JP3317537B2 - Engine control device - Google Patents

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 the torque of an engine mounted on a vehicle.

[0002]

2. Description of the Related Art In a vehicle equipped with an engine of an internal combustion engine, the engine torque can be increased with a very small amount of engine torque, such as when idling or descending downhill, or when performing slip control. , So-called torque-down control for reducing the pressure may be performed. The former torque-down control during idling or downhill is for the purpose of saving fuel consumption, and the latter torque-control during slip control is for effectively suppressing slip.

[0003] As a means of reducing the torque in such a case, there is a so-called cylinder number control for cutting off the supply of fuel to a specific engine among engines of a plurality of cylinders. As a method in which this cylinder number control is applied to slip control, a method disclosed in Japanese Patent Application Laid-Open No. 3-67042 as a vehicle traction control method is known.

According to the traction control method disclosed in this publication, when slippage occurs in a vehicle, when the torque of the drive wheels is reduced in order to suppress the slippage, fuel is supplied to a specific engine cylinder as described above. The fuel supply is stopped (fuel cut), and a lean mixture of fuel is supplied to the remaining cylinders.

[0005] By supplying the lean mixture to the remaining cylinders, the amount of unburned gas such as carbon monoxide and hydrocarbons in the combustion exhaust gas is reduced. It is described that even if the oxygen-rich exhaust gas and the combustion exhaust gas are mixed, combustion in the exhaust pipe hardly occurs, and therefore, the exhaust pipe does not reach a high temperature, which is convenient. Particularly, in the case where an exhaust gas purification device filled with a catalyst is interposed in the middle of the exhaust pipe, it is described that the catalyst can be effectively prevented from being deteriorated due to exposure to a high temperature, which is advantageous. ing.

[0006]

By the way, in the conventional cylinder number control system disclosed in Japanese Patent Application Laid-Open No. 3-67042, a lean-mixed torque generating operating cylinder is not fuel-cut. Supply of air, which is good for the purpose of reducing engine torque, but conversely, combustion in the engine becomes unstable, and not only is it not possible to obtain smooth rotation of the engine shaft, but also in the worst case May lead to an engine stop.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and the engine rotation is smoother and the engine is less likely to stop.
Moreover, it is an object of the present invention to provide an engine control device capable of effectively suppressing high-temperature deterioration of an exhaust purification catalyst provided in an exhaust pipe.

[0008]

According to a first aspect of the present invention, there is provided an engine control device comprising a first cylinder group and a second cylinder group.
A first exhaust pipe connected to the first cylinder group and a second cylinder
A second exhaust pipe connected to the group, and a second exhaust pipe provided in the first exhaust pipe.
One purifier and a second purifier provided in the second exhaust pipe.
An engine configured to perform a fuel cut of a preset cylinder when a predetermined torque-down condition is satisfied, and to perform a control to make the air-fuel mixture supplied to the remaining operating cylinders lean. In the control unit, when the combustion of the engine is unstable, the fuel with the lean air-fuel ratio
To reduce fuel consumption and to cut fuel
Cylinders in one of the first cylinder group or the second cylinder group
It is characterized in that an engine torque control means for controlling the rotation of the engine is provided.

[0009] Control device according to claim 2, wherein the engine of the present invention is the control apparatus according to claim 1, wherein the engine, the low temperature der than the temperature at which the cooling water is set in advance of the engine
Ri and is characterized in that determining the engine torque control means combustion engine unstable is provided when the engine is rotating at a low rotational speed than the preset rotational speed .

According to a third aspect of the present invention, there is provided the engine control apparatus according to the first or second aspect, wherein the engine torque control means determines that the torque down condition is satisfied when the vehicle slips. Is provided.

[0011]

According to the engine control apparatus of the first aspect, when the combustion of the engine is unstable, the fuel having the lean air-fuel ratio is obtained.
To reduce fuel consumption and to cut fuel
Cylinders in one of the first cylinder group or the second cylinder group
In the exhaust pipes connected to the cylinder groups, the exhaust cylinders of the oxygen-rich working cylinder groups and the deactivated cylinder groups (fuel
It does not mix with the exhaust of the cylinder group that performs the cut . Accordingly, the combustible components in the exhaust pipes connected to the operating cylinder group do not burn and the temperature does not rise. Therefore, by providing an exhaust purification device filled with a catalyst in each of the above exhaust pipes, high temperature deterioration of the catalyst is effective. Is blocked.

According to the control apparatus for an engine of the second aspect, the engine torque control means Ri cold der than the temperature at which the cooling water of the engine is set in advance, and the rotation number of the engine is set in advance Is configured to determine that the combustion of the engine is unstable when the engine is rotating at a low rotational speed. Therefore, the unstable combustion of the engine can be easily detected. Engine torque down control can be performed.

According to the engine control device of the third aspect, the engine torque control means is configured to determine that the torque down condition is satisfied when the vehicle slips. The engine torque-down control based on the fulfillment of the torque-down condition is executed, and eventually the torque of the driving wheels that are slipping and driving and rotating is reduced, and the slip is effectively suppressed.

[0014]

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 FIG. 1, the drive system of the vehicle 1 includes an engine 2 as a drive source, an engine drive control unit (engine control unit) 3 for controlling the drive of the engine 2, and front wheels as drive wheels of the vehicle 1. And a drive wheel control means (traction control unit) 4 for performing drive control of 11 and 12. In FIG. 1, the vehicle 1 and the engine 2 are shown at positions far apart from each other for the sake of illustration, but the engine 2 is actually mounted on the vehicle 1, and the rotational drive of the engine 2 is performed by a crankshaft (not shown) or the like. Front wheel 1 via other power transmission means
1 and 12, and no driving force is transmitted from the engine 2 to the rear wheels 13 and 14 that are driven wheels. The roles of the front wheels 11, 12 and the rear wheels 13, 14 may be interchanged.

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

Each of the cylinder groups E1 and E2 of the engine 2 arranged in a V-shape has a head portion 21 provided on an upper portion thereof.
The intake pipe 22 is connected via the intake pipe 22, and the intake air is sent to each of 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.

Accordingly, the intake air accompanies the atomized fuel injected from the head unit 21 to each of the unit cylinders E11 to E23.
And is exhausted after rotating the engine 2 to be exhausted 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. Are discharged to the outside air through the merged exhaust main pipe 23.

Each of the exhaust pipes 23a and 23b is provided with a purifier K filled with a catalyst for purifying exhaust gas. This 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, an electronically controlled fuel injection nozzle 5 is used. The electronically controlled fuel injection nozzle 5 opens an electromagnetic injection valve (injector) incorporated therein in accordance with the cycle of the engine 2 and 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. The opening degree of the intake throttle valve 24 is adjusted in accordance with the accelerator operation amount, so that each of the cylinder groups E1 and E2 is controlled. The amount of intake air to be supplied is controlled.

The mixture of intake air and fuel supplied to the cylinder groups E1 and E2 is ignited and burned by spark discharge of a not-shown spark plug provided at the top of each of the unit cylinders E11 to E23. ing. The ignition plug is supplied with a high-voltage current 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 surrounding conditions, and is constituted by a so-called microcomputer. Various command signals for driving the engine 2 in an optimal state are transmitted in accordance with the four-circumferential situation that is input every moment.

The above-mentioned four situations are detected by various sensors disposed around the engine. Various detected 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 previously input in accordance with the input various detected values. And transmits a command signal to a target location around the engine.

In the control system of the engine 2 as described above, the present invention provides a fuel cut to one of the unit cylinders set in advance when a predetermined torque-down condition is satisfied, and A control is performed to supply a mixture having a lean air-fuel ratio to the remaining unit cylinders (operating cylinders) without performing combustion in the (idle cylinders), and when the torque reduction condition is satisfied when combustion of the engine 2 is unstable. The engine is basically configured by providing engine torque control means for controlling the supply air-fuel mixture to be lean to the working cylinder (i.e., to make the air-fuel mixture lean). The condition that the combustion of the engine 2 is unstable in the present invention refers to a situation where the engine water temperature is low and the engine speed is low.

Further, an engine torque control means 3b is provided inside the engine drive control means 3, and the engine torque control means 3b satisfies a torque down condition based on information from each of the sensors. It is always checked whether or not the engine 2 is operating, 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 to various places.

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

In order to control the engine torque, an injection pulse signal 51 for lowering the engine torque is transmitted from the engine torque control means 3b. That is, in the present embodiment, the reduction of the engine torque is executed by the cylinder number control for reducing the number of operating cylinders of the engine 2 as described above.
The injection pulse signal 51 to a predetermined cylinder set in advance according to the torque value to be reduced is set to 0. Therefore, the fuel injection nozzle 5 receiving this pulse signal 51 stops its operation, and eventually becomes in a state where fuel is not supplied. As the cylinder is not driven, the torque is reduced accordingly. In order to obtain a fuel having a lean air-fuel ratio, the pulse cycle of the pulse signal 51 is adjusted and the fuel
Supply may be restricted more than usual.

FIG. 2 is an explanatory diagram for explaining a state in which one cylinder group functions as an operating cylinder group using a lean air-fuel mixture and the other cylinder group serves as a stopped cylinder group. FIG. 4 is an explanatory diagram for explaining a state in which an operating cylinder and a stopped cylinder are mixed in both cylinder groups.

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

The torque-down driving of the engine 2 in such a state is performed during a cold time when the engine water temperature is relatively low.
This is applied when the engine 2 is rotating at low speed. In other words, during cold low-speed operation, the combustion of the engine is unstable, and therefore the lean air-fuel mixture is restricted. Therefore, the exhaust gas containing a large amount of unburned components and the oxygen discharged from the deactivated cylinder are generated. Exhaust pipe 23 to reach purifier K
This is so as not to merge in the areas a and 23b.

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 cylinder E21 and the unit cylinder E23 of the second cylinder group E2 are fuel cut, and the unit cylinder E11 and the unit cylinder E13 of the first cylinder group E1 and the second cylinder E13. Unit cylinder E22 of cylinder group E2
Are in a so-called double-bank cut state in which the fuel is not cut. In this case, leaned fuel is supplied to the working cylinders E11, E13, and E22 that have not been cut.

The torque down drive of the engine 2 in such a state is applied when the engine water temperature is relatively low and the engine 2 is rotating at high speed. That is, since the engine 2 is rotating at high speed even when the engine water temperature is low, the combustion state of the engine 2 is good, the unburned component in the exhaust gas is small, and the combustion in the first and second exhaust pipes 23a and 23b is performed. Does not occur, and the catalyst in the purifier K does not deteriorate at high temperature.

In the above, one bank cut and one example of both bank cuts have been described with reference to FIGS. 2 and 3.
In this embodiment, a fine-grained engine torque down control including adjustment of the ignition timing is performed according to the degree of the slip amount. Hereinafter, the torque down control will be specifically described.

First, the drive wheel control means 4 determines whether or not the vehicle is in a predetermined slip state according to slip detection, and performs slip control according to the degree of slip when the vehicle enters the predetermined slip state. , Calculation of the control level, and the like. The right and left driving wheel speed sensors 1a and 1b are provided on the front wheels 11 and 12, respectively.
The right and left driven wheel rotation speed sensors 1c and 1d are provided on the rear wheels 13 and 14, which are the driven wheels, respectively.

The function of the driving wheel control means 4 will be described in detail. The rotation speed of each wheel detected by the rotation speed sensor is inputted one by one into the driving wheel control means 4 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, which are drive wheels, and the rotational speeds of the rear wheels 13, 14, which are driven wheels. That is, when the rotational speed of the drive wheel is extremely higher than the rotational speed of the driven wheel, it is determined that the drive wheel is slipping.

