JPH0240035A - Engine control device for vehicle with automatic speed change gear - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a slip during gear shifting on a low mu road, e.g. a snow road, by a method wherein when a low mu road surface is discriminated by a road surface state discriminating means, an engine output during gear shifting is more widely reduced than a case in which a rod surface mu is high. CONSTITUTION:An electronic control device 3 inputs signals from a throttle opening sensor 31, a car speed sensor 32, and a crank angle sensor 34, and performs speed change of an automatic speed change gear 2 based on setting of a speed change step responding to a running state. During gear shifting, an ignition control signal is outputted to an ignition plug 36 so that an engine 1 output is slightly reduced by means of an engine output reducing means 38. Meanwhile, when it is discriminated by a road surface state discriminating means 37 by means of a mode signal from a mode select switch 33 that a road surface mu is low, an ignition control signal is outputted to the ignition plug 36 so that by means of a discriminating signal therefrom, the engine output reducing means 38 reduces an engine output more widely than a case in which a road surface mu is high. this constitution enables prevention of the occurrence of a slip during gear shifting on a low road, e.g. a snow road.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine control device for a vehicle with an automatic transmission.

[Conventional technology]

Conventionally, engine control devices for vehicles with automatic transmissions have been known to reduce engine output according to the magnitude of the shift impact during gear shifting of the automatic transmission, thereby reducing the shift impact. (Japanese Unexamined Patent Publication No. 119432/1983).

[Problem to be solved by the invention]

In general, in vehicles with automatic transmissions, when you shift up while driving at a predetermined gear ratio and speed, the gear ratio increases without changing the vehicle speed immediately after the shift-up. In other words, the engine speed will be lowered to match the vehicle speed and high gear ratio. However, after an upshift, the engine also tries to maintain the rpm before the upshift, so the energy that tries to lower the engine rpm is not absorbed by the engine but escapes to the tires, increasing the driving force of the tires. You will be able to do it.

Particularly on low μ roads such as snowy roads, the frictional resistance between the tires and the road surface is small, so energy that attempts to reduce the engine speed tends to escape to the tires. For this reason, in vehicles equipped with automatic transmissions, there is a problem in that when shifting up on a low μ road such as a snowy road, the driving force of the tires increases and slip occurs.

With a conventional engine control device, that is, one equipped with an engine control device that reduces engine output during gear shifting, if the engine output is significantly reduced during gear shifting in response to low μ roads, it is possible to upshift. This can prevent the driving force of the tires from increasing at times, and can solve the problem of slipping on low μ roads. However, in such a case, even on a normal road surface (high μ road), the engine output decreases significantly during upshifting, and the driving force of the tires decreases, causing a problem that acceleration performance on a normal road surface is impaired. Furthermore, the same problem of slipping and deterioration of acceleration performance occurs during downshifting when accelerating.

In view of the above circumstances, it is an object of the present invention to provide an engine control device for a vehicle with an automatic transmission that can prevent slippage on low μ roads without impairing acceleration performance on high μ roads during gear shifting. That is.

(Means for Solving the Problems) An engine control device for a vehicle with an automatic transmission according to the present invention is an engine control device for reducing engine output by a predetermined amount during shifting of an automatic transmission. The present invention includes a road surface condition determining means for determining a road surface condition, and an engine output reducing means for reducing the engine output during gear shifting when the road surface μ determined by the road surface condition determining means is low than when the road surface μ is high. This is what I did.

[Effect]

According to the above configuration, on a low μ road, the road surface condition determining means determines that the road surface μ is low, and in that case, the engine output reducing means significantly reduces the engine output during gear shifting, thereby suppressing an increase in tire driving force. Become. In addition, on a high μ road, the road surface condition determining means determines that the road surface μ is high, and in that case, the engine output reducing means only slightly reduces the engine output during gear shifting, thereby preventing the tire driving force from decreasing excessively. That will happen.

〔Example〕

FIG. 1 schematically shows an embodiment of an engine control device for a vehicle with an automatic transmission according to the present invention. In this figure, 1 is an engine, and its intake passage 11 is provided with a throttle valve 12 as an output adjustment means for adjusting the engine output by adjusting the amount of intake air.
The throttle valve 12 is opened and closed by a throttle actuator (not shown) comprising a two-phase step motor or the like. Further, reference numeral 2 denotes an automatic transmission, which is composed of a torque converter 21, a transmission mechanism 22, and a hydraulic control circuit 23. The hydraulic control circuit 23 includes a first circuit that controls the hydraulic pressure supply to a gear shifting friction element (not shown) of the gear shifting mechanism 22 to shift gears.
．． A second shift solenoid 24.25 is included.

