JP2007032698A - Vehicle control device, system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize behavior of a vehicle in recovering from a fail-safe control caused by abnormality of a rotating system of the vehicle. <P>SOLUTION: In this vehicle control device, a target transmission ratio corresponding to an accelerator opening in recovering is set to control a gear ratio with a variation, when a normal shift control is recovered from the fail-safe control when a normal state of the input of the rotating system to a continuously variable transmission is recovered from an abnormal state. Thus sudden starting of the vehicle caused by kick-down in recovering from the abnormal state, can be prevented even when a driver steps on an accelerator pedal, and the behavior of the vehicle can be kept in safety. In particular, as the variation is determined on the basis of a water temperature of an engine, the shift control can be smoothly performed, and the stability in the behavior of vehicle can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle control device, and more particularly, to a vehicle control device that performs fail-safe control for ensuring the safety of a vehicle by lowering a gear ratio when the state of a rotating system of the vehicle is abnormal.

Conventionally, continuously variable transmissions (also referred to as “CVT”) have been widely used as automatic transmissions for vehicles because of their excellent robustness.
In a vehicle equipped with such a continuously variable transmission, the rotational system input becomes abnormal, for example, when the turbine speed of the torque converter arranged on the input shaft side becomes higher than the expected range. In this case, the target gear ratio is reduced to correspond to the high gear position, and fail-safe control is performed so that the engine torque is not suddenly applied to the drive wheels (see, for example, Patent Document 1).

  FIG. 9 is a timing chart showing an example of such conventional vehicle control. In the figure, the horizontal axis represents the passage of time, and the vertical axis represents the state of the rotational system input from the upper stage and the control amount of the transmission ratio.

As described above, when an abnormality occurs in the rotational system input of the vehicle traveling at a certain gear ratio, the target gear ratio is temporarily reduced to a small value in order to ensure the safety of the vehicle. When the rotational system input returns from the abnormal state to the normal state, the target gear ratio is raised and normal shift control is executed. This prevents the behavior of the vehicle from becoming unstable due to unexpected torque applied to the drive wheels when the rotating system is abnormal.
Japanese Patent Laid-Open No. 8-178046

  However, since the gear ratio is fixed to a small value during execution of such fail-safe control, the vehicle speed does not increase even if the accelerator pedal is depressed. For this reason, there is a possibility that the driver fully opens the accelerator pedal in order to satisfy his / her acceleration request. For this reason, when the rotational system input is subsequently returned from the abnormal state to the normal state and returned to the normal shift control, the vehicle may start suddenly due to kick-down.

  The present invention has been made in view of the above points, and a vehicle control device, a vehicle control system, and a vehicle that can stabilize the behavior of the vehicle when returning from fail-safe control due to an abnormality in the rotation system of the vehicle. An object is to provide a control method.

  In the present invention, in order to solve the above problem, state acquisition means for acquiring a state of a rotating system based on a rotating system input to an automatic transmission mounted on a vehicle, and the automatic transmission based on the rotating system input Shift control means for performing fail-safe control so as to reduce the speed ratio when the state of the rotating system acquired by the state acquisition means is abnormal. In the apparatus, when the shift control unit determines that the rotation system input acquired by the state acquisition unit has returned from an abnormal state to a normal state, a target shift corresponding to an accelerator opening or a throttle opening at the time of the return is determined. There is provided a vehicle control device characterized in that a ratio is set and the gear ratio is controlled to be changed.

  In the vehicle control device of the present invention, when the rotational system input returns from the abnormal state to the normal state and returns from the failsafe control to the normal shift control, the target corresponding to the accelerator opening or the throttle opening at the time of the return A gear ratio is set, and the gear ratio is controlled to be changed.

  According to the vehicle control device of the present invention, at the time of return from fail-safe control due to an abnormality in the rotation system input, the change control is performed so that the gear ratio corresponds to the accelerator opening or throttle opening at the time of return. Therefore, the behavior of the vehicle can be stably maintained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, the vehicle control device of the present invention is applied to a vehicle control system equipped with a continuously variable transmission. FIG. 1 is a system configuration diagram showing a configuration of a vehicle control system including a vehicle control device according to the present embodiment.

