JP6439348B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device.

  An engine and a transmission mounted on a vehicle are controlled based on sensor values of various sensors by an electronic control unit (hereinafter referred to as ECU). However, if a sensor, actuator, etc. breaks down, various controls by the ECU become inaccurate, leading to deterioration of exhaust emission, an increase in engine load, or excessive temperature rise of the exhaust system, which may affect the running of the vehicle. is there.

  In order to solve such a problem, a so-called retreat mode (also referred to as a limp mode) is known in which a failure of a sensor or actuator is diagnosed and the engine torque or the like is limited according to the result of the failure diagnosis. (See Patent Documents 1 and 2).

JP-A-1-124354 JP-A-7-180570

  However, in the conventional evacuation travel mode, the engine torque is limited while allowing self-running, so that there is a problem that driving torque is insufficient when the vehicle travels on an uphill road, and drivability is deteriorated.

  It is an object of the disclosed apparatus to effectively prevent drive torque shortage during the retreat travel mode.

  The disclosed apparatus determines whether or not a failure detection unit that detects a failure of each part of the vehicle and a retreat traveling mode that limits the traveling speed of the vehicle based on the failure detected by the failure detection unit. An execution determining unit; and a vehicle speed limiting unit that executes vehicle speed limiting control for controlling the traveling speed of the vehicle to a predetermined limited vehicle speed when the execution determining unit determines that the retreat traveling mode is necessary.

  According to the disclosed device, it is possible to improve the drive torque shortage in the retreat travel mode.

1 is an overall configuration diagram of a vehicle according to an embodiment of the present invention. It is a functional block diagram of the electronic control unit which concerns on one Embodiment of this invention. It is a time chart figure of the vehicle control device concerning one embodiment of the present invention.

  Hereinafter, based on an accompanying drawing, a vehicle control device concerning one embodiment of the present invention is explained. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  FIG. 1 is an overall configuration diagram showing a vehicle 1 of the present embodiment. The output shaft of the engine 10 is connected to the input shaft of the transmission 12 via the clutch 11. The output shaft of the transmission 12 is connected to drive wheels (left and right rear wheels) 16L and 16R via a propeller shaft 13, a differential device 14, and a drive shaft 15, respectively. Further, the transmission 12 is provided with a power take-off mechanism (hereinafter referred to as PTO) 80 capable of taking out a part of the power of the engine 10.

  In FIG. 1, reference numeral 17 denotes an injector that injects fuel into each cylinder of the engine 10, reference numerals 18 </ b> L and 18 </ b> R denote steering wheels (left and right front wheels), reference numeral 21 denotes a vehicle speed sensor, reference numeral 22 denotes an engine speed sensor, reference numeral 23. Represents an accelerator opening sensor, and reference numeral 50 represents an ECU.

  The vehicle speed sensor 21 detects the actual vehicle speed V of the vehicle 1 from the rotational speed of the propeller shaft 13. The engine speed sensor 22 detects the engine speed N from the speed of the output shaft of the engine 10. The accelerator opening sensor 23 detects the accelerator opening Q from the depression amount of the accelerator pedal 30. The sensor values of these various sensors 21 to 23 are transmitted to the electrically connected ECU 50.

  The ECU 50 performs various controls of the engine 10 and the transmission 12, and includes a known CPU, ROM, RAM, input port, output port, and the like. Further, as shown in FIG. 2, the ECU 50 includes an idle state detection unit 51, a failure detection unit 52, a retreat travel mode execution determination unit 53, a vehicle speed limit FB control unit 54, a limit vehicle speed setting unit 55, and an end. The time transition control unit 56 and the torque limit control switching unit 57 are included as some functional elements. In the present embodiment, these functional elements are described as being included in the ECU 50, which is an integral piece of hardware. However, any one of these functional elements may be provided in separate hardware.

The idle state detection unit 51 is idle detection means of the present invention, and is detected by the actual vehicle speed V detected by the vehicle speed sensor 21, the engine speed N detected by the engine speed sensor 22, and the accelerator opening sensor 23. Whether or not the engine 10 is in an idling state is detected based on the accelerator opening Q. When the idle state is detected, the idle flag is turned ON (F _ID = 1) (see time t ₂ in FIG. 3B).

  The failure detection unit 52 is failure detection means of the present invention, and detects failures that have occurred in various sensors and actuators. For example, if the difference between the sensor value and a preset threshold value is large, it is detected as a sensor failure. Further, when the actuator does not operate according to the operation signal, it is detected as an actuator failure.

The retreat travel mode execution determination unit 53 is an execution determination unit of the present invention, and determines whether or not to execute a retreat travel mode that limits the speed of the vehicle according to the failure detected by the failure detection unit 52. . More specifically, when a sensor failure or actuator failure detected by the failure detection unit 52 corresponds to a failure that affects vehicle travel, it is determined that execution of the retreat travel mode is necessary, and the retreat travel mode execution flag is , ON (F _LIM = 1) (see time t ₁ in FIG. 3A). Incidentally, for example, when a failure by the failure detection unit 52 is not detected, the limp mode execution flag (see time t ₄ in FIG. 3 (A)) to OFF is the (F _LIM = 0).

The vehicle speed limiting FB control unit 54 is vehicle speed limiting means of the present invention, and the actual vehicle speed V detected by the vehicle speed sensor 21 when the evacuation travel mode execution flag is ON (F _LIM = 1) will be described later. as the limiting vehicle speed value V _T, in accordance with the deviation between the vehicle speed limit value V _T and the actual vehicle speed V, the feedback control of the fuel injection amount of the injector 17 (hereinafter, referred to as speed limiting FB control). This vehicle speed limit FB control uses PI control that adjusts the control amount based on a proportional term (P term) and an integral term (I term) calculated from the deviation between the limit vehicle speed value V _T and the actual vehicle speed V. .

The limit vehicle speed setting unit 55 is a limit vehicle speed reduction means of the present invention, and reduces the limit vehicle speed value V _T stepwise according to the elapsed time of the vehicle speed limit FB control. More specifically, the limit vehicle speed setting unit 55 starts counting by a timer (not shown) from the time when the retreat travel mode execution flag becomes ON (F _LIM = 1), and the retreat travel mode execution flag becomes OFF (F _The limit vehicle speed value V _T is reduced stepwise in accordance with the accumulated time until _LIM = 0) (see times t _{1 to} t ₄ in FIG. 3C). As a result, the traveling speed of the vehicle 1 can be gently limited according to the elapsed time of the vehicle speed limiting FB control.

Further, when the evacuation travel mode execution flag is ON (F _LIM = 1) and the idle flag is ON (F _ID = 1), the limit vehicle speed setting unit 55 thereafter turns the idle flag OFF ( until F _ID = 0), to stop the timer time measurement reference time t ₂ ~t ₃ (FIG. 3 (D)). Thus, reduction of the speed limit value V _T corresponding to the accumulated time, during the idle period is temporarily interrupted (see time t ₂ ~t ₃ in FIG. 3 (C)). As a result, it is possible to prevent the limit vehicle speed value V _{T from} being excessively lowered while the vehicle is stopped in an idle state due to traffic jams and the like, and prevent the vehicle 1 from getting off the expressway or the like.

The end-time transition control unit 56 is an end control means of the present invention, and executes end-of-evacuation mode end-time transition control that gradually increases the limit vehicle speed value V _T when the vehicle speed limit FB control is ended. More specifically, the end-time transition control unit 56 finishes gradually increasing the limit vehicle speed value V _T so that the vehicle speed does not increase rapidly when the retreat travel mode execution flag is OFF (F _LIM = 0). Hourly vehicle speed control is performed (see times t _{4 to} t ₅ in FIG. 3C). The end-time transition control unit 56 also executes end-time fuel injection amount control that gradually increases the fuel injection amount in accordance with the end-time vehicle speed control. Thereby, the shock to the vehicle 1 due to the rapid increase in the vehicle speed or the rapid increase in the fuel injection amount can be effectively mitigated.

Torque limitation control switching section 57, in a switching means of the present invention, the state of the limp mode execution flag is ON (F _LIM = 1) (see time t ₁ ~t ₄ in FIG. 4 (A)), When the power extraction by the PTO 80 is executed, the vehicle speed limit control by the vehicle speed limit FB control unit 54 is switched to the torque limit control of the engine 10. In this torque limit control, for example, the engine output torque becomes a target torque value based on the engine speed N detected by the engine speed sensor 22 and the accelerator opening Q detected by the accelerator opening sensor 23. This is executed by feedback control. When the power is taken out by the PTO 80, the vehicle 1 is in a non-traveling state and the vehicle speed limit FB control cannot be performed. Therefore, the retreat travel mode control is enabled by switching from the vehicle speed limit control to the torque limit control.

  Next, the effect by the vehicle control apparatus of this embodiment is demonstrated.

