JPH0573618B2 - - Google Patents

Description

[Detailed description of the invention]

[Summary] The driving feeling during constant speed driving is improved by setting the automatic transmission to return to the highest gear after a delay time corresponding to the slope of the road surface during driving has elapsed from the time when the return conditions were satisfied. [Industrial Field of Application] The present invention relates to a constant speed driving control device for a vehicle equipped with an automatic transmission (AT), and particularly to an apparatus for optimally setting the return timing to the highest gear during constant speed driving according to the road surface gradient. It is something to do. [Conventional technology] Recent AT cars have 4-speed AT with OD (1st, 2nd, 3rd)
4th gear = OD) is the mainstream, and at vehicle speeds of approximately 50 km/h or higher, the vehicle usually runs in the highest gear, OD (overdrive). However, when driving in autodrive, it is difficult to drive at a constant speed in OD on steep slopes, causing the vehicle speed to drop. For this reason, autodrive
The ECU outputs an OD cut signal to limit gear selection by the automatic gear shift controller. In other words, even in cases where the automatic shift controller determines that the vehicle is in the OD range based on the relationship between vehicle speed and throttle opening, there is a function that prohibits selection and downshifts to 3rd gear. This function becomes unnecessary once the vehicle speed returns to a certain value, but the OD cut signal is not turned off until the time _TOD (for example, 14 seconds) set by the OD return timer has elapsed. This is a frequent OD when the vehicle speed returns quickly.
This is to prevent repeated cuts and returns. [Problems to be solved by the invention] By the way, as shown in Fig. 5 a to c, while climbing a hill,
Even if the return conditions are met while driving at a constant speed after the OD cut, if the subsequent road surface gradient is different, the return delay time T _OD is suitable for the flat road shown in b, but is too short for the gently climbing road shown in a. , it may become OD cut again. On the other hand, the downhill slope of c is too long and is a waste of 3.
This means that the vehicle will be traveling at a high speed, and the driving feeling will not be comfortable in either case. The present invention attempts to improve the running feeling by varying the return delay time _TOD according to the slope after the return condition is satisfied. [Means for Solving the Problems] The present invention provides a constant speed cruise control device for a vehicle equipped with an automatic gear shift controller that automatically switches gears of a transmission based on the relationship between vehicle speed and throttle opening. a constant speed driving control means that controls the throttle opening according to the traveling vehicle speed and causes the vehicle to travel at a memorized vehicle speed; and a transformer that sends a highest gear selection prohibition signal to the automatic transmission controller when the vehicle speed decreases. A transmission control means, a road surface slope detection means for detecting the slope of the road surface, and a road surface gradient detection means that determines that a return condition including that the traveling vehicle speed has increased to a predetermined value or more and the road surface slope has decreased to a predetermined value or less has been satisfied. The present invention comprises a return condition determining means, a setting means for setting a return delay time according to the slope after the return condition is satisfied, and a means for canceling the selection prohibition signal when the time has elapsed. It is characterized by: [Function] If the delay time T _OD for returning to the highest speed gear is not set to a constant value as in the past, but is made to be a variable value depending on the slope after the return condition is satisfied, the case shown in Figure 5 a will be set longer than the case shown in b. Therefore, the degree of OD cut is reduced again, and in the case of c, since it is set shorter than b, the OD can be returned quickly, and the running feeling is improved in both cases. Of course, there may be cases where the recovery time of b is shortened depending on how the standard is set. [Embodiment] FIG. 1 is a functional block diagram within a microcomputer showing an embodiment of the present invention. Inputs include a vehicle speed signal, set switch, vacuum switch, etc., and outputs include control valve control and transmission control (OD cut). The purpose of control valve control is to use duty D to control the force generated by the actuator for adjusting the throttle opening while driving at a constant speed. This output duty D is the target vehicle speed stored in memory.
It is determined according to the difference between VM and traveling vehicle speed Vn,
In general, the skip vehicle speed Vs is the sum of the vehicle speed change component (differential component), not the traveling vehicle speed Vn itself.
Use. This is to advance and compensate for dead time due to actuator delay, throttle, drive system hysteresis, and play. The output duty D is determined by the following equation. D=G×ΔV+SD G: Gain (1=/V _B ) SD: Set duty corresponding to target vehicle speed VM ΔV: Vehicle speed deviation (=VM−Vs) The stored vehicle speed VM is the traveling vehicle speed when the set switch is turned on. When the vehicle speed Vn falls below (VM-A), the comparator _CMP1 outputs "1" and sets the flip-flop FF. Also, the comparator
CMP ₂ sets its output to "1" when the vehicle speed Vn returns to (VM-B) or higher. The OD return condition has three elements: the output of the comparator CMP ₂ is "1", the vacuum switch is off, and the output of the comparator CMP ₃ is "1". indicates recovery of vehicle speed. indicates an increase in the intake manifold negative pressure above a certain value (a decrease in slope below a certain value). indicates a decrease in the average duty value DM (a decrease in the throttle opening). Expressed as a formula, it is as follows. SDF+5%+α-DM>0 DM: Average value of output duty D SDF: DM after 24 seconds have elapsed after setting α: Correction value added on uphill road Gate _G1 returns when the above three conditions ~ are satisfied Start the delay timer _TOD . this
The value of _TOD is variably set by the _TOD selection logic L.
Then, after the time T _OD has elapsed, the flip-flop FF
If you reset , it returns from OD cut to OD on. This OD ON is an instruction that it is OK to shift up to OD if the conditions are met on the transmission side. On the other hand, an OD cut is an instruction to always downshift to 3rd gear. FIG. 2 is a flowchart regarding the transmission control of FIG. 1. Step S1 is a process to judge the output of comparator _CMP1 , and A=4.
Km/h. If it is determined in this process that the vehicle speed Vn has decreased by 4 km/h or more from the memorized vehicle speed VM, the recovery counter CNT is set to -8s (minus 8 seconds) in step S2, and the OD is cut in step S3. This 8s determines the minimum period of OD cut. If the vehicle speed reduction condition in step S1 is not satisfied, it is determined in step S4 whether OD cutting is in progress, and
If no (N), OD is turned on in step S5. If OD cutting is in progress at step S4, step
It is determined in S6 whether the counter value is positive, and if it is negative, the counter value is incremented in step S7. If the counter value CNT is not negative in step S6, the output of the comparator _CMP2 is checked in step S8 (B=2 Km/h). At this time, if the vehicle speed has not recovered, the counter CNT is
However, if the vehicle speed has recovered, the above-mentioned return condition has been satisfied, so it is checked in the next step S10 whether the return condition is satisfied. Jesus (Y)
If so, it is established, so take the next step.
Check that the return condition is satisfied in S11. If any of these conditions are not satisfied (N), the process moves to step S9, but if all of the conditions .about. are satisfied (Y), the _TOD selection logic shown in FIG. 2B is executed. and,
If T _OD ≦CNT is established in step S12, step
Turn on OD on S5. Steps S21 to S24 in Figure 2B are (SDF + 5%)
+α) and DM is determined, and this corresponds to gradient detection after the return condition ~ is satisfied. Based on the result of this judgment, the timer _TOD is set in steps S25 to S29 as shown in the table below.

