JP2007032614A - Controller for transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a transmission capable of ensuring stability of a vehicle securely when the vehicle becomes an unstable condition during operation of engine brake. <P>SOLUTION: This controller for the transmission is provided with a detection part for detecting whether stability of the vehicle is reduced during operation of engine brake or not (step SA105) and a clutch pressure control part for reducing pressure of a clutch constituting the engine brake when detecting that stability of the vehicle is reduced during operation of engine brake by the detection part (step SA107). The clutch pressure control part reduces clutch pressure by a plurality of inclinations being different from each other when reducing clutch pressure. The clutch pressure control part is further provided with a minimum value calculating part for obtaining the minimum value of clutch pressure for preventing slip of the clutch based on degree of deceleration of the vehicle (step SA103). The clutch pressure control part changes inclination for reducing clutch pressure in the vicinity of the minimum value of clutch pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmission control device, and more particularly to a transmission control device that can ensure vehicle stability when the vehicle becomes unstable during engine braking.

  Japanese Patent Laid-Open No. 5-60214 (Patent Document 1) discloses a technique for performing shift control to a shift stage at which engine braking is effective. This technology controls the engine braking force by controlling the hydraulic pressure of the friction engagement device that controls the engine brake, and improves the riding comfort during traveling.

JP-A-5-60214 JP-A-5-20951

  There is no mention of control when the vehicle is in an unstable state at a gear position where the engine brake is effective. It is desirable to ensure the vehicle stability more reliably when the vehicle becomes unstable during engine braking.

  An object of the present invention is to provide a transmission control device that can ensure vehicle stability more reliably when the vehicle becomes unstable during engine braking.

  The transmission control device according to the present invention includes a detection unit that detects whether or not the engine brake is in operation and the vehicle stability is lowered, and the detection unit is operating the engine brake and the vehicle A clutch pressure control unit that reduces the clutch pressure of the clutch that constitutes the engine brake when it is detected that the stability is lowered, and the clutch pressure control unit is configured to reduce the clutch pressure. The clutch pressure is reduced at a plurality of different inclinations.

  The transmission control apparatus according to the present invention further includes a minimum value calculation unit that obtains a minimum value of a clutch pressure at which a clutch constituting the engine brake does not slip based on a deceleration of the vehicle, and the clutch pressure control The section is characterized in that the inclination when the clutch pressure is lowered is changed in the vicinity of the minimum value of the clutch pressure.

  In the transmission control device of the present invention, the clutch pressure control unit lowers the clutch pressure with a relatively large inclination in the initial stage when the clutch pressure is decreased, and is relatively small after the initial stage. The clutch pressure is reduced by an inclination.

  The transmission control device according to the present invention includes a determination unit that determines whether or not there is a possibility that the vehicle stability is lowered due to the engine brake while the engine brake is operating, and the vehicle that is operating the engine brake and the vehicle A detection unit for detecting whether or not the stability is lowered, and the engine brake is configured when the detection unit detects that the engine brake is in operation and the vehicle stability is lowered. A clutch pressure control unit that lowers the clutch pressure of the clutch being operated, and the clutch pressure control unit is operating the engine brake by the determination unit, and vehicle stability may be reduced by the engine brake. If it is determined, the clutch pressure is determined by the determination unit while the engine brake is operating, and the engine brake reduces the vehicle stability. Possibility than normal clutch pressure at the time other than when it is determined that there is and sets a small value.

  In the transmission control apparatus of the present invention, a minimum value calculation unit that obtains a minimum value of the clutch pressure at which the clutch constituting the engine brake does not slip based on the deceleration of the vehicle, and clutch slipping occur. A determination unit that determines the possibility, and the clutch pressure control unit corresponds to a possibility that the clutch slip occurs with respect to a minimum value of the clutch pressure as a value smaller than the clutch pressure at the normal time. It is characterized in that a value obtained by adding the added value is used.

  In the transmission control apparatus according to the present invention, the value corresponding to the possibility that the clutch slip occurs is set based on an inter-vehicle distance.

  In the transmission control apparatus according to the present invention, the value corresponding to the possibility of occurrence of clutch slip is set based on driving orientation.

  In the transmission control apparatus according to the present invention, the value corresponding to the possibility of occurrence of clutch slip is set based on a friction coefficient of the road surface.

  In the transmission control apparatus according to the present invention, the value corresponding to the possibility of clutch slippage is set based on the magnitude of torque input from the road surface.

  The transmission control device according to the present invention includes a detection unit that detects whether or not the engine brake is in operation and the vehicle stability is lowered, and the detection unit is operating the engine brake and the vehicle A clutch pressure control unit that reduces the clutch pressure of the clutch that constitutes the engine brake when it is detected that the stability is lowered, and the clutch pressure control unit is configured to reduce the clutch pressure. At least in the initial stage, the clutch pressure is reduced with a relatively large inclination including a step-down so that the initial responsiveness is increased.

  According to the transmission control device of the present invention, it is possible to ensure vehicle stability more reliably when the vehicle becomes unstable while the engine brake is operating.

  Hereinafter, an embodiment of a transmission control device of the present invention will be described in detail with reference to the drawings.

(First embodiment)
The first embodiment will be described with reference to FIGS. 1 to 3.

  During engine brake operation, vehicle stability may be reduced by engine brake. For example, in a rear-wheel drive vehicle, when the gear position is low and the engine brake is large, the tire (rear wheel) cannot exert sufficient lateral force in the tire friction circle, and the tire tends to lock. Oversteering may occur. Even on a straight road, when the engine brake is large, the rear wheels tend to lock, and the vehicle stability may be reduced. Furthermore, on low μ roads, the engine brakes tend to lock the rear wheels, which may reduce vehicle stability.

  An object of the present embodiment is to provide a transmission control device that can ensure vehicle stability more reliably when the vehicle becomes unstable during engine braking.

  In the present embodiment, when control for reducing the engine brake is performed, the initial value of the clutch pressure before the control for reducing the engine brake is started is changed according to the current deceleration or the expected deceleration in the future. By doing so, it becomes possible to suppress clutch slipping while ensuring the response of deceleration by reducing the engine braking force. In addition, at the start of control to reduce engine brake, the clutch pressure is stepped down to the clutch pressure that does not cause clutch slip at the current deceleration, and then the clutch pressure is reduced by sweeping. It becomes possible to improve the property.

  The configuration of the present embodiment is premised on the provision of a transmission system that can control the clutch that constitutes the engine brake and an inter-vehicle distance measuring unit. A more detailed configuration will be described next.

  In FIG. 2, the vehicle is an FR vehicle. Therefore, the front wheels 204 and 205 are driven wheels, and the rear wheels 206 and 207 are driving wheels. Reference numeral 10 denotes an automatic transmission, 40 denotes an engine, and 200 denotes a brake device. The automatic transmission 10 is capable of five-speed shifting by controlling the hydraulic pressure by energization / non-energization of the solenoid valves 121a, 121b, and 121c. In FIG. 2, three electromagnetic valves 121a, 121b, and 121c are illustrated, but the number of electromagnetic valves is not limited to three. The solenoid valves 121a, 121b, and 121c are driven by a signal from the control circuit 130.

  The throttle opening sensor 114 detects the opening of the throttle valve 43 disposed in the intake passage 41 of the engine 40. The engine speed sensor 116 detects the speed of the engine 40. The vehicle speed sensor 122 detects the rotation speed of the output shaft 120c of the automatic transmission 10 that is proportional to the vehicle speed. The shift position sensor 123 detects the shift position. The pattern select switch 117 is used when instructing a shift pattern.

  The steering angle sensor 85 detects the steering angle. The yaw rate sensor 88 detects the yaw rate of the vehicle. The acceleration sensor 90 detects vehicle deceleration (deceleration acceleration). The manual shift determination unit 95 outputs a signal indicating the necessity of downshift (manual downshift) or upshift by the driver's manual operation based on the driver's manual operation. The road surface μ detection / estimation unit 115 detects or estimates the road surface friction coefficient μ. The inter-vehicle distance measuring unit 101 includes a sensor such as a laser radar sensor or a millimeter wave radar sensor mounted on the front of the vehicle, and measures the inter-vehicle distance from the preceding vehicle. The relative vehicle speed detection / estimation unit 112 detects or estimates the relative vehicle speed between the host vehicle and the preceding vehicle.

  The road gradient measurement / estimation unit 118 can be provided as a part of the CPU 131. The road gradient measurement / estimation unit 118 can measure or estimate the road gradient based on the acceleration detected by the acceleration sensor 90. Further, the road gradient measuring / estimating unit 118 may store the acceleration on the flat road in the ROM 133 in advance and obtain the road gradient by comparing with the acceleration actually detected by the acceleration sensor 90.

  The driving orientation estimation unit 119 can be provided as a part of the CPU 131. The driving direction estimation unit 119 estimates the driving direction (sport driving direction or normal driving direction) of the driver based on the driving state of the driver and the driving state of the vehicle. Details of the driving orientation estimation unit 119 will be described later. Note that the configuration of the driving orientation estimation unit 119 is not limited to the content described later, and includes various configurations as long as the driving orientation of the driver is estimated. Here, the term “sports driving orientation” refers to a direction that emphasizes power performance, an acceleration direction, or a preference for sports driving in which the response of the vehicle to the driver's operation is quick.

  The driving orientation estimation unit 119 includes a neural network NN in which the driving operation related variable is input and the estimation calculation is started every time one of a plurality of types of driving operation related variables is calculated, and based on the output of the neural network NN. To estimate the driving direction of the vehicle.

For example, as shown in FIG. 3, the driving direction estimation unit 119 includes a signal reading unit 96, a preprocessing unit 98, and a driving direction estimation unit 100. The signal reading means 96 reads detection signals from the sensors 114, 122, 116, 123 and the like at a relatively short predetermined cycle. The pre-processing means 98 uses a plurality of types of driving operation-related variables closely related to the driving operation reflecting the driving direction from the signals sequentially read by the signal reading means 96, that is, the output operation amount (accelerator pedal operation) when starting the vehicle. Amount), that is, the throttle valve opening TA _ST when the vehicle _starts , the maximum change rate of the output operation amount during acceleration operation, that is, the maximum change rate A _CCMAX of the throttle valve opening, the maximum deceleration G _NMAX when braking the vehicle, A driving operation related variable calculating means for calculating the coasting traveling time T _COAST , the constant vehicle speed traveling time T _VCONST , the section maximum value of the signal input from each sensor within the predetermined section, the maximum vehicle speed V _max after the start of driving, etc. is there. The driving orientation estimation unit 100 includes a neural network NN that performs the driving orientation estimation calculation by permitting the driving operation related variable every time the driving operation related variable is calculated by the preprocessing unit 98, and outputs the neural network NN. A certain driving direction estimation value is output.

The preprocessing means 98 in FIG. 3, the starting time of the output control input calculation means 98a for calculating the throttle valve opening TA _ST when output operation amount i.e. vehicle starting when the vehicle start, the maximum change in the output operation amount when the acceleration operation rate i.e. accelerating operation when the output operation amount maximum change rate calculating means 98b for calculating the maximum change rate a _CCmax of the throttle valve opening, braking maximum deceleration calculating means for calculating the maximum deceleration G _NMAX during braking operation of the vehicle 98c , input signals from the sensors in the coasting time calculation means 98d, constant vehicle speed running time calculating means 98e for calculating the constant vehicle speed running time T _VCONST, for example 3 seconds to a predetermined section within which calculates the coasting time T _COAST vehicle maximum value periodically calculates the input signal interval maximum value calculating means 98f of the maximum vehicle speed calculating means for calculating a maximum vehicle speed V _max of the operation after the start 98g Nadogaso Each is provided.

The maximum values of the input signals in the predetermined interval calculated by the input signal interval maximum value calculating means 98f include throttle valve opening TA _maxt , vehicle speed V _maxt , engine speed N _Emaxt , longitudinal acceleration NOGBW _maxt (deceleration Negative value) or deceleration G _NMAXt (absolute value) is used. The longitudinal acceleration NOGBW _maxt or the deceleration G _NMAXt is obtained from the rate of change of the vehicle speed V (N _OUT ), for example.

  The neural network NN provided in the driving orientation estimation means 100 of FIG. 3 can be configured by modeling a living nerve cell group by software based on a computer program or hardware consisting of a combination of electronic elements. For example, it is comprised so that it may be illustrated in the block of the driving | operation direction estimation means 100 of FIG.

In FIG. 3, the neural network NN includes an input layer composed of _r nerve cell elements (neurons) X _i (X _{1 to} X _r ) and s nerve cell elements Y _j (Y _{1 to} Y _s ). Is a three-layered hierarchical type composed of an intermediate layer composed of _t and an output layer composed of _t neuron elements Z _k (Z _{1 to} Z _t ). In order to transmit the state of the nerve cell element from the input layer to the output layer, the r nerve cell elements X _i and s nerve cell elements Y having a coupling coefficient (weight) W _Xij are provided. a transfer element D _Xij coupling the _j respectively, the coupling coefficient (weight) W _Yjk the have the s neuronal elements Y _j and t pieces of transmission elements D _Yjk of neuronal elements Z _k and the coupling respectively Is provided.

The neural network NN is its coupling coefficient (weight) W _Xij, pattern associative system that is made to learn the coupling coefficient (weight) W _Yjk called backpropagation learning algorithm. Learning, so are allowed to advance completed by running experiments in matching driving manner and the value of the driving operation related variables, during vehicle assembly, the coupling coefficient (weight) W _Xij, the coupling coefficient (weight) W _Yjk Is given a fixed value.

  In the above learning, sports-oriented driving and normal driving (normal) -oriented driving are carried out for a plurality of drivers on various roads such as highways, suburban roads, mountain roads, and city roads, respectively. With the directivity as a teacher signal, n indicators (input signals) obtained by pre-processing the teacher signal and the sensor signal are input to the neural network NN. The teacher signal is converted into a value from 0 to 1 for driving orientation. For example, normal driving orientation is 0 and sports driving orientation is 1. The input signal is used after being normalized to a value between -1 and +1 or between 0 and 1.

  In the above description, the driving direction is estimated by the driving direction estimation unit 119. However, the driver may input the driving direction to the control circuit 130 by operating a switch or the like.

  The navigation system device 113 has a basic function of guiding the host vehicle to a predetermined destination, and includes an arithmetic processing device and information necessary for traveling of the vehicle (map, straight road, curve, uphill / downhill, highway) Etc.), a first information detection device including a geomagnetic sensor, a gyrocompass, and a steering sensor, and a current position of the vehicle by radio navigation. It is for detecting a position, road conditions, etc., and is provided with a second information detection device including a GPS antenna and a GPS receiver.

  The control circuit 130 inputs signals indicating the detection results of the throttle opening sensor 114, the engine speed sensor 116, the vehicle speed sensor 122, the shift position sensor 123, the yaw rate sensor 88, and the acceleration sensor 90, and the pattern select switch 117. A signal indicating the switching state of the vehicle, a signal indicating the result of detection or estimation by the road surface μ detection / estimation unit 115, and a signal indicating the necessity of shifting from the manual shift determination unit 95 are input. In addition, a signal from the navigation system device 113 is input, a signal indicating a result of detection or estimation by the relative vehicle speed detection / estimation unit 112 is input, and a signal indicating a measurement result by the inter-vehicle distance measurement unit 101 Enter. Based on the input information, the control circuit 130 determines whether or not there is a shift determination (command) of shift point control including downhill control, corner control, intersection control, and follow-up control.

  The control circuit 130 is configured by a known microcomputer and includes a CPU 131, a RAM 132, a ROM 133, an input port 134, an output port 135, and a common bus 136. The input port 134 has signals from the sensors 114, 116, 122, 123, 90, 88, signals from the switch 117, road surface μ detection / estimation unit 115, manual shift determination unit 95, inter-vehicle distance measurement. Signals from the unit 101, the relative vehicle speed detection / estimation unit 112, and the navigation system device 113 are input. The output port 135 is connected to the electromagnetic valve driving units 138a, 138b, 138c and the brake braking force signal line L1 to the brake control circuit 230. A brake braking force signal SG1 is transmitted through the brake braking force signal line L1.

  The ROM 133 stores a program in which the operations (control steps) shown in the flowchart of FIG. 1 are described in advance, and a shift map for shifting the gear stage of the automatic transmission 10 and a shift control operation (not shown). Is stored). The control circuit 130 shifts the automatic transmission 10 based on various input control conditions.

  The brake device 200 is controlled by a brake control circuit 230 that receives a brake braking force signal SG1 from the control circuit 130, and brakes the vehicle. The brake device 200 includes a hydraulic control circuit 220, brake devices (brakes) 208, 209, 210, 211 provided on front wheels (driven wheels) 204, 205 and rear wheels (drive wheels) 206, 207 of the vehicle, respectively. It has. Each of the braking devices 208, 209, 210, and 211 controls the braking force of the corresponding wheels 204, 205, 206, and 207 when the hydraulic pressure is controlled by the hydraulic control circuit 220. The hydraulic control circuit 220 is controlled by the brake control circuit 230.

  The hydraulic control circuit 220 performs brake control by controlling the braking hydraulic pressure supplied to each braking device 208, 209, 210, 211 based on the brake control signal SG2. The brake control signal SG2 is generated by the brake control circuit 230 based on the brake braking force signal SG1. The brake braking force signal SG1 is output from the control circuit 130 of the automatic transmission 10 and input to the brake control circuit 230. The brake force applied to the vehicle during the brake control is determined by a brake control signal SG2 generated by the brake control circuit 230 based on various data included in the brake braking force signal SG1.

  The brake control circuit 230 is configured by a known microcomputer and includes a CPU 231, a RAM 232, a ROM 233, an input port 234, an output port 235, and a common bus 236. A hydraulic control circuit 220 is connected to the output port 235. The ROM 233 stores an operation for generating the brake control signal SG2 based on various data included in the brake braking force signal SG1. The brake control circuit 230 controls the brake device 200 (brake control) based on each input control condition.

  Next, the operation of the first embodiment will be described with reference to FIGS.

[Step SA101]
As shown in FIG. 1, in step SA101, the control circuit 130 determines whether or not a precondition for this control is satisfied. The precondition for this control is that the engine brake is activated and the vehicle may become unstable due to the engine brake. Specifically, for example, the gear position of the automatic transmission 10 can be equal to or lower than a preset gear position (third speed in this example). Here, the preset gear position can be a gear position that may cause the vehicle to become unstable due to the engine brake. As a result of the determination in step SA101, if the precondition for this control is satisfied, the process proceeds to step SA102.

[Step SA102]
In step SA102, the control circuit 130 determines the current vehicle deceleration or the vehicle deceleration expected in the future. In the future, when it is expected that manual downshift or downshift by shift point control will be performed, deceleration by the shift stage after the shift is required, or when the brake is operated, by the brake If deceleration is required, or if the shift is not expected and the brake is not operated, the current deceleration is determined. Following step SA102, step SA103 is performed.

[Step SA103]
In step SA103, the control circuit 130 causes the clutch that constitutes the engine brake to not slip easily based on the current vehicle deceleration obtained in step SA102 or the vehicle deceleration expected in the future. The pressure (minimum value of the clutch pressure at which the clutch does not slip) Pb1_bse is obtained.

  That is, in step SA103, first, the torque capacity for preventing the clutch from slipping is obtained based on the current vehicle deceleration or the expected vehicle deceleration, and the engine brake is determined based on the torque capacity of the clutch. The clutch pressure Pb1_bse is determined so that the clutch constituting the clutch does not slip. In this case, a map for obtaining the clutch pressure based on the clutch capacity may be set in advance, and the clutch pressure Pb1_bse may be obtained according to the map. The clutch pressure Pb1_bse may be obtained through learning or learning during vehicle travel. The clutch pressure Pb1_bse may be a value such that the safety factor against clutch slip is approximately 1 (a clutch pressure corresponding to a torque capacity necessary for the clutch not to slip). Following step SA103, step SA104 is performed.

[Step SA104]
In step SA104, the control circuit 130 determines the safety factor SF1. As will be described later, the possibility of clutch slippage is determined, and the safety factor SF1 is determined so as to prevent clutch slippage. The safety factor SF1 can be obtained based on the possibility of sudden braking or the possibility of a tire locking.

  When it is determined that the possibility of clutch slip is relatively high, the safety factor SF1 is set to a relatively high value. As a result, the command value Pb1_tgt of the pressure of the clutch constituting the engine brake (engine brake constituent engagement clutch pressure) is set to a relatively high value (step SA106), and the clutch slip is suppressed.

  On the other hand, when it is determined that the possibility of clutch slip is relatively low, the safety factor SF1 is set to a relatively low value. As a result, the command value Pb1_tgt of the engine brake configuration engagement clutch pressure is set to a relatively low value (step SA106), and when it is determined that the vehicle stability is reduced due to the engine brake (step SA105-Y). ), The response when the engine brake force is reduced by stepping down the command value Pb1_tgt of the engine brake configuration engagement clutch pressure to the clutch pressure Pb1_bse is improved. Here, “step down” means to greatly reduce in a very short time. Following step SA104, step SA105 is performed.

[Step SA105]
In step SA105, the control circuit 130 determines whether or not the vehicle stability is reduced due to engine braking. Here, it is possible to determine whether or not the vehicle stability has been lowered by the engine brake by determining whether or not the driving wheel tends to be locked by the engine brake. The determination as to whether or not the driving wheel tends to be locked can include, for example, an oversteer determination.

  Even in cases other than oversteer, for example, when the engine brake is large even on a straight road, the drive wheels may tend to lock, and when the engine brake is not so large on a low μ road Even so, since the drive wheels may tend to be locked, it is determined in step SA105 whether or not the drive wheels tend to be locked by engine braking. As a result of the determination in step SA105, when it is determined that the vehicle stability is reduced due to engine braking (step SA105-Y), the process proceeds to step SA107. Otherwise (step SA105-N), Proceed to step SA106.

[Step SA106]
In step SA106, the control circuit 130 sets the command value Pb1_tgt for the engine brake configuration engagement clutch pressure to a value based on the clutch pressure Pb1_bse and the safety factor SF1. Here, the command value Pb1_tgt of the engine brake configuration engagement clutch pressure is set to the following value, for example.
Pb1_tgt = Pb1_bse × (1 + SF1)

  In step SA106, the command value Pb1_tgt of the engine brake configuration engagement clutch pressure is set to an optimum value according to the possibility of clutch slippage (safety factor SF1) (see step SA104 above). That is, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure is set to an optimum value in consideration of a balance between suppression of clutch slip and responsiveness when reducing the engine braking force. Following step SA106, the control flow of FIG. 1 is returned.

[Step SA107]
In step SA107, the control circuit 130 causes the command value Pb1_tgt of the engine brake constituent engagement clutch pressure to be stepped down to the clutch pressure Pb1_bse, and after it has reached the clutch pressure Pb1_bse, it is swept down (gradually decreased). The command value Pb1_tgt of the engine brake configuration engagement clutch pressure is stepped down to the clutch pressure Pb1_bse, thereby improving the response when the engine brake is reduced. The step-down amount may be a value near the limit that causes clutch slip.

  Further, in step SA107, after the command value Pb1_tgt of the engine brake constituent engagement clutch pressure becomes the clutch pressure Pb1_bse, the sweep down is performed when the step is lowered to a value lower than the clutch pressure Pb1_bse. This is because there is a possibility. Following step SA107, the control flow of FIG. 1 is returned.

According to the control flow of FIG. 1, the following effects can be obtained.
(1) In step SA106, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure is set to a predetermined required amount (Pb1_bse) in consideration of the possibility of clutch slipping to the clutch pressure Pb1_bse at which the clutch slip does not occur. XSF1) is set to the added value, and when it is determined that the vehicle stability is lowered by engine braking (step SA105-Y), the clutch pressure is reduced to reduce engine braking. The initial responsiveness is improved.

(2) When it is determined in step SA107 that the vehicle stability is reduced by engine braking (step SA105-Y), the command value Pb1_tgt of the engine brake configuration engagement clutch pressure is stepped down to the clutch pressure Pb1_bse. Therefore, the initial response when the engine brake is reduced is improved.

(3) In step SA104, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure is set according to the safety factor SF1 corresponding to the possibility of clutch slipping, for example, wasteful clutch slipping due to sudden braking, for example. Thus, it is possible not only to suppress the deterioration of the durability of the clutch, but also to suppress the shock at the time of engagement.

  Next, the effects of the present embodiment will be described with reference to FIGS. 13 and 14 while comparing with the prior art.

  FIG. 13 is a time chart showing changes in vehicle stability when control for reducing engine brake (engine brake reduction control) is performed in the prior art. FIG. 14 is a time chart showing a change in vehicle stability when control for reducing engine braking is performed in the present embodiment.

  In FIG. 13, reference numeral 401 denotes a synchronous rotational speed (clutch rotational speed) when the deceleration is large, reference numeral 402 denotes a synchronous rotational speed when the deceleration is small, and reference numeral 403 denotes a turbine rotational speed (engine speed when the deceleration is large). ), 404 is the turbine speed when the deceleration is small, 405 is the command value Pb1_tgt of the engine brake constituent engagement clutch pressure, 406 is the actual yaw rate when the deceleration is large, and 407 is the small deceleration. The actual yaw rate and the reference numeral 408 indicate the target yaw rate.

