JP2016118240A - Travel control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel control device of a vehicle capable of improving fuel economy of a vehicle, safety of a driver and drivability.SOLUTION: A travel control device of a vehicle includes driving force control means (20) of the vehicle using a brake system; and inertial travel control means (20) of executing inertial travel in a case where a predetermined inertial travel start condition is established. The inertial travel control means, when operation of the driving force control means is continuously detected for a predetermined time (t) or more (S1), prohibits inertial travel (S4).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle travel control device.

  As an automatic transmission of a vehicle, a so-called AMT (Automated Manual Transmission) that automatically switches a transmission gear and connects / disconnects a clutch has been developed. AMT does not require a clutch operation by the driver, but has an advantage of less fuel transmission loss and improved fuel efficiency than an automatic transmission using a torque converter.

  In such an AMT, when the driver does not depress the accelerator pedal or the brake pedal, the engine friction is disconnected from the drive system by automatically disengaging the clutch or shifting the transmission gear to the neutral state. Inertia can be performed. Thereby, the load of driving | running | working can be reduced and the improvement in a fuel consumption can be aimed at by being able to avoid the re-acceleration for the speed reduction by engine brake and subsequent speed return.

  A technique is disclosed in which inertial running control is prohibited when it is recognized that the vehicle is traveling on a low μ road (low friction road) (see Patent Document 1).

JP 2002-30711 A

  In the technique of Patent Document 1, whether or not the road surface on which the vehicle is traveling is a low μ road is determined by detecting the difference in the rotational speed of the wheel based on the slip signal output from the control unit of the ABS (anti-lock brake system). Judging. Therefore, strictly speaking, the signal that the ABS is actually operated is not used as a trigger for detecting the low μ path. For this reason, it is determined that the vehicle is traveling on a gravel road or a mud road that is not a low μ road such as a frozen road, or is running on a low μ road even when the tire is idling, and the accuracy of detecting the low μ road may be significantly reduced. This prohibits inertial travel unnecessarily, resulting in a problem that vehicle drivability and fuel consumption deteriorate.

  Further, in Patent Document 1, if it is determined that the road is not a low μ road after traveling on a low μ road, the inertia travel prohibition is immediately released. However, since the low μ road is detected by an indirect signal called the slip signal of the ABS, the coasting prohibition is canceled in spite of actually traveling on the low μ road, and coasting may start. Not only can vehicle safety be ensured, it can also give the driver a sense of discomfort and fear.

  The present invention has been made to solve such a problem. The object of the present invention is to detect a low-μ road with high accuracy and reliably prohibit inertial running during low-μ road travel. An object of the present invention is to provide a travel control device for a vehicle that can improve all of the fuel efficiency, driver safety, and drivability.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

  (1) A travel control device for a vehicle according to this application example is a travel control device for a vehicle in which an engine that is a drive source of the vehicle is connected to an automatic transmission via a clutch, and Driving force control means and inertial traveling control for executing inertial traveling by setting at least one of the clutch disengaged state and the neutral state of the gear of the automatic transmission when a predetermined inertial traveling start condition is satisfied And the inertia running control means prohibits the inertia running when the operation of the driving force control means is continuously detected for a predetermined time or more.

  (2) In the vehicle travel control apparatus according to this application example, the brake system of the driving force control means is ABS or ASR.

  (3) A vehicle travel control apparatus according to this application example includes a low μ road start mode switch that enables low μ road start of the vehicle, and accelerator opening detection means that detects the opening of an accelerator pedal. The inertial travel control means further comprises the accelerator that the vehicle stops after the inertial travel prohibition, the low μ road start mode switch is off, and the accelerator opening detection means detects the accelerator. When the pedal opening is equal to or greater than a predetermined first threshold value and the inertia travel prohibition release condition that the vehicle has started is satisfied, the prohibition of inertia travel is canceled.

  (4) In the vehicle travel control device according to this application example, the inertia travel prohibition release condition further includes a condition that the engine is in a non-operating state, and the inertia travel control means includes the inertia travel prohibition When any of the release conditions is satisfied, the prohibition of the inertia traveling is canceled.

  (5) The vehicle travel control apparatus according to this application example further includes an inertial travel switch capable of switching on and off the inertial travel by the inertial travel control unit, and the inertial travel prohibition release condition includes the inertial travel prohibition release condition. A condition that the travel switch is operated from off to on is further included, and the inertial travel control means cancels the inertial travel prohibition when any of the inertial travel prohibition release conditions is satisfied.