A control unit (ECU) 3 controls the engine 1 and automatic transmission 2, and is formed using a microcomputer or the like.

The control unit 3 receives signals from a throttle opening sensor 31 and a vehicle speed sensor 32, as well as a mode signal from a moto select switch 33 for selecting either normal mode or slip mode. Furthermore, various signals from a crank angle sensor 34 that detects the engine crank angle are also input.

The vehicle speed sensor 32 outputs a vehicle speed signal (pulse signal) every time the propeller shaft 35 rotates 45 degrees, and the crank angle sensor 34 outputs a crank angle signal (pulse signal) every time TDC (top dead center) of each cylinder of the engine. from TDC to ATDC
It is designed to output for a period of up to 30 degrees (after top dead center). Further, the mode signal from the mode select switch 33 can be switched by the driver operating the mode select switch 33.

In this case, the driver looks at the road surface condition and selects the mode so that if the driver determines that the road is a high μ road, the normal mode is selected, and if the driver determines that the road is a low μ road such as a snowy road, the slip mode is selected. Operate switch 33. The control unit 3 outputs a speed change control signal to each of the shift solenoids 24 and 25, and also outputs an ignition control signal to the ignition coil 36.

The control unit 3 includes a road surface condition determining means 37 and an engine output reducing means 38.

The road surface condition determination means 37 includes a mode select switch 33
It is determined whether the road surface μ is high or low based on the mode signal from the vehicle. The road surface condition determination means 37 outputs a road surface μ determination signal to the engine output reduction means 38 . The engine output reducing means 38 receives a road surface μ determination signal from the road surface condition determining means 37 during gear shifting, and when a determination signal determining that the road surface μ is low is input, a determination signal determining that the road surface μ is high is input. An ignition control signal is output to the ignition coil 36 that causes the engine output to be significantly reduced compared to when the ignition coil 36 is turned on. The gear shift control is performed by turning on and off the above-mentioned shift solenoids 25 and 26 based on the setting of the gear according to the operating condition, and the relationship between the state of each shift solenoid 25 and 26 and the gear is as follows. It is as shown in Table 1.

Table 1 and Figure 2 show the internal structure of the control unit 3 in a smaller scale. In this figure, the CP in the control unit 3
U41 includes a vehicle speed sensor 32 and a crank angle sensor 3.
4 is sent as an interwoven signal via the waveform shaper 42, and signals from the mode select switch 33 and throttle opening sensor 31 are sent via the analog buffer 43 and A/D converter 44. . The mode select switch 33 has each terminal for specifying one of two modes: normal mode and slip mode, and the voltage is determined depending on which terminal is connected by the driver's operation. Mode signals with different levels are output. In other words, when the slip mode is specified by the driver's operation, a mode signal with a voltage level exceeding 2.5V is output, and when the normal mode is specified, a mode signal with a voltage level below 2.5V is output. It looks like this. Then, the CPU 41 controls the vehicle speed sensor 3 by processing according to a flowchart to be described in detail later.
2. Based on the signals from the throttle opening sensor 31, mode select switch 33, and crank angle sensor 34, a shift control signal is output to each shift solenoid 24, 25 of the automatic transmission 2 via the output boat 45 and output buffer 46. In addition, the ignition coil 3
6 to output an ignition control signal. Furthermore, the control unit 3 includes a CPU to count the time.
Programmable timer (PTM) 47, which can be set by commands from 41, Free running counter (FRC)
) 48, ROM 49 and RAM 50 are provided, and the R0M 49 has an ignition timing map that corresponds to the throttle opening and the engine rotational speed, and a gear shift that sets the gear stage corresponding to the engine rotational speed and the throttle opening. Maps, slow color amounts when shifting in each mode, etc. are stored.

Next, a specific example of control by the control unit 3 will be explained with reference to flowcharts shown in FIGS. 3 to 5.

FIG. 3 shows the main routine. In this routine, initialization is first performed in step S1, and the shift time C8 of the shift counter and the free lining counter (FR
C) Current time T from 48.

is set to O, and the throttle opening TA and mode select switch 33 are set to O in step S2 and step S3, respectively.
After inputting the voltage level MD of the mode signal, in step S4 and step s5, the vehicle speed vv and engine rotation speed NE are determined from the vehicle speed signal interrupt period TP and TDC period TE obtained by the interwoven routine described later.
to be measured.

Next, in step S6, it is determined whether the mode is normal mode or slip mode, that is, whether the road surface μ is high or low, based on the voltage level MD of the mode signal.

That is, in step S6, processing is performed by the road surface condition determining means 37 that determines the road surface μ.

Then, in step S6, when the voltage level MD of the mode signal exceeds 2.5■, it is determined that the slip mode is present, and in step $7, the shift retard angle mAR8 is set to a preset large value AR8L.

Further, in step S6, the voltage level MD of the mode signal is set to 2.
．． When it is less than 5■, it is determined that the mode is normal mode, and in step S8, the slow color amount AR8 during shifting is set to a preset small value AR8S.

After that, in step S9, the basic ignition timing AB is calculated from the ignition timing map that corresponds to the throttle opening TA and the engine speed NE, and then in step S10, the basic ignition timing AB is calculated in accordance with the engine speed NE and the throttle opening TA. The gear position PG is measured from the shift map in which the gear position is set, and in step S++, the shift solenoid 24. , 25, the shift control signal SS1. S.S.
Outputs 2.

After executing step S11, it is determined in step S12 whether or not a shift control signal has been output. That is, if the previous gear position PG is different from the updated gear position PGB, it is determined that the shift control signal has been output, and if the previous gear position PG is the same as the updated gear position PGB, the shift control signal is not output. It is determined that

If it is determined in step S12 that the shift control signal has been output, the current time TO is read from the FRC48 in step S13, the shift time O8 is set to the shift required time C8O in step S14, and the previous gear position PG is set in step S15. After updating the gear position PGB,
In step S1a, the current time T1 is read again from the FRC48. Here, the shift required time C8O indicates the time required from when the shift control signal is output to when the shift is completed,
This time is checked and stored in advance.

If it is determined in step S12 that the shift control signal is not output, steps 313 to S15 are skipped and the current time T1 is read from the FRC 48 in step S16.

After executing step S16, in step S17 the formula [C3=
C8-(T1-To)], the shift time O8 of the shift counter is subtracted, and it is determined in step S+a whether the calculated shift time C8 is greater than O. If the required shift time C8O has not elapsed, that is, if the shift is in progress, the shift time C8 calculated in step $17 is greater than O, so it is determined in step S18 that the shift time O8 calculated is greater than O. Ru. Also, the time required for shifting C8O
has passed, that is, the shift has been completed, or if the shift control signal is not output and the shift is not performed, the shift time C8 obtained in step S17 will be smaller than O, so the calculation result will be changed in step S818. It is determined that the shift time O8 is smaller than O. Therefore, if the calculated shift time O8 is greater than O, the shift is in progress, and if it is smaller than O, the shift is not in progress.

If it is determined in step 818 that the calculated shift time O8 is larger than O, then step S20 is directly executed, and if it is determined in step 318 that the calculated shift time O8 is smaller than O, then step S20 is executed directly. In Step 19, set the calculated shift time O8 to O, and then proceed to Step S2.
Execute 0.

In step S20, the current time T1 of the FRC48 is set to
After executing step S20, steps 82 and subsequent steps are executed again.

FIG. 4 shows the first interwoven routine.

This routine is executed every time the vehicle speed signal is sent from the vehicle speed sensor 32, that is, every time the propeller shaft rotates by 45 degrees. When started by the vehicle speed signal every 45 degrees, the interrupt time T4 is read from the FRC 48 in step IS+. Then, in step IS2, the vehicle speed signal interrupt period TP is calculated based on the difference between the current interrupt time T4 and the previous interrupt time T5.
In step 183, the previous interrupt time T5 is calculated as [T
5=T4]. The vehicle speed signal interrupt period TP obtained in this routine is determined by the vehicle speed V
It is used to find V.

FIG. 5 shows the second interlab mill routine.

This routine is executed for each crank angle signal from the crank angle sensor 34, that is, for each TDC of the engine, and when started by the crank angle signal for each TDC, the interrupt time T2 is read from the FRC 48 in step IS4. Then, in step IS5, the TDC period TE is calculated based on the difference between the current interrupt time T2 and the previous interrupt time T3, and in step ISs, the previous interrupt time is calculated as [T3=
Updated with T2. After executing step IS6, step I
In S7, it is determined whether the shift time C8 is longer than O, that is, whether or not the gear is being shifted.

If it is determined in step IS7 that the shift time C8 is longer than O, that is, the shift is in progress, step ISs
The final ignition timing SA is calculated from the difference between the basic ignition timing AB and the shift-time retarded color amount AR3. Also, step IS
If it is determined in step IS9 that the shift time C8 is smaller than 0, that is, that the shift is not in progress, the final ignition timing SA is set to the basic ignition timing AB in step IS9.

When the final ignition timing SA is determined in step TSa or step IS9, step l5 is performed based on the result.
The energizing time TC at 1o is calculated using the formula [TC-(15O-8A)*T
E/180] and calculate the result in step S
11 to set PTM47. Note that the energization start time is set to a constant time with respect to TDC.

In this way, in these controllers 1 to 3, when it is determined that the gears are not shifting, the final ignition timing SA is set to the basic ignition timing AS, but when it is determined that the gears are shifting, the final ignition timing SA is set to the basic ignition timing AS. The timing SA is the value obtained by subtracting the late color amount AR8 during shifting from the basic ignition timing AS. Therefore, when shifting, the final ignition timing S
A becomes smaller. When the final ignition timing SA becomes smaller, the energization time TC becomes longer according to the formula in step l51o,
As a result, the ignition timing is delayed. Therefore, when the gear is being changed, the engine output is lower than when the gear is not being changed, and the shift shock during the gear change can be reduced.

Moreover, as shown in the main routine, the late color amount AR8 during shifting is set to a large value AR8L when in slip mode, and is set to a small value AR3S when in normal mode.
It is now set to . For this reason, during gear shifting,
Further, in the slip mode, that is, when the road surface condition determining means 37 determines that the road surface μ is low, the ignition timing is significantly delayed, the engine output is greatly reduced, and the driving force of the tires is extremely small. Therefore, it is possible to prevent the vehicle from slipping when upshifting or the like on a low μ road such as a snowy road. Furthermore, when the gear is being shifted and the normal mode is in effect, that is, when the road surface condition determining means 37 determines that the road surface μ is high, the final ignition timing SA is only slightly reduced, and the amount of decrease in engine output is also small. This prevents the tire driving force from becoming extremely small. Therefore, it is possible to obtain sufficient acceleration when shifting up on a high μ road such as a normal road surface.In the above flowchart, steps S7 and Sa of the main 1 routine and steps In step IS7, 188, processing by the engine output reduction means 38 is performed.

In the embodiment described above, the ignition timing is retarded as a method of reducing engine output, but the method is not limited to this. For example, when the road surface μ is low, the air-fuel ratio may be made leaner or the amount of intake air may be reduced than when the road surface μ is high. Further, in the embodiment, when the road surface μ determined by the road surface condition determining means is low, the engine output is reduced to a greater extent than when the road surface μ is high during any of the shift up and shift 1 to shift down. However, it may be possible to perform only one of upshifting and downshifting.

[Effects of the Invention] The engine control device for a vehicle with an automatic transmission according to the present invention includes a road surface condition determining means for determining road surface μ, and when the road surface μ determined by the road surface condition determining means is low, the road surface μ is high. The engine output reducing means is provided to greatly reduce the engine output during gear shifting. Therefore, when the road surface condition determination means determines that the road surface μ is low, the engine output reduction means greatly reduces the engine output during gear shifting, thereby suppressing an increase in tire driving force. Therefore, slippage can be prevented from occurring during gear changes on low μ roads such as snowy roads. Further, when the road surface condition determining means determines that the road surface μ is high, the engine output reducing means only slightly reduces the engine output during gear shifting, thereby preventing the tire driving force from being extremely reduced. Therefore, it is possible to prevent the acceleration performance from being impaired when changing gears on a normal road surface with a high μ road.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of an engine control device for a vehicle with an automatic transmission according to the present invention, FIG. 2 is a block diagram showing the internal configuration of the control unit, and FIG.
Figures 1 through 5 are flowcharts 1-1 showing specific examples of control.
It is. 1... Engine, 2... Automatic transmission, 37... Road surface condition determination means, 38... Engine output reduction means.

Claims (1)

[Claims] 1. In an engine control device that reduces engine output by a predetermined amount during gear shifting of an automatic transmission, road surface μ
and engine output reducing means for reducing the engine output during gear shifting to a greater extent when the road surface μ determined by the road surface condition determining means is low than when the road surface μ is high. An engine control device for a vehicle with an automatic transmission, characterized in that: