JP2011225129A - Brake control device and brake system equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance operability of operation release of a hill hold function and to stably control the hill hold function.SOLUTION: The required torque arithmetic section 19 of a brake control device 15 calculates a required torque that is necessary for a vehicle to start on an uphill road on the basis of gradient information and specification information of the vehicle. A vehicle load arithmetic section 20 calculates a load on the vehicle on the basis of the gradient information and the specification information of the vehicle. On the basis of this vehicle load, a brake release point correction value arithmetic section 21 calculates a brake release point correction value. Then, on the basis of this brake release point correction value, the required torque correction section 22 corrects a required torque and determines brake release approval on the basis of the corrected required torque.

Description

The present invention relates to a technical field of a brake control device that controls a brake by a hill hold function that automatically holds and releases a brake operation state and releases the brake operation state, and a brake system including the brake control device. It is.

  2. Description of the Related Art Conventionally, a brake control device for controlling a brake is provided in a vehicle brake system. As this brake control device, the brake is automatically held in the operating state when the vehicle is stopped, and the brake control is performed by the hill hold function that automatically releases the brake held in the operating state at the start of the vehicle. There has been proposed a brake control device for assisting the above (see, for example, Patent Document 1).

  In the brake control device described in Patent Document 1, the brake force release timing (release permission issuance instruction) in the hill hold function is taken into account, including the gradient information such as the inclination angle of the slope where the vehicle is located and the vehicle specification information. The brake operation is controlled so that the brake force is released at the calculated release timing. In this case, the vehicle specification information includes vehicle running information such as hill running, stopping, wheel speed, etc., ignition key switch on / off status, brake operation status (brake pedal depression status, etc.), gear application status, etc. There are vehicle driving operation information, and vehicle information such as the weight of the vehicle itself, the engine output capability of the vehicle, and the suspension length of the vehicle when empty.

  When schematically showing an example of the control of the brake operation described in Patent Document 1, when a vehicle having a hill hold function tries to move forward from a state where it stops on an uphill road, as shown in FIG. By calculating the running resistance based on the vehicle specification information and gradually connecting the clutch based on the calculated running resistance, the engine torque required to maintain the state where the vehicle does not move backward (that is, does not move backward). Calculate the required torque. On the other hand, based on a brake release point correction instruction input signal by the driver, a correction value of a brake release point (that is, a brake release timing, in other words, a timing at which the engine torque is calculated as a necessary torque) is calculated.

  Then, the necessary torque is corrected using the calculated necessary torque and the calculated brake release point correction value. The reason why the necessary torque is corrected by the brake release point correction value is as follows. In other words, there are various different vehicle situations for the same vehicle depending on the loading and empty loading of the vehicle, but the above-mentioned necessary torque varies depending on this vehicle situation. Since the required torque is different in this way, it is necessary to correct the brake release timing to an appropriate release timing (that is, a timing at which the engine torque becomes the required torque) according to the vehicle situation.

  Then, brake release is determined based on the corrected required torque, and when it is determined that the engine has output the torque of the corrected required torque, a brake release signal is output to the brake control unit. As a result, the brake control unit releases the brake, the hill hold function is turned off, and the vehicle starts smoothly uphill and climbs the uphill road without going backward (backward).

The operation control of the hill hold function by this conventional brake control device is performed, for example, according to the flow shown in FIG. That is, as shown in FIG. 6, in step S1, the ignition key switch is turned on. Next, whether or not the hill hold function is in operation is determined in step S2 by turning on the ignition key switch. If it is determined that the hill hold function is not in operation, the process of step S2 is repeated. If it is determined that the hill hold function is in operation, it is determined in step S3 whether or not a vehicle starting operation, that is, a vehicle driving operation such as a forward or backward starting gear shift operation has been performed. If it is determined that the vehicle start operation is not performed, the process of step S3 is repeated. If it is determined that the vehicle start operation has been performed, it is determined in step S4 whether or not the stop position of the vehicle is an uphill road. If it is determined that the stop position of the vehicle is an uphill road, the running resistance is calculated in step S5, the required torque is calculated in step S6, and the brake release point correction value is calculated in step S7. Next, the required torque is corrected by the brake release point correction value calculated in step S8.