〔Effect of the invention〕

As described above, according to the present invention, the delay time (T _OD ) for returning to the highest speed gear is determined by the return condition (~
) is made variable depending on the gradient (ΔD) after the establishment of the gradient (ΔD), which has the advantage of reducing the strangeness of the driving feeling caused by shift changes during constant speed driving.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a flowchart of transmission control, Fig. 3 is an explanatory diagram of the operation of the present invention, and Fig. 4 is an OD
The operation waveform diagram at the time of recovery, FIG. 5, is an explanatory diagram of the conventional OD recovery method.

Claims (1)

[Claims] 1. In a constant speed cruise control device for a vehicle equipped with an automatic shift controller that automatically switches the gear position of a transmission based on the relationship between vehicle speed and throttle opening, the throttle opening is controlled according to the traveling vehicle speed, constant speed driving control means for causing the vehicle to travel at a memorized vehicle speed; transmission control means for transmitting a highest gear selection prohibition signal to the automatic transmission controller when the vehicle speed decreases; and a road surface for detecting the slope of the road surface. slope detection means, and when the traveling vehicle speed increases above a certain value,
and a return condition determining means for determining that a return condition including that the road surface gradient has decreased to a predetermined value or less is satisfied, and a setting means for setting a return delay time according to the gradient after the return condition is satisfied. , and means for canceling the selection prohibition signal when the time period has elapsed.