JP2015074343A - Drive force control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive force control device of a vehicle capable of exactly outputting a variation amount in braking drive force expected by sn operator, in a case of operating an accelerator when changing the braking drive force by changing a gear ratio.SOLUTION: A drive force control device of a vehicle is configured so as to set a braking drive force corresponding to an output torque of a drive force source and a basic gear ratio or a change gear ratio, by selectively setting the basic gear ratio of a transmission determined based on a request drive force operation quantity by the operator and a vehicle speed and the change gear ratio different from the basic gear ratio, and is configured for controlling a variation amount in the output torque of the drive force source so that a variation amount in the braking drive force when changing the request drive force operation quantity in a state of setting the change gear ratio, coincides with a variation amount in the braking drive force when changing the request drive force operation quantity in a state of setting the basis gear ratio (Step S2 or Step S6).

Description

  The present invention relates to a driving force control apparatus for a vehicle including a transmission that increases and decreases output torque of a driving force source.

  Conventionally, in order to improve turning performance and vibration control performance, a vehicle driving force control device configured to output a driving force different from a required driving force determined according to an accelerator operation amount by a driver, etc. Are known. An example of the driving force control configured as described above is described in Patent Document 1. The driving force control device described in Patent Document 1 reduces the actual output torque from the engine output torque determined according to the required driving force when the understeer state is detected, and shifts the speed. By changing the gear ratio of the machine, a driving force smaller than the required driving force is output. Thus, it is described that understeer is eliminated by outputting a driving force smaller than the required driving force. Further, when the driver depresses the accelerator pedal while performing the control for reducing the driving force, the control for reducing the driving force is terminated. When the accelerator pedal is depressed and the above control is terminated, the speed ratio changed by the above control is returned to the speed ratio determined from the speed change characteristics of the transmission set in advance according to the driving state. If the gear ratio deviation at that time is equal to or greater than the predetermined value on the downshift side, the deviation increases in order to suppress or prevent the drive torque from being increased and causing the understeer state again. The speed ratio changed by the above control is maintained until it becomes less than a predetermined value. On the contrary, when the deviation is less than the predetermined value, the speed ratio is changed to a speed ratio determined from the speed change characteristics. .

JP 2002-114059 A

  As described above, when the speed ratio is changed to increase or decrease the driving force, the speed ratio may not be returned according to a predetermined condition when the accelerator pedal is depressed. When the engine is controlled according to the accelerator operation when the speed ratio is not restored in this way, the target speed ratio determined based on the speed change characteristics set in advance is different from the actual speed ratio, so that There is a possibility that the actual amount of change in driving force is excessive or insufficient with respect to the amount of change in driving force expected by a person.

  The present invention has been made paying attention to the above technical problem, and changes in braking / driving force expected by the driver when the accelerator is operated while changing the gear ratio to change the braking / driving force. It is an object of the present invention to provide a vehicle driving force control device capable of outputting a quantity without excess or deficiency.

  In order to achieve the above object, the invention of claim 1 is directed to a basic transmission gear ratio determined based on a driver's requested driving force manipulated variable and a vehicle speed, and a changed transmission gear ratio different from the basic transmission gear ratio. In the vehicle driving force control device configured to set braking / driving force according to the output torque of the driving force source and the basic gear ratio or the changed gear ratio. The amount of change in the braking / driving force when the required driving force manipulated variable is changed in a state where the ratio is set is the same as the amount of change in the braking / driving force when the required driving force manipulated variable is changed while the basic speed ratio is set The change amount of the output torque of the driving force source is controlled so as to coincide with the change amount of the braking / driving force.

  According to a second aspect of the present invention, in the first aspect of the invention, when the change gear ratio is greater than the basic gear ratio, the basic gear ratio is set as the amount of change in the output torque of the driving force source. The vehicle driving force control device is controlled to be smaller than a basic change amount of the output torque of the driving force source when the required driving force operation amount is changed in a state.

  According to a third aspect of the invention, in the first aspect of the invention, when the change gear ratio is smaller than the basic gear ratio, the basic gear ratio is set as the amount of change in the output torque of the driving force source. The vehicle driving force control device is controlled to be larger than a basic change amount of the output torque of the driving force source when the required driving force operation amount is changed in a state.

  According to the present invention, the braking / driving in the case where the requested driving force operation amount is changed in a state where the changed transmission gear ratio different from the basic transmission gear ratio determined based on the requested driving force operation amount by the driver and the vehicle speed is set. The amount of change in the output torque of the driving force source is controlled so that the amount of change in force matches the amount of change in braking / driving force when the required driving force is changed while the basic gear ratio is set. Therefore, even when the change gear ratio is set, it is possible to suppress or prevent the actual amount of change in braking / driving force from deviating from the amount of change in braking / driving force expected by the driver. In other words, the amount of change in braking / driving force expected by the driver can be output without excess or deficiency. As a result, it is possible to suppress or prevent the driver from feeling uncomfortable.

It is a flowchart for demonstrating an example of control of the driving force control apparatus which concerns on this invention. 5 is a time chart showing changes in output torque, transmission ratio, engine torque, and accelerator opening of a transmission when an accelerator pedal is depressed when deceleration is increased by braking / driving force control. 5 is a time chart showing changes in output torque, transmission ratio, engine torque, and accelerator opening of a transmission when an accelerator pedal is depressed when acceleration is reduced by braking / driving force control. It is a schematic diagram which shows an example of the vehicle made into object by this invention.

  An example of the configuration of the vehicle targeted by the present invention will be described with reference to FIG. The vehicle shown in FIG. 4 includes an internal combustion engine 1 (hereinafter referred to as engine 1) that is a driving force source, and a transmission 3 that increases and decreases the output torque of engine 1 and transmits the torque to drive wheels 2 and 2. Yes. Specifically, the transmission 3 is connected to the output shaft of the engine 1, and the drive wheels 2 and 2 are connected to the output shaft of the transmission 3 via the propeller shaft 4 and the differential gear 5. The transmission 3 can increase or decrease the output torque of the engine 1 or control the rotation speed of the engine 1, and can continuously change the output torque of the engine 1 or the rotation speed of the engine 1. preferable. Therefore, the transmission 3 is preferably a continuously variable transmission such as a conventionally known belt-type continuously variable transmission, toroidal continuously variable transmission, or an electric continuously variable transmission using an electric motor. In the vehicle shown in FIG. 4, the front wheels 6 and 6 are steering wheels, and the front wheels 6 and 6 and the rear wheels 2 and 2 are provided with brakes 7. Further, in the example shown in FIG. 4, a front engine / rear drive type vehicle is shown, but a front engine / front drive type vehicle may be used.

  An electronic control device 8 for controlling the engine 1 and the transmission 3 is provided. The electronic control device 8 receives signals detected by the sensors 9 such as an accelerator opening sensor that detects an operation amount of an accelerator pedal, a sensor that detects a steering angle, a sensor that detects a vehicle speed, and the like. According to the signal and a map or arithmetic expression prepared in advance, the throttle valve, the spark plug, the actuator for controlling the transmission ratio of the transmission 3, the actuator 10 for controlling each brake 7, and the like are configured to output signals. ing. The operation amount of the accelerator pedal corresponds to the required driving force operation amount in the present invention.

  In the vehicle configured as described above, the output torque of the engine 1 and the gear ratio of the transmission 3 are normally determined according to the operation amount of the accelerator pedal and the vehicle speed. As an example, the output torque of the engine 1 and the gear ratio of the transmission 3 are determined by the conventionally known torque demand control. The torque demand control will be briefly described. In the torque demand control, first, the driving force required for the vehicle (required driving force) is determined based on the accelerator pedal operation amount and the vehicle speed based on a driving force map prepared in advance, and the engine 1 is controlled based on the driving force. Output (power) is determined. Next, the target rotational speed of the engine 1 is determined from the output of the engine 1 and the optimum fuel consumption line prepared in advance, and the gear ratio of the transmission 3 is determined according to the target rotational speed and the vehicle speed. Then, the output torque of the engine 1 is calculated from the output of the engine 1 and the target rotational speed of the engine 1 determined as described above, and the throttle valve opening and ignition timing are determined based on the output torque. . The gear ratio set by this torque demand control corresponds to the basic gear ratio in the present invention.

  On the other hand, a target driving force different from the required driving force determined based on the amount of operation of the accelerator pedal by the driver as described above is determined by various conditions such as improving the turning performance and improving the damping performance. There is a case. Specifically, when the actual turning travel route tends to understeer than the turning travel route determined according to the steering angle or the like, the target driving force is decreased or the braking force is increased from the required driving force. Let On the other hand, in the case of an oversteer tendency, the target driving force is increased or the braking force is decreased than the required driving force. Alternatively, the target driving force may be increased or decreased from the required driving force or the braking force may be increased or decreased in order to improve the vibration damping performance by changing the ground load of the front wheels 6 and 6 and the rear wheels 2 and 2. The control for determining the target driving force different from the required driving force in this way is referred to as braking / driving force control in the following description, and when there is no need to distinguish between driving force and braking force, braking / driving is performed. Sometimes referred to as force.