  According to the present invention using the above-described means, it is possible to accurately detect low μ roads and reliably prohibit inertial running while traveling on low μ roads, so that all of the fuel consumption of the vehicle, driver safety and drivability can be achieved. Can be improved.

It is a schematic block diagram which shows the drive system of the vehicle provided with the traveling control apparatus of the vehicle in one Embodiment of this invention. It is a flowchart which shows the inertial traveling control routine which ECU of the traveling control apparatus of the vehicle in one Embodiment of this invention performs.

  Hereinafter, an embodiment of a vehicle travel control device embodying the present invention will be described.

  FIG. 1 is a schematic configuration diagram showing a drive system of a vehicle provided with a vehicle travel control device of the present embodiment, and the configuration of the present embodiment will be described below based on the same diagram.

  The vehicle 1 in this embodiment is a truck, and a diesel engine (hereinafter referred to as an engine) 2 is mounted as a traveling power source. An input shaft 4 a of an automatic transmission (hereinafter simply referred to as a transmission) 4 is connected to the output shaft 2 a of the engine 2 via a clutch device 3, and the rotation of the engine 2 is transmitted to the transmission 4 when the clutch device 3 is connected. It has come to be. The transmission 4 is based on, for example, a manual transmission having 12 forward speeds and 1 reverse speed. As described below, the speed change operation and the connection / disconnection operation of the clutch device 3 associated with the speed change are performed. This is an automated so-called AMT (Automated Manual Transmission).

  The clutch device 3 is configured as a friction clutch that is connected to the flywheel 5 by press-contacting the clutch plate 6 with a pressure spring 7 while being disconnected by separating the clutch plate 6 from the flywheel 5. An air cylinder 9 is connected to the clutch plate 6 via an outer lever 8, and an air tank 12 filled with compressed air is connected to the air cylinder 9 via an air passage 11 in which an electromagnetic valve 10 is interposed.

  When the solenoid valve 10 is opened, compressed air is supplied from the air tank 12 to the air cylinder 9 through the air passage 11, and the air cylinder 9 is operated to separate the clutch plate 6 from the flywheel 5 through the outer lever 8. Thus, the clutch device 3 is switched from the connected state to the disconnected state. On the other hand, when the solenoid valve 10 is closed, the air cylinder 9 stops operating due to the stop of the supply of compressed air, so that the clutch plate 6 is pressed against the flywheel 5 by the pressure spring 7, and the clutch device 3 is thereby released from the disconnected state. Switch to connected state. As described above, the air cylinder 9 is operated according to the opening and closing of the electromagnetic valve 10, and the clutch device 3 can be automatically connected and disconnected.

  The transmission 4 is provided with a gear shift unit 13 for switching the gear stage. Although not shown, the gear shift unit 13 includes a plurality of air cylinders that operate shift forks corresponding to the respective gear stages in the transmission 4, and It incorporates multiple solenoid valves that actuate the air cylinder. The gear shift unit 13 is connected to the above-described air tank 12 through an air passage 14, and compressed air from the air tank 12 is supplied to the corresponding air cylinder according to the opening and closing of each solenoid valve, and the air cylinder is operated. When the corresponding shift fork is switched, the gear position of the transmission 4 is shifted according to the switching operation. In this way, the air cylinder is operated in accordance with the opening / closing of the electromagnetic valve of the gear shift unit 13, and the transmission 4 can be automatically operated for shifting. In the present embodiment, the clutch device 3 and the transmission 4 are mainly operated by air, but the operation method is not limited to this, and for example, hydraulic pressure may be used.

  In the vehicle 1, an ECU (control unit) including an input / output device (not shown), a storage device (ROM, RAM, etc.) used for storing control programs and control maps, a central processing unit (CPU), a timer counter, etc. ) 20 is installed, and comprehensive control of the engine 2, the clutch device 3, and the transmission 4 is performed.

