JPH0474215B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention detects that an automobile is in a dangerous dismounting state and issues a warning to the driver to prompt the driver to take predetermined measures. The present invention relates to a driving safety device for automobiles that performs processing such as automatically operating the exhaust brake.

(Prior art and problems with the prior art) Automatic transmissions (easy drive systems) installed in passenger cars, etc. are configured to automatically shift up when the speed of the vehicle increases and exceeds a predetermined level. ing. When such an automatic transmission is installed in a large vehicle, the following problems arise.

FIG. 6 is an explanatory diagram of a state in which a large vehicle A equipped with an automatic transmission is traveling on a slope.

Suppose now that the vehicle is going down a hill in second gear at vehicle speed A, and the vehicle speed increases to B. In this state, if you reach a gentle slope and press the accelerator, the gear will not change when the accelerator pedal is released, but when the accelerator pedal is depressed, the gear will change in relation to the vehicle speed. For this reason, if the vehicle is shifted up to, for example, 3rd gear and continues to drive onto a steep hill, even if the engine brake is activated, the brakes will not be effective, resulting in a dangerous situation and the driver will have to drive with a manual shift. As a result, there was a problem that the function of the automatic transmission was impaired.

(Objective of the Invention) The present invention inputs various signals such as an engine rotation speed signal to a calculation device, and the calculation device executes predetermined calculation processing to determine the safety of exiting the vehicle, and provides the determination result to the driver. The purpose of this system is to drive the vehicle safely by prompting necessary responses by displaying or issuing a warning, or by performing processing such as automatically operating the exhaust brake.

(Summary of the Invention) The vehicle driving safety device of the present invention includes an engine rotation speed detection means for detecting the engine rotation speed, an engine load detection means for detecting the engine load, a vehicle speed detection means for detecting the vehicle speed, and an exhaust system. Exhaust brake operation detection means for detecting brake operation, and a calculation device for inputting each detection signal detected by the various detection means, and the calculation device receives each of the detection signals to cause the vehicle to run in the exit mode. Determines the optimal gear to use, clutch status, and whether or not the engine brake is activated, and outputs a warning signal, automatic transmission shift drive signal, and exhaust brake operation signal control signal based on the determination results. A driving safety device for an automobile, characterized in that the vehicle can be safely driven when exiting the vehicle.

(Example) FIG. 1 is a schematic block diagram of the present invention.

Various signals such as an accelerator position signal, an engine rotational speed signal, and a vehicle speed signal are input to the calculation device 1, which performs predetermined calculations and sends an output signal to the alarm device or the processing device 2.

FIGS. 2 and 3 are characteristic diagrams, FIG. 4 is a flowchart showing the processing procedure for safely driving a car when driving on a disembarkation, and FIG. 5 is a block diagram of FIG. 1. FIG. 2 is a block diagram showing an embodiment of the present invention, which explains the drawings in more detail.

Next, the flowchart shown in FIG. 4 will be explained.

Inside the arithmetic unit 1 shown in Fig. 1, the engine speed N, engine load L (a signal converted from the easy position or accelerator position), and the shaft average effective pressure are stored.
(1) Based on the map data, the shaft average effective pressure Pme (N,
L) is determined (step 30).

Here, if the driving force of the vehicle is F (Kg),
There is a relationship between the axial average effective pressure Pme (Kg−Cm ^-2) as follows: F=Pme・K ₁ ...(1) K ₁ is a proportionality constant.

On the other hand, if the amount of change in the engine rotation speed △N (rpm) at each fixed time △T while exiting the vehicle, that is, the acceleration is α, and the total weight of the vehicle is m (Kg), then F- (running resistance) = mα... (2) holds true.

Here, running resistance can be determined from the shaft average effective pressure Pme and acceleration α, so the slope of descent is estimated by determining the amount of change in shaft average effective pressure and engine speed, and this is used as the basis for subsequent processing. It is something.

(2) Determine the gear to be used from the engine speed N and vehicle speed or gear switch (step
31). In this case, if the coordinate point (vehicle speed, N) is in the shaded area in Figure 2, it is determined that the clutch is disengaged or in a eutral state, and the number of gears to be used is determined depending on which non-shaded area it is in. You can decide.

(3) When the vehicle runs at a constant speed, that is, the driving force F
Shaft average effective pressure when and running resistance are balanced
Pmeconst. is expressed as Pmeconst.=Pme(N,L)−K(R/μf) ² × (1/μt) ² ×(m/Vs) ×(△N/△T)……(3) . Where, R: Effective radius of tire (Cm) μf: Reduction ratio of final gear μt; Reduction ratio of transmission m: Total vehicle weight (Kg) Vs: Total engine displacement (cc) △N: Constant Increase/decrease amount K of engine rotational speed N for each period ΔT: is a constant.

