not there is a slope on the road surface. When the determination result is “YES” (with a gradient), the process proceeds to step S707, and when the determination result is “NO” (without a gradient), the process ends.
[0067]
Next, in step S707, the motor torque according to the road surface gradient is instructed to the motor, and the process proceeds to step S708.
Here, the motor torque set in accordance with the road surface gradient in step S707 indicates the torque_1 in FIG. 2B. This torque_1 is obtained by a search using a road surface gradient and motor torque map (not shown). Desired.
[0068]
In step S708, it is determined whether the rotation speed of the motor is lower than the reference rotation speed_1. When the determination result is “YES” (lower than the reference rotation speed_1), the process proceeds to step S709, and when the determination result is “NO” (reference rotation speed_1 or more), the process proceeds to step S710. In step S709, the instruction motor torque is gradually decreased, for example, and the process proceeds to step S710.
Here, the instruction motor torque in step S709 indicates, for example, a one-dot chain line torque_2 in FIG. 2B, and this torque_2 is a value when the engine is started and the starting clutch is OFF (weak creep torque is generated). (Smaller than the first embodiment) is applied.
[0069]
In step S710, it is determined whether or not the motor speed is greater than the reference speed_2. If the determination result is “YES” (greater than the reference rotational speed_2), the process proceeds to step S711, and if the determination result is “NO” (reference rotational speed_2 or less), the process proceeds to step S714.
In step S711, the instruction motor torque (torque_2) is increased and the process proceeds to step S712. In step S712, it is determined whether the motor torque is lower than the maximum value that can be indicated. If the determination result is “YES” (lower than the maximum value that can be indicated), the process proceeds to step S713. If the determination result is “NO” (greater than the maximum value that can be specified), the process proceeds to step S714. In step S713, the maximum value of the instruction motor torque is instructed, and the process proceeds to step S714.
[0070]
In step S714, it is determined whether or not the accelerator pedal is depressed. If the determination result is “YES” (with depression), the process proceeds to step S715. If the determination result is “NO” (without depression), the process returns to step S708 and the above-described processing is repeated. By this determination, it is determined that the driver is going forward.
In step S715, the motor torque is increased, the process proceeds to step S715B, the starting clutch is connected, and the process proceeds to step S716. In step S716, a driving force is generated by the engine and the motor. In step S717, the vehicle is confirmed to move forward, and the process is terminated.
[0071]
Therefore, according to the fifth embodiment, compared to the fourth embodiment, since the start clutch 14 is connected only immediately before starting, the load is not applied to the engine and the fuel consumption is improved accordingly. it can.
As described above, when there is a creep torque and the start clutch is connected, the torque_2 can be reduced, and when there is no creep torque and the start clutch 14 is disconnected, the creep is caused by the torque_2. Thus, the vehicle can be reliably prevented from moving backward without being affected by the presence or absence of the creep torque and the connection and disconnection of the start clutch 14 so that the torque can be secured.
[0072]
The present invention is not limited to the four-wheel drive hybrid vehicle of the above-described embodiment. For example, a motor that can drive the wheel independently from the engine is provided on the front wheel side, and this motor generates creep torque. In addition, the invention may be applied to a four-wheel drive hybrid vehicle in which the front wheels are driven by a motor and the rear wheels are driven by an engine. Further, the engine E may be of a type other than the in-line four cylinders.
[0073]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the engine is idle-stopped on an uphill road, it is possible to generate a torque corresponding to the creep torque of the engine using the motor. Therefore, there is an effect that it is possible to reliably prevent the vehicle from retreating on the uphill road by effectively using the motor in order to avoid the problem of the drag of the brake that hinders the improvement in fuel consumption.
[0074]
Also Because the motor torque can be gradually reduced as the vehicle stops due to the motor torque, the motor rotation can be prevented from being disadvantageously stopped and the motor can be protected from thermal load. There is an effect that can.
[0075]
further Since the motor torque is insufficient and the motor speed increases and the vehicle tries to move backward, the torque of the motor can be increased, so that it is possible to reliably prevent the vehicle from moving backward. .
[0076]
Claim 2 According to the invention described above, in addition to the effect of the first aspect, since an appropriate motor torque according to the road surface gradient can be applied, the vehicle can smoothly prevent the vehicle from retreating smoothly corresponding to the road surface gradient. There is.
[0077]
Claim 3 According to the invention described in claim 1, Or 2 In addition to the effects of the above, a motor torque equivalent to the braking force that stops the vehicle can be applied, so the motor torque based on the driver's brake operation corresponding to the road gradient is generated to prevent the vehicle from retreating reliably. it can.
[0078]
Claim 4 According to the invention described in claim 2 Or claim 3 In addition to the above effect, the first command torque applied when the front brake is released smoothly shifts the torque for stopping the vehicle from the brake device to the motor, and then shifts to the second command torque. Since this can be made to act continuously, there is an effect that there is no sense of incongruity with a normal vehicle and the merchantability can be improved.
[0079]
Claim 5 According to the invention described in claim 4 In addition to the above effect, when there is a creep torque and the start clutch is connected, the second command torque can be reduced, and when there is no creep torque and the start clutch is disconnected, the second command torque Thus, the creep torque can be ensured, and therefore, there is an effect that the vehicle can be reliably prevented from retreating regardless of the presence or absence of the creep torque and the connection and disconnection of the starting clutch.
[0080]
Claim 6 According to the invention described in claim 3 Or claim 4 In addition to the above effect, it is possible to prevent a sense of incongruity by securing a torque equal to or higher than the creep torque.
[0081]
Claim 7 According to the invention described in claim 1 to claim 1 6 In addition to any of the above effects, the creep torque can always be applied to one wheel by the motor alone, so that the motor for creep torque can be effectively used as a drive source for four-wheel drive. There is.
[Brief description of the drawings]
1 is an overall configuration diagram of a four-wheel drive hybrid vehicle according to an embodiment of the present invention;
FIG. 2 is a graph showing motor torque according to the embodiment of the present invention.
FIG. 3 is a flowchart showing a main part of the first embodiment of the present invention.
FIG. 4 is a flowchart corresponding to FIG. 2 of a second embodiment of the present invention.
FIG. 5 is a flowchart corresponding to FIG. 2 of a third embodiment of the present invention.
FIG. 6 is a flowchart corresponding to FIG. 2 of a fourth embodiment of the present invention.
FIG. 7 is a flowchart corresponding to FIG. 2 of a fifth embodiment of the present invention.
[Explanation of symbols]
4 Motor ECU (motor control means)
Wf front wheel
Wr rear wheel
E engine
M1 Rear wheel side motor
S2 Motor rotation sensor (rotational speed detection means)
S7 Brake pedal sensor (operation detection means)
S9 G sensor (gradient detection means)

Claims (7)

In a control apparatus for a hybrid vehicle including an engine and a motor as a vehicle drive source, an operation detection unit that detects an operation of a brake pedal, a gradient detection unit that detects a road surface gradient, and the operation detection unit and the gradient detection unit Motor control means for causing the motor to generate a forward torque as a first command torque when it is detected that the road surface on which the vehicle has stopped based on the detection result is an uphill road and the brake pedal is released; And a rotation speed detection means for detecting the rotation speed of the motor, wherein the motor control means is configured to apply the forward direction torque, which is a second command torque, by the motor . detected when the rotational speed of the motor falls below the lower limit rotational speed, the torque of the second indicated torque in a forward direction in the forward direction of the motor by Gradually reducing, when being gradually reduced a second torque in the forward direction is indicated torque of the motor, the rotational speed of the motor detected by the rotational speed detecting means exceeds the upper limit rotational speed In this case, the hybrid vehicle control apparatus increases the forward torque, which is the second command torque of the motor. Forward direction of torque of the motor to be generated when it is detected that the brake pedal is released, to claim 1, characterized in that the first indicated torque set according to the road surface gradient of the uphill The hybrid vehicle control device described. The torque in the forward direction of the motor that is generated when it is detected that the brake pedal is released is set to a torque equivalent to the braking force generated by the brake mechanism by operating the brake pedal when the vehicle is stopped. The control apparatus for a hybrid vehicle according to claim 1, wherein the control torque is a specified torque. When detecting that the brake pedal has been released, the motor control device gradually decreases the torque in the forward direction of the motor as time elapses after releasing the brake from the first instruction torque , 4. The hybrid vehicle control device according to claim 2, wherein when the forward torque reaches the second command torque, the second command torque is maintained.   5. The hybrid vehicle according to claim 4, wherein the second command torque is set based on presence or absence of creep torque of the engine and presence or absence of connection of a start clutch that transmits driving force to wheels. Control device.   5. The hybrid vehicle control device according to claim 3, wherein the second command torque is set to be equal to or less than a creep torque of the engine.   The hybrid vehicle control device according to any one of claims 1 to 6, wherein one of the front and rear wheels is a four-wheel drive in which one is driven by an engine and the other is driven by a motor.

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