JPH04166669A - Engine output control device for vehicle - Google Patents

Abstract

PURPOSE:To restrict retard of ignition timing, namely, an ignition lead angle value, when the ignition timing is controlled, and interrupt generation of explosion burning state which brings excessive rising of the temperature of an engine and exhaust gas, by setting a limit value to the retard amount of the engine ignition timing. CONSTITUTION:By an ignition/injection timing detecting means 31, the timing signal of ignition and fuel injection is generated in response to the signal of a crank angle sensor 7 and a cam angle sensor 8 so as to apply this signal to the ignition control means 32 of each of ignition plugs 12a to 12f and the injection control means 33 of each of injectors 13a to 13f. And by the output reducing amount setting means 44 of an engine, an engine output reducing amount is set in response to the real engine torque from an engine output torque conversion means 38 and the target engine torque of a target engine torque setting means 42. In this case, a limit value is set to the retard amount of ignition timing. The limit value of the retard amount is set on the basis of a fuel injection amount and an engine rotational speed.

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
-68537 Publication), a type that calculates the limit torque that can drive the tires from the road surface condition and the ground contact load of the vehicle, and controls the engine to obtain that torque (for example, Japanese Patent Application Laid-Open No. 147546/1982). etc. are known.

[Problem to be solved by the invention]

However, with the slip detection type, if the engine output is controlled by feedback control that responds to the slip value, for example, the control system may be delayed or the response may change depending on the engine speed, resulting in deceleration or acceleration. There is a problem in that this repeatedly occurs, which 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 coefficient of friction of the road surface to predict the torque. detection is required, and such detection cannot be easily performed.

The present invention controls the driving force without depending on the slip value,
Ignition timing control is related to the control of the torque that the engine should generate from the engine side, and the control of the engine output by controlling the number of injection cylinders and ignition timing of the engine according to the target engine torque and actual engine torque. An object of the present invention is to provide a vehicle engine output control device that prevents overheating of the engine and exhaust gas caused by the engine.

[Means to solve the problem]

In order to achieve the above object, the present invention sets the engine output reduction amount from the target engine torque and the actual engine torque] 31, and controls the engine output by controlling the number of injection activated cylinders and ignition timing according to the output reduction group. A vehicle engine output control device is characterized in that a limit value is set for the amount of retardation of ignition timing.

[For production]

Due to this configuration, when controlling the ignition timing, the ignition timing is retarded, and therefore the ignition advance value is limited, thereby preventing the occurrence of an explosive combustion state that causes excessive temperature rise of the engine and exhaust gas. I will do it.

〔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 3a.

3b, has an engine 4, and the rotation of the engine is transmitted to the drive wheels 2a, 2 via a power transmission device 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 connects a 6f spark plug 1.2 to each cylinder 6a based on signals from a crank angle sensor 7 and a cam angle sensor 8.
The ignition timing of the cylinders a to 12f is controlled, and the 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 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 standard 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 a slip state determination from an ASR control unit 16, and controls brake pads 19a, 1.9b of drive wheels 2a, 2b. , the slip is controlled by brake control.

Engine control unit 11. ! : Three signal lines 20a, 2 between the ASR control unit 16 and
0b and 20e 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 20e indicates that the ASR control unit 16 gives a status signal to the engine control unit 11 indicating whether or not brake control based on the slip condition determination is possible. Sometimes the signal line 20a
, 20b for disconnection, and when a disconnection condition is detected, a detection signal is given to the ASR control unit 16, and a signal indicating when engine output control cannot be performed due to engine-specific problems such as low water temperature. This is a line that applies the voltage 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 timing signals for ignition and fuel injection 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 13a 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 calculation 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 of the injector Tpt-
It is calculated based on Tp-kQ/N and 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 controls the ignition timing correction means 37 in red in response to the output signal of the normal ignition timing calculation means 36, and when a slip condition is not determined, the spark plugs 12a to 12f adjust to the ignition timing calculated by the normal ignition timing calculation means 36. is ignited.

The engine output torque converting means 38 calculates, based on the injection amount Tp of the fuel injection amount calculating means 35, instantaneous information, that is, in a state where all cylinders are assumed to be operating during control.
The actual engine torque, that is, the value of the engine torque Tr corresponding to all-cylinder 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 is a linear function of the injection amount Tp expressed as Tr-ATp-B (where A and B are constants). be.

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 R 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, which is generated by slipping. 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 slip will be greater. 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 and the rotation speed of the engine and drive system to decrease. If the moment of inertia J of the engine and drive system is constant, the acceleration torque of the engine and drive system has 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.
Then, from the actual engine torque Tr and engine speed change rate ~, Trb-Tr-kf;J, where k is set to <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 , inertia motor due to steering etc. =
There is a problem with the existence of various error factors such as changes in performance. death,
(The difference in the compensatory moment is reflected in a change in the engine speed), and the presence of various error factors such as engine torque detection errors will also ultimately appear as a change in the engine speed. . Therefore, it is possible to remove the influence of the error factor by adding a feedback term that returns the engine speed to the initial value, and the target engine torque setting means 42 has the initial target engine torque Trb as well as the initial target engine torque Trb. In order to introduce a feedback amount, an initial target engine speed No. and an engine speed N are introduced, and the target engine torque Trd is T r d-T r h-K (N-No), where K
is set based on the relational expression of engine speed feedback gain.

The engine output paper lti amount setting means 44 responds to the actual engine torque T from the engine output torque converting means 38 and the engine torque Trd of the target engine torque setting stage 42 (,5, engine output reduction The number of cylinders in which injection is activated in the J-engine and the retard control of the ignition timing for the cylinders in which injection is activated, that is, ignition advance value control, are performed according to the amount of reduction. As the reduction in personnel increases, the number of cylinders in which injection is activated is reduced as shown by a, and the engine generated torque is controlled in stages over a wide range as shown by a. then b
By changing the amount of retard of the ignition timing as shown in Figure 2, retard control, that is, ignition advance value control, is performed in the injection activated cylinder by changing the amount of retard of the ignition timing, as shown in Fig. Continuously control over a wide range. 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 takes the maximum value when the amount of output reduction is the minimum, and the reduction index takes the maximum value when the amount of output reduction is the maximum.The horizontal axis is the actual value assuming that all six cylinders are operating. Engine torque T', the interval axis is the actual -7->): ・'n torque T' and the target L engine torque T
rd, that is, the normalized target engine torque Tn (0~
]), and in the case of a six-cylinder engine, the reduction index takes a value of 0 to 6, for example. For example, as shown by the dotted line in the figure, when the actual engine torque Tr is normalized by Tri [1 standard engine] and the torque Tn is Trll, the index is 4.8. The number obtained by adding 1 to the number in the first digit indicates the number of cylinders in which injection is activated.2 Based on this index value, the number of injection cylinders and pattern settings 1st stage 45 is set so that 5 out of 6 cylinders are activated in injection. At the same time, each injector is controlled via the injection control first stage 33 by setting a pattern of which cylinder's fuel injection is to be cut and which cylinder is to be operated.

Then, the parts 0 and 2 obtained by subtracting the reduction index 4.8 from the injection operating cylinder value 5 indicate the amount of retard of the ignition timing, and this is added to the ignition timing supplementary means 37 and the normal ignition timing calculation means 36 The ignition timing is corrected to delay the ignition timing by the retard amount, and the ignition plug is controlled via the ignition control means 32, that is, the ignition advance value is controlled.

A limit value is set for the retard amount of the ignition timing. When ignition timing retard control and ignition advance value control are performed, engine efficiency decreases, combustion energy that is not converted into mechanical power increases, and the temperature of the engine and exhaust gas increases. In particular, an excessive temperature rise in exhaust gas causes damage to the catalyst of the exhaust purification device. Combustion energy is fuel injection amount T
Since it increases in proportion to p and the engine speed N, the limit value of the retard amount is set based on the fuel injection amount and the engine speed.

As described above, engine output reduction control is performed,
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 of 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 of the driving wheel speed sensors 15a 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 15a 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 manually input to the brake control condition determining means 56, which responds to the ground speed by the ground speed converting means 52, the manually operated ASR/OFF switch, and the engine monitor signal, and determines the ground speed by 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 ASR-OFF switch, and the engine monitor signal, but the ASR is turned off while the slip determination 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, the intake air 11Q,
Calculation of engine rotation speed N, calculation of fuel injection RTp, and setting of normal ignition timing are performed in sequence. Then the slip signal (
It is determined whether or not A E T) is occurring (1,0
5), 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 10 is performed.
In step 7, 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 Tr is calculated (11,
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 ignition timing are set from the reduction index, and then the ignition timing and injection cylinder pattern are set (113
, 114), injection and ignition are performed, and the process returns to step 101.

In step 7, if a slip signal was generated last time in step 106 (YES), step 109 is immediately performed.
Proceed to target engine torque setting.

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]6 by a microcomputer.

Initialized in step 201, step 202
~204, the driving 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 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, the brake control condition is set as i■ (YES) based on whether the vehicle speed is lower than the set value or not, and step 211.
At step 212, 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, proceed to step 214; if there is no slip condition in step 208, proceed to step 215; and if the brake control condition is not satisfied in step 2]0, proceed to step 21.
6 and returns to step 202 again.

〔Effect of the invention〕

As explained above (1), the present invention has a limit value set for the amount of retardation of the engine ignition timing. This can prevent the occurrence of explosive combustion conditions that would cause an excessive rise in the temperature of the engine and exhaust gas.

In this way, the engine output can be controlled safely and reliably when a slip occurs.

[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. , 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 means, 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 Patent attorney Nobu Kobashi Slag amount Patent attorney Wataru Ogura Figure 6 Figure 8 Figure 4 Figure 5

Claims (2)

[Claims] (1) In 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 by controlling the number of injection activated cylinders and ignition timing according to the output reduction amount, the ignition An engine output control device for a vehicle, characterized in that a limit value is set for a timing retard amount. (2) The vehicle engine output control device according to claim (1), wherein the limit value of the retard amount is set based on engine speed and fuel injection amount.