  On the input side of the ECU 20, for example, a lever position sensor 21 that detects the switching position of the shift lever 15 provided in the driver's seat, and an accelerator that detects the amount of operation of the accelerator pedal 16 (accelerator opening and accelerator opening change rate). A sensor 22, a brake switch 23 for detecting the operation of the brake pedal 17, a shift speed sensor 24 for detecting the current shift speed of the transmission 4, a gradient sensor 25 for detecting the gradient of the road surface on which the vehicle 1 is traveling, An engine speed sensor 26 that detects the engine speed from the rotational speed, a vehicle speed sensor 27 that is provided on the output shaft 4b of the transmission 4 and detects the vehicle speed from the output shaft speed, an acceleration sensor 28 that detects the acceleration of the vehicle 1, Sensors such as are connected.

  Further, the vehicle 1 is equipped with an ABS (anti-lock brake system) and an ASR (anti-spin regulator) that control the driving force of the vehicle 1 by a brake system.

  The ABS is a device that reduces the sliding of the vehicle 1 caused by the wheel lock in the operation of the brake pedal 17 on a sudden brake or on a low μ road. The ABS is also referred to as an anti-lock braking system. When the low-μ road is detected by the ECU 20, the brake pedal 17 is gradually depressed instead of depressing at once, and when the vehicle 1 starts to slide, the brake pedal 17 Repeat the operation of releasing the step a little and then pressing it again. That is, a brake operation called a so-called pumping brake is automatically performed by the ECU 20.

  The ASR uses a vehicle speed sensor 27 and a brake mechanism that can control each wheel independently. When the driving force of the vehicle 1 suddenly increases and the wheel spins, the brake is automatically operated to spin. This is an apparatus that automatically performs an operation to suppress the above-mentioned by the ECU 20. The ASR also automatically controls the output of the engine 2 to suppress wheel spin caused by excessive depression of the accelerator pedal 16. The ASR is formed by adding an engine control output mechanism and a mechanism for controlling the differential operation torque by the braking force to the ABS brake system, and is generally equipped in combination with the ABS.

  Further, the electromagnetic valve 10 of the clutch device 3 and the electromagnetic valves of the gear shift unit 13 are connected to the output side of the ECU 20, and the fuel injection valve of the engine 2 is connected, although not shown. . In addition, you may make it provide ECU for exclusive use of engine control separately from ECU20, for example, without controlling comprehensively by single ECU20 in this way.

  For example, the ECU 20 calculates the fuel injection amount to each cylinder of the engine 2 from a map (not shown) based on the engine speed detected by the engine speed sensor 26 and the accelerator opening detected by the accelerator sensor 22. The fuel injection timing is calculated from a map (not shown) based on the engine speed and the fuel injection amount. Based on these calculated values, the engine 2 is operated while controlling the fuel injection valve of each cylinder.

  The ECU 20 executes the automatic shift mode when the shift of the shift lever 15 to the D (drive) range is detected by the lever position sensor 21, and based on the accelerator opening and the vehicle speed detected by the vehicle speed sensor 27, A target shift speed is calculated from a shift map described later. Then, while opening / closing the electromagnetic valve 10 of the clutch device 3 and connecting / disconnecting the clutch device 3 by the air cylinder 9, the predetermined electromagnetic valve of the gear shift unit 13 is opened / closed and the corresponding shift fork is switched by the air cylinder. Thus, the vehicle shifts to the target shift stage, and the vehicle is always driven with an appropriate shift stage.

  The shift position that can be selected by the shift lever 15 includes a P (parking) range selected during parking, a N (neutral) range in which the gear of the transmission 4 is neutral, a D (drive) range selected during forward travel, There are an R (reverse) range that is selected during reverse travel, an M (manual) range that allows manual shift-up or shift-down.

  Further, the vehicle 1 includes an inertial travel switch 29 that turns on and off inertial travel, which will be described later, an auxiliary brake switch 30 that turns on and off an auxiliary brake that generates a braking force other than braking according to the operation of the brake pedal 17, Also provided is a low μ road start mode switch 31 that enables the vehicle 1 to start on a low μ road. Examples of the auxiliary brake include an exhaust brake, a compression release brake of the engine 2, and a retarder.

  Further, the ECU 20 executes inertial traveling by setting the gear of the transmission 4 in the neutral state and the clutch device 3 in the connected state when various conditions described below are satisfied during vehicle traveling (inertial traveling). Control means).

  Here, referring to FIG. 2, there is shown a flowchart representing an inertial traveling control routine executed by the ECU 20, and the inertial traveling control will be described in detail along the same flowchart.

  First, as step S1, the ECU 20 determines whether the ABS or ASR has been operated continuously for a predetermined time t or longer. The time t is set to a time (for example, 1 sec) in which it is possible to discriminate that the ABS or ASR has been reliably operated by eliminating the malfunction of the ABS or ASR. If the determination result is true (Yes), the process proceeds to step S2. On the other hand, if the determination result is false (No), the routine is returned.

  In step S2, the ECU 20 determines whether or not inertial running is being performed. If the determination result is true (Yes), the process proceeds to step S3, where inertial running is terminated, and the process proceeds to step S4. If the determination result is false (No), the process directly proceeds to step S4.

In step S4, the ECU 20 prohibits coasting and proceeds to the next step S5. When the inertia traveling is prohibited, the inertia traveling is not executed even if the inertia traveling switch 29 is turned on by the driver, for example.
In step S5, the ECU 20 determines that the vehicle 1 is stopped, the low μ road start mode switch 31 is OFF, and the accelerator opening is greater than or equal to a predetermined first threshold value P1, based on information from the accelerator sensor 22, that is, P1 ≦ accelerator. It is determined whether or not a relational expression of the opening degree is established. The state satisfying P1 ≦ accelerator opening assumes a case where the driver clearly depresses the accelerator pedal 16.

  Specifically, at the accelerator opening P1, it is estimated that the driver's willingness to start the vehicle 1 stopped by depressing the accelerator pedal 16 and immediately start inertial driving when the vehicle speed stabilizes. A value of the opening (for example, 60%) is set. When the determination result is false (No), the vehicle 1 is traveling, the low μ road start mode switch 31 is on, or the accelerator opening is less than 60%, Since it is assumed that the driver is performing a careful accelerator operation and the vehicle 1 is traveling on a low μ road, the process proceeds to step S6 to continue prohibition of inertial traveling. Step 5 to the subsequent step S7 correspond to inertial travel prohibition release conditions.

  In step S6, the ECU 20 determines whether or not the vehicle 1 is in a key-off state and the engine 2 is stopped. If the determination result is false (No), that is, if the engine 2 is operating, the process proceeds to step S7.

  In step S7, the ECU 20 determines whether the inertial travel switch 29 has been operated from the off state to the on state. If the determination result is false (No), that is, if the inertial travel switch 29 remains off, it can be estimated that the driver does not intend to perform inertial travel, so step S5 is determined again. If the inertial travel switch 29 remains on, it can be estimated that the driver has no strong intention to perform inertial travel, so step S5 is determined again.

  On the other hand, when any of the inertia running prohibition release conditions of steps S5 to S7 is satisfied, that is, when at least one determination result of steps S5 to S7 is true (Yes), the process proceeds to step S8, and the ECU 20 Cancel the travel prohibition and return to this routine.

  In step S5, after the vehicle stops, the low μ road start mode switch 31 is turned off and the condition that the amount of operation of the accelerator pedal 16 is large is established. Since there is a strong will, the prohibition on coasting is lifted. In step S <b> 7, the end of the low μ road and the driver's intention to execute inertial traveling are discriminated from the operation of the inertial traveling switch 29.

  Further, step S6 means that if the engine 2 is stopped, the driver carefully starts the vehicle 1 even if the vehicle is parked on a low μ road, so that the inertial running prohibition state is temporarily reset. Is provided. Basically, when the vehicle 1 is keyed off, the drivability of the driver is improved by resetting various controls including inertial running control. For this reason, when the key-off determination result is obtained in step S6, the inertia running prohibition is forcibly canceled.

  Further, as described above, when the inertia traveling switch 29 remains on in step S7, it can be estimated that the driver does not have a strong intention to perform inertia traveling, so step S7 is determined again. However, if the inertial travel switch 29 is turned on after being turned off once, it can be estimated that the driver has a strong intention to perform inertial travel, so the process proceeds to step S8 and the inertial travel prohibition is canceled.

  As described above, the fuel consumption of the vehicle 1, the driver's safety, and the drivability can all be improved by accurately detecting the low-μ road and reliably prohibiting the inertial traveling during the low-μ road traveling. it can.

