JPH04166634A - Engine output controller for vehicle - Google Patents

Abstract

PURPOSE:To simply detect engine torque, restrain generation of excessive slip and generate suitable drive force by determining the engine torque from a fuel injection quantity on the basis of a functional relationship between the engine torque and the fuel injection quantity. CONSTITUTION:During travel of a vehicle, an engine output torque converter 38 determines instant real engine torque, i.e., engine torque Tr corresponding to all cylinder injection on the basis of a fuel quantity Tp of a fuel injection quantity calculator 35 since real engine torque Tr is proportional to a fuel injection quantity Tp. An engine output decrease quantity setter 44 sets an engine output decrease quantity in response to the real engine torque Tr from the engine output torque converter 38 and target engine torque Trd of a target engine torque setter 42 upon generation of an output signal Sp from a slip start deciding means 39, to retard-correct an ignition timing, for decrease control of an engine output.

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 (traction 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 driving safety in the entire low and high speed range. The point is that it can be eliminated by controlling the

As for drive force control technologies on the low vehicle speed side, there are already known technologies such as those that throttle the engine output on the drive side, those that control the gears, and those that control the brakes. A slip detection type that controls the driving force according to slip (for example, Japanese Patent Application Laid-open No. 59
(Japanese Unexamined Patent Publication No. 60-147546), which calculates the limit torque that the tires can drive based on the road surface condition and the ground contact load of the vehicle, and controls the engine to obtain that torque. etc. are known.

[Problems to be Solved by the Invention] However, in the slip detection type, for example, if the engine output is controlled by feedback control that responds to the slip value, the response situation may change due to the delay in the control system or the engine speed. There is a problem in that, due to changes in It is necessary to detect the ground load of the vehicle, the friction coefficient of the road surface, and the actual engine torque to be compared with the calculated torque, and there is a problem that 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 engine output control device that can easily detect the actual engine torque by grasping the torque generated by the engine from the engine side.

[Failure to solve the problem]

In order to achieve the above object, the present invention provides a vehicle engine output control device that sets an engine output reduction amount from a target engine torque and an actual engine torque, and controls the engine output according to the output reduction amount. The present invention is characterized in that the actual engine torque is determined based on the fuel injection amount.

[For production]

As shown in FIG. 6, based on the functional relationship between engine torque T' and fuel injection 11Tp, engine torque can be determined from the fuel injection amount, and engine torque can be determined from the engine operation result after fuel injection. Since the cause of the operation can be determined at the stage of determining the cause of the operation, the response of driving force control can be accelerated.

〔Example〕

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

FIG. 2 shows a schematic diagram of the device implemented in a front-wheel drive vehicle using a horizontally opposed engine.The vehicle 1 has drive wheels (front wheels) 2a. 2b, driven wheel 3a.

3b, has an engine 4, and the rotation of the engine is transmitted through a power transmission device 5 having a transmission and a differential device (7) to drive wheels 2a,
2b. A crank angle sensor 7, a cam angle sensor 8, a water temperature sensor 9, an intake air amount sensor (air flow meter) 10 provided in the intake pipe, etc., which detect the operating stroke of each cylinder 6a to 6f of the engine and the operating state of the engine. The detection signal is introduced into the engine control unit 11, which controls the crank angle sensor 7 and the cam angle sensor 8.
Spark plugs 12a of each cylinder 6a=6f based on the signal of
The ignition timing of the cylinders 182f to 182f is set to tl[l, and fuel injection by the injectors 13a to 13f of each cylinder is controlled.

Speed sensor 14a, 1 consisting of a gear and an 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 the AsR control unit (drive slip control unit I=) 16.
The unit measures driving wheel speed and driven wheel speed 1. Therefore, the vehicle vs. j1i! The slip rate of the driving wheels is calculated based on the difference from the speed, and when the slip rate exceeds the target slip rate, the slip state is determined and a brake control signal is output. Hydraulic control circuit supplied with oil by hydraulic pump 17 as a hydraulic source] 8 is A3B control unit two.
16 (brake pads 19a of drive wheels 2a, 2b)
, 19b, and the slip is controlled by brake control.

Three signal lines 20a are provided between the engine control I/roll unit l-11 and the ASR control unit 1-6,
20b and 20e are provided. The signal line 20a is ASR
When the control unit I.16 determines a slip condition, it gives a slip signal (AET) to the engine control unit 11.
responds to the slip signal and controls engine power. The signal line 2Ob is for the ASR control unit 16 to give a status signal to the engine control unit 11 regarding whether or not brake control based on the slip condition determination is possible. The signal lines 20a and 20b are checked for disconnection when the signal line 20a and 20b start up, and if a disconnection condition is detected, the detection signal is sent to the ASR control unit 16, and the engine output cannot be controlled due to engine-specific problems such as low water temperature. This is a line that applies a signal indicating this to the ASR control unit 16.

FIG. 1 is a block diagram showing the configuration of the engine control unit 11. As shown in FIG. Ignition/injection timing detection means 3
1 generates ignition and fuel injection timing signals in response to signals from the crank angle sensor 7 and cam angle sensor 8, and includes ignition control means 32 for each spark plug 12a to 12f and injection control means 33 for each injector 138 to 13f. to be applied. 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 is
From the engine speed N obtained by the engine speed calculating means 34 and the intake air amount Q measured by the intake air amount sensor 10, the fuel injection amount, that is, the fuel injection pulse width Tp of the injector is calculated as T.
It is calculated based on p −k Q/N and is given to the injection control means 33.

The normal ignition timing calculation means 36 responds to the engine speed N and the fuel injection amount Tp, and determines the ignition timing to advance the ignition timing when the engine speed N is high. The ignition control means 32 responds to the output signal of the normal ignition timing calculation means 36 via the ignition timing correction means 37, and when a slip state is not determined, the spark plugs 12a to 12f adjust to the ignition timing calculated by the normal ignition timing calculation means 36. ignited.

The engine output torque converting means 38 converts the actual engine torque based on the injection amount Tp of the fuel injection amount calculating means 35 into the instantaneous, that is, the actual engine torque under the assumption that all cylinders are operating at the time of control, that is, all cylinders. The value of engine torque Tr corresponding to injection is output. This actual engine torque Tr is in a proportional relationship with the fuel injection amount Tp as shown in Fig. 6, and Tr=ATp-B (A and B are constants).
It is a linear function of the injection amount Tp shown by .

The slip signal (AET) input from the ASR control unit 16 to the engine control unit 11 via the signal line 20a is sent to the slip start determination means 39.
is introduced, determines the start of slip, and applies the output signal Sp to the initial target engine 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 calculation 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 rate group from the engine rotation speed change rate calculation means 43 responsive to the engine rotation speed N, and the initial target engine rotation speed is determined. Set No.

The initial target engine torque setting means 41 responds to the actual engine torque Tr of the engine output torque converting means 38 and the engine speed change rate ~ 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. Then, 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. When the vehicle is running, the following relationship holds: engine torque - acceleration torque of the vehicle body + acceleration torque of the engine and drive system. Therefore, when a slip occurs, if the engine torque is suppressed to the torque necessary to accelerate the vehicle body, 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, the amount of slip will be larger. This does not occur, making it 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 rotation speed, this acceleration torque causes slip to occur, causing the rotation speed of the engine and drive system to change. If the moment of inertia J of the engine and the drive system is constant, the acceleration torque of the engine and the drive system has a value proportional to the rate of change R of the engine speed.

As understood from the above, the initial target engine torque setting means 41 sets the initial target engine torque Trb.
A torque value is set based on the relational expression Trb-Tr-klQ, where k is a constant, from the actual engine torque T' and the engine speed change rate.

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 is a problem that there are many 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 the engine speed N, the target engine torque Trd is Trd-Trb-K (N-No). However, K is set based on the relational expression of the engine speed feedback gain. do.

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, the engine output reduction amount is set. Figure 7 shows the engine output reduction index Ao expressed as a three-dimensional map.
ut is shown in a plan view. The horizontal axis is the actual engine torque T, assuming all six cylinders are operating.
The vertical axis represents the ratio between the actual engine torque Tr and the target engine torque Trd, that is, the normalized target engine torque Tn (0
~1), and in the case of a 6-cylinder engine, the reduction index takes a value of 0 to 6, for example, and as shown by the dotted line in the figure, the actual engine torque Tr is Tri, and the normalized target engine torque Tn is Tnl. Then the index is 4.8. Based on this index value, the injection cylinder number/pattern setting means 45 sets five of the six cylinders to be injected, and also cuts fuel injection in any cylinder.
A pattern of which cylinders are to be operated is set, and each injector is controlled via the injection control means 33. and 5
The reduction of -4.8-0.2 is the retard amount of the ignition timing, and this is added to the ignition timing correction means 37 to correct the ignition timing so that it is delayed by the retard amount from the ignition timing determined by the normal ignition timing calculation means 36. The spark plug is controlled via the ignition control means 32. 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 20c in FIG.

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

The driving wheel speed converting means 51 calculates the driving wheel speed Vd based on the signals from the driving wheel speed sensors 14a and 14b, and the ground speed converting means 52 calculates the driving wheel speed Vd based on the signals from the driving wheel speed sensors 15g and 15b.
The ground speed Vg is calculated from the signal. The slip rate calculating means 53 calculates the slip rate S from the driving wheel speed Vd and the ground speed Vg based on S-(Vd-Vg)/Vd, where 0≦S≦1. The target slip ratio calculating means 54 calculates the target slip ratio St from the signals of the speed sensors 15g and 15b of the driven wheels. For example, when the speed is high or when a large lateral force is required during steering, The target slip ratio St is calculated depending on the speed of the driven left and right wheels so as to reduce the slip ratio. 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 judgment signal, the ASR/OFF switch, and the engine monitor signal, but the ASR is turned off while the slip judgment signal is present, or is turned off even if an abnormality occurs in the engine. If 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.

FIG. 4 shows a flowchart regarding engine control by the engine control unit 11 by the microcomputer.

First, in steps 101 to 104, calculation of the intake air amount Q1 and engine rotational speed N, calculation of the fuel injection amount Tp, and setting of the normal ignition timing are performed in sequence. Then the slip signal (A
It is determined whether or not ET) is occurring (105).
If a slip signal has occurred (YES), it is determined whether or not it happened last time (106), and if a new slip signal has occurred this time (NO), the initial target engine torque Trb is calculated and set in step 107. Then, in step 108, an initial target engine speed No. is set.

Next, the target engine torque Trd is set (109
), the actual engine torque Tr is calculated (110).
, 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, 1
14), 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, turn off the ASR/OFF lamp in step 207, that is, turn off the ASR.
Step 2
At step 08, it is determined whether or not the vehicle is in a slip state.

If the vehicle is in a slip state, a slip signal (AET) is generated (209), and in step 210, for example, if the vehicle speed is low based on whether the ground speed (vehicle speed) is below a set value, the brake control condition is enabled (YES); Step 211.21
2 generates a brake signal and executes brake control,
Return 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 ASRφOFF 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 engine torque is determined from the fuel injection amount based on the fact that the engine torque and the fuel injection amount have a functional relationship, so that the engine torque can be easily detected. Since engine torque can be determined from the cause of engine operation rather than from the result of engine operation, the response of engine output control based on target engine torque and actual engine torque is improved when slip is detected. The occurrence of excessive slip is suppressed, and appropriate driving force can be generated.

[Brief explanation of drawings]

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. , FIG. 5 is a flowchart regarding the ASR control unit, FIG. 6 is a characteristic diagram showing the relationship between engine torque and fuel injection amount, and FIG. 7 is an explanatory diagram regarding the amount of engine output reduction. DESCRIPTION OF SYMBOLS 10... Intake air amount sensor, 32... Ignition control means, 33... Injection control means, 34... Engine rotation speed calculation means, 35... Fuel injection amount calculation means, 38...
Engine output torque converting means, 39...Slip start determining means, 42...Target engine torque setting means, 4
4... Output reduction amount setting means. Patent Applicant Fuji Heavy Industries Co., Ltd. Agent Nobu Kobashi Patent Attorney Wataru Ogura Figure 4 Figure 5

Claims (3)

[Claims] (1) In a vehicle engine output control device that sets an engine output reduction amount based on a target engine torque and an actual engine torque, and controls the engine output according to the output reduction amount, the actual engine torque is set based on the fuel injection amount. 1. A vehicle engine output control device, characterized in that it is configured as specified. (2) The vehicle engine output control device according to claim (1), wherein the fuel injection amount is determined by the injection pulse width of the injector based on the ratio of the intake air amount of the engine to the engine speed. (3) A vehicle engine output control device configured such that the actual engine torque is determined by a linear function of the fuel injection amount.