  In order to cause the actual driving force to follow the target driving force determined by the braking / driving force control as described above, the output torque and the gear ratio of the engine 1 are mainly controlled. Specifically, when the braking force is increased by the braking / driving force control, first, the engine braking force based on the pumping loss of the engine 1 is increased. In addition, when the engine driving force alone cannot output the target driving force determined by the braking / driving force control, the gear ratio of the transmission 3 is increased in order to increase the engine braking force. On the other hand, when the braking force is reduced by braking / driving force control, the engine braking force is reduced and the gear ratio is reduced. When the driving force is reduced by the braking / driving force control, first, the output torque of the engine 1 is reduced. Further, when the driving force cannot be reduced by following the target driving force determined by the braking / driving force control due to a response delay of the engine 1 or the like, the gear ratio is reduced to reduce the torque amplification factor by the transmission 3. Make it smaller. On the contrary, when the driving force is increased by the braking / driving force control, the output torque of the engine 1 is increased and the gear ratio of the transmission 3 is increased. Note that the engine braking force can be increased or decreased by controlling the throttle opening, ignition timing, and the like, as in conventionally known engine control. Further, the gear ratio determined by the braking / driving force control corresponds to the changed gear ratio in the present invention.

  In the vehicle driving force control device according to the present invention, the accelerator pedal is depressed by the driver when a gear ratio different from the gear ratio determined based on the required driving force is set by the braking / driving force control as described above. In this case, the driving force change amount expected by the driver can be output without excess or deficiency. An example of the control will be described with reference to the flowchart shown in FIG. In addition, the flowchart shown in FIG. 1 is repeatedly performed for every predetermined time. In the control shown in FIG. 1, it is first determined whether or not the shift control according to the braking / driving force control is being performed (step S1). In step S1, a target braking / driving force different from the required braking / driving force determined by torque demand control or the like is determined by the braking / driving force control, and the target braking / driving force determined by the braking / driving force control is output. Therefore, it is determined whether or not the gear ratio is changed from a gear ratio determined by torque demand control or the like. Therefore, even when the braking / driving force control is being executed, when only the output torque of the engine 1 is controlled to change the braking / driving force, or when the braking / driving force control is not being executed, Judgment is negative. If the determination is negative in step S1, the process returns. That is, when the braking / driving force control is not executed, the engine 1 and the transmission 3 are controlled in accordance with the output torque and the gear ratio of the engine 1 determined by normal torque demand control or the like, and the braking / driving force control is performed. If only the output torque of the engine 1 is controlled to increase or decrease the braking / driving force, the braking / driving force is controlled by controlling only the output torque of the engine 1 as it is.

  On the contrary, if the speed ratio is controlled according to the braking / driving force control and the determination is affirmative in step S1, the speed ratio when the braking / driving force control is not executed is calculated (step S1). S2). This step S2 estimates the gear ratio set when the braking / driving force control is not executed. Therefore, the speed ratio set by the torque demand control or the like is calculated, or the speed ratio is calculated from the engine braking force based on the power loss of the engine 1 and the required driving force. Further, the engine speed when the braking / driving force control is not executed is calculated (step S3). Similar to step S2, step S3 also estimates the speed ratio set when braking / driving force control is not being executed. Therefore, based on the speed ratio calculated in step S2 and the current vehicle speed. It can be calculated.

  Next, based on the gear ratio calculated in step S2 and step S3, the engine speed, and the change amount of the accelerator opening detected by the accelerator opening sensor, if the braking / driving force control is not executed, the output of the vehicle A change amount ΔTe of the braking / driving force is calculated (step S4). In step S4, the amount of change in the output (power) of the engine 1 is obtained based on the amount of change in the accelerator opening, and the engine 1 is calculated from the amount of change in the output of the engine 1 and the engine speed calculated in step S4. The amount of change in the output torque can be estimated, and the amount of change ΔTe in the braking / driving force of the vehicle can be calculated from the amount of change in the output torque of the engine 1 and the gear ratio calculated in step S3.

  Further, a change amount of the engine torque necessary to realize the change amount ΔTe of the braking / driving force calculated in step S4 at the current gear ratio set by the braking / driving force control is calculated (step S5). This step S5 is a state in which the change amount of the braking / driving force when the accelerator operation amount is changed in a state where the predetermined gear ratio is set by the braking / driving force control, and another gear ratio is set by the torque demand control, The amount of change in the output torque of the engine is controlled so that the amount of change in the braking / driving force when the accelerator operation amount changes in step S4, and the amount of change ΔTe in the braking / driving force calculated in step S4. Can be divided by the current gear ratio to calculate the amount of change in engine torque. Then, the output torque of the engine 1 is controlled by controlling the throttle opening and the fuel injection amount based on the change amount of the engine torque calculated in step S5 (step S6), and the process returns.

  2 and 3 are time charts for explaining changes in the output torque, the transmission ratio, the engine torque, and the accelerator opening of the transmission 3 when the control shown in FIG. 1 is executed. FIG. 2 shows changes in output torque, transmission ratio, engine torque, and accelerator opening of the transmission 3 when the accelerator pedal is depressed when the deceleration is increased by braking / driving force control. FIG. 3 shows changes in the output torque, transmission ratio, engine torque, and accelerator opening of the transmission 3 when the accelerator pedal is depressed when the acceleration is reduced by the braking / driving force control. ing. Note that changes in the output torque, the transmission ratio, and the engine torque of the transmission 3 when the braking / driving force control is not executed are indicated by broken lines.

  In the example shown in FIG. 2, first, since the accelerator opening is “0”, the engine brake is applied by stopping the supply of fuel to the engine 1 or the like. Therefore, the output torque of the transmission 3 is a value based on the product of the braking torque and the gear ratio according to the engine braking force, so that the output torque of the transmission 3 is a negative value, that is, the braking force is applied. It has become. When the braking force is applied in this way and the braking / driving force is increased by the braking / driving force control, the engine braking force cannot be further increased by the control of the throttle opening or the like. Increased. That is, the torque gain is increased. Therefore, in the example shown in FIG. 2, when the braking / driving force control is executed so as to increase the braking / driving force at the time point t1, the speed ratio is increased, and as a result, the output torque of the transmission 3 increases. It should be noted that the rate of change of the output torque of the transmission 2 is preferably determined so that the driver does not feel uncomfortable due to a change in driving force and a shock.

  Next, when the driver depresses the accelerator pedal (time t2) while the braking force is being increased by the braking / driving force control, the output torque of the engine 1 is controlled according to steps S2 to S5 in FIG. In the example shown in FIG. 2, the gear ratio is increased by braking / driving force control. Therefore, the change amount of the output torque of the engine 1 with respect to the change amount of the accelerator opening is controlled to be smaller than the change amount when the braking / driving force control is not executed. On the other hand, the change amount of the output torque of the engine 1 is determined from the change amount ΔTe of the braking / driving force when the braking / driving force control is not executed and the current gear ratio. Therefore, the actual change amount ΔTa of the braking / driving force is the same as the change amount ΔTe of the braking / driving force when the braking / driving force control is not executed. As a result, the amount of change in driving force expected by the driver can be output without excess or deficiency.

  Further, when the accelerator opening is reduced when the braking force is reduced as described above (at time t3), the engine 1 is controlled in the same manner as described above, and the output torque of the engine 1 is reduced. As a result, the actual change amount ΔTa of the braking / driving force is the same as the change amount ΔTe of the braking / driving force when the braking / driving force control is not executed. In the example shown in FIG. 2, since the braking force that is increased by the braking / driving force control starts to decrease at time t4, the gear ratio starts to decrease accordingly. When the braking / driving force increased by the braking / driving force control decreases and coincides with the braking / driving force when the braking / driving force control is not executed (at time t5), the braking / driving force control ends.

  Next, FIG. 3 shows changes in output torque, transmission ratio, engine torque, and accelerator opening of the transmission 3 when the accelerator pedal is depressed when the driving force is reduced by the braking / driving force control. This will be described with reference to FIG. In the example shown in FIG. 3, first, since the accelerator pedal is depressed to some extent, torque set by torque demand control or the like is output from the engine 1 based on the depression amount of the accelerator pedal and the vehicle speed. In the example shown in FIG. 3, the output torque of the engine 1 is a positive torque. Therefore, the output torque of the transmission 3 becomes a value corresponding to the product of the driving torque of the engine 1 and the gear ratio, and therefore the output torque of the transmission 3 outputs a positive value, that is, a driving force. Yes. When the driving force is output in this way, when the gear ratio is changed by the braking / driving force control to reduce the driving force, the torque is increased up-shifted so that the amplification factor becomes small. Therefore, in the example shown in FIG. 2, when the braking / driving force control is executed so as to reduce the driving force at time t6, the gear ratio is lowered, and as a result, the output torque of the transmission 3 is lowered. It should be noted that the rate of change of the output torque of the transmission 3 is preferably determined so that the driver does not feel uncomfortable due to a change in driving force and a shock.

  Next, when the driver depresses the accelerator pedal (time t7) while the driving force is being reduced by the braking / driving force control, the output torque of the engine 1 is controlled according to steps S2 to S5 in FIG. In the example shown in FIG. 3, the transmission gear ratio is reduced by braking / driving force control. Therefore, the change amount of the output torque of the engine 1 with respect to the change amount of the accelerator opening is controlled to be larger than the change amount when the braking / driving force control is not executed. On the other hand, the change amount of the output torque of the engine 1 is determined from the change amount ΔTe of the braking / driving force when the braking / driving force control is not executed and the current gear ratio. Therefore, the actual change amount ΔTa of the braking / driving force is the same as the change amount ΔTe of the braking / driving force when the braking / driving force control is not executed. As a result, the amount of change in driving force expected by the driver can be output without excess or deficiency.

  Further, when the accelerator opening is reduced when the driving force is reduced as described above (at time t8), the engine 1 is controlled in the same manner as described above, and the output torque of the engine 1 is reduced. As a result, the actual change amount ΔTa of the braking / driving force is the same as the change amount ΔTe of the braking / driving force when the braking / driving force control is not executed. In the example shown in FIG. 3, since the driving force that is reduced by the braking / driving force control starts increasing at time t9, the gear ratio starts increasing accordingly. When the driving force reduced by the braking / driving force control increases and coincides with the driving force when the braking / driving force control is not executed (at time t10), the braking / driving force control ends.

  As described above, the driver requested that the braking / driving force be changed when the speed ratio determined based on the driver's accelerator pedal operation or the like is changed by the torque demand control or the like by the braking / driving force control. In this case, the change amount ΔTe of the braking / driving force that changes when the braking / driving force control is not executed can be made the same as the change amount of the actual braking / driving force ΔTa. Specifically, the braking / driving force control is executed by controlling the output torque of the engine 1 from the change amount ΔTe of the braking / driving force that changes when the braking / driving force control is not executed and the actual gear ratio. The change amount ΔTe of the braking / driving force that changes when the braking force is not applied can be made the same as the change amount ΔTa of the actual braking / driving force. Therefore, it is possible to suppress or prevent the actual braking / driving force variation ΔTa from deviating from the braking / driving force variation expected by the driver. In other words, the amount of change in braking / driving force expected by the driver can be output without excess or deficiency. As a result, it is possible to suppress or prevent the driver from feeling uncomfortable.

  2 and 3 show an example in which the accelerator pedal is depressed when the gear ratio is changed so that the driving force decreases or the braking force increases. The same control may be performed when the accelerator pedal is depressed when the gear ratio is changed so that the driving force increases or the braking force decreases.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Drive wheel, 3 ... Transmission, 4 ... Propeller shaft, 5 ... Differential gear, 6 ... Front wheel, 7 ... Brake, 8 ... Electronic control unit, 9 ... Sensor, 10 ... Actuator

Claims (3)

A basic transmission gear ratio determined based on the amount of driving force required by the driver and the vehicle speed, and a change transmission gear ratio different from the basic transmission gear ratio can be selectively set. In a vehicle driving force control device configured to set a braking / driving force according to a gear ratio or the changed gear ratio,
The amount of change in the braking / driving force when the requested driving force manipulated variable is changed while the changed gear ratio is set, and the requested driving force manipulated variable is changed while the basic gear ratio is set. The driving force control device for a vehicle is configured such that the amount of change in the output torque of the driving force source is controlled so as to coincide with the amount of change in the braking / driving force in the event of a failure.   When the changed gear ratio is larger than the basic gear ratio, the amount of change in the output torque of the driving force source is the same as when the requested driving force operation amount is changed while the basic gear ratio is set. The vehicle driving force control apparatus according to claim 1, wherein the vehicle driving force control device is controlled to be smaller than a basic change amount of an output torque of the driving force source.   When the changed transmission gear ratio is smaller than the basic transmission gear ratio, the amount of change in the output torque of the driving force source is the same as when the requested driving force operation amount is changed while the basic transmission gear ratio is set. The vehicle driving force control apparatus according to claim 1, wherein the vehicle driving force control device is controlled to be larger than a basic change amount of an output torque of the driving force source.

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