  In this vehicle control system, a belt-type continuously variable transmission 3 is installed between an engine 1 which is a drive source of a vehicle and a drive wheel 2, and each control object is an electronic control unit (hereinafter referred to as “electronic control unit”). ECU "). That is, engine control is performed by an engine ECU (hereinafter referred to as “engine ECU”) 4, and shift control is performed by an ECU for continuously variable transmission (hereinafter referred to as “CVTECU”) 5. An oil pump 6, a torque converter 7, a forward / reverse switching device 8, a continuously variable transmission 3, and a reduction gear 9 are sequentially connected to the output shaft of the engine 1, and the output of the reduction gear 9 is left and right via a differential 10. It is transmitted to the drive wheel 2.

  Each of the engine ECU 4 and the CVTECU 5 is an independent electronic control unit that is configured around a calculation unit including a microcomputer. Each ECU includes a CPU (Central Processing Unit) that executes various arithmetic processes, a ROM (Read Only Memory) that stores various control arithmetic programs and data, and a RAM (Random) that stores numerical values and flags of arithmetic processes in a predetermined area. Access Memory), A / D (Analog / Digital) converter for converting an input analog signal into a digital signal, an input / output interface for inputting / outputting various digital signals, a timer for timing used in the calculation process, and these It has a bus line to which each device is connected. Each ECU has a built-in communication control unit for performing communication processing with each other via the communication line L so that data can be transmitted and received with each other.

  The engine ECU 4 incorporates a signal input / output unit that takes in output signals from various sensors that detect the state of the engine 1 and outputs drive signals to various actuators provided in the engine 1. That is, the signal input / output section of the engine ECU 4 includes an accelerator opening sensor that detects the amount of depression of the accelerator pedal, an air flow meter that detects the amount of intake air, an intake air temperature sensor that detects the temperature of intake air, and an open throttle valve. Sensors and switches such as a throttle opening sensor that detects the degree of water, a water temperature sensor that detects the cooling water temperature, an engine speed sensor that detects the engine speed, a vehicle speed sensor that detects the vehicle speed from the rotation of the vehicle drive shaft, and an ignition switch An injector provided for each cylinder of the engine 1, an igniter that generates a high voltage for ignition, a fuel pump that pumps fuel from the fuel tank and supplies it to the injector, and a throttle provided in the intake pipe of the engine 1 Engines such as throttle drive motors for opening and closing valves Various actuators for control is connected. The engine ECU 4 performs a predetermined engine control process according to a control program stored in the ROM.

  The CVTECU 5 incorporates a signal input / output unit for receiving output signals from various sensors for detecting the state of the continuously variable transmission 3 and outputting drive signals to various actuators provided in the continuously variable transmission 3. ing. That is, as shown in the figure, the signal input / output unit of the CVTECU 5 includes an input shaft rotational speed sensor for detecting the rotational speed Nin of the input shaft of the continuously variable transmission 3, and an output shaft of the continuously variable transmission 3. An output shaft rotational speed sensor for detecting the rotational speed Nout of the vehicle, a vehicle speed sensor for detecting the vehicle speed V from the rotation of the vehicle drive shaft, an oil temperature sensor for detecting the temperature of the hydraulic oil, and a hydraulic pressure (secondary pressure) Pout in the secondary pulley described later. Sensors and switches such as a secondary pressure detection sensor for detecting the transmission are connected, a shift solenoid for controlling the shift of the continuously variable transmission 3, and a belt clamp for suppressing slippage of the belt of the continuously variable transmission 3. A secondary pressure solenoid that controls pressure, a line pressure control solenoid that controls the line pressure that is the source pressure of the hydraulic pressure used for shift control, and the input / output shaft of the torque converter 7 are fastened. Described later lockup clutch lockup pressure solenoid for operating the fastening force of the various actuators for the shift control such is connected. The CVTECU 5 performs a predetermined shift control process according to a control program stored in the ROM.

  The torque converter 7 is for smoothly transmitting the power of the engine 1 to the axle. The pump impeller 11 connected to the output shaft of the engine 1, the turbine liner 12 connected to the output shaft of the torque converter 7, these And a lockup clutch 14 that fastens the pump impeller 11 and the turbine liner 12 under a predetermined condition.

  The forward / reverse switching device 8 includes a planetary gear, and includes a sun gear 15 connected to the output shaft of the torque converter 7, a carrier 16 connected to the input shaft of the continuously variable transmission 3, and a ring gear 18 connected to the brake 17. Yes.

  The continuously variable transmission 3 includes a primary pulley 21 connected to an input shaft arranged on the driving side, a secondary pulley 22 connected to an output shaft arranged on the driven side, and the primary pulley 21 and the secondary pulley 22. A V-belt 23 stretched between them is provided, and torque transmitted from the input shaft is transmitted to the output shaft. The continuously variable transmission 3 changes the groove width of the primary pulley 21 by hydraulic control, while holding the pinching force of the secondary pulley 22 to the V belt 23 by hydraulic control, so that the engagement diameter of the V belt 23 in each pulley is increased. By changing each, the gear ratio which is the ratio of the rotational speeds of the input shaft and the output shaft is continuously changed. The hydraulic control of the primary pulley 21 and the secondary pulley 22 is performed by a hydraulic control device 24.

  The reduction gear 9 matches the rotation direction of the axle with the rotation direction of the output shaft of the engine 1. That is, in the continuously variable transmission 3, the rotation direction is reversed between the input shaft and the output shaft, but the reduction gear 9 further reverses the rotation direction of the reversed output shaft to rotate the input shaft. To match.

  The differential 10 transmits the output of the reduction gear 9 to the accelerator shafts connected to the left and right drive wheels 2 respectively, and absorbs the rotational difference between the left and right drive wheels 2 when the vehicle travels on a curve, so that the vehicle travels smoothly. Is realized.

  Next, an outline of engine control and shift control will be described. FIG. 2 is a functional block diagram illustrating an example of the vehicle control process. The process shown in the figure may be performed by either engine ECU 4 or CVTECU 5.

  First, referring to a predetermined control map, based on the current vehicle speed (actual vehicle speed) spd detected by the vehicle speed sensor and the accelerator opening accp detected by the accelerator opening sensor, the driving force force required for the vehicle Is calculated. Then, the driving force force is set as the target driving force force_cnt, and the target output power of the vehicle is calculated from the target driving force force_cnt and the actual vehicle speed spd. Here, the target output power is obtained by multiplying the target driving force force_cnt and the actual vehicle speed spd.

  Subsequently, with reference to a predetermined control map, the target engine torque trqtgt and the target engine speed nintgt are calculated from the target output power so that the optimum fuel consumption condition is satisfied. Here, a control map representing the relationship between the engine torque TE, the engine speed NIN, and the output power is used, and the engine torque calculated so as to satisfy the point where the optimum fuel consumption line set in the control map and the target output power intersect. And the engine speed are a target engine torque trqtgt and a target engine speed nintgt, respectively.

  The engine ECU 4 controls the engine control actuator so as to realize the target engine torque trqtgt. Further, the CVTECU 5 calculates a target speed ratio for controlling the continuously variable transmission 3 from the target engine speed nintgt, and controls the shift control actuator so as to realize the target speed ratio.

  Thereby, favorable engine control and shift control are executed, and acceleration / deceleration traveling of the vehicle based on the operation amount including the accelerator opening based on the depression amount of the accelerator pedal by the driver is realized.

  Next, the vehicle control method of the present embodiment will be described. The vehicle control method according to the present embodiment is characterized by control at the time of return from fail-safe control due to an abnormality in the rotation system of the vehicle. FIG. 3 is a timing chart showing an example of a vehicle control process executed by the CVTECU. In the figure, the horizontal axis represents the passage of time, and the vertical axis represents the rotational system input state, the accelerator opening, and the control amount of the gear ratio from the top.

  For example, when an abnormality in the rotational system input on the input shaft side of the continuously variable transmission 3 is detected at time t1, the CVTECU 5 performs control so that the gear ratio is reduced in order to hold the vehicle safely. The determination of the abnormality of the rotation system input is performed using a predetermined control map.

  FIG. 4 is a control map used to determine the transition from the normal state to the abnormal state and the return from the abnormal state to the normal state. In the figure, the horizontal axis represents the accelerator opening, and the vertical axis represents the rotational speed (referred to as “input shaft rotational speed”) Nin of the input shaft of the continuously variable transmission 3 that is a rotational system input.

  That is, the control map includes an abnormality determination rotational speed for determining that the rotational system input has shifted from the normal state to the abnormal state, and for determining that the rotational system input has returned from the abnormal state to the normal state. Normal return speed is set. The abnormality determination rotational speed is basically set so that the determination value becomes higher as the accelerator opening increases, but the determination value becomes constant when the predetermined accelerator opening is exceeded. Therefore, it is determined that the input shaft rotation speed is normal until the input shaft rotation speed exceeds the abnormality determination rotation speed. On the other hand, if the normal return rotational speed is set to be the same as or close to the abnormality determination rotational speed, the behavior of the vehicle may become unstable when the input shaft rotational speed slightly varies. A judgment value that is sufficiently lower than the abnormal return speed is set. Therefore, once it is determined that the state is abnormal, it is determined that the state is abnormal until the input shaft rotational speed falls below the normal return rotational speed.

  Returning to FIG. 3, as a result of the reduction of the gear ratio as described above, even if the accelerator pedal is depressed because the driver feels unintentional deceleration, the accelerator opening increases as shown, but the gear ratio decreases. Will remain. For example, at time t2 after the accelerator opening is fully opened, if it is determined that the rotation system input on the input shaft side of the continuously variable transmission 3, that is, the input shaft rotation speed has returned to normal, Shift control is performed by setting a target gear ratio based on the accelerator opening and the vehicle speed. At this time, the control amount for the shift control is not rapidly increased, but is controlled so as to gradually approach the target gear ratio as shown in the figure. In the present embodiment, this variable amount is set based on the water temperature detected by the water temperature sensor.

  FIG. 5 is a control map used for setting the variable amount of the control amount in this shift control. In the figure, the horizontal axis represents the engine coolant temperature, and the vertical axis represents the variable amount (the magnitude of the correction coefficient).

  In this control map, the water temperature is set so as to change the variable amount based on a predetermined value T1 (for example, 50 ° C.). That is, the variable is set to α when the water temperature is lower than T1, and β is set to be higher than T1 when the water temperature is T1 or higher.

  For this reason, as shown in FIG. 3, when the water temperature is low, the variable amount is smaller than when the water temperature is high, and the control amount is changed gently. This is because when the water temperature is low, the behavior of the vehicle is not stable, and the shock due to the change in the input shaft speed increases, so the change in the gear ratio is made small.

  Next, the flow of the vehicle control process centering on the shift control of the present embodiment will be described. FIG. 6 is a flowchart showing a flow of vehicle control processing executed by CVT ECU. Hereinafter, the flow of this process will be described using step numbers (hereinafter referred to as “S”).

  The process shown in FIG. 7 is repeatedly executed at regular time intervals after the engine is started. First, it is determined whether or not the rotation system input is abnormal as described above (S110). At this time, if it is determined that the rotational system input is abnormal (S110: YES), the process shifts to fail-safe control, and the gear ratio is reduced to correspond to the high gear position (S120).

  On the other hand, if it is determined in S110 that the rotation system input is not abnormal (S110: NO), it is determined whether or not the rotation system input has returned from the abnormal state to the normal state by comparison with the previous determination result. (S130). At this time, if it is determined that there has been no change in the state of the rotational system input (S130: NO), the rotational system input has been in a normal state, and therefore normal shift control up to the previous time is continued (S200). .

  On the other hand, when it is determined in S130 that the rotational system input has returned from the abnormal state to the normal state (S130: YES), the target gear ratio is set based on the accelerator opening and the vehicle speed at the time of the return (S140). ).

  Subsequently, it is determined whether or not the water temperature of the engine 1 is lower than a predetermined value T1 (S150). At this time, if the water temperature is less than T1 (S150: YES), the variable amount of the shift control is set to α as described above (S160), and if the water temperature is equal to or higher than T1 (S150: NO), the variable amount Is set to β (S170).

  Then, it is determined whether or not the actual speed ratio that is the current speed ratio is smaller than the target speed ratio (S180). At this time, if the actual gear ratio is smaller than the target gear ratio (S180: YES), the variable amount is added to the control amount of the current gear ratio (S190), and the shift control according to the control amount is executed (S190). S200). On the other hand, if it is determined in S180 that the actual speed ratio has reached the target speed ratio (S180: NO), the speed change control is continued (S200).

  As described above, in the present embodiment, when the rotation system input to the continuously variable transmission 3 returns from the abnormal state to the normal state and returns from the failsafe control to the normal shift control, The target gear ratio corresponding to the accelerator opening is set, and the gear ratio is controlled to be changed. For this reason, even if the driver steps on the accelerator pedal, the behavior of the vehicle can be safely maintained without causing the vehicle to suddenly start due to kick-down when returning from the abnormal state. In particular, since the removal amount is changed depending on the water temperature of the engine 1, the shift control becomes smooth and the stabilization of the behavior of the vehicle can be enhanced.

In the present embodiment, CVTECU 5 corresponds to the state acquisition unit and the shift control unit, and the input shaft rotational speed sensor and CVTECU 5 correspond to the state detection unit.
The preferred embodiment of the present invention has been described above, but the present invention is not limited to the specific embodiment, and it can be changed and modified within the spirit of the present invention. Not too long. 7 and 8 are explanatory diagrams showing modifications of the above embodiment.

  For example, in the above embodiment, as shown in FIG. 3, when returning from fail-safe control, the speed ratio corresponding to the accelerator opening and the vehicle speed at the time of return is fixed as the target speed ratio, and the control amount is An example is shown in which control is performed so as to approach the target gear ratio. However, since the accelerator opening and vehicle speed may change from moment to moment from the time of return, when the controlled variable reaches the target gear ratio, the target gear ratio originally obtained from the accelerator opening and the vehicle speed at the time of arrival. It may be a far away value and shock may be given to the vehicle. Therefore, the target gear ratio may be changed in response to this change.

  That is, as shown in FIG. 7, a gear ratio corresponding to the accelerator opening and the vehicle speed that change from time to time is virtually calculated, this virtual gear ratio is set as the target gear ratio, and the controlled variable is the target gear ratio. You may make it control so that ratio may be approached. Thereby, since the control amount is appropriately set toward the target gear ratio, the stability of the vehicle can be further ensured.

  Further, the target gear ratio may be set based on the throttle opening detected by the throttle opening sensor instead of being set based on the accelerator opening detected by the accelerator opening sensor.

  Furthermore, in the above embodiment, as shown in FIG. 5, an example in which the amount of change in the controlled variable is changed stepwise before and after a certain water temperature T1, but as shown in FIG. The variable amount may be continuously changed. In this way, smoother shift control can be realized.

  In the above embodiment, an example in which the state of the rotation system input of the vehicle is determined based on the input shaft speed of the continuously variable transmission 3 detected by the input shaft speed sensor has been described. The determination may be made on the basis of the engine speed or the turbine speed, which is the speed on the input shaft side of the machine 3.

  In the above embodiment, the example in which the variable amount is changed based on the water temperature of the engine 1 is shown. However, for example, the variable amount is changed based on the oil temperature of hydraulic oil for hydraulically controlling the continuously variable transmission 3 or the like. It may be changed.

  Furthermore, in the above-described embodiment, an example in which the vehicle control device of the present invention is applied to a vehicle control system equipped with a continuously variable transmission is shown, but it is also possible to apply to a so-called multistage automatic transmission. In a multi-speed automatic transmission, the gear ratio is originally changed stepwise, but if the gear ratio changes significantly before and after returning from fail-safe control, this change control is performed step by step. The effects of the invention can be obtained. However, application to a vehicle of a type in which the gear ratio is continuously changed like a continuously variable transmission is considered preferable from the viewpoint of improving the stability of the vehicle.

  In the above embodiment, the engine ECU 4 and the CVTECU 5 are configured as independent electronic control units. However, the functions of the engine ECU 4 and the CVTECU 5 can be configured as one electronic control unit.

1 is a system configuration diagram illustrating a configuration of a vehicle control system including a vehicle control device according to an embodiment. It is a functional block diagram showing an example of vehicle control processing. It is a timing chart showing an example of the vehicle control processing which CVT ECU performs. It is a control map used in order to determine the transition from the normal state of a rotation system input to an abnormal state, and the return from an abnormal state to a normal state. It is a control map used in order to set the variable amount of the control amount in shift control. It is a flowchart showing the flow of the vehicle control process which CVT ECU performs. It is explanatory drawing showing the modification of embodiment. It is explanatory drawing showing the modification of embodiment. It is a timing chart showing the example of the conventional vehicle control.

Explanation of symbols

1 Engine 2 Drive Wheel 3 Continuously Variable Transmission 4 Engine ECU
5 CVTECU
7 Torque Converter 21 Primary Pulley 22 Secondary Pulley 23 V Belt 24 Hydraulic Control Device

Claims (10)

State acquisition means for acquiring the state of the rotation system based on the rotation system input to the automatic transmission mounted on the vehicle;
The gear ratio of the automatic transmission is controlled based on the rotation system input, and when the state of the rotation system acquired by the state acquisition unit is an abnormal state, fail-safe control is performed so that the gear ratio becomes small. Shift control means to perform,
In a vehicle control device comprising:
When the shift control means determines that the rotational system input acquired by the state acquisition means has returned from an abnormal state to a normal state, it sets a target gear ratio corresponding to the accelerator opening or throttle opening at the time of the return. And the vehicle control apparatus characterized by carrying out diversification control of the said gear ratio.   When the shift control means determines that the rotational system input has returned from an abnormal state to a normal state, it sets a target gear ratio corresponding to the accelerator opening or throttle opening at the time of the return, and changes the gear ratio. The vehicle control device according to claim 1, wherein the vehicle control device is controlled.   2. The vehicle control apparatus according to claim 1, wherein the speed change control means makes the speed change amount of the speed change ratio by the speed change control more gradual as the cooling water temperature of the engine is lower.   When determining that the rotational system input has returned from the abnormal state to the normal state, the shift control means sets a target gear ratio corresponding to an accelerator opening or a throttle opening that changes from the return point, and sets the gear ratio. 2. The vehicle control device according to claim 1, wherein the vehicle control is performed.   5. The vehicle control according to claim 4, wherein the speed change control means sets a virtual speed ratio predicted from a change in accelerator opening or throttle opening at the time of return as the target speed ratio at the time of return. apparatus.   6. The vehicle control apparatus according to claim 5, wherein the speed change control means makes the change amount of the speed change ratio up to the virtual speed change ratio more gradual as the engine coolant temperature is lower.   The vehicle control device according to claim 1, wherein the automatic transmission is a continuously variable transmission. State detecting means for detecting the state of the rotating system based on the rotating system input to the automatic transmission mounted on the vehicle;
The transmission ratio of the automatic transmission is controlled based on the rotation system input, and when the abnormal state of the rotation system is detected by the state detection means, the transmission ratio is reduced to transmit the engine torque to the drive wheels. Shift control means for performing fail-safe control to be limited;
In a vehicle control system comprising:
When the state detection means detects that the rotation system input has returned from the abnormal state to the normal state, the speed change control means sets the speed change ratio corresponding to the accelerator opening or the throttle opening at the time of the return to the target speed change. A vehicle control system characterized in that the gear ratio is controlled as a ratio.   The vehicle control system according to claim 8, wherein the automatic transmission is a continuously variable transmission. Vehicle control that controls a gear ratio based on a rotation system input to an automatic transmission mounted on a vehicle, and performs fail-safe control so that the gear ratio becomes small when the state of the rotation system is abnormal In the method
When the rotational system input returns from an abnormal state to a normal state, a target gear ratio corresponding to an accelerator opening or a throttle opening at the time of the return is set, and the gear ratio is subjected to variable control. Vehicle control method.

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