JPH02277908A - Valve control device of internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a valve control device for an internal combustion engine in which the valve head characteristics of an intake valve and/or an exhaust valve can be changed to J. This invention relates to a +lt valve control device.

(Prior art) The valve lift characteristics of at least one of the intake valve and the exhaust valve are set to low-speed brake lift characteristics suitable for the low rotation range of an internal combustion engine, and
In an internal combustion engine that can switch to a high-speed valve lift characteristic suitable for a high-speed range, the IuJ ratio between engine rotation speed and output torque is generally set as shown in Figure 8, and is set as shown in Figure 8. The shore! In the high speed range, a relatively large output torque can be obtained when the low speed valve lift characteristic is selected, and in the high speed range, a relatively large output torque can be obtained when the high speed valve lift characteristic is selected. t is 41 depending on the engine operating condition (mainly engine speed).
A brake lift characteristic that provides a relatively large output torque is selected. Therefore, the engine output can be reduced by changing the brake lift characteristic to the side opposite to the normal one.

Focusing on this point, when excessive slip between the drive wheels and the road surface is detected, the valve lift characteristic is changed to one that relatively reduces the engine output, thereby reducing the degree of slip of the drive wheels. A valve control device according to the present invention has already been proposed by the present applicant (Japanese Patent Application No. 330938/1983).

(Problem to be solved by the invention If1) The above proposed valve B111 all device Pe can effectively reduce the engine output when detecting the excessive slip state of the driving wheels, and therefore is effective in suppressing the excessive slip of the driving wheels. be. However, if the normal valve head characteristics (valve head characteristics on the side where the output torque is relatively large) are immediately restored after excessive slip of the drive wheels is suppressed, the output torque increases and, depending on the road surface condition, excessive slip may occur again. There is a possibility that the valve head characteristic must be changed to tl # degree, and the valve head characteristic must be changed to the valve head characteristic on the opposite side from the normal one. There is a problem in that such frequent switching of the valve head characteristics reduces the life of the valve head characteristics switching slide.

The present invention has been made in view of the above-mentioned points, and by appropriately changing the BR lift characteristic to suppress excessive slip of the driving wheels, the frequency of switching the JP lift characteristic is reduced and the switching TI is reduced. Internal combustion engine valve with improved sliding durability
The purpose is to provide one 'lJ II device.

(1st stage for solving problem II!I) In order to achieve the above object, the present invention includes a seven-stage drive wheel slip detection stage for detecting an excessive slip state of the drive wheels, and a drive wheel slip detection means that responds to the output of the drive wheel slip detection means. In the valve control device for an internal combustion engine, the valve control device for an internal combustion engine is provided with a "valve lift characteristic change" P stage for changing the lift characteristic of at least one of the intake valve and the υr air valve of the internal combustion engine. 1. A delay means is provided for delaying the restoration of the valve head characteristic by the valve head characteristic changing means when it is detected that the excessive slip of the driving wheels has decreased.

In this specification, the valve lift characteristic indicated in blue means a characteristic of one or a combination of a valve opening period, a valve opening/closing angle, and a valve lift amount.

(Function) The valve lift characteristic is restored to the characteristic of excessive slip detection 0;1 with a delay from the time when it is detected that the excessive slip of the driving wheels has decreased.

(Example) Here's the first one! An embodiment of II will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of a control device for an internal combustion engine according to an embodiment of the wooden invention, in which 1 out of 1 is a 6-cylinder engine in which each cylinder is provided with one pair of intake valves and one pair of exhaust valves. DO[lG is an internal combustion engine. A throttle valve 3 is provided in the middle of the intake pipe 2 of the engine 1, and a throttle valve resistance (QTI) sensor 4 is connected to the throttle valve 3.
An electronic control unit for engine control (hereinafter [1ζNG
-1':C:U'') 5.

A fuel injection valve 6 is provided for each cylinder between the engine 1 and the throttle valve 3 and slightly on the -L flow side of the intake valve of the intake pipe 2, and each injection valve is connected to a fuel pump (not shown). and electrically connected to the 1-NG-IE CU 5 and the (
The valve opening time of fuel injection is controlled by No. F3.

- Absolute pressure in the intake pipe (
['1 B^) sensor 7 is provided, and the absolute pressure signal converted into electrical Y) by this absolute pressure sensor 7 is supplied to the IENG-ECU 5. Engine rotation speed (
Ne) The sensor 10 is installed around the camshaft of the engine l or around the crank 'I'l11. The engine rotation speed sensor 10 generates a pulse (hereinafter referred to as Fr') at a predetermined crank angle position 14 every 120 degree rotation of the crankshaft of the engine 1.
) C (referred to as "n-hour pulse"),
Each of these signal pulses is supplied to the rENG-ECU 5.

Also, IENG-ECU! 'i' is equipped with an electronic/control unit/roll unit (hereinafter referred to as 'r i') for detecting drive wheel slip.
C3-[ECUJ] 20 is connected. This 'l' G S-1 older brother CU 20 includes a driving wheel speed sensor 21 that detects the rotational speed Vn of a driving wheel (not shown) and a driven wheel that detects the rotational speed Vv of a driven wheel (not shown). Speed sensor 22 and steering wheel (not shown)
A steering sensor 23 that detects the steering angle δ of the vehicle and a yaw rate sensor 24 that detects the yaw 1-Yaw of the +1r vehicle are connected, and these sensors 21 to 2
4 supplies the detection signal to '1' C3-ECLI 20. The driving wheel speed sensor 21 and the driven wheel speed sensor 22 detect the average value of the left and right driving wheel speeds or the driven wheel speeds. The detection side of the driven wheel and the detection side of the driven wheel may be the same). The steering sensor 23 detects a positive angle (+1.+2°...
), this is a sensor that outputs an absolute angle of negative angle (-1° -2°...) when steering to the left, and the yaw rate sensor 2
4 detects the driven wheel speed O;j separately for the left and right driven wheels, and detects the actual yaw rate based on the difference between the detected left and right driven wheel speeds. As the yaw rate sensor, a gyro that directly detects the actual yaw rate may be used.

Further, the ENG-E CU 5 is connected to the electromagnetic valve 26, and controls valve timing switching of the intake valve and the exhaust valve as described later. Note that "valve timing" in this embodiment is used in the same meaning as "valve head characteristic J" described in 11:1.

E N G -E CU 5 is each push sensor and i"C
S-1C: Shapes the input signal waveform from U3O, corrects the electric power level to a predetermined level, and converts the analog signal 1111
an input circuit 5a having functions such as converting the value into a digital borrow value, and a central processing circuit (hereinafter referred to as FrCl'LJJ)
5b, a storage means 5c for storing various calculation programs and calculation results executed by the CPU 5b, an output circuit 5d for supplying an immediate action signal to the fuel injection valve 6, and the like.

The CPU 5L) determines various engine operating states such as the air-fuel ratio feedback control operation region and the open loop control operation region, based on the -1 series and various engine parameter information (omitted explanations), and also determines the engine operation state. Depending on the state, based on the following formula (1), 0] I 'I'
L) Calculate the fuel injection time ']'0υT of the fuel injection valve 6 that is synchronized with the C signal pulse.

"l'ouv='l'i X KrcsX K+ +
K2 --- (1) Here, l''i is the basic fuel amount, specifically, the basic fuel injection time determined according to the engine rotation speed Ne and the absolute J!-l' n^ in the intake pipe. .

K yes is a lean correction coefficient that is set to a value smaller than (iQ l and Q, as described later) when an excessive slip state of the drive wheels is detected. Otherwise, the value is set to 1.0.

K+ and 2 are variables calculated according to various engine parameter signals, respectively, and are variables that determine the optimum characteristics such as fuel consumption characteristics and engine acceleration characteristics depending on the range of engine operating conditions. A predetermined value V1 is determined so that the

The CPU 5b further controls the on/off control of the valve 2G for valve timing switching, which will be described later, depending on the engine operating state (e.g. engine speed Ne, intake pipe absolute pressure 1) 0^) and the slip state of the driving wheels. conduct.

CPtJ 5 b outputs a signal for driving the fuel injection valve 6 and the electromagnetic valve 26 via the output circuit 5 d based on the results calculated and determined in two series.

In this embodiment, ENG-IEC (J5 is a part of the valve head characteristic changing means, a delay means, a part of the torque reduction f-stage,
and one stage of invalidation is formed tIVt, i' CS-1ζCU
Reference numeral 20 constitutes drive wheel slip detection means.

Fig. 2 shows an intake valve FI11 valve train 30 that drives the intake valves 40 of each cylinder of the engine 1, but basically the same FF4 valve train is provided on the exhaust valve side as well. . This valve train 30 includes a camshaft 31 that is rotatably driven from the crankshaft (not shown) of the engine 1 at a speed ratio of 1/2, and a high-speed camshaft 31 that is provided on a camshaft I/31 corresponding to the 6-flti. cam 34 and low speed cam 3
2.33, camshaft 31 and fixed arrangement r
A rocker shaft 35, which is connected to the rocker shaft 35, and a rocker shirt corresponding to each cylinder.
l1 rocker arm 38 and each rocker arm corresponding to each cylinder: 3G.

37 and 38, the connecting J switching machine (1"
1ff39.

In FIG. 2(b), the connection switching mechanism: 3') includes the first drive rocker arm 36 and the self-drive rocker arm 38.
a first switching bin 41 capable of connecting between the free rocker arm 38 and the second driving rocker arm 37; a second switching bin 42 capable of connecting the free rocker arm 38 and the second driving rocker arm 37;
A regulation bin 43 that regulates the movement of 2 and each bin 41 to 43
and a return spring 44 that urges the connection release side.

The first drive rocker arm 36 includes a free rocker arm 38.
A first guide hole 45 with a bottom and open to the side is drilled in a downward direction relative to the rocker shaft 35, and a nineteenth changeover bin 41 is slidably fitted into this first guide hole 45, and the first changeover bin 41 is slidably fitted into the first guide hole 45. A hydraulic chamber 4 is defined between the negative end of the bottle 41 and the closed end of the first guide hole 45 . Moreover, the first driving rocker arm 3
A passage 47 communicating with the hydraulic chamber 46 is bored in G, and an oil supply passage 48 is provided in the rocker shaft 35.
is the path 4 regardless of the swinging state of the first drive rocker arm 36.
The oil j1: is constantly communicated with the chamber 46 via the oil j1.

In the free rocker arm 38, a guide hole 49 corresponding to the first guide hole/15 is provided parallel to the rocker shaft 35 and extending between both sides, and one end is in contact with the bottom end of the first switching bin 4I. A tB2 switching pin 42 is slidably fitted into the guide hole 49.

The second drive rocker arm 37 has a guide hole 4 marked with 1);
A second guide hole 50 with a bottom corresponding to 9 is opened to the free rocker arm 38 side and is bored parallel to the rocker shaft 35, and a disc-shaped guide hole 50 that abuts the thin end of the second switching bin 42 is provided. ] The bottle 4:3 is slidably fitted into the second guide hole 50. A guide tube 51 is fitted into the closed end of the second guide hole 50, and the lF7 is inserted into the guide gap 51.
! A 111 portion 52 that fits into the I'JI'M function is coaxially and integrally protruded from the regulation bin 712. Further, the return spring 44 is fitted between the guide 11j51 and the regulation bin 43, and this release spring 44 causes each of the bins /II, 42,
4:3 is pushed 1.1 force toward the hydraulic chamber 4G side.

In this connection 9 switch mechanism 39, as the oil pressure in the 411 pressure chamber 46 increases, the 11th WJ change bin 41 fits into the guide hole 49, and the second switch bin 42 fits into the second guide hole 50. and each rocker arm 36.38.37
are concatenated. Further, when the oil pressure in the hydraulic chamber 46 becomes low, the spring force of the return spring 44 causes the contact surface of the first switching bin 4j with the second switching bin 42 to return to the position corresponding to between the first driving rocker arm 36 and the free rocker arm 38. The contact surface of the 21st coin exchange bin 42 with the regulation bin 43 is the free rocker arm 38 and the 2nd j? Since the movable rocker arms 37 return to the corresponding positions, the connection between the rocker arms 16.3B and 37 is released.

11; The oil supply passage 48 in the rock shaft 35 is connected to the oil pump 28 via a switching valve r27, and the switching operation of the switching valve 27 changes the oil pressure in the oil supply passage 48, and therefore the connection switching in 11;I is connected to the oil pump 28. Mine ff43 '1's Oil II (chamber 4
The oil pressure in 6 is switched between high and low. This switching valve 27 is connected to the electromagnetic valve 26, and the switching operation of the switching valve 27 is controlled by IENG-V:C (J5) via the electromagnetic valve 26.

Intake side valve operating device 3 of engine I configured as described above
0 operates as follows. Incidentally, the exhaust side valve train operates in the same manner.

When a valve opening command signal is output from IEN G r', G U 5 to the electromagnetic valve 26, the electromagnetic valve 26 is opened and the switching valve 27 is activated. &
The oil pressure of the passage 48 rises by 2''. As a result, Concatenation 9” conversion tit #T: 3! > is activated and each rocker arm 3G
, 38.37 are connected, and the high speed cam: 3/I connects each rocker arm: 3G, 38. :3'l operates as one unit (Figure 3(A) shows this state),
The pair of intake valves 40 are opened and closed at high-speed valve timing with a relatively large valve opening period and lift song.

On the other hand, when the valve closing command 18:00 is output from the 13NG-1 OU5 to the solenoid valve 2 (5), the solenoid valve 26 and the switching valve 2
7 is closed, and the oil pressure in the oil supply path 48 is low (;).As a result, the connection switching machine ffI? The connected state is released, and the corresponding rocker arms 36, 37 are operated by the low-speed cams 32.:33, and the pair of intake valves 40 are operated at low-speed valve timing with a relatively small valve opening period and lift amount.

Figure 3 shows i? Il Book 1'CS-1', G U
20, the detection number 1^ (VD) of the drive wheel speed sensor 21 is manually input to a first subtraction circuit 203 and a third subtraction circuit 210. Further, the detection number 111 (corresponding to the body speed Vv) of the driven wheel speed sensor 22 is the first reference driving wheel speed (N'l
! EF) calculation circuit 201, base 1'l Lyo rate (Yl
! EF) calculation circuit 206, third subtraction circuit 210, and acceleration (α) calculation circuit 211. The detection signal (δ) of the steering sensor 23 is sent to the base f111 yaw rate calculation circuit 206, and the detection signal (Yaw) of the n; I yaw rate sensor 24 is sent to the second subtraction circuit 207.
are input respectively.

The first reference driving wheel speed calculation circuit 201 calculates the driven wheel speed,
That is, the first base fIll driving wheel speed N'REF is calculated according to the vehicle body speed Vv, and the calculation result is used as the second base r11! It is input to the drive wheel drive calculation circuit 202. This first reference driving wheel speed N'REF is the same as the 11 body speed in rail where the slip ratio of the driving wheels is about 15% (slip ratio that can obtain a large Mt driving force) and the vehicle is traveling straight. This is determined based on the relationship with the driving wheel speed.

The base y1q yaw rate calculation circuit 206 calculates +1 (body speed V
The base yaw rate Yl! is the current yaw rate based on the steering angle δ and the steering angle δ. EF is calculated and the calculation result is input to the second subtraction circuit 207. This base lift rate is based on a mathematical model of the vehicle (for example, Japanese Patent Application Laid-Open No. 6127763
It is calculated by a calculation formula based on a physical model (described in Japanese Unexamined Patent Publication No. 63-218866, for example). The second subtraction circuit 207 has base 111! The difference ΔY (yaw rate deviation) between yaw rate 1-Y p and the detected actual yaw rate Yaw is calculated, and the calculation result is sent to the absolute value calculation circuit 208.
Enter. The absolute value calculation circuit 208 calculates yawlay 1-0.
;it difference ΔY is the absolute value lΔY1, and correction 1/((Ny
) is input to the calculation circuit 209. The correction value calculation circuit 209 calculates a supplementary value of the reference driving wheel speed according to the absolute (fl, IΔY1) of the yaw rate deviation, and manually inputs the calculation result to the second base Qll driving wheel speed calculation circuit 202. .This complement 1l-fl' (N Y is 11[
Both yaw movements (base v111 yaw rate Y l!EF corresponds) and actual yaw movement (actual yaw rate 1-Yaw
When QJ tn (corresponding to yaw rate aMΔY) is large (for example, when the traveling direction of the vehicle shifts due to IQ wind), the first reference driving wheel speed N'REF is set to This is a correction to a small value, and ultimately acts in the direction of further reducing the engine output.

The second base r(g driving wheel speed calculation circuit 202 calculates the following equation (2
), the second base Qli drive wheel speed N REF is calculated, and the calculation result is input to the first subtraction circuit 203 .

Ni! EF=N'REF-Ny・
...(2) The first subtraction circuit 203 calculates V (speed a difference) to the difference between the driving wheel speed Vo and the second reference driving wheel speed NRεF.
is calculated, and the calculation result is sent to the slip signal (S) calculation circuit 2.
Enter in 04. The slip signal calculation circuit 204 calculates the speed deviation ΔV and the gain setting circuit 205.
The control gains K P , K + , K n for P I +) control, which are manually operated by the IECU 5, are expressed by the following formulas (:3) to (
6) to calculate the slip signal SO3.

S = S Pn+ S [n+ S l)n
...(:3)SPn==KrXΔVn
-('I)S rn=s, In-++ +XΔVn
−(5)31)n=KnX (ΔVn−ΔV
n-+) -(ti) where the subscript "1-1's i・1
Since the calculation in 1) is repeated every time the C signal pulse is generated, the calculated value represents the value at the current occurrence of the C signal pulse, and the value at the time of the 11:1 occurrence. .

The slip signal S is the base 711■ Yaw-1-YRE.
F and yawley] and deviation ΔY +:, N ('
;-13 is supplied to CU5.

-)j, the third subtraction circuit 210 calculates the speed difference ΔVw between the driving wheel speed vI) and 11 (speed Vv), and inputs the calculation result to the friction coefficient <11> calculation circuit 212. The acceleration calculation circuit 211 has: 1 "acceleration α of velocity Vv"
is calculated, and the calculation result is input to the friction coefficient calculation circuit 212. The friction coefficient calculation circuit 212 calculates an estimated value 11 (
For the following, calculate [road surface /jJ] and feed the calculation result to 1-NG-1ζ(': LJ 5 (''l:).

Note that the friction coefficient It of the road surface is determined by the speed pΔVw as described in 1.
and l (111 based on the acceleration α of the body: actual, not limited to) 11! ! Detection may be performed using a sensor that detects Ig (coefficient, for example, a combination of an ultrasonic sensor and a road surface temperature sensor).

Figure 4 shows i' C in ENG-IE CU 5.
S-1': Engine l based on the signal from Cu2O
engine output control (hereinafter referred to as ``traction control'') by making the air-fuel mixture supplied to
1 is a flowchart of a program that executes 1. This program is executed in synchronization with each i' I) C signal pulse generation.

First, in step 401, it is determined whether traction control should be performed. This determination is made depending on whether a predetermined condition (for example, that the slip signal S is -71- or more than a predetermined value) is satisfied. When the answer to step 401 is 17 constant (Yes), that is, it is determined that traction control should be performed, the lean correction II: coefficient is set to the first lean predetermined value W(X T(2S (for example, air-fuel ratio Δ /F=1
(a value of about 8.0) (step 402)
. Next, the number of cylinders to be cut (NFC) is selected according to the value of the slip signal (i) S (step 403).
, determines the ki g1 to be cut in accordance with the NPC value (step 4o4).

The value of this unit cut air number Np<: is set to 1'lJ as the value of the slip signal S becomes larger, and becomes larger y(as the degree of drive wheel slip increases; for example, No. In an engine having G cylinders of I to No. 6, if NFc=3, No. 1, 3.
A twin cylinder cut is made for the 5th cylinder.

Next, in step /106, it is determined whether the engine rotation speed Ne is equal to or higher than a first predetermined rotation speed N+ (for example, 9000+-concave).If the answer is 1 degree (Yes), that is, Ne
When ≦N1 holds true, the absolute 11 in the intake pipe;
It is determined whether or not (step 410). Step 410
If the answer is negative (NO) (1'B^<PTI), select low speed valve timing (Step 11)
On the other hand, the answer to step old 0 is 1'' (Yes) (ρII
When A≧Pt1), high-speed valve timing is selected (step 409), and then an L (IFF timer, which will be described later), is set to OFF for a first predetermined period of time to start it (step 412), and this program ends.

n7j,! 8 When the answer to step 406 is negative (No), that is, when Ne>N+ holds true, the engine speed Ne
is higher than the second predetermined rotation speed N2 (for example, 5.00 rpm) which is higher than the first predetermined rotation speed N1 (step 407).
), that is, when Ne over N2 holds true, the absolute pressure I's^ in the intake pipe is n;
It is determined whether or not the predetermined pressure 1'T2 (for example, 620 mml 1 g) is higher than the predetermined pressure 1'T2 (step 408). The answer to step 408! When YES (PB^≧I'r2), select low speed valve timing (step 411).
The answer to Tsuba step 40B is negative (No) (PB^<I'
If T2), high-speed valve timing is selected (step 409); 1) proceed to step 412;

The answers to steps 406 and 407 are both negative (No).
.

That is, when N 1 (N e (N 2 ) is established, the process immediately proceeds to Step 412, and the valve timings selected up to 073 times are held.

That is, according to steps 406 to 409, as shown in 51) 1, high-speed valve timing is selected in areas i and ■, low-speed valve timing is selected in areas II and TV, and the previous valve timing is selected in area I11. The timing is changed to ('Jtl. As a result, I and IJ switching of the valve timing is not performed in region 1!], and in the regions of Ne≦N1 and Ne≧N2, high load condition @
(P BA > P Tl or Ph3 (7) Toki)
Since the valve timing that reduces the engine output is selected only in a negative manner (that is, the valve timing is changed when excessive slip condition of the drive wheels is detected),
The frequency of valve timing switching can be reduced, and the -H durability of the connection switching mechanism 39 can be improved.

If the answer to step 401 is negative (No), that is, it is determined that there is no need to perform I-traction control, the
It is determined whether or not the traction control described in I has been executed (step old 3). If the answer is negative (No), immediately, and if I'r is constant (Yes), the number of cylinders to be cut N F (: is decremented by ll+' (l) (step 414), and then the process proceeds to step 415. Step In step 415, it is determined whether the value of the tOFF timer is equal to 0, and if the answer is negative (No), that is, the first predetermined time tOFF has not elapsed, the LVT timer, which will be described later, is Second predetermined time 1. VT is set and started (step old 9), and the twin cut cylinder is determined from Npel'E as in step 404 (step 420), and this program is ended.

The answer to step 415 is 11 (Yes), that is, IL
When OFF=0, Tsuyunirukatki 1 number NFC
Determine whether or not is equal to the value 0 (step 416)
. When the answer is negative (No), that is, Npc) 0,
Decrement the NPC value by the value l (step old 7)
, after starting the L□FF timer by setting L OFF for the first predetermined time (step old 8),
Proceed to step 419.

When the state in which traction control is required changes to the state in which traction control is not required in steps 413 to 420, the number of cylinders cut NFC is
Immediately after the transition, the value is decremented by 1 (step old 4).
), thereafter, it is decremented by the Vth value every time the first predetermined time period topp passes (step old 6, 417). As a result, the number of cylinders cut off gradually decreases, resulting in a rapid increase in engine output immediately after the excessive slip condition of the drive wheels is resolved. Prevent rising 1
1. As a result, drivability can be improved.

The answer to step 41G is 1°1 constant (Yes), that is, N
When pc=0, it is determined whether the value of the LVT timer is equal to the value 0 (step 421). When the answer is negative (No), that is, Lvr) 0, the tA
Set the third predetermined time 1^' in the F timer and start it (step 422), and end this program.
'do.

According to the two series of steps 3 to 422, after the traction control transitions from on to off, the following equation (7) is obtained.

The valve timing is not changed during the available time 1', and therefore the valve timing immediately before the traction control is switched from on to off is maintained (see FIG. 7).

T= LOFFXNFCO+ Lvt ---
(7) However, NFCO is Npcffl just before traction +II II transitions from on to off.

As a result, a hunting phenomenon occurs in which the excessive slip state of the drive wheels is resolved -> the valve timing is switched (return to normal state) - the excessive slip state -> the valve timing is switched again, and the frequency of valve timing switching increases. It is +l-L to prevent that.

It also prevents excessive slipping of the drive wheels, which is likely to occur if the valve timing is returned to normal immediately after traction control is switched from on to off. Furthermore, during the above-mentioned time period "l", the insufficient engine output due to not returning the valve timing to the high torque side is compensated for by stopping the engine cut.

If the answer to step 421 is affirmative (Yes), that is, tvτ
When = 0, it is determined whether the conditions for selecting high-speed valve timing are satisfied (step 424).
. This determination is made according to, for example, the engine speed Ne, the intake pipe absolute pressure 1'B^, the engine cooling water temperature '1'W, etc., and the valve timing on the side where the engine output is relatively large is selected by this determination. be done.

If the answer to step 424 is negative (No), that is, the condition for selecting high-speed valve timing is not satisfied, then low-speed valve timing is selected (step 425), and it is determined whether low-speed valve timing was selected last time (step 425).
step 426). The answer is 17 (Yes), i.e.
``+: When the low speed valve timing is selected once, the lean supplementary coefficient KTe3 is set to the value 1.0 and this program is terminated.

However, if the answer to step 426 is negative (No), then
If l1il fast valve timing was selected.

It is determined whether the value of the tAF timer is equal to the value 0 (step 427), and this answer is I'i (Yes) (
When tAp=o), the program proceeds to step /131, and when the answer is negative (jAp>0), the lean correction coefficient Krcs is set to the second lean predetermined value 11XvT (step 428), this program. Exit (
(See Figure 7). Here, the second lean predetermined value XVT is set depending on the engine rotation speed Ne, for example, as shown in FIG.

If the answer to step 424 is negative (Yes), the condition for selecting high-speed valve timing is satisfied t'1. If so, select high-speed valve timing in step 421.
1) It is determined whether the fai1 high-speed valve timing has been selected (step 430). Step 4
If the answer to step 30 is n-definite (Yes), step 43 is performed.
1, and if negative (NO), proceed to step 427.
Proceed to.

According to steps 424 to 431 described above, normal valve timing selection is performed, that is, the valve timing on the side where the engine output is relatively large is selected, but after the traction control is completed, the valve timing is selected on the side where the valve timing is different from the previous one. In the case where the air-fuel ratio is changed to K↑(:5=Xvt), the air-fuel ratio of the air-fuel mixture is made lean until the third predetermined time LAP has elapsed.

As a result, when the valve timing on the side with relatively low engine output is selected during traction control, and the valve timing is switched to the side on the side with relatively high engine output after traction control ends, the engine output due to valve timing switching As the air-fuel ratio becomes leaner, the degree of increase in
It is possible to prevent the engine from climbing up and improve drivability.

In the embodiment described above, when the third predetermined time LAF elapses 1)1, Krcs=Xvr, and after the LAF elapses, 1(T(:
Although S=1,0, KveS may be gradually increased from XVT to 1.0 as time passes. In addition, instead of setting the lean correction coefficient KT(:S) to the second lean predetermined value XVT, a sudden increase in engine output can be prevented by delaying the ignition timing.
It is also possible to do so.

In addition, traction control in the two embodiments is carried out by making the air-fuel ratio of the air-fuel mixture supplied to the engine leaner and by cutting the air-fuel ratio, but is not limited to this. For example, traction control is carried out by reducing the opening of the throttle valve. You can do it like this.

In this case, it is better to use the accelerator pedal position as the engine load parameter instead of the intake pipe absolute pressure Pe^.

(Effects of the Invention) As described in detail above, the present invention includes a drive wheel slip detection means for detecting an excessive slip state of an IfI drive wheel, and an intake valve and an exhaust valve of an internal combustion engine according to the output of the drive wheel slip detection means. In the valve control device for an internal combustion engine, the valve control device includes a valve head characteristic changing means for changing at least one valve lift characteristic, and the output of the driving wheel slip detection means indicates that the excessive slip of the driving wheels has decreased. Since a delay means is provided for delaying restoration of the valve head characteristic by the valve head characteristic changing means when detected, the valve head characteristic (M
Therefore, it is possible to reduce the switching frequency of the valve head characteristic and improve the durability of the switching mechanism, and to comparatively reduce excessive slip of the driving wheel when the valve timing returns to the normal state. It is possible to improve the drivability of the vehicle.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a valve control device according to an embodiment of the present invention, FIG. 2 is a diagram showing an engine valve train and its control system, and FIG. 3 is an electronic control unit for detecting drive wheel slip.] Figure 5 is a flowchart of a program that executes drive wheel slip control and head lift characteristic switching control, and Figure 5 shows the engine speed and intake pipe absolute pressure during drive wheel slip control. Figure 6 is a diagram showing an example of setting a predetermined value to make the air-fuel ratio lean, Figure 7 is a diagram to explain how to select the valve head characteristic according to the traction, valve timing switching, and lean air-fuel ratio. 8 is a diagram showing the change in the engine output torque with respect to the engine rotation speed in the valve lift characteristic fij. Driving wheel speed sensor, 22... Driven wheel speed sensor, 2:3
...Steering sensor, 24...Yaw rate sensor, 26...m both valves, 27...Switching valve; 30...
・Valve train 1'C139...Connection switching ta structure.

Claims (1)

[Scope of Claims] 1. Drive wheel slip detection means for detecting an excessive slip state of the drive wheels, and valve lift characteristics of at least one of an intake valve and an exhaust valve of an internal combustion engine according to the output of the drive wheel slip detection means. In the valve control device for an internal combustion engine, the valve head characteristic changing means changes the valve head characteristic changing means when it is detected that the excessive slip of the driving wheels has decreased based on the output of the driving wheel slip detecting means. 1. A valve control device for an internal combustion engine, comprising: a delay means for delaying restoration of valve head characteristics by . 2. The valve control device for an internal combustion engine according to claim 1, wherein the delay means includes a timer for measuring a predetermined delay time. 3. The valve control device for an internal combustion engine further includes a torque reduction means for reducing engine torque according to an output of the drive wheel slip detection means, and an output of the drive wheel slip detection means to reduce excessive slip of the drive wheels. and a disabling means for disabling the operation of the torque reducing means when it is detected that the engine torque reduction is disabled, and the delay means is configured to adjust the valve head characteristic after the disabling of the engine torque reduction by the disabling means is performed. The valve control device for an internal combustion engine according to claim 1, characterized in that the valve control device performs restoration. 4. The valve control device for an internal combustion engine according to claim 3, wherein the nullifying means gradually nullifies the reduction in engine torque by the torque reducing means.