JP3589689B2 - Vehicle control device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a vehicle control device that controls a running state of an automobile, and more particularly, to a control device that performs effective running control when an abnormality such as a failure or malfunction occurs in an airbag system.
[0002]
[Prior art]
The operation of the clutch pedal, the change lever, and the accelerator pedal at the time of shifting operation when traveling by car, particularly in long-distance traveling or traveling in a congested area such as an urban area, is troublesome and may cause the driver to get tired. The automatic transmission eliminates these shifting operations. Electronically controlled transmissions (hereinafter abbreviated as ECT) that control the transmission by a computer based on information such as vehicle speed and throttle opening even under normal driving conditions have been developed and spread, and fuel efficiency, ride comfort, drivability, etc. have been improved. .
[0003]
Also, if a sudden brake is applied on a slippery road surface such as a wet road surface or a frozen road surface, the tires are likely to lock. Generally, when a tire is locked, if it is the front wheel, steering operation becomes impossible. If the rear wheels are used, the vehicle becomes unstable, and problems such as an unstable state with respect to a lateral force are likely to occur. In order to solve these problems, an anti-lock brake system (hereinafter abbreviated as ABS) for controlling a braking force in accordance with a slip state of a wheel (tire) has been developed and spread. Vehicles equipped with ABS increase or decrease the brake oil pressure so that the wheels do not lock even if the sudden braking is applied on the road surface as described above, maintain the slip ratio between the tire and the road surface at a desired value, and stably In addition, electronic control by a computer for stopping the vehicle quickly is performed.
[0004]
If an abnormality such as a failure or malfunction occurs in the ABS, it can be detected quickly. When an abnormality is detected, the warning lamp is turned on, and the control function inherent in the ABS is released to ensure safety, and the normal brake function is restored.
In addition, seatbelts must be worn to minimize the impact on the human body in the event of an emergency involving a driver or other occupants, such as in the event of a car crash. Recently, airbag systems have been widely used for protecting human lives. The airbag serves as an auxiliary restraint device for a seat belt, and inflates an airbag incorporated in a steering wheel or the like at the time of a vehicle collision to reduce the impact at the time of the collision. The airbag system has a failure diagnosis function of detecting disconnection or short circuit of a circuit or a signal line, and if an abnormality occurs in the system, the abnormality can be quickly detected. When an abnormality is detected, an airbag warning lamp is turned on to notify the driver. However, when an accident such as a collision occurs in such a state, the airbag does not operate and the effect cannot be exhibited in spite of an emergency.
[0005]
As described above, the ABS and the airbag system both function independently, exhibiting excellent functions during normal times and contributing to safe driving. Further, when an abnormality occurs in the system, a lamp is turned on to notify the driver and call attention. However, after the occurrence of the abnormality, the mode is changed to the fail-safe mode, and the automatic control by the computer is released, so that the burden on the driver increases. Therefore, it is considered that by making the ABS and the airbag system cooperate well with the ECT, it is possible to operate the ECT function more effectively even when an abnormality occurs.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a vehicle control device in which ECT complements the function of an airbag system and performs more stable and safe driving control even if an abnormality occurs in the airbag system when the vehicle runs. With the goal.
[0007]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention achieves the above-described object, and detects an abnormality in an airbag system that controls inflation of an airbag at the time of a vehicle collision, and controls a transmission ratio of a transmission according to a vehicle speed and a throttle opening. An abnormal signal is transmitted to the system, and upon receiving the abnormal signal, the transmission system changes a control characteristic of a gear ratio so as to increase engine braking. Further, the transmission system changes the control characteristic of the speed ratio so as to increase the engine brake when receiving the abnormal signal and determining that the vehicle is in a rapid deceleration state.
[0008]
[Action]
According to the present invention, when an abnormality occurs in the airbag system, an abnormality signal is transmitted to the ECT computer. When the ECT computer receives the abnormality signal, the ECT computer changes the control characteristics of the gear ratio so that the engine brake is strengthened. Therefore, the engine brake becomes stronger than usual.
[0010]
【Example】
An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention, FIG. 2 is a flowchart showing processing executed by the ECT computer 14, and FIG. 5 is a shift diagram showing control characteristics of the ECT.
[0011]
Reference numeral 14 denotes an ECT, which controls a transmission ratio change of the transmission 19 and a lock-up clutch operation (clutch disengagement operation) by a microcomputer, and generally includes various types such as a throttle opening sensor, a vehicle speed sensor, and a shift position sensor. It comprises a sensor 16, an actuator (a valve of a hydraulic system or the like) 17, and an ECT computer 15 which processes signals from the various sensors 16 and controls the actuator 17.
[0012]
Reference numeral 10 denotes an ABS, which is a device for preventing the wheels from being locked even when a sudden brake is applied when traveling on a slippery road surface, and generally controls a rotation speed sensor 12 for detecting the rotation speed of the wheels and a braking force. For this purpose, a hydraulic actuator (such as a valve of a hydraulic system) 13 for adjusting the brake hydraulic pressure and an ABS computer 11 for processing signals from the rotational speed sensor 12 and controlling the hydraulic actuator 13 are provided.
[0013]
The ABS 10 detects the rotation state of each wheel by the wheel rotation speed sensor 12 and electronically controls the brake oil pressure according to the difference in wheel speed, that is, the degree of slippage of the wheel. In general, the control system of the wheels is a three-system control in which the front wheels are independently controlled left and right and the rear wheels are simultaneously controlled left and right.
The ABS 10 monitors and controls the entire system with the ABS computer 11, and when an abnormality is detected, prohibits the operation of the hydraulic actuator 13 and returns to a normal brake function, and turns on a warning lamp. The driver is informed that the ABS does not operate.
[0014]
The abnormality of the ABS 10 is monitored by monitoring the hydraulic actuator 13 (the hydraulic pressure of the hydraulic system and the drive current to the valve), and the ABS computer 11 is set up with a program so as to output a pulse of a constant cycle during normal operation. This pulse can be detected by a method such as a so-called watchdog timer that monitors the pulse.
Reference numeral 18 denotes a communication cable for transmitting information from the ABS computer 11 to the ECT computer 15. When the ABS 10 is normal, the ABS computer 11 outputs a high-level signal (for example, 5 volts) to the ECT computer 15. , Is programmed to output a low level signal (0 volt) when an abnormality occurs.
[0015]
Next, processing executed by the ECT computer 15 will be described with reference to FIG.
This process is started from the point when the engine is turned on by the ignition key, and is repeated as needed thereafter.
In step S21, it is determined from the signal transmitted from the ABS computer 11 to the ECT computer 15 via the communication cable 18 whether or not the ABS 10 has an abnormality. If it is determined that the signal is normal (high-level signal), the process proceeds to step S25, and the gear ratio control in the normal state is performed. In the gear ratio control in the normal state, gear shift control is performed according to a gear shift point map (only downshifts are shown) as shown in FIG. The normal speed ratio control is a control in accordance with a speed line normally used as shown by a dotted line in FIG. 5, and the state of the throttle opening and the output rotation speed (vehicle speed) exceeds each speed line. The gear ratio is changed according to the shift line that has been exceeded. Reference numeral 55 denotes a shift line for shifting down from overdrive (fourth speed) to third speed, 53 denotes a shift line for shifting down from third speed to second speed, and 51 denotes a shift line for shifting down from second speed to first speed.
[0016]
This control is performed by a method such as storing a shift point map in a memory and reading out a gear ratio from the memory in accordance with the detected throttle opening and output shaft speed.
If it is determined in step S21 that there is an abnormality, the process proceeds to step S22. In step S22, it is determined whether or not the brake is applied. If the brake is not applied, the process of step 25 (normal speed ratio control) is performed. If it is detected that the brake is applied, , To step S23. The presence or absence of the brake operation can be detected by a method such as the ECT computer 15 monitoring a signal from a brake lamp switch.
[0017]
In step S23, deceleration is calculated from the amount of change in vehicle speed monitored by the ECT computer 15, and the braking state (strength) of the brake is determined. Note that the brake braking state can be detected not only from the amount of change in the vehicle speed but also from the amount of depression of the brake pedal, the hydraulic value of the hydraulic system, and the amount of change in the wheel speed. Therefore, when it is determined that the speed is the reduction speed, the process proceeds to step S25 to perform the normal speed ratio control.
[0018]
When it is determined that the vehicle is suddenly decelerated (sudden braking), the process proceeds to step S24.
In step S24, gear ratio control at the time of abnormality is performed. In the gear ratio control at the time of abnormality, the gear shift control is performed according to a shift point map (only downshift is shown) as shown by a solid line in FIG. As shown by the solid line, in the case of the gear ratio control at the time of abnormality, as shown by the solid line, 56 is a downshift from overdrive (4th speed) to 3rd speed, 54 is 3rd speed to 2nd speed, and 52 is 2 A shift line that shifts down from the first speed to the first speed, which is shifted to a higher vehicle speed side than a shift line performed during normal control as indicated by a dotted line. By providing the shift line (indicated by the dotted line) and the shift line on the higher vehicle speed side (indicated by the solid line) performed during the normal control in this manner, the shift in two stages of the low vehicle speed side and the high vehicle speed side can be achieved. It becomes possible.
[0019]
With this control, when the vehicle is suddenly braked, the engine is switched to the engine brake control in which the gear is shifted down earlier than before, and the stronger engine brake braking is performed. Therefore, the stop braking distance can be shortened by effectively using the engine brake.
As described above, according to the present embodiment, the ABS computer 11 and the ECT computer 12 are communicatively connected to each other, so that the ECT computer 12 can operate even if a malfunction or malfunction occurs in the ABS and the effect of the ABS cannot be expected. Thus, more efficient gear ratio control can be performed, and the engine brake can be used more efficiently.
[0020]
In addition, the ECT takes into consideration the riding comfort during normal braking, and controls so as not to apply too strong engine braking. In this embodiment, however, the ECT control is not changed in consideration of this point during normal braking, and the riding comfort is not changed. Only at the time of sudden braking that needs to give priority to sudden braking, the ECT control is changed so that the engine brake is sufficiently applied, so that the riding comfort and safety can be made compatible at a high level.
[0021]
Next, a second embodiment will be described.
FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention, and FIG. 4 is a flowchart showing processing executed by the ECT computer 14.
The same components as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0022]
Reference numeral 30 denotes an airbag system, which is a protection device for inflating an airbag between an occupant and a vehicle interior member (mainly, a steering wheel) at the time of a collision to alleviate an obstacle caused by the occupant hitting the front vehicle interior member. is there. The airbag system 30 includes an acceleration sensor and a destruction sensor, and detects a collision. A collision detection sensor 32, an airbag gas generator 33 for rapidly filling gas into the airbag and inflating the airbag, and the collision detection sensor An airbag computer 31 processes input signals from the airbag gas generator 32 and controls activation of the airbag gas generator 33 and the like. The entire system is monitored and controlled by the airbag computer 31.
[0023]
If an abnormality occurs in the airbag system 30, it is quickly detected, and an airbag warning lamp is turned on to warn the driver. It should be noted that the abnormality of the airbag system 30 is monitored for disconnection of a circuit or a signal line, a short circuit, or the like, and a program is set for the airbag system computer 31 so as to output a pulse of a constant cycle during normal operation. This pulse can be detected by a method such as a so-called watchdog timer that monitors the pulse.
[0024]
Reference numeral 18 denotes a communication cable for transmitting information from the airbag system computer 31 to the ECT computer 15. The airbag system computer 31 sends a high-level signal (for example, 5) to the ECT computer 15 when the airbag system 30 is normal. Volts), and is programmed to output a low-level signal (0 volts) when an abnormality occurs.
[0025]
Next, processing executed by the ECT computer 15 will be described with reference to FIG.
This process is started from the point when the engine is turned on by the ignition key, and is repeated as needed thereafter.
In step S41, it is determined from the signal sent from the airbag system computer 30 to the ECT computer 15 via the communication cable 18 whether or not an abnormality has occurred in the airbag system 30. When it is determined that the signal is normal (high-level signal), the process proceeds to step S45, and the gear ratio control in the normal state is performed.
[0026]
If it is determined in step S41 that there is an abnormality (low-level signal), the process proceeds to step S42. In step S42, it is determined whether or not the brake is applied. If the brake is not applied, the process of step 45 (normal speed ratio control) is performed, and it is detected that the brake is applied. Moves to step S43. The presence or absence of the brake operation can be detected by a method such as the ECT computer 15 monitoring a signal from a brake lamp switch.
[0027]
In step S43, the deceleration is calculated from the amount of change in vehicle speed monitored by the ECT computer 15, and the braking state (strength) of the brake is determined. Note that the brake braking state can be detected not only from the amount of change in the vehicle speed but also from the amount of depression of the brake pedal, the hydraulic value of the hydraulic system, and the amount of change in the wheel speed. Therefore, if it is determined that the speed is the reduction speed, the process proceeds to step S45 to perform the normal speed ratio control.
[0028]
When it is determined that the vehicle is suddenly decelerated (sudden braking), the process proceeds to step S44.
In step S44, gear ratio control at the time of abnormality is performed. Note that the speed ratio control in the normal state and the speed ratio control in the abnormal state are the same as those described in the first embodiment, and therefore, the description thereof is omitted.
[0029]
As described above in detail, according to the present embodiment, the airbag system computer 31 and the ECT computer 15 are communicatively connected to each other, so that in the event of an emergency such as a sudden brake, a failure or malfunction of the airbag system 30 occurs. Even when the effect of operating the airbag cannot be expected, the ECT computer 15 selects the combined use of the engine brake control based on the information from the airbag system computer 31, and the stopping braking distance of the vehicle is shortened. In the unlikely event of a collision, the impact is reduced, and injury to the driver and other occupants can be reduced.
[0030]
【effect】
As described above, according to the present invention, even if a failure or malfunction occurs in the airbag system, the ECT computer complements this, and more stable running and improvement in safety can be achieved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.
FIG. 2 is a flowchart illustrating processing executed by an ECT computer according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.
FIG. 4 is a flowchart illustrating a process executed by an ECT computer according to a second embodiment of the present invention.
FIG. 5 is a shift diagram illustrating control characteristics of ECT in the embodiment of the present invention.
[Explanation of symbols]
10 ABS system 11 ABS computer 12 Speed sensor 13 Actuator (for brake)
14 ECT system 15 ECT computer 16 ECT sensor 17 Actuator (for transmission)
18 Communication Cable 19 Automatic Transmission 30 Airbag System 31 Airbag System Computer 32 Airbag Sensor 33 Airbag Gas Generator

Claims (2)

When an abnormality of the airbag system that controls the inflation of the airbag is detected at the time of a vehicle collision, an abnormal signal is transmitted to a transmission system that controls a transmission gear ratio according to a vehicle speed and a throttle opening,
The vehicle control device, wherein the transmission system changes the control characteristic of the speed ratio so that the engine brake becomes strong when the abnormal signal is received. 2. The transmission system according to claim 1, wherein when the abnormality signal is received and the vehicle is determined to be in a rapid deceleration state, the transmission ratio control characteristic is changed so that engine braking is increased. The vehicle control device according to any one of the preceding claims.

Images