  Specifically, since it is assumed that the driving of the driving force control such as ASR and ABS by the brake system is not necessarily completed, the driving of the driving force control is terminated. However, it should be noted that driving on a low μ road may continue for a while. Therefore, for example, on a low μ road, the driver generally starts the vehicle 1 slowly. When the accelerator pedal 16 is fully depressed with a depression amount of 60% or more, the vehicle 1 starts. The road is assumed to be finished. Therefore, it is preferable that the determination in step S5 is performed, and if the determination result is false (No), it is determined that the vehicle 1 has not escaped from the low μ road and the inertial travel prohibition is continued.

  Thus, in the inertial running control of the present invention, inertial running is prohibited when a low μ road is detected based on whether or not the driving force control such as ASR and ABS by the brake system operates reliably without malfunction, and thereafter Inertia travel is prohibited until the driver's driving operation, that is, low μ road start mode operation, accelerator operation, key operation, and inertial travel switch operation, is estimated to be appropriate. In this way, coasting on low-μ roads is prohibited, and by prohibiting coasting based on the appropriate driving operation of the driver, coasting is not inadvertently prohibited, but coasting is possible. In this case, the fuel efficiency of the vehicle 1 can be improved while respecting the driver's intention as much as possible and ensuring safety without impairing the convenience of the driver.

  Although the description of the embodiment of the vehicle travel control device according to the present invention has been completed above, the embodiment is not limited to the above embodiment.

  In the said embodiment, although the vehicle 1 is made into the track, the vehicle which can apply this invention is not restricted to this, It can apply also to a passenger car.

  Moreover, in the said embodiment, although the engine 2 is a diesel engine, an engine is not restricted to this, For example, a gasoline engine may be sufficient. Further, in the above-described embodiment, the transmission has a shift speed of 12 forward speeds and 1 reverse speed, but the configuration of the transmission is not limited to this, and for example, a transmission such as 6 forward speeds or 16 forward speeds. It may be.

  In the above embodiment, the inertial running is performed by setting the gear of the transmission 4 in the neutral state and the clutch device 3 in the connected state. However, the inertial traveling may be performed by disconnecting the engine from the drive system. It is not limited to. For example, the inertial running may be performed only by setting the clutch device to the disconnected state or setting the clutch device 3 to the disconnected state and setting the gear of the transmission to the neutral state.

  In addition, the inertia running start condition and the inertia running end condition of the above embodiment are not limited to the above-described determination of each step and the determination order, and various changes can be made according to the vehicle 1.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Clutch apparatus 4 Transmission 16 Accelerator pedal 20 ECU (Inertial traveling control means, Driving force control means)
22 Accelerator sensor (accelerator opening detection means)
29 Inertia travel switch 31 Low μ road start mode switch

Claims (5)

A vehicle travel control device in which an engine that is a vehicle drive source is connected to an automatic transmission via a clutch,
A driving force control means for the vehicle by a brake system;
An inertial traveling control means for performing inertial traveling by setting at least one of the disengaged state of the clutch and the neutral state of the gear of the automatic transmission when a predetermined inertial traveling start condition is satisfied;
The inertial running control means prohibits the inertial running when detecting the operation of the driving force control means for a predetermined time or longer.   The vehicle travel control apparatus according to claim 1, wherein the brake system of the driving force control means is ABS or ASR. A low μ road start mode switch that enables low μ road start of the vehicle;
An accelerator opening detecting means for detecting the opening of the accelerator pedal;
The inertial travel control means is configured to stop the vehicle after the inertial travel prohibition, and then turn off the low μ road start mode switch and detect the accelerator pedal opening detected by the accelerator opening detection means. 3. The vehicle travel control device according to claim 2, wherein when the inertial travel prohibition release condition that the vehicle has started is satisfied when the value becomes equal to or greater than a predetermined first threshold value, the inertial travel prohibition is canceled.   The inertia travel prohibition cancel condition further includes a condition that the engine is in a non-operating state, and the inertia travel control means prohibits the inertia travel prohibition when any of the inertia travel prohibition cancel conditions is satisfied. The vehicle travel control device according to claim 2, wherein the vehicle travel control device is canceled. An inertial travel switch capable of switching on and off the inertial travel by the inertial travel control means;
The inertial travel prohibition release condition further includes a condition that the inertial travel switch is operated from off to on, and the inertial travel control means, when any of the inertial travel prohibition release conditions is satisfied, The travel control device for a vehicle according to any one of claims 2 to 4, wherein the prohibition of inertial travel is canceled.

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