JPH06229361A - Control device for engine - Google Patents

Abstract

PURPOSE:To effectively perform the torque-down control of an engine by retarding the ignition timing. CONSTITUTION:In a control device for engine provided with a torque-down control means 3b for performing the torque-down control by retarding the ignition timing when a specified torque-down condition is established, a torque-down level judging means 42 for judging the torque-down level is provided, and an ignition timing retard restricting means 3c for restricting the retard of the ignition timing when the torque-down level is found to be great based on the adjustment results, is provided. Especially when an engine 2 is operated at low speed, the torque-down control is performed by the fuel cut-off of some cylinders and retardation of the ignition timing of the cylinders, and when the engine 2 is operated at high speed, the torque-down control can be performed mainly by the fuel cut-off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device for surely controlling torque down of an engine mounted on a vehicle.

[0002]

2. Description of the Related Art In a vehicle equipped with an internal combustion engine, the engine torque is reduced when the engine torque can be added with an extremely small amount of engine torque, such as during idling or when descending downhill, or when slip control is performed. In some cases, so-called torque down control for reducing the torque is performed. The former torque down control at the time of idling or descending on a slope is for saving fuel consumption and the like, and the latter torque down control at the time of slip control is for effectively suppressing slip.

As means for reducing the torque in such a case, ignition timing control for delaying the ignition timing for igniting the fuel supplied to the engine (referred to as ignition timing retard), and for a multi-cylinder engine Among them, there is so-called cylinder number control in which the supply of fuel to a specific engine is cut off.

Regarding the former ignition timing control, Japanese Unexamined Patent Publication No. Sho 6-62
Japanese Patent Laid-Open No. 3-263243 discloses a control method in which the retard amount of the ignition timing is increased according to the increase of the torque down level (torque down amount). In addition, in the ignition timing control shown in this publication, making the fuel air-fuel ratio lean is also used.

The latter control of the number of cylinders is disclosed in Japanese Patent Laid-Open No. 3-67042, and the supply of fuel to a specific engine cylinder is stopped (fuel cut) in response to a request for torque reduction. It is shown that a lean mixture is supplied to the remaining cylinders (operating cylinders).

[0006]

By the way, in the torque reduction of the engine by adjusting the ignition timing as disclosed in Japanese Patent Laid-Open No. 63-263243, the retard amount depends on the torque reduction level. As the retard amount increases, the temperature of the exhaust gas discharged from the engine rises. Therefore, when the torque down level is large, there is a disadvantage that the exhaust gas purifying catalyst filled in the exhaust pipe is deteriorated at high temperature.

Further, in the cylinder number control system as disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-67042, the lean air-fuel mixture is supplied to the torque generating operating cylinders which are not fuel cut. Although it serves the purpose of reducing the engine torque, on the contrary, there is a problem that combustion in the engine becomes unstable and smooth rotation of the engine shaft cannot be obtained.

The present invention has been made to solve the above-mentioned conventional problems, and it is an object of the present invention to provide an engine control device capable of effectively reducing the torque of the engine due to the delay of the ignition timing. Has an aim.

[0009]

According to a first aspect of the present invention, there is provided an engine control device including a torque down control means for performing a torque down control by delaying an ignition timing when a predetermined torque down condition is satisfied. The engine control device is provided with a torque down level discriminating means for discriminating a torque down level, and an ignition timing retard limiting means for limiting a delay of the ignition timing when the torque down level is large based on the discrimination result. It is characterized by that.

According to a second aspect of the present invention, there is provided the engine control system according to the first aspect, wherein the torque reduction control delays fuel cut and ignition timing for some cylinders when the engine is at low speed. The torque down control device is configured so that the torque down control is performed mainly by the fuel cut when the engine is at a high rotation speed.

An engine control device according to a third aspect of the present invention is the engine control device according to the first or second aspect, wherein the torque is determined so that it is determined that the torque down condition is satisfied when the vehicle slips. The down-level discriminating means is configured.

[0012]

According to the engine control device of the present invention, the ignition timing retard limiting means provided in the control device is configured to limit the delay of the ignition timing when the torque down level is large. Therefore, when the torque down level is large, the retard amount of the ignition timing is limited, and as a result, the amount of unburned components in the exhaust gas discharged from the engine is suppressed, effectively suppressing afterburning in the exhaust pipe. can do.

According to another aspect of the engine control device of the present invention, the torque down control device performs the torque down control by cutting the fuel for some cylinders and delaying the ignition timing when the engine is in a low rotation speed. Is configured to perform torque reduction control mainly by fuel cut at high rotation speed, so when the engine is at low rotation speed, the torque cut of the engine can be more effectively and stably achieved by combining fuel cut and ignition timing retard. After burning, afterburning is unlikely to occur because the engine is running at a low speed. Further, when the engine is at a high speed, the fuel is mainly cut off and the ignition timing retard is limited. Therefore, afterburning is suppressed and a torque reduction with good accuracy according to the torque reduction level is realized.

According to the engine control device of the third aspect, the torque down level determining means is configured to determine that the torque down condition is satisfied when the vehicle slips. At times, torque down control of the engine is executed due to satisfaction of the torque down condition, and eventually the torque of the drive wheels that are slipping and drivingly rotated is reduced, and slip is effectively suppressed.

[0015]

FIG. 1 is a system diagram of engine control and drive wheel control for explaining an engine control device according to the present invention. As shown in this figure, the drive system of the vehicle 1 is an engine 2 which is a drive source, an engine drive control means (engine control unit) 3 for controlling the drive of the engine 2, and a front wheel which is a drive wheel of the vehicle 1. A driving wheel control means (traction control unit) 4 for controlling the driving of 11 and 12 is basically configured. In the figure, the vehicle 1 and the engine 2 are shown at positions far apart from each other for the sake of illustration, but in reality, the engine 2 is mounted on the vehicle 1, and the rotational driving of the engine 2 is performed by a crankshaft or an unillustrated crankshaft. Front wheel 1 via other power transmission means
The driving force is not transmitted from the engine 2 to the rear wheels 13 and 14 which are driven wheels. The roles of the front wheels 11, 12 and the rear wheels 13, 14 may be interchanged.

FIGS. 2 and 3 are explanatory views in plan view illustrating the driving conditions of the engine 2 under specific conditions. As shown in these figures and FIG. 1, the engine 2 of this embodiment is shown. Is a so-called V type engine in which a plurality of cylinders are arranged side by side in a V type, and is composed of a first cylinder group E1 and a second cylinder group E2. Then, the first cylinder group E
Three unit cylinders E11, E12, E13 are arranged in the first cylinder group, and unit cylinders E21, E22, E2 are arranged in the second cylinder group E2.
3 is arranged in three cylinders.

Each of the cylinder groups E1 and E2 arranged in the V-shape of the engine 2 has a head portion 21 provided above it.
The intake pipe 22 is connected via the intake pipe 22, and intake air is sent to the unit cylinders E11 to E23 through the intake pipe 22. On the other hand, a fuel injection nozzle 5 is provided at the tip of the intake pipe 22 near the head portion 21, and fuel is injected and supplied from the fuel injection nozzle 5 into the intake pipe 22.

Therefore, the intake air entrains the atomized fuel injected from the head portion 21 to the respective unit cylinders E11 to E23.
Is supplied to the first cylinder group E1 and is exhausted after the engine 2 is rotationally driven, and is discharged through a first exhaust pipe 23a connected to the first cylinder group E1 and a second exhaust pipe 23b connected to the second cylinder group E2. The air is discharged to the outside air through the exhaust main pipe 23 where they merge.

A purifier K filled with a catalyst for cleaning exhaust gas is provided in each of the exhaust pipes 23a and 23b. The purifier K includes a first purifier K1 provided in the first exhaust pipe 23a and a second purifier K2 provided in the second exhaust pipe 23b. A rear purifier 25 is provided in the exhaust pipe 23.

In this embodiment, the fuel injection nozzle 5 is of an electronically controlled type. The electronically controlled fuel injection nozzle 5 has an electromagnetic injection valve (injector) incorporated therein adapted to the cycle of the engine 2 and opened for a time corresponding to the intake air amount or the like. Is determined by the period of the electric pulse applied to the injector.

An intake throttle valve (throttle valve) 24 is provided in the middle of the intake pipe 22, and the opening degree of the intake throttle valve 24 is adjusted in accordance with the accelerator operation amount, so that each cylinder group E1, E2 is provided. The amount of intake air supplied is controlled.

The mixture of intake air and fuel supplied into the cylinder groups E1 and E2 is ignited and burned by spark discharge of a spark plug (not shown) provided at the top of each unit cylinder E11 to E23. ing. A high voltage current is supplied to the ignition plug from an ignition coil (ignition coil) 6 via a distributor 61.

The engine drive control means 3 is a control means for optimizing the rotational drive of the engine 2 in accordance with the conditions of the four circles, and is constituted by a so-called microcomputer. Various command signals for driving the engine 2 in an optimum state are transmitted according to the conditions of the four boxes input momentarily.

The conditions of the above four circles are detected by various sensors arranged around the engine. Then, various detection values detected by these sensors are input to the engine drive control means 3, and the engine drive control means 3 performs predetermined arithmetic processing based on a program input in advance according to the input various detection values. And sends a command signal to a target location around the engine.

An engine torque control means 3b is provided inside the engine drive control means 3, and this engine torque control means 3b determines whether or not a torque down condition is satisfied based on the information from the above-mentioned sensors. Whether or not the above condition is satisfied, a predetermined command signal for torque reduction is transmitted to various places. The engine torque control means 3b also has a function as torque down control means.

In the control system of the engine 2 as described above, the present invention is premised on performing the torque down control by delaying the ignition timing when a predetermined torque down condition is satisfied. In the engine drive control means 3, an ignition timing retard limiting means 3c for limiting the delay of the ignition timing when the torque down level is large is provided in the engine torque control means 3b.

Specifically, when the engine torque control means 3b and the engine 2 are rotating at a low speed, the torque down control is performed by fuel cut for some cylinders and ignition timing retard for delaying the ignition timing. At the same time, when the engine 2 is rotating at high speed, the torque reduction control is mainly performed mainly for fuel cut. Particularly, the ignition timing retard control is performed by the ignition timing retard limiting means 3 described above.
It is executed based on a command signal transmitted from c to the ignition coil 6.

In this embodiment, the engine 2
The torque reduction is performed by slip control applied when the vehicle slips. Therefore, the predetermined torque-down condition of the present invention is satisfied when the slip of the vehicle body is detected and when the vehicle is in the predetermined region where the slip control is required. The sensor plays an important role in detecting such a torque down condition.

Further, in this embodiment, in order to control the engine torque, the control of the number of cylinders by the fuel cut is performed in addition to the control of the ignition timing retard. That is, the injection pulse signal 51 for reducing the engine torque is output from the engine torque control means 3b.
Is transmitted, and the injection pulse signal 5 to the predetermined cylinder preset according to the torque value to be reduced is transmitted.
1 is set to 0. The fuel injection nozzle 5 which receives the pulse signal 51 stops its operation, and eventually the fuel is not supplied, and the cylinder (rest cylinder) is not driven, so that the torque is reduced accordingly. A lean air-fuel mixture is supplied to the operating cylinders that are also being driven, and the torque is also reduced by this. In order to obtain lean air-fuel ratio fuel, the pulse width of the pulse signal 51 is adjusted so that the engine 2
The supply to the above may be restricted more than usual.

The cylinder number control will be briefly described below.
FIG. 2 is an explanatory diagram for explaining a state in which a cylinder group belonging to one bank functions as an operating cylinder group due to a lean air-fuel mixture and a cylinder group belonging to the other bank is a deactivated cylinder group. FIG. 3 is an explanatory diagram for explaining a state in which both operating cylinders and idle cylinders are mixed in both cylinder groups.

First, the torque down control by the cylinder number control illustrated in FIG. 2 will be described. In the case of this example, the three unit cylinders (unit cylinders E11, E12, E13) forming the first cylinder group E1 of the engine 2 are fuel cut (×).
(Indicated by a circle), the three unit cylinders (unit cylinders E21, E22, E23) constituting the second cylinder group E2 are not fuel cut (indicated by a circle), and are in a so-called one-bank operating state. . In this case, the second cylinder group E2 is supplied with the fuel whose lean air-fuel ratio is limited to lean. The degree of restriction of leaning can be set variously, but a mixture having a maximum normal concentration may be supplied.

In the torque down drive of the engine 2 in such a state, when the engine water temperature is relatively low and cold,
It is applied when the engine 2 is rotating at a low speed. In other words, during cold low speed operation, combustion of the engine is unstable, which limits leaning of the air-fuel mixture. And
Although unburned components in the exhaust gas from the operating cylinder increase due to the restriction of leaning, the exhaust gas and the oxygen discharged from the idle cylinder join together in the exhaust pipes 23a and 23b until reaching the purifier K. To avoid afterburning.

Next, the torque down control by the cylinder number control illustrated in FIG. 3 will be described. In this case,
The unit cylinder E12 of the first cylinder group E1 of the engine 2 and the unit cylinders E21 and E23 of the second cylinder group E2 are fuel cut, and the unit cylinders E11 and E13 of the first cylinder group E1 are Unit cylinder E22 of cylinder group E2
And are not fuel cut, so-called both bank cut. Then, in this case, the lean fuel is supplied to the operating cylinders E11, E13, and E22 that have not undergone the fuel cut.

The torque-down driving of the engine 2 in such a state is applied when the engine 2 is rotating at high speed even when the engine water temperature is high or when cold. That is, even if the engine water temperature is low, the engine 2 is rotating at high speed, so the combustion state of the engine 2 is good,
The unburned components in the exhaust are small, and the first and second exhaust pipes 23
No combustion occurs in a and 23b, and the catalyst in the purifier K is not deteriorated at high temperature.

The one bank cut and one example of both bank cuts have been described above with reference to FIGS. 2 and 3.
In the present embodiment, the cylinder number control as described above is executed in accordance with the ignition timing retard control according to the degree of the slip amount, and the torque down control of the fine engine is performed.

The torque down control will be specifically described below. First, the drive wheel control means 4 determines whether or not a predetermined slip state is present according to slip detection, and if the predetermined slip state is reached, slip control according to the degree of slip is performed. Performs level calculation, etc. Therefore, the front drive wheels 11 and 12 have a right drive wheel rotation speed sensor 1a and a left drive wheel rotation speed sensor 1 respectively.
b is provided, and the right driven wheel rotation speed sensor 1c and the left driven wheel rotation speed sensor 1d are provided on the rear wheels 13 and 14 which are driven wheels, respectively.

The function of the drive wheel control means 4 will be described in detail. The rotation speed of each wheel detected by the rotation speed sensor is input into the drive wheel control means 4 one by one and provided in the control means 4. The slip detecting means 41 detects whether or not a slip has occurred. This detection is performed by comparing the rotational speeds of the front wheels 11 and 12 that are drive wheels with the rotational speeds of the rear wheels 13 and 14 that are driven wheels. That is, when the rotational speed of the drive wheel is considerably higher than the rotational speed of the driven wheel, it is determined that the drive wheel is slipping.

Inside the driving wheel control means 4, there is provided a slip degree judging means 42 for judging the degree of slip of the driving wheel detected by the slip detecting means 41.
The slip degree determination means 42 calculates the degree of slip (torque down level) from the rotational speed difference, and determines what combination of cylinder number control is to be performed based on the calculated slip degree and other conditions. To do. That is, the slip degree determining means 42 has a function as torque down level determining means.

Table 1 is a fuel cut table showing the engine water temperature according to the torque down level and the combination number of the fuel cut cylinder for each engine speed.

[0040]

[Table 1]

In Table 1, the horizontal columns show the torque down levels of 1 to 12, and the vertical columns show the condition of the engine water temperature and the engine speed. The torque down level is associated with the degree of slip when the vehicle slips, and the larger the numerical value of this level, the greater the degree of slip. This table is input into the slip degree judging means 42 in advance, and the actual torque down control is performed by referring to this table.

In the column where the vertical and horizontal crosses in Table 1, the cylinder number control number is described. Therefore, for example, when the engine water temperature is low, the engine speed is 5000 rpm or more, and the torque down level is 5, the cylinder number control combination number (cylinder cut combination number) is 3.

Then, according to the cylinder cut combination number, the torque down drive of the engine 2 is performed by the combination of the operating cylinder and the idle cylinder shown in the cylinder number control table of Table 2.

[0044]

[Table 2]

In Table 2, the cylinder numbers of the engine 2 of 1 to 6 are added to the horizontal columns (correspondences to the symbols of the unit symbols in FIGS. 2 and 3 are displayed below the cylinder numbers), and the vertical direction. The cylinder cut combination numbers from "0" to "7" are added to the column. This combination number corresponds to the cylinder cut combination number in Table 1 above. Further, in Table 2, the mark “◯” represents the fuel injection “present”, and the mark “x” represents the fuel injection “absent”.

Therefore, for example, when the combination number is "3", as shown in Table 2, fuel is supplied to three unit cylinders of cylinder number (1), cylinder number (4) and cylinder number (5). This indicates that fuel injection is not performed but fuel is injected to the remaining three unit cylinders of cylinder number (2), cylinder number (3) and cylinder number (6). In the V-type engine, the cylinder numbers (1), (3), and (5) are assigned to the unit cylinders in one bank, and the unit cylinders in the other bank are assigned (2), (5). The cylinder numbers 4) and (6) are attached.

A signal indicating to which cylinder the fuel injection is to be cut, that is, an FC signal (fuel cut signal) 4
3 is the above-mentioned Table 1 and Table 2 of the slip degree judging means 42.
It is formed by the determination result based on the above, and is transmitted from the drive wheel control means 4 to the engine drive control means 3.

The FC signal 43 is composed of a pulse signal having a constant cycle, and the torque down level of "0" to "12" can be expressed by variously changing the duty ratio of the pulse signal. It has become. Therefore, when such an FC signal 43 is transmitted to the engine drive control means 3, the engine torque control means 3b of the engine drive control means 3 which receives this signal reads the torque down level from the signal, and based on this, a predetermined value. Pulse signal 51 of each fuel injection nozzle 5
As a result, the torque of the engine 2 is reduced by controlling the number of cylinders corresponding to the degree of slip.

According to the present invention, the ignition timing retard control of the ignition plug is performed according to the operating state and the slip condition in accordance with the above-described cylinder number control. In this retard control, when the torque down level is large, The greatest feature is that it is configured to limit the amount of retard.

Regarding the control of the number of cylinders, when the engine 2 is rotating at a low speed, the number of cylinders is controlled by cutting the fuel and the ignition timing retard is used in combination to perform the torque down control so that the engine 2 rotates at a high speed. During this time, the torque down control is mainly performed only by controlling the number of cylinders.

The ignition timing retard control is performed by setting various retard amounts (retard amounts) according to slip conditions. Table 3 shows this retard amount by the crank angle. In this table, the engine water temperature and the engine speed are expressed in the vertical direction, and the torque down level corresponding to slip divided into 12 stages is expressed in the horizontal direction. Further, a retard angle symbol is entered in the rightmost column, and this symbol represents the driving member of the engine 2.

[0052]

[Table 3]

Therefore, for example, when the engine water temperature is low and the engine speed is 3500 to 5000 rpm,
That is, if the retard symbol is “C2” and the torque down level is “2”, the retard amount is “12 °” from Table 3. This retard amount is transmitted from the ignition timing retard limiting means 3c in the drive control means 3 to the engine ignition coil 6, and the torque of the engine 2 is reduced by adjusting the ignition timing.

In this embodiment, when the driving state of the engine 2 is "C1", that is, when the engine water temperature is 0 ° C or lower and the rotation speed is 3500 rpm or less, the torque down level is "3". Up to ", the retard amount of the ignition timing is set to increase according to the torque reduction amount, but after that, the retard amount is limited, and the retard amount is set to" 0 ° "at which retard is not performed.

The limit of the retard amount of the ignition timing in the cold state is set to be stricter as the rotation speed of the engine 2 increases, and the torque is retarded in the engine drive state where the retardation symbol is "C2". The retard amount is set up to the down level "2", but is limited thereafter. When the retard symbol is "C3", that is, the rotation speed is 5
At 000 rpm or more, the retard amount is set only when the torque down level is slightly "1".

Since the driving state of the engine 2 is stable while the engine water temperature is 0 ° C. or higher, when the engine speed is 5000 rpm or less, that is, when the retardation symbol is “H1”, Until the torque down level becomes "9", the increasing retard amount is set according to the increase of the same level. After that, the retard amount is limited and is set to "0".

The torque down level is "3",
With "4", "6" and "8", the retard amount is "0"
This is because the torque reduction amount is gradually changed in association with the change in the number of fuel cut cylinders.

When the retard symbol is "H2" and the engine speed is high at 5000 rpm or higher, the retard amount of the ignition timing is set only when the torque dowbell is "1". The retard amount is limited to "0".

As described above, regardless of whether it is cold or warm, when the engine speed is 5000 rpm or less, the engine 2 is controlled by both ignition timing retard control and cylinder number control.
Torque is reduced, but the rotation speed is 5000 rpm
At the above high rotation speed, the torque reduction is mainly performed by controlling the number of cylinders.

FIG. 4 is a flow chart for explaining the operation of the engine control system of the present invention. The operation of the present invention will be described below based on this flowchart. First, in step S1, it is asked whether or not the water temperature of the engine 2 is 0 ° C. or higher. When the result is NO, that is, when the water temperature is 0 ° C. or lower, the torque down control is performed in the cold state of step S2 and below.

In step S2, it is asked whether the engine speed is 3500 rpm or less. YE
When S, that is, when the rotation speed is 3500 rpm or less, step S5 is executed, and according to the torque down level,
In addition, the ignition timing retard corresponding to the retardation symbol "C1" in Table 3 is executed. At this time, the cylinder cut combination number corresponding to the torque down level is set at the same time from Table 1, and the cylinder cut corresponding to the cylinder cut number shown in Table 2 is performed.

If NO at step S2,
That is, if the rotation speed of the engine 2 is higher than 3500 rpm, it is asked in step S3 whether the rotation speed of the engine 2 is 5000 rpm or more. Yes
In case of, the step S7 is executed, and the retard amount of the retardation symbol "C3" in Table 3 is set.

When the result of step S3 is NO, that is, the rotation speed of the engine 2 is 3500 to 5000 rpm.
In case of, the step S6 is executed and the retard amount of the retardation symbol "C2" in Table 3 is set. These steps S
Also in 5 and step S7, the cylinder number control is executed based on Tables 1 and 2 as in step S5.

When the water temperature of the engine 2 is 0 ° C. or higher in step S1, the step S4 and subsequent steps, which are warm control, are executed. First, in step S4, it is asked whether the engine speed is 5000 rpm or more. And the rotation speed is less than 5000 rpm N
When it is O, step S9 is executed, the ignition timing retard amount shown in the retardation symbol "H1" of Table 3 is set, and based on Table 1 and Table 2 according to the torque down level at that time. The cylinder number control is executed.

When the engine speed is 5000 rpm or more in step S4, step S8 is executed to set the retard amount of the ignition timing based on the retardation symbol "H2" in Table 3, and at the same time control the number of cylinders in the same manner as above. Is also executed.

As described in detail above, the present invention is based on the fact that the torque reduction control of the engine 2 is performed by the combined use of the retard amount of the ignition timing and the reduction of the operating cylinders by the fuel cut. By properly setting the combination of the control and the cylinder number control (that is, the retard amount control and the cylinder number control are used together when the engine 2 is rotating at a low speed, and the cylinder number control is mainly performed during the high speed transfer. At the same time, when the torque down level is large, the retard amount of the ignition timing is limited), so that the torque down of the engine 2 is more appropriately performed, and unburned components in the exhaust gas can be reduced. This is possible, and as a result, high temperature deterioration of the exhaust purification catalyst filled in the exhaust pipe can be effectively suppressed.

In this embodiment, in addition to the above torque down control, torque down prohibition control is also performed. The torque down inhibition control will be briefly described below.

First, the atmospheric pressure sensor 31 is provided at an appropriate portion of the vehicle body. The atmospheric pressure sensor 31 is provided for that purpose because it is necessary for the atmospheric pressure sensor 31 to know the proper amount of fuel injection because the fluctuation of atmospheric pressure inherently affects the amount of fuel injection.

When the atmospheric pressure sensor 31 is abnormal, the fuel injection amount, which is closely related to the slip control, is affected. Therefore, it is determined whether or not the atmospheric pressure sensor 31 is abnormal. ing. This determination is
This is performed by the abnormality detection means 3a formed inside the engine drive control means 3. That is,
In this embodiment, the fluctuation range of the atmospheric pressure that can actually occur is input, and it is constantly compared whether or not the detected value of the detected atmospheric pressure is included in this fluctuation range, and the value is outside the fluctuation range. When it does, the atmospheric pressure sensor 31 is determined to be abnormal. Instead of such a fluctuation range confirmation method, a plurality of atmospheric pressure sensors may be provided and an abnormality may be determined to occur when a considerable difference occurs in their detected values. If the atmospheric pressure sensor 31 is determined to be abnormal, the torque down control is not performed even if the torque down condition is satisfied.

Next, the intake pipe 22 is provided with an intake air temperature sensor 32.
Is provided. The intake air temperature sensor 32 is provided because the intake air temperature immediately affects the control of the fuel injection amount, and the abnormality of the intake air temperature sensor 32 is also detected by the abnormality detecting means 3a. Has become. The abnormality detection mechanism of the intake air temperature sensor 32 is similar to that of the atmospheric pressure sensor 31. The torque down control is not performed even when the intake air temperature sensor 32 is determined to be abnormal.

In addition to the above, the water temperature sensor 33 is provided in the jackets of the cylinder groups E1 and E2, the throttle sensor 34 is provided in the intake throttle valve 24, and the intake flow rate sensor 35 is provided upstream of the throttle sensor 34. A rotation sensor 36 is provided on each of the crankshafts, and these detected values are used for optimal driving of the engine 2, and the abnormality of the detected values is discriminated by the abnormality detecting means 3a depending on the situation. The torque down control may not be performed even when any of them is determined to be abnormal.

Further, an engine torque control means 3b is provided inside the engine drive control means 3, and the engine torque control means 3b establishes a torque down condition based on information from the above-mentioned sensors. It is always checked whether or not there is, and when the above condition is satisfied, a predetermined command signal for performing torque reduction by controlling the number of cylinders of the engine 2 is transmitted.

The atmospheric pressure sensor 31 and the intake air temperature sensor 32
In addition to detecting the abnormality of the sensor from the above, the abnormality of the driving wheel control means 4 is detected from the FC signal 43. That is, the cycle of the pulse that constitutes the FC signal 43 is set to 8 msec, and if this cycle is measured and it is within the range of 8 msec ± 10%, the control is performed according to it and the above range It is configured to be ignored as a temporary failure if it is up to three times outside, and to be judged to be abnormal if the outside of the above range occurs three times in a row.

On the other hand, the drive wheel control means 4 is provided with an alarm means 7 composed of a warning lamp, and when the torque down inhibition signal 44 is transmitted to the drive wheel control means 4, the alarm means 7 is generated by this signal. Is configured to light up. If the slip control system is configured to brake the front wheels 11 and 12 that are the drive wheels based on the control by the drive wheel control means 4 to reduce the torque, the torque reduction is prohibited. Signal 4
Alternatively, the braking may be released by step 4.

When an abnormality is found in the FC signal 43, it is judged that an abnormality has occurred in the drive wheel control means 4, and the engine drive control means 3 first drives the drive wheel control means 4 first.
A torque down prohibition signal 44 is transmitted to the drive wheel control means 4 which receives the signal to turn on the warning means 7.
The driver can recognize that an abnormality has occurred in the slip control.

The pulse signal 51 transmitted from the engine torque control means 3b of the drive control means 3 to the fuel injection nozzle 5 of the engine 2 after the elapse of a preset fixed time is a normal pulse from the slip-corresponding mode. It is switched to the signal, and the one in the slip compatible mode is never transmitted. This state is configured to continue until the ignition switch is turned off. The engine torque control means 3b formed in the engine drive control means 3 functions as a slip control prohibition means.

By limiting the torque down control in this way, the torque down control of the engine, which is a rather irregular drive mode in the engine drive, is always in a normal state when the necessity arises. Conveniently done in.

[0078]

As described above in detail, the engine control apparatus of the present invention is provided with the torque down control means for performing the torque down control by delaying the ignition timing when a predetermined torque down condition is satisfied. The apparatus is provided with a torque down level discriminating means for discriminating a torque down level, and ignition timing retard limiting means for limiting the ignition timing delay when the torque down level is large based on the discrimination result. Is.

Therefore, when the torque down level is large, the retard amount of the ignition timing is limited, and as a result, the rise in exhaust temperature is suppressed. Therefore, even if the torque down control of the engine is executed, it is possible to effectively suppress the high temperature deterioration of the exhaust gas purifying catalyst filled in the exhaust pipe.

Further, when the engine is running at a low speed, the torque down control is performed by cutting the fuel for some cylinders and delaying the ignition timing, and when the engine is running at a high speed, the torque down control is performed mainly by the fuel cut. If the down control device is configured, the fuel cut and ignition timing retard can be used together to reduce the torque of the engine more effectively and stably when the engine is running at low speed. Since it is rotating, the absolute amount of unburned components is small and afterburning hardly occurs. Further, when the engine is running at a high speed, the fuel cut is mainly controlled, and the ignition timing retard is limited. Therefore, afterburning is suppressed and a torque reduction with a good system according to the torque reduction level is realized.

Further, if the torque down level determining means is configured to determine that the above torque down condition is satisfied when the vehicle slips, the torque down control of the engine due to the torque down condition being satisfied when the vehicle slips. Is executed, and eventually the torque of the drive wheels that are slipping and rotating is reduced, and the slip is effectively suppressed.

[Brief description of drawings]

FIG. 1 is a system diagram for explaining an engine control device according to the present invention.

FIG. 2 is an explanatory diagram for explaining a state in which one cylinder group functions as an operating cylinder group based on a lean air-fuel mixture and the other cylinder group is a deactivated cylinder group.

FIG. 3 is an explanatory diagram for explaining a state in which working cylinders and idle cylinders are mixed in both cylinder groups.

FIG. 4 is a flow chart for explaining the operation of the engine control device of the present invention.

[Explanation of symbols]

1 vehicle 1a right drive wheel rotation speed sensor 1b left drive wheel rotation speed sensor 1c right driven wheel rotation speed sensor 1d left driven wheel rotation speed sensor 11, 12 front wheel 13, 14 rear wheel 2 engine E1 first cylinder group E11, E12, E13 (first cylinder group) unit cylinder E2 second cylinder group E21, E22, E23 (second cylinder group) unit cylinder 21 head part 22 intake pipe 23 exhaust main pipe 23a first exhaust pipe 23b second exhaust pipe 24 Intake throttle valve 25 Rear purifier 3 Engine drive control means 3a Abnormality detection means 3b Engine torque control means (torque down control means) 3c Ignition timing retard limiter 31 Atmospheric pressure sensor 32 Intake temperature sensor 33 Water temperature sensor 34 Throttle sensor 35 Intake flow rate Sensor 4 Drive wheel control means 41 Slip detection means 42 Slip degree determination means (torque dow Level-indicating means) 44 Inhibition signal 5 Fuel injection nozzle 51 Pulse signal 6 Ignition coil 61 Distributor 7 Alarm means

Claims (3)

[Claims] 1. An engine control device having a torque down control means for performing torque down control by delaying ignition timing when a predetermined torque down condition is satisfied, wherein torque down level determination means for determining a torque down level is provided. An engine control device provided with ignition timing retard limiting means for limiting the delay of the ignition timing when the torque down level is large based on the determination result. 2. When the engine is at low speed, the torque down control is performed by cutting the fuel for some cylinders and delaying the ignition timing, and when the engine is at high speed, the torque down control is mainly performed by the fuel cut. The engine control device according to claim 1, wherein a torque down control means is configured. 3. The engine control device according to claim 1, wherein the torque down level determination means is configured to determine that the torque down condition is satisfied when the vehicle slips. .