JPH02176130A - Driving wheel slip control device - Google Patents

Abstract

PURPOSE:To prevent engine stall by changing engine revolution number to restrain an engine output reducing means when a valve head characteristic switching means for controlling a valve head characteristic to the lower output side according to the slip state of driving wheels is operated. CONSTITUTION:A traction control system 51 detects the deviation V between the driving wheel speed Vw and car speed Vv, that is, the slip state of driving wheels, and an engine control system 52 controls fuel cut cylinders corresponding to it and a variable valve timing control part 53 changes a valve timing characteristic to the lower output torque side through a switching solenoid. In this case, the control unit 53 switches the valve timing to the torque characteristic on the low speed valve timing side when the engine revolution number Ne is lower than the predetermined value, and to the torque characteristic on the high speed valve timing side when it is higher than the predetermined value. In this way, both prevention of engine stall and expansion of slip control zone can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a drive wheel slip control device, and in particular to a control prohibited area during slip control in an internal combustion engine in which the lift characteristics of an intake valve or an exhaust valve can be changed to 1 level. This invention relates to a drive 1*slip +iI control device that can appropriately set the following.

(Prior art and problem to be solved by the invention) In controlling an internal combustion engine, when slip of the drive wheels is detected, the output of the engine is reduced to prevent the slip, thereby reducing the torque of the drive wheels. Drive wheel slip control (traction control; TC3) that suppresses excessive slip of the drive wheels is known.

Such traction control can be performed, for example, by reducing engine output by sequentially increasing the number of cylinders in which fuel should be cut when drive wheel slip is detected, but there is a possibility that engine stall will occur as a result of executing traction control. becomes higher. That is, if the engine speed drops due to the fuel cut, there is a high possibility that the engine will stall.

For this reason, basically, in areas where there is a high possibility of engine stalling as described above, a control that prohibits the traction control itself, that is, cancels the operation of the traction control (such as the
However, if the prohibited area is set too wide, that is, if the prohibited area is set to an area with enough margin to prevent engine stalling. Conversely, the control range of the traction control itself becomes narrower.

In other words, when setting a prohibited area, if the method is used to set this strictly, if emphasis is placed on preventing engine stall, the target area of the slip control that should be performed will be reduced by the expansion of the prohibited area. You will end up being
On the other hand, the more emphasis is placed on the control area, the more likely engine stall will occur.

An object of the present invention is to simultaneously achieve these conflicting demands, and by focusing on the engine output torque characteristics of an internal combustion engine whose valve head characteristics can be switched, the present invention utilizes the engine output torque characteristics to prevent engine stall and control slippage. It is an object of the present invention to provide a drive wheel slip control device that can realize both expansion of the area.

(Means for Solving the Problem) In order to achieve the above object, the present invention includes a valve lift characteristic changing means for changing the lift characteristic of at least one of an intake valve and an exhaust valve of an internal combustion engine, and an engine driven engine as described in Ili+. A driving wheel slip control device comprising: a driving wheel slip detecting means for detecting a slip of the driving wheel; and an engine output reducing means for reducing the engine output according to an output of the driving wheel slip detecting means. Valve head characteristic switching means for controlling the valve head characteristic so that the engine output torque is lower than when controlled by the valve head characteristic changing means in response to the output of the slip detection means, and the valve head characteristic switching means are operated. The engine rotation speed changing means for changing the engine rotation speed for suppressing the engine output reduction means when the engine is running is configured to be able to be changed.

(Example) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of a fuel supply control device for an internal combustion engine to which the control device of the present invention is applied. In the figure, 1 is a DOHC in which each cylinder is provided with a pair of intake valves and an exhaust valve.
It is an in-line four-cylinder internal combustion engine.

An intake pipe 2 having an air cleaner 17 attached to its open end and an exhaust pipe 18 are connected to the engine l. A throttle body 3 is provided in the middle of an intake pipe 2 of an engine 1, and a throttle valve 3' is arranged inside the throttle body 3. A throttle valve opening (Oth) sensor 4 is connected to the throttle valve 3', and outputs an electric signal according to the opening of the throttle valve 3' and supplies it to an electronic control unit (hereinafter referred to as rECUJ) 5. .

A fuel injection valve 6 is provided between the engine 1 of the intake '172 and the throttle body 3.

A fuel injection valve 6 is provided for each cylinder slightly upstream of the intake valve, and each injection valve is connected to a fuel pump (not shown) and electrically connected to the ECU 3.
The valve opening time of fuel injection is controlled by the signal from U5.

Further, a solenoid valve 16 for performing valve timing switching control, which will be described later, is connected to the output side of the ECU 3, and the opening/closing operation of the solenoid valve 16 is controlled by the ECU 3.

An intake pipe absolute pressure (Pa^) sensor 8 is provided immediately downstream of the throttle valve 3 via a pipe 7, and the absolute pressure signal converted into an electrical signal by this absolute pressure sensor 8 is sent to the ECU 3. is supplied to

Further, an intake air temperature <-r^) sensor 9 is attached downstream thereof, which detects the intake air temperature T^ and outputs a corresponding electrical signal to be supplied to the ECU 3.

The engine water temperature (Tw) sensor lO attached to the main body of the engine l is made up of a thermistor, etc., and detects the engine water temperature (cooling water temperature) Tw and outputs a corresponding temperature signal to control the EC.
Supply to U3. An engine rotational speed (Ne) sensor 11 and a cylinder discrimination (CYL) sensor I2 are attached around the camshaft or crankshaft of the engine I. The engine rotation speed sensor 11 outputs a pulse (TDC signal pulse) at a predetermined crank angle position every 180 degree rotation of the crankshaft of the engine 1, and the cylinder discrimination sensor 12 outputs a signal pulse at a predetermined crank angle position of a specific cylinder. These signal pulses are supplied to the ECU 3.

The ECU 3 further includes a vehicle speed sensor 13 and a drive wheel speed sensor 1.
4 and other sensors and switches 15 are connected, and their detection signals are supplied to the ECU 3.

EC: U5 is an input circuit 5 having functions such as shaping the input chi δ waveform from various sensors, correcting the voltage level to a predetermined level, and converting analog signal values into digital signal values.
a, central processing circuit (hereinafter referred to as rCPUJ) 5b,
It is comprised of a storage means 5c for storing various calculation programs and calculation results executed by the CPU 5b, an output circuit 5d for supplying drive signals to the fuel injection valve 6 and the electromagnetic valve 16, and the like.

The CPU 5b determines the engine operating state of the raccoon based on the various engine parameter signals described above, and also determines the 'r' according to the engine operating state based on the following equation (1).
The fuel injection time Tour of the fuel injection valve 6 synchronized with the DC signal pulse is calculated.

Tour=T i XK1+2 --- (1) Here, Ti is the basic fuel amount, specifically the engine speed Ne
This is the basic fuel injection time determined according to the intake pipe absolute pressure P++^, and T to determine this '1゛1 value.
Two i-maps are stored in the storage means 5c, one for low-speed valve timing (TiL map) and one for high-speed valve timing (Tin map).

Kl and K2 are correction coefficients and correction variables respectively calculated according to various engine parameter signals, and are set to predetermined values to optimize engine characteristics such as fuel consumption characteristics and engine acceleration characteristics according to engine operating conditions. determined.

The tension cut during traction control, which will be described later, can be performed by setting TOUT to zero.

The CPU 5b further controls the opening and closing of the solenoid valve 16 by issuing a valve timing switching instruction signal using a method that will be described later.

The valve timing is determined based on the value of the engine operating state parameter signal supplied from the engine rotation speed sensor L1 etc., and further based on the vehicle speed signal and drive wheel speed supplied from the vehicle speed sensor 13 and the drive wheel speed sensor 14. It is determined according to the slip state at the time of drive wheel slip detection using a signal. Specific valve timing changes,
Combination patterns of switching modes will be described later.

Based on the results calculated and determined as described above, the CPU 5b sends a drive signal to open the fuel injection valve 6 corresponding to the cylinder in which the intake stroke of the engine 1 starts and a signal to drive the solenoid valve 16 to the output circuit 5d. Output via.

Furthermore, the CPU 5 b determines the engine operating state and the valve timing state, and depending on these determined states, determines, under certain conditions, a region in which engine output reduction processing for preventing drive wheel slip is suppressed. Selectively change that range. In this embodiment, the control prohibited rotation speed that defines the control prohibited area of traction control is set to high,
Do this by setting the switch to low (switching).

Such control to change the prohibited rotational speed is performed in accordance with whether the valve timing is for low speed or high speed and in synchronization with switching of the valve timing.

In this embodiment, the Ti4 configuration is used to switch between high-speed valve timing and low-speed valve timing by selecting a rocker arm and a cam as described below. The present applicant has previously filed an application for valve timing switching control that switches between low-speed valve timing (low-speed V/T) and high-speed valve timing (high-speed V/T) (patent application dated August 1, 1988). FIG. 2 below shows the main parts of a valve train equipped with such a variable valve timing mechanism for the engine I. As shown in FIG.

The figure shows the configuration of an intake valve-side valve operating device for opening and closing a pair of intake valves 20i for one of four cylinders arranged in series in the cylinder block of the engine I. However, the intake valve side valve train in other cylinders has basically the same configuration, and the exhaust valve side valve train for driving the opening and closing of a pair of exhaust valves in each cylinder also has the same structure as the intake valve side valve train. It has basically the same configuration as the valve device.

The intake valve side valve train is housed and arranged in the working chamber defined between the cylinder head and the head cover.
In the figure, reference numeral 21i indicates a flange that is assembled to the upper end of the pair of intake valves 204, and a valve spring (not shown) is compressed between each flange 21i and the cylinder head. is urged upward (toward the surface of the paper in the figure), that is, in the direction of the valve closing force.

The intake valve side valve gear is a high-speed cam and a low-speed cam (both not shown) provided on a camshaft that is rotationally driven at a speed ratio of 1/2 from the engine's crankshaft, and is parallel to the camshaft. Fixedly arranged rocker shaft 22i
, a first driving rocker arm 231, a second driving rocker arm 24i, and a free rocker arm 25i which are pivotally supported on the rocker shaft 22i, and each rocker arm 23i, 241 .
25i, respectively.

First and second drive rocker arms 23i, 24i
A low-speed cam is pressed against the upper surface of each swinging end of the free rocker arm 25i, and a high-speed cam, whose cam surface is formed to protrude more than the low-speed cam, is pressed against the upper surface of the swinging end of the free rocker arm 25i.

In FIG. 2, the connection switching mechanism 26i includes a first switching bin 27 that can connect the first driving rocker arm 23i and the free rocker arm 25i, and a second switching bin 27 that can connect the free rocker arm 25i and the second driving rocker arm 24i. 28, a regulating bin 29 that regulates the movement of the first and ft52 switching bins 27 and 28, and a return spring 30 that biases each bin 27 to 29 toward the disconnection side.

The first drive rocker arm 23i includes a free rocker arm 2.
A first guide hole 31 with a bottom and open to the 5i side is bored parallel to the rocker shaft 22f, and the first switching bin 27"1M is movably fitted into this first guide hole 31, and the first A hydraulic chamber 32 is defined between one end of the switching bin 27 and the closed end of the first guide hole 31. Moreover, a passage 33 communicating with the hydraulic chamber 32 is bored in the first drive rocker arm 23i, and the rocker shaft 22i is provided with an oil supply passage 34i, and the oil supply passage 34i always communicates with the hydraulic chamber 32 via the passage 33 regardless of the swinging state of the first drive rocker arm 23i.

In the free rocker arm 25t, a guide hole 35 corresponding to the first guide hole 31 is bored parallel to the rocker shaft 22i and extends between both sides.
A second switching pin 28, one end of which is in contact with the other end, is slidably fitted into the guide hole 35.

A bottomed second guide hole 36 corresponding to the guide hole 35 is provided in the second driving rocker arm 24i.
5i side and is bored parallel to the rocker shaft 22i, and a disc-shaped regulation bin 29 that abuts the other end of the second switching bin 28 is slidably fitted into the second guide hole 36. . Moreover, a guide tube 37 is fitted into the closed end of the second guide hole 36, and a shaft portion 38 that is slidably fitted into the guide tube 37 is coaxially and integrally protruded with the regulation bottle 29. Ru. Further, the return spring 30 is fitted and pressed between the guide cylinder 37 and the regulating bin 29, and this return spring 30 causes each bin 27 to
, 28 and 29 are forced toward the hydraulic chamber 32 side.

In this connection switching mechanism 26t, as the hydraulic pressure in the hydraulic chamber 32 increases, the first switching bin 27 fits into the guide hole 35 and the second switching bin 28 fits into the second guide hole 36.
The rocker arms 23i, 25i, and 24i are connected to each other. Further, when the oil pressure in the hydraulic chamber 32 becomes low, the first switching pin 27 returns to the position where the contact surface with the second switching pin 28 corresponds between the first drive rocker arm 23i and the free rocker arm 25L due to the spring force of the return spring 30. Second
Since the switching bin 28 returns to the position where the contact surface with the regulation bin 29 corresponds to the free rocker arm 25i and the second drive rocker arm 24i, each rocker arm 23i, 25i,
The connection state of 24i is released.

The oil supply path 34i is connected to an oil gear rally connected to an oil pump that draws oil from the oil pan (none of these are shown), and is also connected to an oil gear rally for supplying oil by switching between high and low oil pressure. A switching valve (not shown) is connected, and hydraulic pressure switching by the switching valve is performed based on the operation of the electromagnetic valve 16.

That is, when the ECU 3 outputs a valve opening command signal to the solenoid valve 16, the solenoid valve 16 is opened, the switching valve is opened, and the oil pressure in the oil supply path 34i increases. the result,
The connection switching machine +126i operates and each rocker arm 23i
. Opens and closes according to valve timing.

On the other hand, when a valve closing command signal is outputted from the ECU 3 to the solenoid valve 16, the solenoid valve 16 and the switching valve are operated to close, and the oil pressure in the oil supply path 34i decreases. As a result, the connection switching mechanism 2
6t operates in the opposite manner to the above, and each rocker arm 23i, 2
4i and 25i are disengaged, the corresponding rocker arms 23i' and 24j are operated by the low-speed cam, and the pair of intake valves 20i are operated at low-speed valve timing with a relatively small valve opening period and lift amount. .

FIG. 3 is a system diagram showing the configuration of the traction control system and engine control system in the ECU 3 of FIG. 1.

In FIG. 3, a traction control system 51 constitutes a drive wheel slip detection means for detecting slip of the drive wheels driven by the engine l, and the drive wheel speed V
A signal representing the deviation ΔV between the two speeds w and vehicle speed Vv is output to the engine control system 52. The engine control system 52 controls the fuel cut cylinders according to the deviation signal.

Specifically, control is performed so that the larger the deviation ΔV, the more cylinders the fuel should be cut off are sequentially increased.
Thus, when an abnormally large drive wheel speed Vw is detected, the engine 1 ends up cutting fuel in all cylinders. In this way, the engine output is reduced in accordance with the drive wheel slip detection output, and the torque of the engine 1 is lowered to prevent excessive slip.

In addition, such slip control by reducing engine output may be used in conjunction with such fuel cut control, or instead of it, for example, by performing ignition f1 turn off (control of ignition timing, stop of ignition). Good too.

The above deviation signal of ΔV is obtained by the variable valve timing control section 5
3 is also supplied. The control unit 53 is for changing the valve timing characteristics of at least one of the intake valve and the exhaust valve of the engine 1 by operating the connection switching mechanism 26i of the valve train configured as shown in FIG. Then, the engine speed Ne is compared with a predetermined value Neo (FIG. 4).

Variable valve timing usually depends on engine speed Ne
The change control is performed based on the result of comparing and determining whether or not is larger than the predetermined value Neo. That is, as shown in the engine rotation speed Ne-torque characteristic shown in FIG. If it is high, the torque characteristic I on the high-speed valve timing side
The valve timing is switched so that it becomes I (first valve timing system #).

As described above, the output torque of the engine 1 increases as the engine speed N increases, for example, as the engine speed Ne increases.
In the range where e is up to a predetermined value Neo, it changes to the characteristic I^ on the low rotational speed side of the characteristic r, and when it exceeds the predetermined value Neo, it changes to the characteristic ■^ on the high rotational speed side of the characteristic H.

However, in addition to such change control, the variable valve timing control section 53 controls the valve timing characteristics so that the engine output torque is lower than that during the normal change control, in accordance with the drive wheel slip detection output. It also has functions.

That is, when traction control is to be performed and the slip condition is large, the variable valve timing control section 53 reverses the valve timing to be selected, unlike the above-mentioned change control.

The slip state can be determined in various ways, such as whether the slip ratio λ obtained from the driving wheel speed Vw and the vehicle speed Vv is larger than a predetermined slip ratio. For example, when switching the valve timing based on the magnitude of the slip ratio λ, , the valve timing is controlled according to the switching pattern shown in the table below.

As shown in the above table of Table 1, when the slip ratio λ is small in each of the low engine speed region and the high engine speed region, the low speed valve timing and the high speed valve timing are respectively selected as the valve timing. That is, in this case, the above-mentioned change control is maintained, and therefore the output torque characteristics are ■^ and ■^.

On the other hand, when the slip ratio λ is large, in the engine speed range from low engine speed to high engine speed, both are reversed as shown in the upper part of the table above. That is, the valve timing can be switched to the high speed valve timing side in the low engine speed range, and to the low speed valve timing side in the high engine speed range. This results in
In the former region, the torque characteristics are as shown in Fig. 4]]3
is selected, and characteristic 1a is selected in the latter region.

Thus, a low engine torque state occurs in both the high engine speed range and the low engine speed range.

This is based on the following reasons.

As mentioned above, normally, when the engine speed is low, the low-speed valve timing side is selected, but on a road surface where the slip ratio λ is large and slips are likely to occur, first of all,
The engine does not require high output torque.6 In a vehicle equipped with a variable valve timing mechanism, as shown in Figure 4, in the region of low engine speed, the characteristic IIB on the high-speed valve timing side is actually As shown by the extended broken line, the torque characteristic 1 on the low-speed valve timing side (=
Since it exhibits a lower torque characteristic than I^), the output torque can be lowered by switching the valve timing to high-speed valve timing under the above-mentioned conditions. Further, even in the region of high engine speed, the output torque can be lowered by similarly switching to select characteristic IB.

Furthermore, in road conditions where μ is extremely low, such as when the road surface slips, the force that lowers the output torque as described above can be used to control the engine output, for example by sequentially cutting the fuel in the cylinders. t+
You can improve your score by 7 degrees. When the base is in a high state as shown in the characteristics I^ and ■^ in Fig. 4, the control torque span during control becomes large, so the control accuracy becomes ill, whereas if the output torque is lowered, This allows for even more precise control.

Therefore, as mentioned above, according to the driving wheel slip detection output, switching control, which can be called second change control regarding valve timing, that is, switching control tn (second valve timing control a1) according to the pattern in the lower column of Table 1 is performed. This includes changing valve timing.

Furthermore, in synchronization with the switching of the valve timing, a lower limit engine speed, an upper limit engine speed (rev limit), or a vehicle speed is set for each of the low-speed valve timing and the high-speed valve timing to set the traction control prohibition area. Set.

The table below shows an example of the settings.

Table 2 As shown in the table above, in the low engine speed region, when the valve timing is low valve timing, the predetermined rotation speed NVTII is the traction control lower limit engine speed, and when the valve timing is high valve timing, the predetermined rotation speed NVT12 is used. is set, and in the high engine speed region, a predetermined speed NVT21 is set as the traction control upper limit engine speed depending on the selection of low speed valve timing and high speed valve timing.
and NVT22 are set.

Here, the predetermined rotation speed Nvr1+ and NVTI2 are NVT
II (NVTI) is set to a relationship of 2, and the predetermined rotation speed N
The V-choice 21 and the NVT 22 are set in the relationship Nvr2+ (NVT22), and the numerical values (rpm) in parentheses in Table 2 above are specific examples of each.

As a result of changing the valve timing according to the magnitude of the slip ratio λ and changing the TC3 control prohibited rotation speed in synchronization with this as shown in Table 6 above, appropriate driving wheel slip control can be performed in the low engine speed region. can be done.

That is, when performing traction control in a low engine speed region, engine stall is prevented by setting a lower limit engine speed, but in this case, if the switched valve timing is low speed valve timing, that is, the slip ratio λ is relatively small, and therefore, if the low-speed valve timing is selected as shown in Table 1, the torque characteristic will be the characteristic I^ shown in Figure 4, and there is a margin in the stall toughness. As the lower limit engine speed, it is possible to set a predetermined engine speed Nvr+t that is lower than when the high-speed valve timing side is selected, and by this setting, the traction control range, that is, the slip control range is expanded, and slip is suppressed in this range. It can be prevented.

Furthermore, when high-speed valve timing is selected, that is, when the slip ratio λ is large, the l-lux characteristic becomes characteristic IIB in the low torque state shown in FIG. Since the control-prohibited rotation speed in several regions can be increased to the predetermined rotation speed NVT12, which is a larger value than the above-mentioned predetermined rotation speed NVTII, the engine stall toughness can be increased, and the control accuracy in the above-mentioned region can be increased. It is possible to improve the performance and prevent stalls.

In addition, in the high engine speed region, valve jump, bubbling, belt tension limit, etc. differ depending on the high speed or low speed cam that is switched in the valve train shown in FIG. From the standpoint of (knocking, exhaust temperature), it is necessary to set a revlit that matches the selected valve timing, so as shown in Table 2,
``rcs lower limit engine speed is selectively changed to NVT21 or NVT22 according to the selected valve timing.

FIG. 5 is a functional diagram showing an example of a configuration for controlling the above-mentioned valve timing switching and traction control operation in a low engine speed region.

In FIG. 5, a slip ratio λ detection unit 501 outputs a high (I-I) level signal when the slip ratio λ is greater than a predetermined value, and outputs a low (L) level signal when the slip ratio λ is less than the predetermined value. In addition, the engine speed signal and comparison signal generation unit 502 generates a high (IT) level signal when the engine speed Ne is higher than the predetermined value Neo.
Further, when the level is low, the configuration is such that a low (L) level signal is output.

In addition to these detection section 501 and signal generation section 502, in FIG.
6, first and second OR gates 5Q7.508, first and second inverters 509.510, high-speed valve timing selection section 511. Low speed valve timing selection section 512
, first and second lower limit engine speed setting sections 513.5
14. Changeover switch 51 for changing the lower limit engine speed
5, a comparator 516 and a traction control operating section 517.

In the illustrated example, the switch 515 is a switch that can be switched in response to the high or low level of the input signal to the high-speed valve timing selection section 511, and when the signal is low (i.e., high-speed valve timing is not selected). (Accordingly, when low-speed valve timing is selected), the first lower limit engine speed setting section 513 side is selected, and in the case of a high level signal, the second lower limit engine speed setting section 514 side is selected. .

First, when the slip is small or no slip occurs and the engine speed is low, a low level signal from the detection unit 501 is transmitted to the first inverter 509.
The low level signal from the signal generator 502 is applied to the third AND gate 505 via the second inverter 510, The high level signal obtained as the output of is supplied to the selection section 512 via the second OR gate 508, and as a result, the low speed valve timing side is selected.

Also, at this time, the signal to the selection unit 511 is a low level signal, so the lower NVTII is selected as the TC8 lower limit Ne, and the comparator 516 selects the lower limit Ne.
It is possible to compare the signal δ representing the NVTII with the signal representing the actual engine speed Ne, and the comparison result is supplied to the input terminal for controlling the operation in the low engine speed region of the TC3 operating section 517. Ru. In this way, the control-prohibited engine speed in the low engine speed range can be set low, and it is thereby possible to determine whether the traction control should be activated or not.

Furthermore, even if the slip is small, if the engine speed is high, a high level signal is output from the signal generating section 502, so a high level signal is applied to the selection section 511 by the fourth AND game h506, resulting in a high speed. Switched to valve timing side.

In FIG. 5, the first valve timing control described above is performed using one of the first to fourth AND gates 503 to 506.
This is performed using the third and fourth AND gates 505 and 506.

In contrast, the second valve timing control is performed using the first and second AND gates 503 and 504.

In other words, when the slip is large and the engine speed is low,
As a result, the high level signal from the detection section 501 is supplied to the first AND gate 503, and the low level signal from the signal generation section 502 is inverted by the second inverter 510 and supplied to the AND gate 503. Since a high level signal is applied to the selection section 511 via the first OR gate 507, the high-speed valve timing side is selected. Moreover, in this case, in conjunction with the switching to the high-speed valve timing side, the switch 515 selects NV12, which is higher than the NVTII, as the TC3 lower limit NO. As a result, the control prohibited rotation speed itself can be set high in the low engine rotation speed region when high-speed valve timing is selected, and stall toughness can be increased.

Further, when the slip is large and the engine speed is high, both of the input signals of the second AND gate 504 become a high level signal, and as a result, the valve timing is switched to the low speed valve timing side.

In addition, in FIG. 5, nij NVT21. NVT
each upper limit engine speed setting section corresponding to 22,
If a switch and a comparator are further added and linked, it is possible to change the prohibited rotation speed in the high engine speed region in synchronization with the switching of the valve timing in the same manner as described above.

(Effects of the Invention) According to the present invention, there is provided a valve lift characteristic changing means for changing the lift characteristic of at least one of an intake valve and an exhaust valve of an internal combustion engine, and a drive wheel that detects slip of a drive wheel driven by the engine. In a driving wheel slip control device comprising a slip detecting means and an engine output reducing means for reducing the engine output according to an output of the driving wheel slip detecting means, the driving wheel slip detecting means reduces the engine output in response to the output of the driving wheel slip detecting means. valve head characteristic switching means for controlling the ρ head characteristic so that the engine output torque is lower than when controlled by the valve head characteristic changing means; Since it is equipped with an engine speed changing means that changes the engine speed that suppresses the reducing means, by combining variable control of the valve lift characteristics, it is possible to both prevent engine stall and expand the slip control area. It has the effect that it can be realized.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a fuel supply control device for an internal combustion engine to which the control device of the present invention is applied, and FIG. 2 is a sectional view of essential parts showing an example of a valve train having a connection switching mechanism for variable valve timing. , Fig. 3 is a system diagram for explaining the present invention in the ECU, Fig. 4 is a diagram showing how the engine output characteristics are changed, and Fig. 5 is a system diagram for changing the valve timing and the prohibited rotation speed of traction control. It is a functional diagram showing a specific example. Wheel speed sensor, 16... Solenoid valve, 20i... Intake valve, 26i... Connection switching mechanism, 51... Traction control system, 52... Engine control system,
53... Variable valve timing control section, 501...
Slip rate detection section, 503-506...AND gate, 511.512...Valve timing selection section, 51
3.514...lower limit engine speed setting section, 515.
...Switch, 516... Comparator, 517... Traction control operating section.

Claims (1)

[Claims] 1. Valve lift characteristic changing means for changing the lift characteristic of at least one of an intake valve and an exhaust valve of an internal combustion engine, a driving wheel slip detecting means for detecting slip of a driving wheel driven by the engine, and the driving wheel slip A driving wheel slip control device comprising an engine output reducing means for reducing the engine output according to an output of the detecting means,
Valve head characteristic switching means for controlling the valve head characteristic so that the engine output torque is lower than when controlled by the valve head characteristic changing means in response to the output of the drive wheel slip detection means; and the valve head characteristic switching means. A drive wheel slip control device comprising: an engine rotation speed changing means for changing an engine rotation speed that suppresses the engine output reduction means when the engine output reduction means is in operation.