JPH072993Y2 - Vehicle running control device - Google Patents

Description

[Detailed description of the device]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel control device, and more particularly, to a device that appropriately controls driving force so that the vehicle does not slip when starting or accelerating on a slippery road surface. (Prior art) With the recent development of microcomputer application technology,
Also in vehicles, control of transmission (gear ratio), control of traveling speed, skid control (control for skidding)
Various attempts have been made to control the vehicle such as vehicle height control to maintain the desired running condition of the vehicle (hereinafter simply referred to as running control), and there is a tendency to achieve higher levels of safety and comfort. is there. The so-called traction control, which is the control that maximizes the torque transmitted from the drive wheels to the road surface, is also one of such traveling controls. In order to realize traction control, the drive wheels have over-rotated (wheel spin). Sometimes it is necessary to control the generated torque promptly. As a conventional device for performing this type of travel control, for example,
There is one described in JP-A-62-150034. In this device, a throttle valve for traction control is provided in addition to a normal throttle valve, and the throttle valve for traction control is opened / closed to control the intake air amount and reduce the engine output. As a result, the driving force of the vehicle is reduced, and, for example, the startability at the time of freezing of the road surface is secured, and the problem that the tire slips due to the drive shaft torque exceeding the frictional force of the road surface and the vehicle slips in the vertical and horizontal directions is prevented. It (Problems to be solved by the invention) However, in the conventional traction control technology, the wheel spin (that is, slip) of the drive wheels is detected, and the throttle valve for traction control is operated to the closing side to output the engine output. This is a series of operations (→) to narrow down the drive wheels to avoid slipping on the drive wheels.
Since it is a conventional symptomatic control, an expensive control system having extremely high responsiveness is required, which causes a problem of cost increase. (Object of the Invention) Therefore, an object of the present invention is to realize a preventive therapeutic slip prevention technique capable of preventing the occurrence of drive slip with a simple configuration. (Means for Solving the Problems) In order to achieve the above-mentioned object, the vehicle travel control device according to the present invention has an accelerator pedal a, an engine intake passage b, and A first throttle valve c that opens and closes the intake passage b at an opening degree according to the depression amount of the accelerator pedal a, and is located in the intake passage b upstream or downstream of the first throttle valve c. While normally in the open state, when the closing operation is instructed by a predetermined control signal, the second throttle valve d for operating the opening area of the intake passage b to the closing side at the opening indicated by the control signal. And a slip detecting means e for detecting the occurrence of the drive wheel slip and measuring the slip amount, a frequency measuring means f for measuring the detection frequency of the drive wheel slip, and a time when the drive wheel slip is detected. The second throttle valve d according to the slip amount And a first calculation means g for calculating the opening value of the driving gear and outputting the opening value as the predetermined control signal, and the transmission gear position at that time when the detection frequency of the drive wheel slip exceeds the set frequency. Becomes a lower gear position, and the degree of depression of the accelerator pedal a at that time becomes lower, the opening value of the second throttle valve d is calculated, and the opening value is calculated by the predetermined control signal. And a second computing means h for setting the output period of the control signal to be longer as the excess amount of the detection frequency of the drive wheel slip from the set frequency is larger. is there. (Effect) In the present invention, not only when the drive wheel slip occurs, but also when the drive wheel slip does not occur, if the frequency of the drive wheel slip before that time is higher than the set frequency, then The opening amount of the second throttle valve is controlled according to the gear position of the vehicle and the degree of depression of the accelerator. Specifically, the opening amount of the second throttle valve is set to a lower gear position and to a lower depression side. Because it is controlled in the direction of becoming smaller,
After all, as long as the drive wheel slip occurrence frequency exceeds the set frequency, the opening area of the intake passage is operated to the closing side by the second throttle valve. Therefore, even if the drive wheel slip does not occur, the output of the engine is narrowed down in advance while traveling on the road surface where the drive wheel slip is likely to occur (that is, the low μ road), so that the drive wheel slip occurs. A preventive therapeutic anti-slip technology that prevents the occurrence of slipping is realized. Moreover, since it is possible to simply measure the occurrence frequency of the drive wheel slip and compare it with the set frequency, for example, an expensive sensor such as an ultrasonic sensor, a raindrop sensor, an outside air temperature sensor or a wiper switch is used. The cost can be significantly reduced as compared with the one in which the friction coefficient is indirectly detected (for example, the technique described in JP-A-63-16141). (Example) Hereinafter, the present invention will be described with reference to the drawings. 2 to 7 are views showing an embodiment of the present invention, in which the present invention is applied to a vehicle equipped with a tandem throttle valve type traction control system. First, the configuration will be described. In FIG. 2, 1 is an engine, and intake air is an intake passage 2 and a throttle chamber 3.