Next, in step S9, it is determined whether or not the engine torque has reached the corrected required torque. If it is determined that the engine torque is not the correction required torque, the process of step S9 is repeated. If it is determined that the engine torque has become the correction required torque, the operation of the hill hold function is canceled in step S10, and the brake is released. Thereby, a vehicle starts an uphill road by step S11.
When it is determined in step S4 that the stop position of the vehicle is not an uphill road, the process proceeds to step S10, and the processes after step S10 are executed.

JP 2002-104147 A.

  However, in the brake control device described in Patent Document 1, it is necessary to input a brake release point correction instruction signal by the driver. Therefore, the driver is not only required to have the skill of input operation of the brake release point correction instruction signal, but is also required to set different brake release point correction for each vehicle loading situation. For this reason, the input of the brake release point correction instruction signal by the driver is a factor that obstructs the driver's operability due to the complexity of the driver's operation, and the setting is often different depending on the driver. There is a problem that the control of the hold function is not stable.

  The present invention has been made in view of such circumstances, and its purpose is to improve the operability of releasing the operation of the hill hold function and to control the hill hold function stably. And providing a brake system including the same.

In order to solve the above-described problem, the brake control device of the present invention includes a hill hold control unit that holds a brake of a vehicle stopped by a brake in an operating state, and gradient information that outputs gradient information of an uphill road where the vehicle stops. The hill hold control based on the output unit, the vehicle specification information output unit for outputting the vehicle specification information, the gradient information from the gradient information output unit and the vehicle specification information from the vehicle specification information output unit A brake control device including at least an electronic control unit for controlling the unit, wherein the electronic control unit converts the gradient information from the gradient information output unit and the vehicle specification information from the vehicle specification information output unit. Based on the vehicle running resistance computing unit that computes the running resistance of the vehicle and the vehicle running resistance computed by the vehicle running resistance computing unit, the vehicle starts the uphill road A vehicle load for calculating a load degree of a vehicle based on a required torque calculation unit that calculates a necessary required torque, and the gradient information from the gradient information output unit and the vehicle specification information from the vehicle specification information output unit A brake release point correction value calculation unit for calculating a brake release point correction value based on the vehicle load degree calculated by the vehicle load degree calculation unit, and the brake release point correction value calculation unit. When the required torque correction unit for correcting the required torque calculated by the required torque calculation unit based on the brake release point correction value and the engine torque becomes the required torque corrected by the required torque correction unit, And a brake release permission determining unit that outputs a signal for permitting brake release to the hill hold control unit.

  Further, the brake system of the present invention includes a brake operation member that performs a brake operation, a brake pressure generation unit that generates a brake pressure by operating the brake operation member, and a brake pressure generated on the wheel by the brake pressure generated by the brake pressure generation unit. A brake system comprising at least a brake force generating means for generating a brake force for applying a brake and a brake control device for controlling a brake operation by the brake pressure, wherein the brake control device is the brake control device of the present invention described above. It is characterized by being.

  According to the brake control device according to the present invention configured as described above, vehicle information such as the gradient information from the gradient information output unit, and the vehicle travel information, vehicle driving information, and vehicle information from the vehicle specification information output unit. Based on the original information, the vehicle load degree calculation unit of the ECU calculates the load degree of the vehicle such as a change in the vehicle weight due to a loaded state or an empty state with respect to the weight of the vehicle itself. When the necessary torque necessary for the vehicle to start smoothly without going back on the uphill road is corrected based on the calculated vehicle load, the hill hold is set when the engine torque becomes the corrected required torque. The function is deactivated. In this way, the required torque can be automatically corrected by the ECU. Accordingly, it is possible to eliminate the input operation of the brake release point correction instruction signal by the driver as in the prior art. As a result, it is possible to eliminate the driver's skill to input the brake release point correction instruction signal, and it is also possible to eliminate the need for different brake release point correction settings for each vehicle loading situation. As a result, the operation of the driver can be simplified and the operability by the driver can be improved, and the hill hold function can be controlled easily and stably.

  Further, according to the brake system equipped with the brake control device of the present invention, the hill hold function can be controlled easily and stably, so that the vehicle can be easily started uphill regardless of the driving skill of the driver. Can be performed.

It is a figure showing typically a brake system provided with an example of an embodiment of a brake control device concerning the present invention. It is a figure which shows the algorithm of the operation control of the hill hold function in the brake system of the example shown in FIG. It is a block diagram showing an example of an embodiment of a brake control device concerning the present invention. It is a figure which shows the flow which controls the action | operation of the hill hold function of the brake control apparatus of the example shown in FIG. It is a figure which shows the algorithm of the operation | movement control of the conventional hill hold function. It is a figure which shows the flow which controls the action | operation of the hill hold function of the conventional brake control apparatus.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing a brake system including an example of an embodiment of a brake control device according to the present invention.
As shown in FIG. 1, a brake system 1 of this example includes a brake pedal 2 that is a brake operating member for applying a normal brake in the same manner as a conventional normal brake system, and a pedaling force of the brake pedal 2 with a predetermined servo ratio. A brake booster 3 comprising a conventionally known negative pressure booster etc. that boosts and outputs at the same time, and a conventionally known brake pressure generating means that operates by the output of the brake booster 3 to generate brake pressure. A tandem master cylinder 4 and first and second wheel cylinders 7 and 8 which are brake force generating means for generating a braking force for braking each of the wheels 5 and 6, one end of which is one pressure of the master cylinder 4 A main brake passage 9 connected to a chamber (not shown) and a branch from the main brake passage 9 are connected to the first and second wheel cylinders 7 and 8, respectively. The first and second branch passages 10 and 11, the hill hold control unit (hill holder) 12 provided in the main brake passage 9, and the electronic control unit (ECU) 13 that controls the operation of the hill hold control unit 12. I have. In the brake control device 1 of this example, the hill hold control unit 12 is composed of a normally open electromagnetic on-off valve. The main brake passage 9 is provided with a check valve 14 that allows only the flow of brake fluid from the master cylinder 4 toward the first wheel cylinder 7, bypassing the hill hold control unit 12. Then, one of the pressure chambers of the master cylinder 4, the first and second wheel cylinders 7 and 8, the main brake passage 9, the first and second branch passages 10 and 11, the hill hold control unit 12, and the check valve 14 One brake system is configured.

Although not shown, the brake system 1 of this example includes the other pressure chamber of the master cylinder 4, a wheel cylinder similar to the first and second wheel cylinders 7, 8, and the main brake passage 9.
A main brake passage similar to the above, a branch passage similar to the first and second branch passages 10 and 11, a hill hold control portion similar to the hill hold control portion 12, and a check valve similar to the check valve 14. These constitute a second brake system. In this case, the hill hold control unit of the second brake system is also configured by a similar electromagnetic on-off valve, and this electromagnetic on-off valve is also controlled by the ECU 13.
Since the operation and control of the second brake system are the same as those of the first brake system, in the following description, only the first brake system will be described, and description of the second brake system will be omitted.

  The brake system 1 of this example has a hill hold function by the hill hold control unit 12. FIG. 2 is a diagram showing an algorithm for operation control of the hill hold function in the brake system of this example. As shown in FIG. 2, in the operation control of the hill hold function of this example, the vehicle moves uphill on the uphill road in the state where the hill hold function is operated based on the gradient information and the vehicle specification information as in the above-described conventional example. When the vehicle is stopped, the running resistance of the vehicle is calculated. In this case, as described above, the vehicle specification information includes vehicle running information such as running on a slope, stopping, and wheel speed, on / off state of an ignition key switch, brake operation state (brake pedal depression state, etc.), gear There are vehicle driving operation information such as the loading status, and vehicle information such as the weight of the vehicle itself, the engine output capability of the vehicle, and the suspension length of the vehicle when it is idle.

  Next, a necessary torque, which is an engine torque necessary for the vehicle to start the uphill road, is calculated based on the calculated running resistance. On the other hand, the vehicle load degree is calculated based on the gradient information and the vehicle specification information. As described above, the vehicle load degree is set according to the vehicle situation because the necessary torque differs depending on various vehicle situations even in the same vehicle depending on the loading situation of the vehicle such as loading or empty loading. For example, a load applied to the suspension, a deflection amount of the suspension, another load sensor, or the like is used as a vehicle loading status detection unit.

Next, based on the calculated vehicle load level, the brake release point correction value, that is, the operation release timing of the hill hold function is calculated. Next, the above-described necessary torque is corrected based on the calculated brake release point correction value. Then, when starting the uphill road, when the engine torque reaches the corrected necessary torque, permission to release the brake, that is, permission to release the hill hold function is determined. Finally, when the brake release permission is determined, a brake release signal is generated, and when the brake release permission is not determined, a brake hold signal, that is, a hill hold function operation hold signal is generated.