  In the prior art, as shown in FIG. 13, before the engine brake reduction control is started, the command value Pb1_tgt405 of the engine brake constituent engagement clutch pressure is set to the maximum value PM. When an unstable state (for example, an oversteer state) of the vehicle is detected at time t1 and engine brake reduction control is started, the command value Pb1_tgt405 of the engine brake configuration engagement clutch pressure is set to the maximum pressure (normal time engagement). The clutch pressure Pb1_bse (indicated by the symbol PL) when the deceleration begins to decrease from the combined pressure (PM) and is large is reached at time t2. In this case, after time t2, the command value Pb1_tgt 405 of the engine brake configuration engagement clutch pressure is released, so that the engine braking force is reduced, the actual yaw rate 406 is suppressed from greatly separating from the target yaw rate 408, and the vehicle The steady state is corrected.

  On the other hand, the clutch pressure Pb1_bse (indicated by the symbol PS) when the deceleration is small is a small value. Therefore, when an unstable state of the vehicle is detected at time t1 and engine brake reduction control is started, and the command value Pb1_tgt405 of the engine brake configuration engagement clutch pressure starts to decrease from the maximum pressure PM, the clutch pressure Pb1_bse ( It takes time to reach (PS), and the command value Pb1_tgt405 of the engine brake constituent engagement clutch pressure has not reached the clutch pressure Pb1_bse (PS) until time t3. At this time, the state of the clutch is delayed with respect to the unstable state of the vehicle detected at time t1, and the actual yaw rate 407 is changed from the target yaw rate 408 before time t3 when the release of the clutch is started. It is difficult to ensure a stable state of the vehicle even if it is far away and the reduction of the engine braking force is started at time t3. Thus, in the case of the prior art, when the deceleration is small, it is difficult to return the vehicle to a stable state due to the delay in releasing the clutch.

  In FIG. 14, reference numeral 501 is a synchronous rotational speed when the deceleration is large, reference numeral 502 is a synchronous rotational speed when the deceleration is small, reference numeral 503 is a turbine rotational speed when the deceleration is large, and reference numeral 504 is a small deceleration. , 505 is an engine brake component engagement clutch pressure command value Pb1_tgt when the deceleration is large, and 506 is an engine brake component engagement clutch pressure command value Pb1_tgt when the deceleration is small. Indicates the actual yaw rate (when the deceleration is large and when the deceleration is small), and reference numeral 508 indicates the target yaw rate.

  In the present embodiment, at the stage before the engine brake reduction control is started after the unstable state of the vehicle is detected at the time t1 (step SA105-N in FIG. 1), the engine brake configuration member when the deceleration is large. The clutch clutch command value Pb1_tgt505 is added with a value of the safety factor SF1 times the clutch pressure Pb1_bse (PL) with respect to the clutch pressure Pb1_bse (PL) (step SA106). The command value Pb1_tgt 506 of the brake configuration engagement clutch pressure is obtained by adding a value of the safety factor SF1 times the clutch pressure Pb1_bse (PS) to the clutch pressure Pb1_bse (PS) (step SA106).

  That is, in the present embodiment, the stage before the engine brake reduction control is started after the unstable state of the vehicle is detected at time t1 (step SA105-N), the command value Pb1_tgt of the engine brake configuration engagement clutch pressure. (505, 506) is not set to the maximum pressure PM as in the prior art, but is just the clutch pressure Pb1_bse (PL, PS, step SA103) at which clutch slip according to the deceleration does not occur Thus, a predetermined required amount of pressure (Pb1_bse × SF1) considering the possibility of clutch slippage is set to an added value (step SA106). Thus, when it is determined that the vehicle stability is reduced by engine braking at time t1 (step SA105-Y), the initial response when the clutch pressures 505 and 506 are reduced to reduce the engine brake. Improves.

  Further, in this embodiment, when it is determined that the vehicle stability is reduced by engine braking at time t1 (step SA105-Y), an engine brake configuration engagement clutch pressure command corresponding to the deceleration is issued. Since the value Pb1_tgt (505, 506, step SA106) is stepped down to the clutch pressure Pb1_bse (PL, PS, step SA103) corresponding to the deceleration (step SA107), the initial response when the engine brake is reduced Will improve. Thereby, unlike the prior art, the clutch release is started at the same time (time t1) regardless of the magnitude of the deceleration. For this reason, even when the deceleration is small, the actual yaw rate 507 is suppressed from being greatly separated from the target yaw rate 508, and vehicle stability is ensured.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS.
In the second embodiment, description of parts common to the first embodiment is omitted.

  In the second embodiment, cooperative control of the automatic transmission 10 and the brake device 200 is performed. Here, the cooperative control of the automatic transmission 10 and the brake device 200 is not particularly limited, but for example, Japanese Patent Application Laid-Open No. 2005-162175, Japanese Patent Application Laid-Open No. 2005-193794, Japanese Patent Application No. 2004-33390, or It can be a technique described in the application documents of Japanese Patent Application No. 2004-112384.

[Step S101]
In step S101 in FIG. 4, the control circuit 130 determines whether or not the precondition for this control is satisfied. Preconditions for this control are that cooperative control of the automatic transmission 10 and the brake device 200 is performed, and that the gear position of the automatic transmission 10 is equal to or lower than a preset gear position (third speed in this example). Suppose that there is. Here, the cooperative control of the automatic transmission 10 and the brake device 200 only needs to be performed, and the fact that the braking force by the brake device 200 is actually acting does not have to be included in the preconditions of this control. As a result of the determination in step S101, if the precondition is satisfied, the process proceeds to step S102, and if not (step S101-N), the control flow is returned.

[Step S102]
In step S102, the control circuit 130 calculates a target deceleration G_tgt for cooperative control of the automatic transmission 10 and the brake device 200. Here, the target deceleration G_tgt is not particularly limited. For example, the target deceleration G_tgt can be a target deceleration when a shift point control or a manual downshift is performed.

  Here, the shift point control is information such as traveling road information related to a road on which a vehicle including a corner R, road gradient, and intersection in front of the vehicle travels, road traffic information related to traffic on a road on which the vehicle including a distance between vehicles, and the like. This is deceleration control by shifting toward a relatively low speed side based on information. That is, the shift point control includes downhill control based on road surface gradient, corner control based on corner R, intersection control based on intersection information, and follow-up control based on inter-vehicle distance. The manual downshift means a downshift that is manually performed when the driver desires an increase in engine braking force.