Is supplied to each cylinder through the fuel, and the fuel is injected by the injector 4 based on the injection signal Si. Then, the air-fuel mixture in the cylinder is ignited and exploded by the discharge action of a spark plug (not shown), becomes exhaust gas, and is discharged to the outside through an exhaust pipe. Here, the flow of intake air is controlled by a throttle valve (first throttle valve) 11 in the throttle chamber 3 which is interlocked with the accelerator pedal 10, and the throttle valve 11 is almost closed during idling. A throttle valve (second throttle valve) 12 is arranged in the intake passage 2 upstream of the throttle valve 11, and the opening degree of the TCS throttle valve 12 is DC for TCS connected via a rod 13. It is controlled by the motor 14. The TCS throttle valve 12 is normally in a fully open state, and a current is supplied from the motor control unit 15 for driving the TCS DC motor 14 to the TCS DC motor 14 by a control signal from a TCS control unit 43 described later. Then, the TCS DC motor 14 rotates a predetermined angle, and in conjunction with this, the TCS throttle valve 12 is closed. The power supply V _B is supplied to the motor control unit 15 from a battery (not shown) via the fuse 16 and the relay 17, and the motor control unit 15 is grounded. When the ignition switch (not shown) is turned on, the coil of the relay 17 is supplied with the ignition power supply V _IGN to the coil of the relay 17 and a current flows, the internal contact opens and becomes an insulating state, and from the battery to the motor control unit 15. Cut off the current supply of.
The rod 13, the TCS throttle valve 14, the motor control unit 15, the fuse 16 and the relay 17 constitute a drive means 18 as a whole. The flow rate Qa of the intake air is detected by the air flow meter 20, and the opening TVO ₁ of the throttle valve 11 is detected by the throttle opening sensor 21. The opening TVO ₂ of the TCS throttle valve 12 is detected by the TCS throttle opening sensor 22, and this opening TVO ₂ signal is once input to the motor control unit 15 and passed through the internal buffer 15a, which will be described later. It is output to the control unit 41. Also, engine 1
The crank angle Ca of is detected by the crank angle sensor 23,
By counting pulses representing the crank angle Ca with the control unit 41, the engine speed N can be known. The vehicle speed VSP is detected by the vehicle speed sensor 24,
The temperature T _{W of the} cooling water flowing through the water jacket is detected by the water temperature sensor 25. Further, the idle state (parking or neutral state) of the vehicle speed is detected by the neutral switch 26, and the rotational speed of the wheels (wheel speed) is detected by the wheel speed sensors 31, 32, 33, 34 provided on the front, rear, left and right wheels. . Here, the wheel speed sensor 31 is the front wheel right wheel speed, the wheel speed sensor 32 is the front wheel left wheel speed, the wheel speed sensor 33 is the rear wheel right wheel wheel, and the wheel speed sensor 34 is the rear wheel left wheel speed. Respectively detected. In the case of FR vehicles, the front wheels are non-driving wheels and the rear wheels are driving wheels, and the actual vehicle speed (body speed) is calculated from the wheel speed V _{F of the} front wheels (non-driving wheels).
From V _F and V _R , the slip state of the drive wheels is detected by a TCS control unit 43 described later based on the difference or ratio between the two. Further, the depression of the brake pedal 35 is detected by the brake switch 36, and the traction control is turned ON / OFF.
