JPH04166642A - Engine output control device for vehicle - Google Patents

Abstract

PURPOSE:To widely and continuously control engine torque by controlling the number operating cylinders and ignition timing of an engine in accordance with engine output reducing quantity based on target engine torque and actual engine torque. CONSTITUTION:A value of actual engine torque Tr in every moment is obtained based on an injection quantity Tp of a fuel injection quantity calculating means 35 by an engine output torque converting means 38 during vehicle running while initial target engine torque Trb is set 41 in answering to the actual engine torque Tr and engine speed changing rate in accordance with generation of an output signal Sp of a ship start judging means 39. Target engine torque Trd is set 42 based on the initial target engine torque Trb, initial target engine speed, and engine speed N. An engine output reducing quantity is set in answering to respective engine torque Tr, Trd, in an output reducing quantity setting means 44, and control of the number of injection operating cylinders and retard control of ignition timing are performed in accordance with this reducing quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle engine output control device for controlling the driving force of a vehicle.

[Conventional technology]

There are two major advantages to vehicle driving force control (traxigin control). One is the improvement of driving force in the low vehicle speed range, and when the road surface is wet on snowy roads or when starting, the tires may slip and the vehicle will not move forward and the speed will not increase.
One point is that it is possible to eliminate such situations and increase the driving force.The other is to improve steering safety throughout the low and high speed range, and to avoid situations where the tires suddenly slip and the vehicle becomes unable to steer. The point is that this can be eliminated by controlling the driving force.

Regarding driving force control technology on the low vehicle speed side, there are already known methods such as reducing the engine output on the driving side, controlling the gear position, and controlling the brakes. , a slip detection type that controls the driving force according to slip (for example, Japanese Patent Laid-Open No. 59-68537), calculates the limit torque that can drive the tire from the road surface condition and the ground contact load of the vehicle, and calculates the torque. A type of engine control is known (for example, Japanese Patent Application Laid-open No. 147546/1983).

[Problem to be solved by the invention]

However, in the case of a slip detection type, for example, if the re-engine output is controlled by feedback control that responds to the slip value, deceleration or acceleration may occur due to delays in the control system or changes in the response situation depending on the engine speed. There is a problem with the repeated occurrence of this condition, which in turn affects the steering performance.In addition, the method based on the limit torque from the tire side requires the ground load of the vehicle and the friction of the road surface to predict the torque. This requires detection of the coefficients, and such detection cannot be easily performed.

The present invention controls the driving force without depending on the slip value,
An object of the present invention is to provide a vehicle engine output control device that can grasp the torque that an engine should generate from the engine side and can continuously control engine output over a wide range.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an engine output control device for a vehicle that includes an engine output control means that responds to an engine output reduction amount set based on a target engine torque and an actual engine torque. The means is characterized in that the engine output is controlled by the number of operating cylinders of the engine and the ignition timing.

[For production]

With the above configuration, the number of operating cylinders of the engine is controlled according to the amount of engine output reduction based on the target engine torque and the actual engine torque, and the generated torque of the engine is controlled in a wide range in stages. Since the torque between stages is continuously controlled by retard control of the ignition timing for the operating cylinders, the engine torque can be continuously controlled over a wide range by jointly controlling the number of operating cylinders and the ignition timing. Can be controlled.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows a schematic diagram of a device implemented in a front wheel drive vehicle using a horizontally opposed six-cylinder engine. Vehicle 1 has driving wheels (front wheels) 2a, 2b% and driven wheels 3g.

3b, has an engine 4, and the rotation of the engine is transmitted to the drive wheels 2a, 2 via a power transmission bag W5 having a transmission and a differential device.
transmitted to b. Crank angle sensor 7 that detects the operating stroke of each cylinder 6a to 6f of the engine and the operating state of the engine
, a cam angle sensor 8 , a water temperature sensor 9 , an intake air amount sensor (air flow meter) 10 provided in the intake pipe line, etc., are introduced into the engine control unit 11 .
The unit detects spark plugs 12a to 12a for each cylinder 6a to 6f based on signals from a crank angle sensor 7 and a cam angle sensor 8.
Controls the ignition timing of 12f, and injector 13 of each cylinder.
Controls fuel injection by a to 13f.

Speed sensor 14g, 1 consisting of gears and electromagnetic pickup
4b is the driving wheel 2a, 2b, and the speed sensor 15a,
15b are respectively provided on the driven wheels 3a and 3b, and the detection signals of these sensors are introduced into an ASR control unit (driving slip control unit) 16, which controls the driving wheel speed, the driven wheel speed, and the ground speed of the vehicle. The slip ratio of the driving wheels is calculated based on the difference between the two, and when the slip ratio becomes equal to or higher than the target slip ratio, the slip state is determined and a brake control signal is output. A hydraulic control circuit 18 supplied with oil by a hydraulic pump 17 as a hydraulic source responds to a brake control signal based on the slip state determination from the ASR control unit 16, and controls the drive wheels 2.
The brake pads 19a and 19b of the brake pads 19a and 2b are controlled, and slip is controlled by brake control.

Three signal lines 20a and 20b are provided between the engine control unit 11 and the ASR control unit 16.
, 20c are provided. The signal line 20a provides a slip signal (AET) to the engine control unit 11 when the ASR control unit 16 determines a slip state, and the unit 11 responds to the slip signal and controls the engine output. signal line 20
A signal line 20b indicates that the ASR control unit 16 provides a status signal to the engine control unit 11 regarding whether or not brake control based on the slip state determination is possible. Sometimes the signal line 20a
, 20b, and when a disconnection condition is detected, the detection signal is sent to the ASR control I/roll unit 16, and the engine output control is performed due to engine-specific problems such as low water temperature. This is a line that applies a signal to the ASR control unit 16 to indicate when the ASR control unit 16 cannot be used.

The first figure is a block diagram showing the configuration of the engine knee control unit 1,1. The ignition/injection timing detection means 3] generates ignition and fuel injection timing signals in response to signals from the crank angle sensor 7 and the cam angle sensor 8, and controls the ignition control means 3 for each of the spark plugs 12'a to 12f.
2 and injection control means 3 for each injector 138 to 13f.
3. Further, the signal from the crank angle sensor 7 is input to the engine rotation speed calculation means 34. The fuel injection amount calculation means 35 calculates the fuel injection amount, that is, the fuel injection pulse width Tp of the injector, from the engine rotation speed N obtained by the engine rotation speed calculation means 34 and the intake air amount Q measured by the intake air amount sensor 10. 1c Calculated based on Q/N I
5. Transfer this to the injection control means 33.

Normal ignition timing calculation 11 stage '36 is the engine rotation speed N
In response to the fuel injection amount Tp (5, the same stage determines the ignition timing to advance the ignition timing when the engine speed N is high.The ignition control means 32 uses the ignition timing correction means 37 to calculate the normal ignition timing. In response to the output signal of the first stage 36, if it is not determined whether there is a slip state, the spark plugs 12a to 12a.
12f is normally ignited at the ignition timing calculated by the ignition timing calculation means 36.

Based on the injection amount Tp of the fuel injection amount calculation means 35, the engine output torque conversion means 38 converts the actual engine torque at the 1 o'clock instant, that is, under the assumption that all cylinders are in operation L2 at the time of control, that is, The value of the engine torque T" corresponding to all-cylinder injection is output. As shown in FIG. ,A,B
is a linear function of the injection 517 U) denoted by a constant).

From ASR control unit 16 to signal line 2 []a
The slip signal (AET) manually input to the engine control unit 11 is sent to the slip start determining means 3.
9, the start of slip is determined and the output signal Sp
is applied to the initial target engine rotation speed setting means 40 and the initial target engine torque setting means 41.

The initial target engine speed setting means 40 sets the engine speed at the time when the slip rate of the driving wheels exceeds the target slip rate, and calculates the difference between this point and the time calculated by the engine speed calculating means 34. In consideration of this, the engine rotation speed N obtained by the engine rotation speed calculation means 34 is corrected by the engine rotation speed change executive from the engine rotation speed change rate calculation means 43 which responds to the engine rotation speed N, and the initial target engine rotation speed No. Set.

The initial engine torque setting means 41 sets the actual engine torque T' of the engine output torque converting means 38 and the engine speed change rate group of the engine speed change rate calculating means 43 in response to the generation of the output signal Sp of the slip start determining means 39. In response to this, the initial target engine torque Trb is set.

Basically, if the engine torque is suppressed to the value of the actual engine torque at the time when the slip starts, further slip will not occur. By the way, when considering the output torque of an engine, it consists of the torque for driving the engine and drive system from the engine to the drive wheels, and the torque for driving the vehicle body by the drive wheels, and this is due to slippage. If you look at it when the engine is running, engine torque - vehicle acceleration!・The relationship of torque + acceleration torque of the engine and drive system is established. l. Therefore, when a slip occurs, if the engine torque is suppressed to the torque required to accelerate the heavy object, which is obtained by subtracting the acceleration torque of the engine and drive system from the actual engine torque at the time of the slip, Larger slips do not occur and it becomes possible to maintain an appropriate slip ratio.

By the way, since the acceleration torque of the engine and drive system is the product of the moment of inertia J of the engine and drive system and the angular acceleration, that is, the rate of change in rotational speed, slip occurs in this acceleration torque, causing the rotational speed of the engine and drivetrain to change. If the moment of inertia J of the engine and drive system is constant, the acceleration torque of the engine and drive system will have a value proportional to the rate of change in engine speed.

As understood from the above, the initial target engine torque setting means 41 sets the initial target engine torque Trb.
As, from the actual engine torque Tr and engine speed change rate, T r b = T r k i'J + However,
k sets a torque value based on a constant relational expression.

The engine generated torque is the initial target engine torque T
If the engine output is controlled so that rb is achieved, the increase in slip can be suppressed and appropriate vehicle driving force can be obtained.However, errors in converting the engine generated torque from the fuel injection amount Tp and transmission gear changes There are problems with the existence of various error factors such as changes in the moment of inertia due to steering, etc. However, the difference in the moment of inertia is reflected as a change in the engine speed, and the presence of various error factors such as engine torque detection errors also ultimately appears as a change in the engine speed. Therefore, by adding a feedback term that returns the engine speed to the initial value, it is possible to eliminate the influence of error factors, and the target engine torque setting means 42 includes such a feedback amount as well as the initial target engine torque Trb. In order to introduce the initial target engine speed NO and engine speed N, the target engine torque Trd is T r d - T r b - K (N - No) where K
is set based on the relational expression of engine speed feedback gain.

The engine output reduction amount setting means 44 combines the actual engine torque Tr from the engine output torque converting means 38 and the target engine torque Tr from the target engine torque setting means 42.
In response to d, an engine output reduction amount is set, and in accordance with this reduction amount, the number of injection-activated cylinders of the engine and the ignition timing retard control for the injection-activated cylinders, that is, ignition advance value control are performed. In Fig. 7, as the amount of output reduction increases, the number of cylinders in which injection is activated is reduced as shown by a, the engine generated torque is controlled stepwise over a wide range as shown by a, and the amount of output reduction changes. The amount of retard of the ignition timing is changed as shown by b according to the amount of output reduction, and the retard control, that is, the ignition advance value control is performed for the cylinder in which the injection is activated. control over a wide range and continuously. The engine output reduction amount is a three-dimensional function value determined from the target engine torque and actual engine torque values, and FIG. 8 shows the engine output reduction index Aout expressed by a three-dimensional function map regarding the engine output reduction amount. This is shown on a plan view. Here, the reduction index assumes the maximum value when the output reduction amount is the minimum, and the reduction index takes the maximum value when the output reduction amount is the maximum.
The horizontal axis is the actual engine torque Tr assuming that all six cylinders are operating, and the vertical axis is the ratio of the actual engine torque T' to the target engine torque Trd, that is, the normalized target engine torque Tn (0 to 1). For a 6-cylinder engine, the reduction index is assumed to take a value of 0 to 6, for example.For example, as shown by the dotted line in the figure, if the actual engine torque T is Tri and the normalized target engine torque Tn is Tn
When l, the exponent is 4.8. The number obtained by adding 1 to the numerical value in the first digit indicates the number of cylinders in which injection is activated, and based on this index value, the injection cylinder number/pattern setting means 45 sets so that five of the six cylinders are activated in injection, A pattern is set for which cylinder fuel injection is to be cut and which cylinder is to be operated, and each injector is controlled via the injection control means 33.

Then, the part 0 and 2 obtained by subtracting the reduction index 4.8 from the injection operating cylinder value 5 indicates the amount of retard of the ignition timing, and this is added to the ignition timing correction means 37 and the ignition timing is determined by the normal ignition timing calculation means 36. The ignition timing is corrected so as to be delayed by the retard amount, and the ignition plug is controlled via the ignition control means 32, that is, ignition advance value control is performed. In this way, the engine output is controlled to reduce, and the engine output is controlled so that the actual engine torque becomes the target engine torque Trd.

In addition, the ASR control unit 16 in FIG.
A signal indicating that brake control cannot be performed from
) occurs, the same signal may be introduced to the target engine torque setting means 42 to change the target engine torque value.

Further, the engine side drive slip control prohibition determination means 46 responds to the slip signal (AET), water temperature sensor 9, and signals from other sensors such as knock sensors, and outputs an output indicating that engine control is not possible when there is a problem on the engine side. The same output is applied to means 47 for generating a monitor signal (EAM) for notifying the ASR control unit 16 of such a condition via signal line 20e in FIG.

Figure 3 shows the ASR control unit 1 in Figure 2.
6 shows a block diagram for 6.

Based on the signals from the drive wheel speed sensors 14a and 14b, the drive wheel speed conversion means 51 calculates the drive wheel speed V(i).
The ground speed converting means 52 is the speed sensor 15a, 1 of the driven wheel.
The ground speed Vg is calculated from the signal 5b. The slip ratio calculating means 53 calculates the slip ratio S from the driving wheel speed Vd and the ground speed Vg based on S-(Vd-Vg)/Vd (2,0≦S≦1). The target slip ratio St is calculated from the signals of the speed sensors 15a and 15b of the driven wheels, and for example, when the speed is high or when a large lateral force is required during steering, the slip ratio is reduced. , the target slip rate St is calculated depending on the speed of the driven left and right wheels.The slip rate S and the target slip rate St are determined by the slip determination means 55.
A slip is determined when the slip rate S becomes equal to or higher than the target slip rate St. This slip determination signal is input to the brake control condition determining means 56, which responds to the ground speed by the ground speed converting means 52, the artificially operated ASR/OFF switch, and the engine monitor signal, and determines the ground speed. When a slip determination signal is input when the brake control is not high, brake control is not turned off, and engine operation is normal and brake control may be performed, a signal allowing brake control is output.

Accordingly, the brake control means 58 controls the target slip rate St.
The brake signal generating means 59 performs brake control so that an appropriate brake amount is obtained according to the actual slip rate S.
is a signal indicating that brake control is being performed (AEB
) occurs.

Further, the slip determination signal is input to the engine control condition determination means 60, which outputs a signal that allows engine control on the condition that ASR is not off and there is no problem with the engine according to the engine monitor signal. Accordingly, the timing signal generating means 61 generates a slip signal (AE
T) is output.

The ASR/OFF display condition determining means 62 responds to the slip determination signal, the ASRφOFF switch, and the engine monitor signal, but while the slip determination signal is present, the ASR/OFF display condition determination means 62 does not display the ASR or OFF display even if an abnormality occurs in the engine. When the slip control continues and the slip disappears, it is determined that the OFF display is allowed, and the ASR
- Operate the OFF display generating means 63.

Figure 4 shows a flowchart regarding engine control by the engine control unit [1] using the micro combi coater.

First, in steps 1.01 to 104, the intake air tQ,
Calculation of engine speed N, calculation of fuel injection amount Tp, and setting of normal ignition timing are performed in sequence. Then the slip signal (
AE T) is occurring (105).
), when a slip signal has occurred (YES), it is determined whether or not it happened last time (106), and when a new slip signal has occurred this time (NO), step 107
In step 108, the initial target engine torque Trb is calculated and set, and in step 108, the initial target engine rotation speed No. is set.

Next, the target engine torque Trd is set (1,0
9), the actual engine torque T is calculated as (1, 1
0), an index Aout for the engine output reduction amount is set based on the target engine torque and the actual engine torque. Then, in steps 112 and 113, the number of injection cylinders and the retard amount of the ignition timing are set from the reduction index, and then the ignition timing and the injection cylinder pattern are set (113
, 114), injection and ignition are performed, and the process returns to step 101.

If the slip signal was generated last time in step 106 (YES), the process immediately proceeds to step 109 to set the target engine torque.

Further, when the slip signal is not generated in step 105, the target engine torque Tr is separately determined in step 116.
a is calculated, and the process moves to step 110. This engine torque Tra is updated each time by adding a predetermined torque increment to the previous torque value until it reaches the maximum torque value.

FIG. 5 shows a flowchart regarding slip detection and brake control of the ASR control unit 16 by the microcomputer.

Initialized in step 201, step 202
In steps 204 to 204, the drive wheel speed, ground speed, and slip ratio are calculated in sequence. In step 205, it is determined whether or not the ASR/OFF switch has been operated.
If the answer is NO, it is determined in step 206 whether or not there is any problem with the engine. If there is no problem with the engine, the ASR-OF lamp is turned off in step 207, indicating that ASR can be performed, and then in step 208 it is determined whether or not there is a slip condition.

If it is in a slip state, a slip signal (AET) is generated (209), and in step 210, for example, the ground speed (AET) is generated.
If the vehicle speed is low based on whether the vehicle speed (vehicle speed) is below the set value, the brake control condition is set as possible (YES), and step 211.2
At step 12, a brake signal is generated, brake control is executed, and the process returns to step 202.

If the ASR/OFF switch has been operated in step 205, it is determined in step 213 whether or not the current slip condition is present. If the slip condition continues, the process moves to step 206 and subsequent steps. If the slip condition is not present, step At 214, the ASR/OFF lamp is turned on, the slip signal (AET) is turned off (215), and the brake signal is turned off (216).

If there is a problem with the engine in step 206, the process moves to step 214, if there is no slip condition in step 208, the process moves to step 215, and if the brake control conditions are not satisfied in step 210, the process moves to step 216 as described above.
, and returns to step 202 again.

〔Effect of the invention〕

Since the present invention is configured as described above, the torque generated by the engine is gradually increased over a wide range by controlling the number of operating cylinders of the engine according to the target engine torque and the amount of engine output reduction based on the actual engine. Since the torque between these stages is continuously controlled by ignition timing retard control, that is, ignition advance value control for the active cylinders, engine torque can be continuously controlled over a wide range.

Therefore, when a slip occurs, it is possible to generate an engine torque corresponding to an arbitrary target engine torque, thereby preventing the occurrence of excessive slip and making it possible to generate an appropriate driving force for the vehicle.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a schematic diagram of an embodiment of the present invention, FIG. 3 is a block diagram of an ASR control unit, and FIG. 4 is a flowchart of an embodiment of the present invention. , Figure 5 is a flowchart for the ASR control unit, Figure 6 is a characteristic diagram showing the relationship between engine torque and fuel injection amount, Figure 7 is an operation explanatory diagram for engine output reduction, and Figure 8 is engine output reduction. It is an explanatory diagram about an index. 32... Ignition control means, 33... Injection control 8f stage, 3
4... Engine rotation speed calculation means, 37... Ignition timing correction means, 38... Engine output torque conversion means, 3
9... Slip start determining means, 42... Target engine torque setting means, 44-... Output reduction amount setting means, 4
5...Injection cylinder number/pattern setting means. Patent applicant Fuji Heavy Industries Co., Ltd. Agent Nobu Kobashi Slag amount Patent attorney Wataru Ogura Figure 6 Figure 8 Engine torque T "Figure 4 Figure 5

Claims (1)

[Claims] (1) In a vehicle engine output control device comprising an engine output control means that responds to an engine output reduction amount set based on a target engine torque and an actual engine torque, the engine output control means controls the number of operating cylinders of the engine and the number of operating cylinders. An engine output control device for a vehicle, characterized in that the engine output is controlled by the ignition timing of a cylinder.