FIG. 3 is a block diagram showing an example of the embodiment of the brake control device according to the present invention.
In order to execute the operation control algorithm of the hill hold function shown in FIG. 2 described above, the brake system of this example includes a brake control device. As shown in FIG. 3, the brake control device 15 includes a gradient information output unit 16, a vehicle specification information output unit 17, an ECU 13, and a hill hold control unit 12. The ECU 13 includes a running resistance calculation unit 18, a necessary torque calculation unit 19, a vehicle load degree calculation unit 20, a brake release point correction value calculation unit 21, a necessary torque correction unit 22, and a brake release permission determination unit 23. Yes.

  The gradient information output unit 16 is composed of a known gradient sensor or the like, and outputs gradient information such as an inclination angle with respect to the level of the road on which the vehicle is located. The vehicle specification information output unit 17 is composed of various known sensors and outputs the same vehicle specification information as the conventional one.

  The traveling resistance calculation unit 18 of the ECU 13 is configured such that when the vehicle is stopped on the uphill road in the hill hold function operating state, the gradient information from the gradient information output unit 16 and the vehicle specification information from the vehicle specification information output unit 17 are displayed. Based on the above, the running resistance when the vehicle starts on the uphill road, that is, the uphill force of the vehicle is calculated. The required torque calculation unit 19 calculates the required torque of the engine necessary for starting the uphill road based on the running resistance from the running resistance calculation unit 18.

  Further, the vehicle load degree calculation unit 20 is based on the gradient information from the gradient information output unit 16 and the vehicle specification information from the vehicle specification information output unit 17, and the vehicle according to the loaded state or the empty state with respect to the weight of the vehicle itself. Calculate the load of the vehicle such as the change in weight. Further, the brake release point correction value calculation unit 21 corrects a brake release point correction value (that is, a required torque that is an engine torque necessary for releasing the brake based on the vehicle load degree from the vehicle load degree calculation unit 20 (that is, a brake release point correction value). , Necessary torque correction value) is calculated. The required torque correction unit 22 corrects the required torque from the required torque calculation unit 19 based on the brake release point correction value from the brake release point correction value calculation unit 21. Further, the brake release permission determination unit 23 outputs the brake release permission to the hill hold control unit 12 when it is determined that the engine torque has become the necessary torque corrected by the necessary torque correction unit 22, and the engine torque is the required torque. When it is determined that the required torque is not corrected by the correction unit 22, the brake release prohibition (that is, brake operation holding) is output to the hill hold control unit 12.

Next, the operation control of the hill hold function by the brake control device 15 of this example will be described. FIG. 4 is a diagram showing a flow for controlling the operation of the hill hold function.
As shown in FIG. 4, first, in step S21, the ignition key switch is turned on. Next, whether or not the hill hold function is in operation is determined in step S22 by turning on the ignition key switch. If it is determined that the hill hold function is not in operation, the process of step S22 is repeated. If it is determined that the hill hold function is in operation, it is determined in step S23 whether or not a vehicle starting operation, that is, a vehicle driving operation such as a gear shift operation for starting forward or starting backward is performed. If it is determined that the vehicle start operation is not performed, the process of step S23 is repeated. If it is determined that the vehicle start operation has been performed, it is determined in step S24 whether the stop position of the vehicle is an uphill road. If it is determined that the stop position of the vehicle is an uphill road, the running resistance is calculated in step S25 and the required torque is calculated in step S26. Further, the vehicle load degree is calculated in step S27, and the brake release point correction value is calculated in step S28. Next, the required torque is corrected in step S29.

Next, in step S30, it is determined whether or not the engine torque has reached the corrected required torque. If it is determined that the engine torque is not the correction required torque, the process of step S30 is repeated. If it is determined that the engine torque has become the correction required torque, the hill hold function is deactivated by setting the hill hold control unit 12 to the non-operation position in step S31. That is, the electromagnetic on-off valve of the hill hold control unit 12 is set to the normally open position, and the brake is released. Thereby, a vehicle starts an uphill road by step S32.
If it is determined in step S24 that the stop position of the vehicle is not an uphill road, the process proceeds to step S31, and the processes after step S31 are executed.

  According to the brake control device 15 of this example, based on the gradient information from the gradient information output unit 16 and the vehicle specification information from the vehicle specification output unit 17, the vehicle load degree calculation unit 20 of the ECU 13 causes the vehicle itself to be The degree of load on the vehicle, such as a change in vehicle weight due to a loaded state or an empty state with respect to the weight, is calculated. When the necessary torque necessary for the vehicle to start smoothly without going back on the uphill road is corrected based on the calculated vehicle load, the hill hold is set when the engine torque becomes the corrected required torque. The function is deactivated. In this way, the required torque can be automatically corrected by the ECU 13. Accordingly, it is possible to eliminate the input operation of the brake release point correction instruction signal by the driver as in the prior art. As a result, it is possible to eliminate the driver's skill to input the brake release point correction instruction signal, and it is also possible to eliminate the need for different brake release point correction settings for each vehicle loading situation. As a result, the operation of the driver can be simplified and the operability by the driver can be improved, and the hill hold function can be controlled easily and stably.

  In addition, according to the brake system 1 including the brake control device 15 of this example, the hill hold function can be controlled easily and stably, so that the vehicle can start on an uphill road regardless of the driving skill of the driver. Can be easily performed.

  In the above-described example, the brake system 1 is a brake system in which the brake booster 3 and the master cylinder 4 are combined. However, the present invention is applied from an air brake system, a pump, or an accumulator that operates the brake with compressed air. The present invention can be applied to any other type of brake system as long as the hill hold control unit 12 can be installed, including a hydraulic brake system that directly operates a brake with hydraulic pressure. Further, the hill hold control unit 12 is not limited to the hill hold control unit 12 schematically shown in FIG. 1, and any hill hold control unit 12 may be employed as long as it has a hill hold function. In short, the present invention can be modified in various ways within the scope of the matters described in the claims.

  A brake control device and a brake system including the same according to the present invention include a brake control device that controls a brake by a hill hold function that automatically holds both the brake operation state and releases the brake operation state. It can use suitably for a brake system provided with.

DESCRIPTION OF SYMBOLS 1 ... Brake system, 2 ... Brake pedal, 3 ... Brake booster, 4 ... Master cylinder, 7 ... 1st wheel cylinder, 8 ... 2nd wheel cylinder, 9 ... Main brake path, 12 ... Hill hold control part, 13 DESCRIPTION OF SYMBOLS ... Electronic control part (ECU), 15 ... Brake control apparatus, 16 ... Gradient information output part, 17 ... Vehicle specification information output part, 18 ... Running resistance calculation part, 19 ... Necessary torque calculation part, 20 ... Vehicle load degree calculation , 21 ... Brake release point correction value calculation unit, 22 ... Necessary torque correction unit, 23 ... Brake release permission determination unit

Claims (2)

A hill hold control unit that holds the brake of the vehicle stopped by the brake in an operating state;
A gradient information output unit that outputs gradient information of an uphill road where the vehicle stops;
A vehicle specification information output unit for outputting vehicle specification information;
An electronic control unit for controlling the hill hold control unit based on the gradient information from the gradient information output unit and the vehicle specification information from the vehicle specification information output unit;
A brake control device comprising at least
The electronic control unit
Based on the gradient information from the gradient information output unit and the vehicle specification information from the vehicle specification information output unit, a vehicle running resistance calculation unit that calculates the running resistance of the vehicle;
Based on the running resistance computed by the vehicle running resistance computing unit, a necessary torque computing unit that computes necessary torque required for the vehicle to start the uphill road;
A vehicle load degree calculation unit for calculating a load degree of the vehicle based on the gradient information from the gradient information output unit and the vehicle specification information from the vehicle specification information output unit;
A brake release point correction value calculation unit for calculating a brake release point correction value based on the vehicle load level calculated by the vehicle load level calculation unit;
A required torque correction unit that corrects the required torque calculated by the required torque calculation unit based on the brake release point correction value calculated by the brake release point correction value calculation unit;
A brake release permission determining unit that outputs a signal for permitting brake release to the hill hold control unit when the engine torque reaches the required torque corrected by the required torque correction unit; apparatus. A brake operating member for operating the brake, a brake pressure generating means for generating a brake pressure by operating the brake operating member, and a brake force for braking the wheel with the brake pressure generated by the brake pressure generating means A brake system comprising at least a brake force generating means for controlling the brake operation by the brake pressure,
The brake system according to claim 1, wherein the brake control device is the brake control device according to claim 1.

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