The vehicle control device of the present embodiment performs vehicle speed limit FB control that adjusts the fuel injection amount of the injector 17 by PI control so that the actual vehicle speed V becomes the limit vehicle speed value V _T when executing the retreat travel mode. It is configured as follows. Therefore, according to the vehicle control apparatus of the present embodiment, the driving torque is increased when the vehicle 1 is traveling on an uphill road where the torque of the engine 10 is required, as compared with the conventional apparatus in which the retreat traveling mode is performed only by torque limitation of the engine 10. The shortage can be surely prevented.

In addition, the vehicle control apparatus of the present embodiment is configured to reduce the limit vehicle speed value V _T stepwise in accordance with the elapsed time of the vehicle speed limit FB control during execution of the retreat travel mode. Therefore, according to the vehicle control device of the present embodiment, the speed limit of the vehicle 1 does not rapidly decrease during the vehicle speed limit FB control, and the travel speed can be gently limited according to the elapsed time.

Further, the vehicle control apparatus of the present embodiment is configured such that the reduction of the limit vehicle speed value V _T is interrupted when the engine 10 is in an idle state during execution of the retreat travel mode. This eliminates that the vehicle speed limit value V _T is too low while stopped in an idle state by the congestion or the like, the vehicle 1 can be prevented from becoming impossible to get off the highway and the like.

Further, the vehicle control device of the present embodiment is configured to gradually increase the limit vehicle speed value V _T and gradually increase the fuel injection amount at the end of the retreat travel mode. Therefore, the shock to the vehicle 1 due to the sudden increase in the vehicle speed or the rapid increase in the fuel injection amount when the evacuation travel mode is ended can be effectively mitigated.

  In addition, the vehicle control device of the present embodiment is configured to switch the vehicle speed limit control to the torque limit control of the engine 10 when power extraction by the PTO 80 is executed during execution of the retreat travel mode. Therefore, the retreat travel mode can be continued even when the vehicle 1 is in a non-traveling state such as when the power is taken out by the PTO 80.

  The present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the spirit of the present invention.

  For example, the vehicle speed limiting FB control is not limited to the above-described PI control, and other control methods such as PID control may be used.

21 Vehicle speed sensor 50 ECU
51 Idle state detection unit 52 Failure detection unit 53 Retreat travel mode execution determination unit 54 Vehicle speed limit FB control unit 55 Limit vehicle speed setting unit 56 End-time transition control unit 57 Torque limit control switching unit 80 Power take-off mechanism

Claims (6)

A failure detection means for detecting a failure of each part of the vehicle;
Execution determination means for determining whether or not a retreat travel mode for limiting the travel speed of the vehicle is necessary based on a failure detected by the failure detection means;
Vehicle speed limiting means for executing vehicle speed limiting control for controlling the traveling speed of the vehicle to a predetermined limited vehicle speed when the execution determining means determines that the retreat driving mode is necessary;
Limiting vehicle speed reducing means for reducing the limiting vehicle speed according to the elapsed time of the vehicle speed limiting control;
Idle detecting means for detecting an idle state of the engine based on an operating state of an engine mounted on the vehicle ,
During the execution of the vehicle speed limiting control, when the idle detection unit detects an idle state, the elapsed time is stopped, and when the idle detection unit no longer detects the idle state, the elapsed time at the time when the idle detection unit stopped is detected. A vehicle control device in which timing is restarted from time . The vehicle control device according to claim 1, wherein the limit vehicle speed reduction means reduces the limit vehicle speed stepwise according to an elapsed time of the vehicle speed limit control. Wherein when said execution determination means during execution of the vehicle speed restriction control by the vehicle speed limiting means is determined to be unnecessary to save drive mode, according to claim 1 or 2 further comprising termination control means for performing a termination control for gradually increasing the speed limit The vehicle control device described in 1. The vehicle control device according to claim 3 , wherein the end control means gradually increases an engine fuel injection amount when executing the end control. A vehicle speed sensor for detecting an actual vehicle speed of the vehicle;
The vehicle speed limiting means when the vehicle speed limiting control, in any one of claims 1 from the deviation between the actual vehicle speed and the vehicle speed limit which is detected engine fuel injection amount by the vehicle speed sensor is set by the PI control 4 The vehicle control device described. The vehicle is provided with a power take-off mechanism for taking out the power of the engine,
When taken out of power by the power take off mechanism during execution of the vehicle speed limiting control is performed, any of claim 1, further comprising a switching means for switching the torque limiting control for limiting the output torque of the engine to a predetermined target torque of 5 The vehicle control device according to claim 1.

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