In step 32, the above equation (3) is calculated. formula
In (3), Pme (N, L) is determined in step 30, μt is the gear ratio corresponding to the number of gears to be used determined in step 31, and
It is obtained by searching the values stored in the memory built into the arithmetic unit 1 shown in the figure. Also,
K, R, μt, and Vs are stored in the above memory. m may be electrically input to the arithmetic device as shown in FIG. 5, or may be stored in the memory of the arithmetic device shown in FIG. .DELTA.N is determined by calculating the increase/decrease in N at every cycle .DELTA.T determined by a timer in the arithmetic unit shown in FIG.

(4) Determine the magnitude of the reduction ratio μt of the gear stage, and calculate the reduction ratio μt.
If is small, the process moves to step A (step 33).

(5) Axial mean effective pressure Pmeconst determined in step 32.
If it is 0 or positive, the process proceeds to step 41, and if it is negative, the process proceeds to step 35 (step 34).

(6-1) If Pmeconst. is negative, the speed of the vehicle will increase even if it runs with engine braking,
If you shift up, the speed will increase to an even greater level, resulting in a dangerous descent. For this reason, Pme
Even if (N, L) is not 0, that is, it is determined that the vehicle is running normally (step 35), it is determined that upshifting is not possible. (Step 36). In this case, a message indicating that upshifting is not possible is displayed or necessary internal processing (processing that does not allow upshifting in the case of an automatic transmission control device) is performed.

(6-2) When Pme (N, L) is 0, that is, when driving with engine braking, Pmeconst.
and the negative value of Pmelevel (step 37). When Pmeconst. is smaller than Pmelevel, that is, when the descent acceleration is large, it is determined whether the exhaust brake is in use,
(Step 38). If the exhaust brake is in use and downshifting is possible, downshifting processing is performed (Step 39). If the exhaust brake is not used, the exhaust brake is activated (step 40).

(7) If Pmeconst. becomes 0 or positive in step 34, it is determined that the driving is on a gentle descending road, a flat road, or an uphill road, and it is determined that the use of the exhaust brake is not necessary, and the exhaust brake is released. (Step 41). In FIG. 5, the exhaust brake control signal is set to low level.

(8) If it is determined in step 37 that Pmeconst. is greater than Pmelevel, it is determined that although it is a disembarkation road, the disembarkation acceleration is small and there is no problem in running, and the process proceeds to step 42 without processing.

As described above, processing for prohibiting upshifting when upshifting driving is determined to be dangerous;
In addition, necessary processing is performed when the gear stage used is not suitable for the slope of descent, and the vehicle is driven safely.

In Fig. 5, the central processing unit (CPU) has a constant cycle △ to find the increase in engine speed △N.
The arithmetic unit, which is composed of a microcomputer, has a built-in timer that determines T, and a memory that stores various characteristic map data necessary for judgment processing. In addition to the throttle brake signal, load signals and the like are input as necessary. The arithmetic device executes predetermined arithmetic operations and outputs an actuator drive signal for shift change of the automatic transmission, a shift instruction signal, an exit travel display signal, an exhaust brake control signal, and the like. The exhaust brake control signal and the exhaust brake manual switch signal are input to the OR gate, and if either one of the two inputs is an operating signal, the exhaust brake control magnetic valve (Mg /V) can be driven.

(Effects of the Invention) As explained above, in the present invention, various signals such as an engine rotational speed signal are input to a calculation device, and the calculation device performs predetermined calculations to prohibit upshifting and change the gear to be used. It outputs a display warning when the vehicle is unsuitable for exiting the vehicle, signals for exhaust brake processing, etc., so the driver can take necessary actions and take automatic safety processing, resulting in the effect of allowing the vehicle to exit the vehicle safely. It will be done. In particular, driver fatigue can be reduced when driving in mountainous areas at night.

Furthermore, since the speed increase determination level is determined for each gear, it is not possible to issue an unexpected warning.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of the present invention, FIG.
Figure 3 is a characteristic diagram, Figure 4 is a flowchart, and Figure 5 is a characteristic diagram.
The figure is a block diagram showing one embodiment of the present invention, and FIG. 6 is an explanatory diagram when the vehicle is traveling downhill. 1...Arithmetic device, 2...Alarm device (processing device).

Claims (1)

[Claims] 1 engine rotation speed detection means for detecting engine rotation speed, engine load detection means for detecting engine load, vehicle speed detection means for detecting vehicle speed, and exhaust brake operation detection means for detecting exhaust brake operation; A calculation device is provided to input each detection signal detected by the various detection means, and the calculation device receives each detection signal and determines the optimum gear stage, clutch state, and engine brake to be used for the vehicle to run while dismounting. Determine the presence or absence of operation,
A driving safety device for an automobile, characterized in that the vehicle is configured to output a warning signal, a shift drive signal for an automatic transmission, and a control signal for an exhaust brake operation signal based on the determination result so that the vehicle can be safely driven when exiting the vehicle. .