Is manually selected by the driver using the traction ON / OFF switch 37. The air flow meter 20 and the crank angle sensor 23 constitute an operating state detecting means 38, and an operating state detecting means 38, a throttle opening sensor 21, a TCS throttle opening sensor 22,
Signals from the vehicle speed sensor 24, the water temperature sensor 25 and the neutral switch 26 are input to the control unit 41,
The control unit 41 controls traveling of the vehicle and combustion of the engine based on the sensor information. The control unit 41 has a function as a frequency measuring means, a first calculating means and a second calculating means, and is constituted by a man-computer etc. The control unit 41 receives signals from the above-mentioned sensors 20, 21, 22, 23, 24, 25 and 26 and a TCS operating signal from a TCS control unit 43 which will be described later.
The opening signal TVO ₁ from the 41 to the motor control unit 15 is A /
An opening signal TVO ₁ and a vehicle speed signal VSP are output to the T control unit 42, an engine speed signal N is output to the TCS control unit 43, and an injection signal Si is output to the injector 4. The injector 4 is the injection signal
The valve is opened based on Si, and combustion is injected into the engine 1. On the other hand, signals from the throttle valve opening sensor 21 and the vehicle speed sensor 24 are input to the A / T control unit 42 via the control unit 41, and the A / T control unit 42 displays the vehicle speed VSP and the accelerator opening TVO _{1 and the} like. The shift solenoid A44 and the shift solenoid B45 inside the automatic transmission are turned ON / OFF based on the input signal to control to the optimum gear position. On the other hand, the signals from the neutral switch 26, the wheel speed sensors 31, 32, 33, 34, the brake switch 36 and the traction ON / OFF switch 37 are input to the TCS control unit 43, and the TCS control unit 43 is based on these sensor information. Traction control to reduce the output torque of the engine to control the slip of the driving wheels and brake control to reduce the driving force of the tire to prevent the slip. The TCS control unit 43 has a function as a slip detecting means and is configured by a microcomputer or the like. The TCS control unit 43 includes signals from the above sensors 26, 31, 32, 33, 34, 35, 37, an actual opening signal of the throttle valve 11 from the motor control unit 15, an engine speed from the control unit 41, and The shift solenoid drive signal from the A / T control unit 42 is input, and the control unit
From 43, a limit signal for operating the opening TVO ₂ of the TCS throttle valve 12 is sent to the motor control unit 15, and a TCS operating signal is sent to the control unit 41 to inform the operating state of the traction control. A brake control signal is output to each. The brake hydraulic actuator 46 is the TCS control unit 43
Brake control signals from the front, rear, left, and right wheels are controlled by the brake control signal from (to increase or decrease the brake fluid pressure). Reference numeral 47 is a TCS operating lamp that indicates the operating state of the traction control of the TCS control unit 43 by the current supply from the ignition power source V _IGN , and 48 is a TCS fail lamp that indicates an abnormality in the traction control or the traction control is OFF. . Next, the operation will be described. First, the traction control system will be described. In particular, it is known to perform traction control to ensure vehicle stability and maneuverability during acceleration on low μ roads (see SAE870337). The basic operation of the traction control system adopted in the present invention is engine torque control brake control, and its outline will be described below. Engine torque control The purpose is to automatically reduce the engine torque according to the condition of the road surface. Road surface condition detection is performed by detecting the slip condition of the drive wheels from the signals of the wheel speed sensors 31, 32, 33, 34 attached to the front and rear wheels, and the reduction of engine torque to the accelerator pedal. This is done by closing the TCS throttle valve 12 that is independent of the linked throttle valve 11. The operation of each throttle valve will be described with reference to FIG. In the figure, the non-driving wheel average speed on the horizontal axis means the actual vehicle speed of the vehicle, and the difference between the driving wheel speed and the non-driving wheel average speed on the vertical axis shows the slip amount that represents the slip state of the driving wheels. In this control, the TCS control unit 4 based on the actual vehicle speed and slip amount
At 3, the target position of the throttle valve 12 for TCS is determined. That is, the TCS throttle valve 12 is fully opened in the region where the drive wheel slip amount is small (indicated by the normal throttle valve moving region in FIG. 3), and the TCS throttle valve 12 is opened in the TCS throttle valve 12 opening holding region. Holds the current opening of 12. For example, when the TCS throttle valve 12 is once opened, the previous opening degree TVO ₂ of the TCS throttle valve 12 is held when the region is entered again in the next process. In the TCS throttle valve 12 closed region, the target opening of the TCS throttle valve 12 is controlled in the closing direction. In addition, the motor control unit 15 has a throttle valve 12 for TCS.
The TCS DC motor 14 linked with the TCS throttle valve 12 is feedback-controlled so that the opening TVO ₂ becomes the target opening. When the target opening is not fully opened, a slip control operating signal (TCS operating signal) is generated to notify the control unit 41 of whether slip control is operating. As described above, the system in which the throttle valve is operated to control the engine torque is an excellent system particularly in that the engine torque can be smoothly and sufficiently reduced with good responsiveness. Brake control Used to reduce tire driving force and prevent slip. In particular, on a road surface of μ in which the left and right driving wheels are different, the control of each of the left and right wheels becomes possible by using this system. FIG. 4 is a diagram showing brake pressure operation in this system. In the figure, the vertical axis represents the slip amount of the left and right driving wheels due to the difference between the left driving wheel speed (or the right driving wheel speed) and the non-driving wheel average speed. Based on this, by making the brake pressure variable for each region shown in the figure, slip suppression control is performed for each of the left and right drive wheels. When the slip amount is the same, the brake control is prioritized over the engine torque control described above. FIG. 5 is a flow chart showing a program for running control of the vehicle, and this program has a predetermined time (for example, 2 ms).
It is executed once every time. First, at P ₁ , wheel speed sensors 31, 32,
The slip of the drive wheels is detected based on the outputs from 33 and 34, and when the drive wheels are slipping, the traction control described above is performed in P ₂ . That is, when the drive wheel slips, a brake control signal is output from the TCS control unit 43 to the brake hydraulic actuator 46 according to the slip amount, and the motor control unit
The limit signal is output to 15. And by the limit signal
The TCS throttle valve 12 opens and closes, the torque is controlled, slip is prevented, and an appropriate driving force is transmitted to the road surface. When the drive wheels are not slipping (hereinafter referred TCS frequency) the frequency of occurrence of TCS during operation signal P ₃ is determined whether a set frequency or more. Here, the TCS frequency increases as the slip amount of the drive wheels increases as shown in FIG. 3, so the TCS frequency indirectly indicates the degree of occurrence of the drive wheel slip. Therefore, the process of P ₃ is
This corresponds to determining whether or not the detection frequency of the drive wheel slip exceeds the set frequency. The present flow a predetermined time, for example, 2ms has been performed for each, because the continuously 2ms every even appear to slip is not being or may not slip, in Step P ₁ The determination of non-slip is that the moment is not slipping. FIG. 6 is a diagram for explaining the determination method of the TCs frequency, and the counter shown in FIG. 6C starts counting in synchronization with the rising or falling of the pulse every 100 ms shown in FIG. However, as shown in (B) of the figure, when the TCS operating signal is input, the count value of the counter is incremented by [+10], and when the TCS operating signal is not input, the count value is increased. [-1] Count down. (However, the lower limit of the counter is

[0]). Therefore, this counter has a positive value (0 or more) when the TCS operating state is 1/10 or more of the non-operating state, and normally the counter is

It is [0]. When the integrated value of the counter is, for example, 50 or more, it is determined that the TCS frequency is high. Returning again to the program shown in FIG. 5, when it is determined that the TCS frequency is high in P ₃ , the road surface is considered to be a low μ road and P ₄
Detects the opening TVO ₁ of the throttle valve 11 with and the gear position with P ₅ . Next, at P ₆ , the TCS throttle valve 12 is controlled based on the opening TVO ₁ and the gear position so that the opening TVO ₂ of the TCS throttle valve 12 becomes the control target value of the opening characteristic shown in FIG. 7. Then, this processing ends. on the other hand,
When it is determined that the TCS frequency is low, the road surface is considered not to be a low μ road, and the processing is ended. In this way, by discriminating the magnitude of the TCS frequency, it is judged whether or not the road is a low μ road, and when the road corresponds to the low μ road, the opening area of the throttle valve 11 suddenly changes even if the accelerator is operated suddenly. It is possible to provide the TCS throttle valve 12 with such a slow opening characteristic. Therefore, when driving on a road surface equivalent to a low μ road, the engine output can be narrowed down without exception as long as the TCS frequency is higher than the set frequency even if the drive wheel slip does not occur. Therefore, it is possible to realize a prophylactic therapeutic slip suppression technique that can prevent the occurrence of drive wheel slips without requiring major repairs. In addition,
Compared to the symptomatic anti-slip technology of slip-prevention, slip-preventive technology like this
Since the number of slips of the driving wheel itself is reduced, the number of times of executing brake control in, for example, traction control can be reduced, and reduction of brake pads can be prevented and drivability can be improved. Further, in this embodiment, as shown in FIG. 7, the air inflow characteristic with respect to the accelerator pedal depression amount is made dull toward the lower depression side or the lower gear side of the accelerator, so that the driver is less likely to feel an unnatural acceleration. It is possible to make the throttle characteristic very easy to control without giving. In addition, although the present embodiment shows an example in which the present invention is applied to a vehicle equipped with an automatic transmission, the present invention is not limited to this, and is also applicable to a vehicle equipped with a manual transmission (M / T). Needless to say. (Effect) According to the present invention, when a drive wheel slip occurs, or
When the drive wheel slip does not occur and the drive wheel slip occurrence frequency exceeds the set frequency, the opening area of the intake passage is closed by the second throttle valve to narrow the intake air of the engine. Therefore, not only immediately after the drive wheel slip occurs, but even when the drive wheel slip does not occur, the engine output during traveling on the road surface where the drive wheel slip easily occurs (that is, low μ road) Therefore, it is possible to realize a preventive therapeutic slip prevention technique that can reduce the occurrence of drive wheel slip. In addition, since it is possible to simply measure the occurrence frequency of the drive wheel slip and compare it with the set frequency, for example, an expensive sensor such as an ultrasonic sensor, a raindrop sensor, an outside air temperature sensor or a wiper switch is used. Compared with the method of detecting the friction coefficient of the road surface as an indirect drop, the cost can be reduced significantly.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of the present invention, FIGS. 2 to 7 are diagrams showing an embodiment of the present invention, FIG. 2 is an overall configuration diagram thereof, and FIG.
FIG. 4 is a diagram showing the operation of each throttle valve, FIG. 4 is a diagram showing the operation of the brake pressure thereof, FIG. 5 is a flow chart showing a program of traveling control of the vehicle, and FIG. 6 is for explaining its action. FIG. 7 is a timing chart showing the control target value of the TCS throttle valve opening. 1 ... Engine, 2 ... Intake passage, 11 ... Throttle valve (first throttle valve), 12 ... TCS throttle valve (second throttle valve), 41 ... Control unit (frequency measuring means, first 1 calculation means, 2nd calculation means), 43 ... TC
S control unit (slip detection means).

Claims (1)

[Scope of utility model registration request] 1. A) an accelerator pedal, b) an engine intake passage, c) a first throttle valve that opens and closes the intake passage at an opening degree according to a depression amount of the accelerator pedal, and d) the above. When it is located in the intake passage on the upstream side or the downstream side of the first throttle valve and is normally in the open state, when the closing operation is instructed by a predetermined control signal, the opening degree indicated by the control signal Second operation of operating the opening area of the intake passage to the closing side by
The throttle valve, e) slip detection means for detecting the occurrence of the drive wheel slip and measuring the slip amount, f) frequency measurement means for measuring the detection frequency of the drive wheel slip, and g) the drive wheel slip. When detected, a first calculation means for calculating the opening value of the second throttle valve according to the slip amount at that time, and outputting the opening value as the predetermined control signal, h) driving wheel When the slip detection frequency exceeds the set frequency, the transmission gear position at that time becomes a lower speed gear position, and the accelerator pedal depression at that time becomes smaller as the depression side becomes a lower depression side. An opening value is calculated, the opening value is output as the predetermined control signal, and the output period of the control signal is set longer as the excess amount from the set frequency of the detection frequency of the driving wheel lip is larger. 2 operations A travel control device for a vehicle, comprising: