JP3687322B2 - Temperature compensation device for preload control in vehicle behavior control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle behavior control apparatus that controls a vehicle horizontal plane behavior by automatic braking of each wheel, and more particularly to a temperature compensation technique for preload control in the apparatus.
[0002]
[Prior art]
As a vehicle behavior control device, for example, as described in Japanese Patent Application Laid-Open No. 7-89427, a vehicle horizontal plane behavior (for example, yaw rate) is controlled to be as intended by an automatic brake for each wheel. The thing of the structure which is made is known.
When the vehicle behavior is controlled by the behavior control device, for example, the deviation between the output from the behavior sensor for detecting the vehicle behavior, that is, the behavior detection value, and the behavior target value obtained from the vehicle speed and the steering angle is reduced. That is, it is conceivable to control the behavior of the vehicle by the difference between the left and right wheel braking forces so that the actual behavior matches the behavior target value.
[0003]
By the way, when behavior control is performed by automatic braking of each wheel, the response delay of the hydraulic pressure is larger than that of electric behavior control, etc., so it is inevitable that behavior control start delay and control amount shortage will occur. .
In order to solve this problem, the behavior control start instant t as shown by a two-dot chain line a in FIG._FourFor example, instant t ahead of₂When the behavior control pressure source is activated, the moment t_FourIn the meantime, the preload is supplied to the brake system, and this preload is, for example, shown in FIG._S0It is conceivable to set the preload target value just before starting to generate the braking force, as determined by.
[0004]
[Problems to be solved by the invention]
However, when the brake fluid temperature is low, such as during engine warm-up operation at low temperatures, the viscosity of the brake fluid is high, so that the preload is instant t at the rise start timing as shown by the broken line b in FIG._ThreeAs a result, there is a shortage of the preload that should be targeted over time a, and the improvement effect relating to sufficient delay in starting the behavior control due to the preload and insufficient control amount cannot be expected.
However, if the start of preload control is made sensitive so that the problem at the time of low temperature does not occur and the preload control is accelerated or the preload target value is set to an excessively high value, The operation frequency of the pressure source and the pressure regulating valve means is unnecessarily increased, and the durability of the behavior control device is significantly reduced due to the fact that the low temperature period is much less than the high temperature period.
[0005]
According to the first aspect of the present invention, from the viewpoint that the effect of improving the behavior control by the preload cannot be expected only when the brake fluid temperature is low, the preload control start determination is made according to the brake fluid temperature. The object is to realize the above solution by changing the sensitivity.
[0006]
  In particular, the first inventionProposal of a suitable method for changing the sensitivity of preload control start judgment
[0007]
  2nd invention of Claim 2An object of the present invention is to more reliably realize the above-described problem solving by changing not only the sensitivity of the preload control start determination in accordance with the brake fluid temperature but also the preload target value.
[0008]
  3rd invention of Claim 3An object of the present invention is to more reliably realize the above-mentioned problem solving by changing not only the sensitivity of preload control start determination and the preload target value but also the preload control gain by the pressure regulating valve means according to the brake fluid temperature. And
[0009]
  4th invention of Claim 4An object of the present invention is to realize the solution to the above problem by changing only the preload target value according to the brake fluid temperature.
[0010]
  5th invention of Claim 5An object of the present invention is to more reliably realize the above-mentioned problem solving by changing not only the preload target value but also the preload control gain by the pressure regulating valve means in accordance with the brake fluid temperature.
[0011]
  6th invention of Claim 6An object of the present invention is to realize the above solution by changing only the preload control gain by the pressure regulating valve means in accordance with the brake fluid temperature.
[0012]
  7th invention of Claim 7An object of the present invention is to estimate the brake fluid temperature instead of directly detecting the above-mentioned problem at low cost.
[0013]
[Means for Solving the Problems]
  For these purposes, first, a temperature compensation device for preload control for a vehicle behavior control device according to the first invention is as follows:
  In a device that controls the behavior of a vehicle so as to reduce the behavior deviation between the behavior detection value and the behavior target value by giving a left-right braking force difference by automatic braking of each wheel by the behavior control pressure from the behavior control pressure source ,
  Prior to the behavior control, the behavior control pressure source is activated to supply a preload to the brake system of each wheel, and the preload is controlled to approach the preload target value by the pressure regulating valve means,
  The preload control start command timing prior to behavior control is advanced as the brake fluid temperature decreases.Configured.
[0014]
  AndIn the case where behavior control is started when the behavior deviation is equal to or greater than the behavior control setting value, the preload control is started when the behavior deviation is equal to or larger than the preload control setting value smaller than the behavior control setting value. In addition, the preload control set value is configured to be smaller as the brake fluid temperature is lower.
[0015]
  Second inventionThe temperature compensation device for preload control for vehicle behavior control device by1st inventionIn
  The preload target value is configured to increase as the brake fluid temperature decreases.
[0016]
  Third inventionThe temperature compensation device for preload control for vehicle behavior control device byIn the first invention or the second invention,
  The preload control gain by the pressure regulating valve means is configured to increase as the brake fluid temperature decreases.
[0017]
  Fourth inventionThe temperature compensation device for preload control for vehicle behavior control device by
  In a device that controls the behavior of a vehicle so as to reduce the behavior deviation between the behavior detection value and the behavior target value by giving a left-right braking force difference by automatic braking of each wheel by the behavior control pressure from the behavior control pressure source ,
  Prior to the behavior control, the behavior control pressure source is activated to supply a preload to the brake system of each wheel, and the preload is controlled to approach the preload target value by the pressure regulating valve means,
  In the preload control, the preload target value is set higher as the brake fluid temperature is lower.Configure
  In the case where behavior control is started when the behavior deviation is equal to or greater than the behavior control setting value, the preload control is started when the behavior deviation is equal to or larger than the preload control setting value smaller than the behavior control setting value. In addition, the preload control set value is configured to be smaller as the brake fluid temperature is lower.It is characterized by this.
[0018]
  5th inventionThe temperature compensation device for preload control for vehicle behavior control device byFourth inventionIn
  The preload control gain by the pressure regulating valve means is configured to increase as the brake fluid temperature decreases.
[0019]
  6th inventionThe temperature compensation device for preload control for vehicle behavior control device by
  In a device that controls the behavior of a vehicle so as to reduce the behavior deviation between the behavior detection value and the behavior target value by giving a left-right braking force difference by automatic braking of each wheel by the behavior control pressure from the behavior control pressure source ,
  Prior to the behavior control, the behavior control pressure source is activated to supply a preload to the brake system of each wheel, and the preload is controlled to approach the preload target value by the pressure regulating valve means,
  In the preload control, the preload control gain by the pressure regulating valve means is increased as the brake fluid temperature is lower.Configure
  In the case where behavior control is started when the behavior deviation is equal to or greater than the behavior control setting value, the preload control is started when the behavior deviation is equal to or larger than the preload control setting value smaller than the behavior control setting value. In addition, the preload control set value is configured to be smaller as the brake fluid temperature is lower.It is characterized by this.
[0020]
  7th inventionThe temperature compensation device for preload control for vehicle behavior control device by1st invention thru | or 6th inventionIn either
  The brake fluid temperature is estimated from the amount of heat generated and the amount of heat released by a heat generation source that affects the brake fluid temperature.
[0021]
【The invention's effect】
The vehicle behavior control device gives a left-right braking force difference by automatic braking of each wheel by the behavior control pressure from the behavior control pressure source so that the behavior deviation between the behavior detection value and the behavior target value is reduced. Perform behavior control.
By the way, in the first invention, prior to the behavior control, the behavior control pressure source is activated to supply a preload to the brake system of each wheel, and the preload is controlled to approach the preload target value by the pressure regulating valve means. And
Since the start command timing of the preload control prior to the behavior control is advanced as the brake fluid temperature is lower,
Preload can be prevented from becoming insufficient at low temperatures when the brake fluid temperature is low, and response delay prevention effect of behavior control due to preload and control amount deficiency canceling effect can be achieved as intended even at low temperatures. Can do.
In addition, since the start command timing for preload control is not unnecessarily advanced except when the temperature is low, the operation frequency of the behavior control pressure source and the pressure regulating valve means is increased, which reduces the durability of the behavior control device. The above effects can be achieved without the occurrence.
[0022]
  Especially in the first invention,When starting the behavior control when the behavior deviation is equal to or greater than the behavior control set value, the preload control is started when the behavior deviation is equal to or greater than the preset value for the preload control smaller than the behavior control set value, Since the preload control set value is decreased as the brake fluid temperature is lower,
  The lower the brake fluid temperature is, the higher the sensitivity of the preload control start determination and the quicker the start of preload control.
  Therefore,Preload can be prevented from becoming insufficient at low temperatures, and the problem of response delay prevention of behavior control due to preload at low temperatures and the problem of insufficient control amount cancellation cannot be solved. it can.
[0023]
  In addition, since the sensitivity of the preload control start determination is not increased unnecessarily except at low temperatures, the behavior control pressure source and the pressure regulating valve means are operated more frequently and the behavior control device is less durable. The above-described effects can be achieved without generating the above.
  And this1st inventionIn particular, since the preload control start determination is performed by the behavior deviation as in the case of the necessity determination of the behavior control, and when the sensitivity of the preload control start determination at the low temperature is increased, the setting value for the preload control of the behavior deviation is decreased as the lower,
  The start time of the preload control is determined based on the behavior control, and the time can be more accurately matched to the above-described effects.
[0024]
  Second inventionIn1st inventionBecause the preload target value in is increased as the brake fluid temperature is lower,
  This also prevents the preload from becoming insufficient at low temperatures, and the problem that the response delay prevention effect of behavior control by preload at the low temperature and the control amount deficiency canceling effect are not as intended,1st inventionCan be resolved more reliably.
[0025]
  Third inventionIn1st invention or 2nd inventionSince the preload control gain of the pressure regulating valve means in the engine is increased as the brake fluid temperature is lower,
  This also prevents the preload from becoming insufficient at low temperatures, and the problem that the response delay prevention effect of behavior control by preload at the low temperature and the control amount deficiency canceling effect are not as intended,1st invention or 2nd inventionThis can be solved more reliably.
[0026]
  Fourth inventionIn the same manner as in the above-mentioned inventions, the preload is supplied to the brake system of each wheel by starting the behavior control pressure source prior to the behavior control, and the preload is brought close to the preload target value by the pressure regulating valve means. Control to
  In the preload control, the above preload target value is increased as the brake fluid temperature is lower.If the behavior deviation starts when the behavior deviation exceeds the behavior control setting value, the preload control starts when the behavior deviation becomes the preload control setting value that is smaller than the behavior control setting value. The preload control set value is made smaller as the brake fluid temperature is lower.From that
  Preload can be prevented from becoming insufficient at low temperatures, and the problem of response delay prevention of behavior control due to preload at low temperatures and the problem of insufficient control amount cancellation cannot be solved. it can.
  Moreover, since the preload target value is not increased unnecessarily except at low temperatures, the frequency of operation of the behavior control pressure source and the pressure regulating valve means increases, resulting in a problem that the durability of the behavior control device decreases. The above-mentioned effects can be achieved without any problems.
[0027]
  5th inventionInFourth inventionSince the preload control gain of the pressure regulating valve means in the engine is increased as the brake fluid temperature is lower,
  This also prevents the preload from becoming insufficient at low temperatures, and the problem that the response delay prevention effect of behavior control by preload at the low temperature and the control amount deficiency canceling effect are not as intended,Fourth inventionCan be resolved more reliably.
[0028]
  6th inventionIn the same manner as in the above-mentioned inventions, the preload is supplied to the brake system of each wheel by starting the behavior control pressure source prior to the behavior control, and the preload is brought close to the preload target value by the pressure regulating valve means. Control to
  In the preload control, the preload control gain by the pressure regulating valve means is increased as the brake fluid temperature is lower.If the behavior deviation starts when the behavior deviation exceeds the behavior control setting value, the preload control starts when the behavior deviation becomes the preload control setting value that is smaller than the behavior control setting value. The preload control set value is made smaller as the brake fluid temperature is lower.From that
  Preload can be prevented from becoming insufficient at low temperatures, and the problem of response delay prevention of behavior control due to preload at low temperatures and the problem of insufficient control amount cancellation cannot be solved. it can.
  Moreover, since the preload control gain by the pressure regulating valve means is not increased unnecessarily except at low temperatures, the behavior control pressure source and the pressure regulating valve means are operated more frequently and the behavior control device is less durable. The above-described effects can be achieved without generating the above.
[0029]
  7th inventionIn, instead of directly detecting the brake fluid temperature in each of the above inventions, to estimate from the amount of heat generated and the amount of heat released by the heat source that affects the brake fluid temperature,
  There is no need for means for directly detecting the brake fluid temperature, and the effects of the above-described inventions can be achieved at a low cost.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a system diagram showing a vehicle behavior control device including a temperature compensation device for preload control for a vehicle behavior control device according to an embodiment of the present invention. In this embodiment, the behavior control device is an automatic brake. It is assumed that the yaw rate of the vehicle is controlled by the difference between the left and right braking forces.
1 in FIG._FL, 11_FRAre left and right wheels to be braked by automatic braking in behavior control, for example, a left front wheel and a right front wheel.
[0031]
Reference numeral 12 denotes a brake master cylinder. When the brake pedal 13 is depressed, the brake fluid in the reservoir tank 14 is changed to a master cylinder hydraulic pressure P corresponding to the brake pedal depression force._mAnd output.
Master cylinder hydraulic pressure P_mIs supplied to a master cylinder hydraulic pressure port 15a of the precharge cylinder 15, and the precharge cylinder 15 has a piston 15c elastically supported by a return spring 15b, and the master cylinder hydraulic pressure port at a normal position shown in the figure of the piston 15c. 15a is configured to communicate with the output port 15e through the piston communication hole 15d.
[0032]
The precharge cylinder 15 is further provided with a precharge pressure port 15f that is opened in a cylinder chamber opposite to the cylinder chamber in which the piston communication hole 15d is opened._prThus, when the piston 15c is moved to the left against the return spring 15b, a free piston 15g that closes the piston communication hole 15d is floated and supported by the spring 15h.
[0033]
A precharge pressure source configured as a mutual parallel circuit of the precharge pump 16, the relief valve 17 and the orifice 18 is connected between the reservoir tank 14 and the precharge pressure port 15f, and the precharge pump 16 is provided as described later. It is appropriately driven by a motor 16a that is ON / OFF controlled.
[0034]
A front wheel brake hydraulic pressure circuit 20 is connected to the output port 15e of the precharge cylinder 15 via a normally open electromagnetic master cylinder hydraulic pressure selection valve 19 on the one hand, and a normally closed electromagnetic precharge pressure selection valve on the other hand. The suction port of the behavior control pressure pump 22 is connected via 21.
[0035]
The behavior control pressure pump 22 is used for the left and right front wheels 11 during behavior control as will be described later._FL, 11_FRThis is for generating a brake fluid pressure for behavior control toward the vehicle, and constitutes a pressure source for behavior control in the present invention. This pump 22 is appropriately driven by a motor 22a that is ON / OFF controlled as described later. To do.
The discharge port of the behavior control pressure pump 22 is connected to the output port 15e of the precharge cylinder 15 via the relief valve 23 and is connected to the front wheel brake hydraulic circuit 20.
[0036]
From the front wheel brake hydraulic circuit 20 to the left and right front wheels 11_FL, 11_FRWheel cylinder 24_FL, 24_FRLeft and right front wheel brake hydraulic circuit 20_FL, 20_FREach has a normally open electromagnetic booster valve 25._FL, 25_FRThese pressure boosting valves 25 are inserted._FL, 25_FRAnd wheel cylinder 24_FL, 24_FRLeft and right front wheel brake hydraulic circuit 20_FL, 20_FRPressure reducing circuit 26 branching off_FL, 26_FRIn each case, a normally closed electromagnetic pressure reducing valve 27_FL, 27_FRIs inserted.
Then, the decompression circuit 26_FL, 26_FRAre connected to a common accumulator 28 and also to a suction port of the behavior control pressure pump 22 through a common check valve 29.
[0037]
Booster valve 25_FL, 25_FRThe input pressure (behavior control pressure from the pump 22) corresponds to the corresponding left and right front wheel cylinders 24._FL, 24_FRTo increase the internal pressure (preload, automatic brake pressure)_FL, 27_FRRespectively, wheel cylinder 24_FL, 24_FRThe internal pressure (preload, automatic brake pressure) of the pressure reducing circuit 26_FL, 26_FRTo eliminate and reduce,
Therefore, these pressure increasing / decreasing valves constitute pressure adjusting means in the present invention for adjusting the internal pressure in each brake system.
[0038]
A check valve 30 is provided in parallel with the master cylinder hydraulic pressure selection valve 19 to perform a check function in the direction of brake fluid pressure release._FL, 25_FRAre provided in parallel with each other, and check valves 31 and 32 that perform a check function with respect to the direction in which the brake fluid pressure enters are provided, thereby ensuring security when the corresponding valve is stuck in a closed state.
[0039]
Motor 16a of precharge pump 16, motor 22a of behavior control pressure pump 22, master cylinder hydraulic pressure selection valve 19, precharge pressure selection valve 21, and pressure increase valve 25_FL, 25_FRAnd pressure reducing valve 27_FL, 27_FRON / OFF of the above is controlled by the controller 41 to perform a predetermined behavior (yaw rate) control,
For this control, the controller 41 has a generated yaw rate γ of the vehicle._SA signal from a yaw rate sensor (behavior sensor) 42 that detects the vehicle speed, a signal from the vehicle speed sensor 43 that detects the vehicle speed VSP, a signal from the throttle opening sensor 44 that detects the engine throttle opening TVO, and the brake fluid temperature K And a signal from the temperature sensor 45 for detecting.
[0040]
The controller 41 executes the control program shown in FIG. 2 based on the input information, and performs the preload control of the brake system and the behavior control of the vehicle aimed by the present invention as follows.
First, at step 51, the yaw rate γ to be targeted by a known method from the vehicle speed VSP and the throttle opening TVO detected by the sensors 43 and 44 in FIG.₀To calculate
Next, at step 52, the target yaw rate γ₀And the yaw rate detection value γ by the sensor 42_SYaw rate deviation Δγ between₀−γ_S) Is calculated.
[0041]
In step 53, based on the brake fluid temperature K detected by the sensor 45 and the vehicle speed VSP detected by the sensor 43, based on the map corresponding to FIG. Yaw rate deviation set value Δγ_STAnd yaw rate deviation set value for starting behavior control for each vehicle speed VSP Δγ_VDCSearch for.
As is apparent from FIG. 3, the behavior control start yaw rate deviation set value Δγ_VDCAs is well known, by increasing the behavior control sensitivity at high vehicle speeds by decreasing the higher vehicle speed, it is possible to ensure driving stability at high speeds,
Preload control start yaw rate deviation set value Δγ_STIs the yaw rate deviation setting value Δγ for starting behavior control over the entire vehicle speed range._VDCSmaller and the lower the brake fluid temperature K, the behavior control start yaw rate deviation set value Δγ_VDCTo increase the deviation from the yaw rate deviation set value for starting preload control Δγ_STBy making the temperature smaller as the temperature is lower, the response delay of the preload at the low temperature is compensated, thereby enabling the temperature compensation of the preload control targeted by the present invention.
[0042]
In the next step 54, the absolute value | Δγ | of the yaw rate deviation Δγ obtained in step 52 is the preload control starting yaw rate deviation set value Δγ in step 53._STWhether or not this is the case, that is, whether or not the preload control for eliminating the response delay of the behavior control should be performed is determined.
In step 54, the absolute value | Δγ | of the yaw rate deviation Δγ is the preload control starting yaw rate deviation set value Δγ._STIn the non-control region of the preload control that is determined to be less than, the control is advanced to step 55 to instruct not to perform the preload control.
[0043]
In this non-control region, the controller 41 includes the motor 16a of the precharge pump 16, the motor 22a of the behavior control pressure pump 22, the master cylinder hydraulic pressure selection valve 19, the precharge pressure selection valve 21, and the pressure increase valve 25._FL, 25_FRAnd pressure reducing valve 27_FL, 27_FRAre all turned OFF.
Therefore, the precharge pressure P from the precharge pump 16 is_prSince the precharge cylinder 15 has the piston 15c in the illustrated position, the master cylinder hydraulic pressure port 15a communicates with the output port 15e,
Precharge pressure selection valve 21 and pressure reducing valve 27_FL, 27_FRIs closed
Master cylinder hydraulic pressure selection valve 19 and pressure increase valve 25_FL, 25_FRIs open.
[0044]
Here, the driver depresses the brake pedal 13, and the master cylinder hydraulic pressure P_mIs generated, this master cylinder hydraulic pressure P_mReaches the master cylinder hydraulic pressure selection valve 19 through the port 15a, the piston communication hole 15d and the output port 15e of the precharge cylinder 15, and then the master cylinder hydraulic pressure P._mHowever, from this valve 19 to the pressure increasing valve 25_FL, 25_FRThrough the wheel cylinder 24_FL, 24_FRThis allows the driver to brake the front two wheels.
[0045]
In step 54, the controller 41 determines that the absolute value | Δγ | of the yaw rate deviation Δγ is the preload control starting yaw rate deviation set value Δγ._STWhen it is determined that the preload control should be performed, in step 56, the target preload value P for each temperature is determined from the brake fluid temperature K based on the map corresponding to the solid line characteristic e in FIG._STSearch for.
Here, the conventional target preload value P_STIs constant regardless of the brake fluid temperature K as indicated by a two-dot chain line f in the figure, but in the present embodiment, the target preload value P_STIs increased as the temperature becomes lower as indicated by the solid line characteristic e.
And the target preload value P_STThe actual preload value after the pressure adjustment regardless of the viscosity change for each brake fluid temperature K is, for example, a predetermined value P shown in FIG._S0This also enables temperature compensation for the preload control targeted by the present invention.
[0046]
In steps 57 to 59, the above target preload value P_STThe target preload value P changes with a predetermined time gradient toward_STPreload command value P with the upper limit value_TGTo calculate
In step 60, the absolute value | Δγ | of the yaw rate deviation Δγ is the behavior control start yaw rate deviation set value Δγ searched in step 53._VDCIt is determined whether or not this is the case, that is, whether or not the behavior control range has been entered.
[0047]
Before entering the behavior control range, the internal pressure of the brake system is the preload command value P determined in steps 57 to 59 in step 61 as follows._TGPreload control is executed so that
That is, in this case, the controller 41 turns on the motor 16a of the precharge pump 16 and the motor 22a of the behavior control pressure pump 22 to drive the corresponding pumps, as well as the master cylinder hydraulic pressure selection valve 19 and the precharge pressure selection valve. 21 is turned on to close the former valve 19 and open the latter valve 21.
[0048]
Precharge pressure P generated by driving the pump 16_pr1 moves the piston 15c of the precharge cylinder 15 to the left in FIG. 1, disconnects the port 15a from the piston communication hole 15d, and simultaneously closes the piston communication hole 15d with the free piston 15h. .
Thereafter, the precharge pressure P is released from the port 15e by further leftward movement of the piston 15c._pr(For convenience, this is also the same precharge pressure P below)_prThis is supplied to the suction port of the behavior control pressure pump 22 via the precharge pressure selection valve 21.
[0049]
As a result, the suction efficiency of the behavior control pressure pump 22 driven by the above-described ON of the motor 22a is increased, and the pump 22 can discharge the pressure for behavior control with a high response. Can be improved.
Therefore, the precharge pressure P_prIs the minimum value necessary to achieve the suction efficiency required for the behavior control pressure pump 22.
[0050]
The behavior control pressure discharged from the pump 22 is the pressure increasing valve 25._FL, 25_FRThe controller 41 performs the preload control before the vehicle behavior (yaw rate) control, and the wheel cylinders 24 of the left and right front wheels are controlled._FL, 24_FRThe above is the preload command value P_TGIf it is less, the pressure booster valve 25 on the corresponding side_FL, 25_FRIs opened and the pressure reducing valve 27 on the same side is opened._FL, 27_FRIs closed by turning OFF the wheel cylinder 24_FL, 24_FRThe above preload command value P with the behavior control pressure from the pump 22 inside_TGIncrease pressure toward.
Conversely, the left and right front wheel cylinders 24_FL, 24_FRThe above is the preload command value P_TGWhen the pressure exceeds the controller 41, the controller 41 increases the pressure boosting valve 25 on the corresponding side._FL, 25_FRON and close the pressure reducing valve 27 on the same side_FL, 27_FRON to open the wheel cylinder 24_FL, 24_FRThe pressure inside the pressure reducing circuit 26_FL, 26_FRThe above preload command value P_TGReduce pressure toward
By repeating the above operation, the left and right front wheel cylinders 24_FL, 24_FRPreload command value P_TGThe preload can be controlled so that
[0051]
In step 60 of FIG. 2, the absolute value | Δγ | of the yaw rate deviation Δγ is the behavior control start yaw rate deviation set value Δγ._VDCIf it is determined that this is the case, that is, if it is determined that it is in the behavior control range, in steps 62 and 63, the absolute value | Δγ | of the yaw rate deviation Δγ is the behavior control start yaw rate deviation set value Δγ._VDCThe behavior control is executed as follows so that it falls within the range.
That is, in this case, the controller 41 is step 62, and the pressure-increasing valve 25 on the one-side front wheel to be braked for the behavior (yaw rate) control for that purpose._FLOr 25_FRIs opened and the pressure reducing valve 27 on the one front wheel is opened._FLOr 27_FRTurn off and close.
Thereby, the wheel cylinder 24 of the one front wheel to be braked_FLOr 24_FRThe inside is supplied with the behavior control pressure from the pump 22 and is increased from the preload value.
[0052]
By the way, in the next step 63, the wheel cylinder 24 of the opposite front wheel._FROr 24_FLHowever, since the preload control similar to that in step 61 is continued, the braking force is not generated with the preload value as it is.
Therefore, the vehicle is given a left-right braking force difference and given a yaw moment, and the vehicle behavior (yaw rate) is set to the target value γ.₀Can be approached.
The controller 41 determines that the vehicle behavior (yaw rate) is the target value γ.₀The absolute value | Δγ | of the yaw rate deviation Δγ approaching the value is the behavior control start yaw rate deviation set value Δγ._VDCWhen entering the non-control region that falls below the limit, in step 62, the pressure-increasing valve 25 for the one-side front wheel that has been braked as described above is used._FLOr 25_FRIs turned on and closed, and at the same time, the pressure reducing valve 27 of the one front wheel_FLOr 27_FRBy turning on and opening the front wheel wheel cylinder 24 on the corresponding side_FLOr 24_FRIt is possible to release the brake by releasing the inside and maintain the yaw rate deviation Δγ in the non-control range.
[0053]
In the behavior control, in step 60, the absolute value | Δγ | of the yaw rate deviation Δγ is the behavior control start yaw rate deviation set value Δγ._VDCFor example, the behavior control start instant t in FIG._FourInstant t before₁In step 54, the absolute value | Δγ | of the yaw rate deviation Δγ is the behavior control start yaw rate deviation set value Δγ._VDCSmaller yaw rate deviation set value for starting preload control Δγ_STSince it is determined as above and the preload control in step 61 is started, preload is generated in the brake system prior to the behavior control, and the behavior control is a hydraulic type using a hydraulic brake device. If this is the case, there will be no response delay that would cause a problem.
[0054]
In addition, the yaw rate deviation set value Δγ used when the preload control start determination is made at step 54._STAs shown in FIG. 3, the lower the brake fluid temperature K, the behavior control start yaw rate deviation set value Δγ._VDCThe yaw rate deviation set value for starting preload control Δγ_STIs made smaller as the brake fluid temperature K is lower (sensitivity of preload control start determination is increased),
In addition, a final target preload value P for preload control in step 61 is also provided._STIs determined so as to be larger than the conventional one as the brake fluid temperature K is lower as shown by e in FIG.
Preload command value P in FIG._TGAs illustrated by the change with time, the start command timing t of the preload control prior to the behavior control₁And the target preload value P illustrated in FIG._STWill be higher at lower temperatures,
As shown in FIG. 5c, the actual preload value at a given low temperature is indicated by c._S0Preload control can be realized.
[0055]
Therefore, it is possible to prevent the preload from becoming insufficient even at low temperatures when the brake fluid temperature is low, and even at low temperatures, the effect of preventing response delays in behavior control by preload and the effect of eliminating the shortage of control amount are achieved as intended. can do.
In addition, since the start command timing of the preload control is not advanced unnecessarily at times other than low temperatures, the behavior control pressure source and the pressure increasing valve 25 configured by the pump 22 are used._FL, 25_FRAnd pressure reducing valve 27_FL, 27_FRThe above-mentioned operation and effect can be achieved without causing the problem that the operation frequency of the pressure regulating valve means constituted by is increased and the durability of the behavior control device is lowered.
[0056]
In the present embodiment, in particular, the preload control start determination is performed based on the absolute value | Δγ | of the yaw rate (behavior) deviation Δγ in the same manner as the determination on whether or not the behavior control is necessary.
The start time of the preload control is determined based on the behavior control, and the time can be more accurately matched to the above-described effects.
[0057]
In the present embodiment, the preload control starting yaw rate deviation set value Δγ_STIs made smaller as the brake fluid temperature K is lower (sensitivity of the preload control start determination is increased),
Final target target preload value P_STIn order to achieve the object of the present invention, the above-mentioned effect is achieved by a combination with increasing the brake fluid temperature K as the brake fluid temperature K decreases.
These can be used alone, although there are differences in the degree, and the same effects can be obtained, and it is a matter of course that the object of the present invention can be achieved.
[0058]
In order to achieve the object of the present invention, the following measures may be employed in addition to the above two requirements, in combination with any of these two requirements, or independently.
That is, the pressure increasing valve 25 constituting pressure regulating valve means for adjusting the preload._FL, 25_FRAnd pressure reducing valve 27_FL, 27_FRBy adjusting the driving time during the preload control, the preload control gain of the pressure regulating valve means is increased as the brake fluid temperature is lower.
This can also prevent the preload from becoming insufficient at low temperatures. It can be solved in the same manner as in the embodiment.
[0059]
In the above description, the brake fluid temperature K is directly detected by the sensor 45. Alternatively, the brake fluid temperature can be estimated and obtained by the method listed below.
(1) Since the brake fluid temperature depends on the engine temperature, the brake fluid temperature is estimated from the intake temperature, exhaust temperature, cooling water temperature, etc. of the engine.
{Circle around (2)} A history (for example, first-order lag) regarding temperature changes such as engine intake air temperature, exhaust gas temperature, and cooling water temperature is estimated using the brake fluid temperature.
(3) The brake fluid temperature is estimated from the intake air temperature when the engine is started, and is estimated from the cooling water temperature after a predetermined time has elapsed.
(4) When the engine is started, the brake fluid temperature is set to a predetermined fixed value, and after a predetermined time has elapsed, a value increased from the fixed value with a predetermined gradient as time passes is set as the brake fluid temperature.
(5) The total calorific value of the engine is calculated from the gasoline consumption from the start of the engine, and the brake fluid temperature is estimated by subtracting the heat release from the total calorific value.
Thus, when estimating the brake fluid temperature from the amount of heat generated by the heat source that affects the brake fluid temperature, or from this amount of heat generation and heat dissipation,
A means for directly detecting the brake fluid temperature is not required, and the above-described effects can be achieved at a low cost, which is advantageous in terms of cost.
[Brief description of the drawings]
FIG. 1 is a hydraulic brake system diagram illustrating a vehicle behavior control device including a temperature compensation device for preload control according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a program for preload control and behavior control executed by a controller in the embodiment;
FIG. 3 is a characteristic diagram showing yaw rate deviation setting values for preload control start and behavior control start in the same embodiment;
FIG. 4 is a characteristic diagram showing a target preload value to be used as a command in the embodiment in comparison with a conventional command target preload value.
FIG. 5 is a time chart showing a preload command value generated at a low temperature in the same embodiment, an actual preload value controlled by the preload command value, and a conventional preload command value and a change over time of the actual value over time.
[Explanation of symbols]
11_FL  Left front wheel
  11_FR  Right front wheel
  12 Master cylinder
  13 Brake pedal
  14 Brake fluid reservoir tank
  15 Precharge cylinder
  16 Precharge pump
  19 Master cylinder hydraulic pressure selection valve
  21 Precharge pressure selection valve
  22 Behavior-controlled pressure pump
  twenty four_FL  Left front wheel cylinder
  twenty four_FR  Right front wheel wheel cylinder
  twenty five_FL  Booster valve for left front wheel
  twenty five_FR  Booster valve for right front wheel
  27_FL  Left front wheel pressure reducing valve
  27_FR  Right front wheel pressure reducing valve
  28 Accumulator
41 Controller
42 Yaw rate (behavior) sensor
43 Vehicle speed sensor
  44 Throttle opening sensor
45 Temperature sensor

Claims (7)

In a device that controls the behavior of a vehicle so as to reduce the behavior deviation between the behavior detection value and the behavior target value by giving a left-right braking force difference by automatic braking of each wheel by the behavior control pressure from the behavior control pressure source ,
Prior to the behavior control, the behavior control pressure source is activated to supply a preload to the brake system of each wheel, and the preload is controlled to approach the preload target value by the pressure regulating valve means,
The start command timing of the preload control prior to the behavior control is configured to advance as the brake fluid temperature decreases ,
In the case where behavior control is started when the behavior deviation is equal to or greater than the behavior control setting value, the preload control is started when the behavior deviation is equal to or larger than the preload control setting value smaller than the behavior control setting value. In addition, a temperature compensation device for preload control in a vehicle behavior control device, wherein the preload control set value is made smaller as the brake fluid temperature is lower . 2. The temperature compensation device for preload control in a vehicle behavior control device according to claim 1, wherein the preload target value is set higher as the brake fluid temperature is lower . 3. A temperature compensation device for preload control in a vehicle behavior control device according to claim 1, wherein the preload control gain by the pressure regulating valve means is increased as the brake fluid temperature is lower . In a device that controls the behavior of a vehicle so as to reduce the behavior deviation between the behavior detection value and the behavior target value by giving a left-right braking force difference by automatic braking of each wheel by the behavior control pressure from the behavior control pressure source ,
Prior to the behavior control, the behavior control pressure source is activated to supply a preload to the brake system of each wheel, and the preload is controlled to approach the preload target value by the pressure regulating valve means,
In the preload control, the preload target value is configured to increase as the brake fluid temperature decreases,
In the case where behavior control is started when the behavior deviation is equal to or greater than the behavior control setting value, the preload control is started when the behavior deviation is equal to or larger than the preload control setting value smaller than the behavior control setting value. In addition, a temperature compensation device for preload control in a vehicle behavior control device, wherein the preload control set value is made smaller as the brake fluid temperature is lower . 5. A temperature compensation device for preload control in a vehicle behavior control device according to claim 4, wherein the preload control gain by the pressure regulating valve means is increased as the brake fluid temperature is lower . In a device that controls the behavior of a vehicle so as to reduce the behavior deviation between the behavior detection value and the behavior target value by giving a left-right braking force difference by automatic braking of each wheel by the behavior control pressure from the behavior control pressure source ,
Prior to the behavior control, the behavior control pressure source is activated to supply a preload to the brake system of each wheel, and the preload is controlled to approach the preload target value by the pressure regulating valve means,
In the preload control, the preload control gain by the pressure regulating valve means is configured to be higher as the brake fluid temperature is lower,
In the case where behavior control is started when the behavior deviation is equal to or greater than the behavior control setting value, the preload control is started when the behavior deviation is equal to or larger than the preload control setting value smaller than the behavior control setting value. In addition, a temperature compensation device for preload control in a vehicle behavior control device, wherein the preload control set value is made smaller as the brake fluid temperature is lower . The vehicle behavior control device according to any one of claims 1 to 6, wherein the brake fluid temperature is estimated from a heat amount and a heat radiation amount generated by a heat generation source that affects the brake fluid temperature . Temperature compensation device for preload control.

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