JPH0573943B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applied to an automatic vehicle (hereinafter referred to as an AT vehicle) in which deceleration is achieved by taking your foot off the accelerator pedal while driving and applying so-called engine braking. This invention relates to an automatic deceleration device for an automatic vehicle that automatically detects the failure and forcibly decelerates the vehicle.

[Conventional technology]

In AT vehicles, when the accelerator pedal is depressed, the transmission is switched according to the vehicle speed, reducing the reduction ratio and increasing the speed. For AT cars, when the transmission is switched to 3rd gear,
Since the reduction ratio is smaller than that of a manual transmission, there is less deceleration when you take your foot off the accelerator pedal and apply engine braking while driving. Further, in an AT vehicle equipped with an overdrive, the effectiveness of engine braking is particularly poor when the vehicle is running in the overdrive.

[Problem that the invention seeks to solve]

Therefore, in the case of AT cars, there is little deceleration when the engine brake is applied, so the foot brake has to be used frequently, which causes problems such as brake heat and severe wear of the brake pads.

[Means for solving problems]

Therefore, in view of the above-mentioned problems, the present invention provides an automatic system that can automatically increase deceleration without applying the foot brake if the engine brake is not applied when deceleration is required. The purpose is to provide automatic deceleration devices for cars.

[Means for solving problems]

In order to achieve the above object, an automatic speed reduction device for an automatic vehicle according to the present invention includes a throttle opening detection device that detects the throttle opening, and a throttle opening detection device that detects the throttle opening when the shift lever is in the drive position. means for detecting an engine braking state by detecting an idling state based on a throttle opening detected by a detection device;
means for detecting a vehicle speed when the means detects an engine braking state and determining whether or not the detected vehicle speed has reached a preset deceleration per unit time; The present invention is characterized by comprising means for forcibly decelerating the speed of the vehicle to a level higher than the deceleration rate per unit time by downshifting the transmission when it is determined that the vehicle speed is not lower than the deceleration rate per unit time.

[Effect]

In the automatic speed reduction device for an automatic vehicle described above, when the shift lever is in the drive position, when the engine braking state is detected by detecting the idle state based on the throttle opening,
It is determined whether the vehicle speed has reached a preset deceleration per unit time, and when it is determined that this deceleration has not been reached, the transmission is shifted by, for example, releasing overdrive. Since the speed of the vehicle is forcibly reduced to a level greater than the deceleration per unit time, the necessary deceleration can be obtained without applying the foot brake.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a throttle opening detection device that detects the opening/closing degree of a throttle valve that opens and closes by operating an accelerator pedal, and sends out an output when the throttle valve is in an idle position; 2 is a transducer, for example. A high-precision vehicle speed detection device that is attached to the driven gear of the transmission and detects the vehicle speed and sends out an output; 3 is a control circuit that includes a timer that performs the operations shown in Figure 2 or 3; 4 is an AT
An overdrive release device for canceling autodrive for switching the transmission in a vehicle to the top gear so that the gear can be changed, and is composed of a relay or the like having contacts connected in series with an overdrive switch. There is. 5 is an actuator for downshifting in another embodiment.

Next, the first embodiment will be explained with reference to the flowchart of FIG. 2. The control circuit 3 monitors whether the shift lever position is the drive position (step a), and if it is the drive position, the control circuit 3 monitors whether the shift lever position is the drive position or not. The next step is to monitor whether the overdrive switch is on (step b).

In this monitoring state, if the driver applies the engine brake due to excessive speed or going downhill, the throttle opening detection device sends an output, so the control circuit 3 detects when the engine is in an idling state. Then, it is detected that the engine brake has been applied (step c).

After the control circuit 3 detects that the engine brake has been applied, it monitors the speed signal from the vehicle speed detection device 2 and determines whether the speed has reached a preset deceleration state per unit time. Monitor (step d). That is, for example, monitoring whether the deceleration rate reaches 3 km/H per second,
If not, output is sent. This output drives the overdrive release device 4 to release the overdrive (step e), and changes the transmission to 3rd speed for deceleration.

Next, as will be explained with reference to the flowchart shown in FIG. 3, even after canceling the above-mentioned overdrive, if the deceleration per unit time does not reach the preset speed state due to a steep slope etc., or In an AT vehicle that does not have an overdrive device, if the predetermined deceleration is not performed despite applying the engine brake, the control circuit 3
monitors whether it is in the drive position or not (step a) in the same way as the operation shown in FIG. When it is detected that the engine brake has been applied, the system monitors whether the deceleration per unit time is equal to or higher than a preset speed (step d), and checks whether the predetermined deceleration is achieved. If not, an output is sent out to drive the actuator 5 for downshifting the transmission to downshift to second speed (step f), thereby attempting to decelerate.

In addition, instead of the throttle opening detection device mentioned above,
It can also be replaced with an engine negative pressure detection device that detects a rise in negative pressure in the carburetor or surge tank and sends out an output.

In addition, a switch is provided to select whether to release the above-mentioned overdrive or downshift the transmission when applying engine braking, and by turning on the switch, the engine will coast without decelerating. It can also be made selectable so that the vehicle can be driven with

Furthermore, the rate of deceleration per unit time may be set arbitrarily.

〔Effect of the invention〕

As explained above, according to the present invention, the shift lever is in the drive position,
And when the engine is braking, it determines whether deceleration is appropriate, and if it determines that deceleration is not appropriate, the transmission is downshifted to automatically increase the vehicle's deceleration without applying the foot brake. Since the necessary deceleration can be obtained, when deceleration is required and the engine brake is not applied, the desired deceleration can be achieved without using the foot brake frequently, and therefore, the brake heating and brake pads can be reduced. This invention is very effective for safe driving as it prevents wear and tear.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart of the same block diagram shown by solid lines, and FIG. 3 is a flowchart of the block diagram shown by broken lines in FIG. DESCRIPTION OF SYMBOLS 1... Throttle opening detection device, 2... Vehicle speed detection device, 3... Control circuit, 4... Overdrive release device, 5... Actuator for downshifting.

Claims (1)

[Scope of Claims] 1. A throttle opening detection device that detects the opening of the throttle; and detection of an idle state based on the throttle opening detected by the throttle opening detection device when the shift lever is in the drive position. means for detecting an engine braking state by; detecting a vehicle speed when the means detects an engine braking state; and determining whether or not the detected vehicle speed has reached a preset deceleration per unit time. and means for forcibly decelerating the speed of the vehicle to more than the deceleration per unit time when the means determines that the deceleration has not been reached. Automatic deceleration device.