  As for the target deceleration when the shift point control or manual downshift is performed, for example, the application documents of the above-mentioned JP-A-2005-162175, JP-A-2005-193794, and Japanese Patent Application No. 2004-33390, Or it is described in the application document of Japanese Patent Application No. 2004-112384. Following step S102, step S103 is performed.

[Step S103]
In step S103, based on the target deceleration G_tgt, the control circuit 130 obtains a clutch pressure (minimum value of the clutch pressure at which the clutch does not slip) Pb1_bse to such an extent that the clutch constituting the engine brake does not slip.

  That is, in step S103, first, based on the target deceleration G_tgt, a torque capacity for preventing the clutch from slipping is obtained, and based on the torque capacity of the clutch, the clutch constituting the engine brake does not slip to the last minute. The clutch pressure Pb1_bse is obtained. In this case, the method for obtaining the clutch pressure Pb1_bse can be obtained by the same method as in step SA103 in FIG. Following step S103, step S104 is performed.

[Step S104]
In step S <b> 104, the safety factor SF <b> 1 against disturbance is set by the control circuit 130 based on the inter-vehicle distance from the preceding vehicle measured by the inter-vehicle distance measuring unit 101. When the inter-vehicle distance is clogged, the driver may suddenly brake the vehicle against deceleration or stop of the previous vehicle. When sudden braking is applied, the deceleration increases rapidly, so it is necessary to increase the clutch pressure rapidly. However, if the clutch pressure does not rise in time, an unintended clutch slip occurs. there is a possibility. Therefore, the safety factor SF1 is set based on the possibility of sudden braking. As shown in FIG. 6, when the inter-vehicle distance is small, the safety factor SF1 is set to a large value. On the other hand, when the inter-vehicle distance is large, the safety factor SF1 is set to a small value because there is little probability of sudden braking with respect to deceleration or stop of the preceding vehicle. Following step S104, step S105 is performed.

[Step S105]
In step S105, the control circuit 130 determines whether or not a start condition for engine brake reduction control is satisfied. The engine brake reduction control start condition is that, as a result of oversteer determination control described below, an oversteer determination flag overstr_F = ON and a throttle opening throttle = 0. When the oversteer determination flag overstr_F = ON and the throttle opening throttle = 0, it is determined that the rear wheel (driving wheel) is in a lock tendency due to engine braking and the oversteer state is set. Then, the engine brake reduction control start condition is satisfied (step S105-Y). On the other hand, if the engine brake reduction control start condition is not satisfied (step S105-N), the process proceeds to step S106.

  In the above description, when the throttle opening throttle = 0, for example, when the manual downshift is performed and the throttle opening is 0, the accelerator is turned off or the brake is turned on (both of which are throttles). The opening degree includes a case where shift point control performed with 0) as a trigger is being executed.

  The oversteer determination control will be described with reference to FIG.

[Step S201]
As shown in FIG. 5, in step SA201, the control circuit 130 determines whether or not the start condition for oversteer determination control is satisfied. Here, the start condition of the oversteer determination control is detected by the steering angle and vehicle speed sensor 122 detected by the steering angle sensor 85 when the steering angle sensor 85, the yaw rate sensor 88, and the vehicle speed sensor 122 are normal, for example. The vehicle speed thus set is not less than a predetermined value set in advance. As a result of the determination in step SA201, if the start condition is satisfied (step SA201-Y), the process proceeds to step SA202. If not (step SA201-N), the control flow in FIG. 5 is returned. The

[Step SA202] to [Step SA205]
In step SA202, the target yaw rate yaw_tgt is calculated by the control circuit 130 based on the detected steering angle and vehicle speed. Next, in step SA203, the yaw rate sensor 88 measures the actual yaw rate yaw_act of the vehicle. Next, in step SA204, the control circuit 130 determines whether or not the absolute value of the deviation between the target yaw rate yaw_tgt and the measured actual yaw rate yaw_act is greater than or equal to a predetermined value yaw_max set in advance. If the result of determination in step SA204 is affirmative, the oversteer determination flag overstr_F = ON is set (step SA205).

[Step SA206] to [Step SA208]
If the result of determination in step SA204 is negative, in step SA206, a predetermined absolute value of the deviation between the target yaw rate yaw_tgt and the measured actual yaw rate yaw_act is preset by the control circuit 130. It is determined whether it is less than the value yaw_min (step SA206). If the result of determination in step SA206 is affirmative and oversteer determination flag overstr_F = ON (step SA207-Y), oversteer determination flag overstr_F = OFF is set (step SA208). If the result of determination in step SA206 is negative, or if the result of determination in step SA207 is negative, the control flow in FIG. 5 is returned.

[Step S106] and [Step S107]
Steps S106 and S107 in FIG. 4 are the same as Steps SA106 and SA107 in FIG. 1 of the first embodiment, and a description thereof will be omitted.

According to the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment.
In step S106, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure is a predetermined required amount of pressure (Pb1_bse × SF1) in consideration of the possibility of clutch slipping to the clutch pressure Pb1_bse, which does not cause clutch slipping. In this case, in step S104, a safety factor SF1 corresponding to the possibility of clutch slippage is set in accordance with the inter-vehicle distance, and the above addition is performed based on the safety factor SF1. By setting the amount (Pb1_bse × SF1) to be used, it is possible to suppress unnecessary clutch slippage due to sudden braking, thereby not only preventing deterioration of the durability of the clutch but also reducing shock at the time of engagement. Can be suppressed.

Next, effects of the second embodiment will be described with reference to FIG.
FIG. 15 illustrates two cases where the target deceleration G_tgt (step S102) is the same but the inter-vehicle distance is different.

  Reference numeral 601 indicates a synchronous rotational speed (when the inter-vehicle distance is large and small), reference numeral 602 indicates a turbine rotational speed (when the inter-vehicle distance is large and small), and reference numeral 603 indicates an engine brake configuration engagement clutch pressure when the inter-vehicle distance is small. Is a command value Pb1_tgt of the engine brake configuration engagement clutch pressure when the inter-vehicle distance is large, reference numeral 605 is the actual yaw rate (when the inter-vehicle distance is large and small), and reference numeral 606 indicates the target yaw rate. ing.

  In the present embodiment, at the stage (step S105-N in FIG. 1) before the engine brake reduction control is started after the unstable state of the vehicle is detected at time t1, the clutch pressure Pb1_bse is determined according to the inter-vehicle distance. When the value obtained by multiplying the set safety factor SF1 is added to the clutch pressure Pb1_bse and the inter-vehicle distance is small, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure becomes a value indicated by reference numeral 603, The command value Pb1_tgt of the engine brake configuration engagement clutch pressure when the distance is large is a value indicated by reference numeral 604 (step S106).

  As described above, the safety factor SF1 corresponding to the possibility of clutch slipping is set according to the inter-vehicle distance, and the added amount (Pb1_bse × SF1) is set based on the safety factor SF1. Thus, it is possible to suppress unnecessary clutch slippage due to sudden braking, thereby suppressing not only deterioration of the durability of the clutch but also shock at the time of engagement.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS.
In the third embodiment, description of parts common to the above embodiment is omitted, and only main characteristic parts are described.

  As shown in step S204 of FIG. 7, in the third embodiment, the safety factor SF1 is set based on the driving direction estimated by the driving direction estimation unit 119. In general, when the driver's sport driving directivity is high, the brakes tend to be suddenly depressed. Therefore, as shown in FIG. 8, when the driver's sport driving directivity is high, the safety factor SF1 is set high. Is done.

According to the third embodiment, the following effects are obtained in addition to the effects of the first embodiment.
In step S206, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure is a predetermined required amount of pressure (Pb1_bse × SF1) in consideration of the possibility of clutch slipping to the clutch pressure Pb1_bse at which the clutch slip does not occur. In this case, in step S204, a safety factor SF1 corresponding to the possibility of clutch slippage is set in accordance with the driving direction, and the above-described addition is performed based on the safety factor SF1. By setting the amount to be used (Pb1_bse × SF1), it is possible to suppress unnecessary clutch slippage due to sudden braking, thereby not only suppressing deterioration of the durability of the clutch but also reducing shock during engagement. Can be suppressed.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIGS. 9 and 10.
In the fourth embodiment, description of parts common to the above embodiment is omitted, and only main characteristic parts are described.

  As shown in step S304 of FIG. 9, in the fourth embodiment, the safety factor SF1 is set based on the road surface μ (inter-tire road surface μ) estimated by the road surface μ detection / estimation unit 115. On low μ roads, the tires are easy to lock and the clutches are easy to slip even with normal braking (brake that is gentler than sudden braking). For this reason, as shown in FIG. 10, the safety factor SF1 is set to a larger value as the road surface μ is smaller.

According to the fourth embodiment, the following effects are obtained in addition to the effects of the first embodiment.
In step S306, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure is a predetermined required amount of pressure (Pb1_bse × SF1) in consideration of the possibility of clutch slipping to the clutch pressure Pb1_bse, which does not cause clutch slipping. Is set to the added value. In this case, in step S304, a safety factor SF1 corresponding to the possibility of clutch slippage is set according to the road surface μ, and based on the safety factor SF1, the extra value is set. By setting the amount to be used (Pb1_bse × SF1), it is possible to suppress unnecessary clutch slippage due to sudden braking, thereby not only suppressing deterioration of the durability of the clutch but also reducing shock during engagement. Can be suppressed.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIGS. 11 and 12.
In the fifth embodiment, description of parts common to the above embodiment is omitted, and only main characteristic parts are described.

  As shown in step S404 of FIG. 11, in the fifth embodiment, the safety factor SF1 is set based on the road surface state (the roughness of the surface of the road surface, the degree of unevenness). When driving on rough roads with rough or uneven road surfaces such as cobblestones or gravel roads, the greater the road disturbance, the easier it is for the tires to lock, so depending on the magnitude of torque generated by the road disturbance By setting the safety factor SF1 based on the road surface condition represented by the bandpass integrated value of the output shaft rotation speed of the automatic transmission 10 that changes in this manner, clutch slipping during normal travel is suppressed.

  On rough roads, the torque changes and the engine speed fluctuates, and resonance occurs in a certain frequency band due to the rigidity of the drive shaft and damper. By applying a band-pass filter in the frequency band, only the component in the frequency band is extracted, and the road surface condition is detected by integrating in a time window.

According to the fifth embodiment, the following effects are obtained in addition to the effects of the first embodiment.
In step S406, the command value Pb1_tgt of the engine brake constituent engagement clutch pressure is a predetermined required amount of pressure (Pb1_bse × SF1) in consideration of the possibility of clutch slipping to the clutch pressure Pb1_bse, which does not cause clutch slipping. Is set to the added value. In this case, in step S404, a safety factor SF1 corresponding to the possibility of clutch slippage is set according to the road surface condition, and the added value is set based on the safety factor SF1. By setting the amount to be used (Pb1_bse × SF1), it is possible to suppress unnecessary clutch slippage due to sudden braking, thereby not only suppressing deterioration of the durability of the clutch but also reducing shock during engagement. Can be suppressed.

According to the above embodiment, the following techniques are disclosed.
(1) In step S106, before starting the engine brake reduction control, the engine brake engagement clutch pressure is set to a value obtained by adding a predetermined amount to the clutch pressure at which clutch slip does not occur.
(2) In step S107, step down to a clutch pressure at which clutch slip occurs at the start of engine brake reduction control.
(3) In step S104, the predetermined amount is set based on the inter-vehicle distance from the preceding vehicle.
(4) In step S204, the predetermined amount is set based on the driving orientation of the driver.
(5) In step S304, the predetermined amount is set based on a friction coefficient between tire road surfaces or an estimation result thereof.
(6) In step S404, the predetermined amount is set based on the magnitude of the road surface disturbance.

  The embodiments described above can be combined as appropriate, and the embodiments can be variously modified. For example, in the above description, an example in which the stepped automatic transmission 10 is used as the transmission has been described. However, the present invention can also be applied to CVT.

It is a flowchart which shows the control content of 1st Embodiment of the control apparatus of the transmission of this invention. It is a schematic block diagram of 1st Embodiment of the control apparatus of the transmission of this invention. It is a schematic block diagram of the driving | operation direction estimation part of 1st Embodiment of the control apparatus of the transmission of this invention. It is a flowchart which shows the control content of 2nd Embodiment of the control apparatus of the transmission of this invention. It is a flowchart which shows the other control content of 2nd Embodiment of the control apparatus of the transmission of this invention. It is a graph for demonstrating the safety factor of 2nd Embodiment of the control apparatus of the transmission of this invention. It is a flowchart which shows the control content of 3rd Embodiment of the control apparatus of the transmission of this invention. It is a graph for demonstrating the safety factor of 3rd Embodiment of the control apparatus of the transmission of this invention. It is a flowchart which shows the control content of 4th Embodiment of the control apparatus of the transmission of this invention. It is a graph for demonstrating the safety factor of 4th Embodiment of the control apparatus of the transmission of this invention. It is a flowchart which shows the control content of 5th Embodiment of the control apparatus of the transmission of this invention. It is a graph for demonstrating the safety factor of 5th Embodiment of the control apparatus of the transmission of this invention. It is a time chart which shows operation | movement of the control apparatus of the conventional transmission. It is a time chart which shows operation | movement of 1st Embodiment of the control apparatus of the transmission of this invention. It is a time chart which shows operation | movement of 2nd Embodiment of the control apparatus of the transmission of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automatic transmission 40 Engine 85 Steering angle sensor 88 Yaw rate sensor 90 Acceleration sensor 95 Manual shift judgment part 101 Inter-vehicle distance measurement part 112 Relative vehicle speed detection / estimation part 113 Navigation system apparatus 114 Throttle opening sensor 115 Road surface μ detection / estimation part 116 Engine speed sensor 118 Road gradient measurement / estimation unit 119 Driving direction estimation unit 120c Output shaft 121a to 121c Solenoid valve 122 Vehicle speed sensor 123 Shift position sensor 130 Control circuit 131 CPU
133 ROM
138a to 138c Solenoid valve driving unit 200 Brake device 230 Brake control circuit 401 Synchronous rotation speed (clutch rotation speed) when deceleration is large
402 Synchronous rotation speed when deceleration is small 403 Turbine rotation speed when engine deceleration is large (engine speed)
404 Turbine speed when deceleration is small 405 Engine brake configuration engagement clutch pressure command value Pb1_tgt
406 Actual yaw rate when deceleration is large 407 Actual yaw rate when deceleration is small 408 Target yaw rate 501 Synchronous rotation speed when deceleration is large 502 Synchronous rotation speed when deceleration is small 503 Turbine rotation when deceleration is large Number 504 Turbine speed when deceleration is small 505 Engine brake configuration engagement clutch pressure command value Pb1_tgt when deceleration is large
506 Command value Pb1_tgt of engine brake configuration engagement clutch pressure when deceleration is small
507 Actual yaw rate (when deceleration is large and deceleration is small)
508 Target yaw rate 601 Synchronous rotation speed (when the inter-vehicle distance is large and small)
602 Turbine speed (when the inter-vehicle distance is large and small)
603 Command value Pb1_tgt of engine brake configuration engagement clutch pressure when the inter-vehicle distance is small
604 Command value Pb1_tgt of engine brake configuration engagement clutch pressure when the inter-vehicle distance is large
605 Actual yaw rate (when the inter-vehicle distance is large and small)
606 Target yaw rate PM Maximum pressure (normal engagement pressure)
The clutch pressure Pb1_bse when the PL deceleration is large
PS Clutch pressure Pb1_bse when deceleration is small
SG1 Brake braking force signal SG2 Brake control signal t1 Time t2 Time t3 Time

Claims (10)

A detection unit for detecting whether the engine brake is in operation and the vehicle stability is reduced;
A clutch pressure control unit that reduces the clutch pressure of the clutch that constitutes the engine brake when it is detected by the detection unit that the engine brake is operating and the vehicle stability is in a reduced state;
The clutch pressure control unit reduces the clutch pressure at a plurality of different slopes when the clutch pressure is reduced. The transmission control device according to claim 1,
Furthermore,
A minimum value calculation unit for obtaining a minimum value of the clutch pressure at which the clutch constituting the engine brake does not slip based on the deceleration of the vehicle;
The transmission control apparatus according to claim 1, wherein the clutch pressure control unit changes an inclination when the clutch pressure is reduced in the vicinity of a minimum value of the clutch pressure. The transmission control device according to claim 1 or 2,
The clutch pressure control unit lowers the clutch pressure with a relatively large gradient at an initial stage when the clutch pressure is decreased, and reduces the clutch pressure with a relatively small gradient after the initial stage. A control device for a transmission. A determination unit that determines whether the engine stability is likely to decrease due to the engine brake being operated and the engine brake;
A detection unit for detecting whether the engine brake is in operation and the vehicle stability is reduced;
A clutch pressure control unit that reduces the clutch pressure of the clutch that constitutes the engine brake when it is detected by the detection unit that the engine brake is operating and the vehicle stability is in a reduced state;
The clutch pressure control unit determines the clutch pressure by the determination unit when the determination unit determines that there is a possibility that the vehicle stability is lowered due to the engine brake being operated. A transmission control device, characterized in that the brake pressure is set to a value smaller than a clutch pressure at a normal time other than when it is determined that there is a possibility that the vehicle stability is lowered due to engine braking. The transmission control apparatus according to claim 4, wherein
Furthermore,
A minimum value calculation unit for obtaining a minimum value of the clutch pressure at which the clutch constituting the engine brake does not slip based on the deceleration of the vehicle;
A judgment unit for judging the possibility of clutch slipping,
The clutch pressure control unit uses a value obtained by adding a value corresponding to the possibility of clutch slipping to a minimum value of the clutch pressure as a value smaller than the normal clutch pressure. A control device for a transmission. The transmission control device according to claim 5, wherein
The transmission control device is characterized in that a value corresponding to the possibility of the occurrence of clutch slip is set based on the inter-vehicle distance. The transmission control device according to claim 5 or 6,
The transmission control device is characterized in that a value corresponding to the possibility of occurrence of clutch slip is set based on driving orientation. The transmission control device according to any one of claims 5 to 7,
The transmission control device is characterized in that a value corresponding to the possibility of clutch slippage is set based on a friction coefficient of a road surface. The transmission control device according to any one of claims 5 to 8,
A value corresponding to the possibility of clutch slippage is set based on the magnitude of torque input from the road surface. A detection unit for detecting whether the engine brake is operating and the vehicle stability is reduced;
A clutch pressure control unit that reduces the clutch pressure of the clutch that constitutes the engine brake when the detection unit detects that the engine brake is in operation and the vehicle stability is in a reduced state,
The clutch pressure control unit reduces the clutch pressure with a relatively large inclination including a step-down so that initial response is enhanced at least in an initial stage when the clutch pressure is decreased. Control device.

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