A slip degree judging means 42 for judging the degree of slip of the driving wheel detected by the slip detecting means 41 is provided inside the driving wheel control means 4.
The slip degree determining means 42 calculates the degree of slip, and determines what combination of cylinder number control is to be performed based on the calculated slip degree and other conditions.

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

[0038]

[Table 1]

In this table, the horizontal columns show the torque down levels of 1 to 12, and the vertical columns show 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 numerical value of this level indicates that the degree of slip increases as the level increases.
This table is input in advance to the slip degree determination means 42, and the actual torque down control is performed with reference to this table.

In the column where the length and width cross in this table, the cylinder number control number is described. Therefore, for example, when the engine water temperature is low and the engine speed is 5000 rpm or more,
When the torque down level is 5, the combination number of the cylinder number control is 3.

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

[0042]

[Table 2]

In this table, the cylinder numbers of the engines 2 of 1 to 6 are given in the horizontal columns (corresponding to the unit symbol in FIGS. 2 and 3 is shown below the cylinder number), In the column, the combination numbers of the cylinder number control from “0” to “7” are given. This combination number corresponds to the cylinder number control combination number in Table 1 above. In Table 1, a circle indicates a fuel injection “present”, and a cross indicates a fuel injection “none”.

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

A signal indicating to which cylinder the fuel injection is cut, that is, an FC signal (fuel cut signal) 4
3 shows the results of Tables 1 and 2 of the slip degree determining means 42.
And 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 period. By changing the duty ratio of the pulse signal in various ways, the combination numbers of the cylinder number control of "0" to "7" are set. ing. 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 receiving this signal converts the signal into a predetermined pulse signal 51, and thereafter, Since the output is output to each fuel injection nozzle 5, the torque of the engine 2 is reduced by controlling the number of cylinders corresponding to the degree of the slip.

In accordance with the control of the number of cylinders, the ignition timing of the ignition plug is adjusted according to the operating state and the slip condition. This ignition timing adjustment is to set the basic ignition timing according to the operating state and variously set the retard amount (retard amount) according to the slip condition. Table 3 shows the retard amount by the crank angle. In this table, the vertical axis represents the engine water temperature and the number of revolutions of the engine, and the horizontal axis represents the torque reduction level corresponding to the slip, which is divided into 12 steps as in the above.

[0048]

[Table 3]

Therefore, for example, if the torque down level is “2” when the engine water temperature is low and the engine speed is 3500 to 5000 rpm, the retard amount is referred to as “12.0 °” from Table 3. Will be. This retard amount is transmitted from the drive control means 3 to the spark plug of the engine 2, and the ignition timing is adjusted, whereby the optimum drive state of the engine 2 is obtained.

In such slip control by reducing the engine torque, it may be inappropriate to reduce the torque. Therefore, in the present embodiment, the torque down control is prohibited when a predetermined condition occurs. Hereinafter, the inhibition of the torque down control will be briefly described.

First, an atmospheric pressure sensor 31 is provided at an appropriate portion of the vehicle body. The atmospheric pressure sensor 31 is required to know an appropriate fuel injection amount because fluctuations in the atmospheric pressure naturally affect the fuel injection amount, and is provided for that purpose.

When the atmospheric pressure sensor 31 is abnormal, it affects the fuel injection amount which is closely related to the slip control. Therefore, it is determined whether or not the atmospheric pressure sensor 31 is abnormal. ing. This determination is
This is performed by an abnormality detecting means 3a formed inside the engine drive control means 3. That is,
In the present embodiment, the range of the atmospheric pressure that can actually occur is input, and it is always compared whether or not the detected value of the detected atmospheric pressure is included in this range of fluctuation. When it is determined that the atmospheric pressure sensor 31 is abnormal. Instead of such a fluctuation range confirmation method, a plurality of atmospheric pressure sensors may be provided, and when a considerable difference occurs between the detected values, it may be determined that an abnormality has occurred. 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, an intake air temperature sensor 32 is
Is provided. The intake air temperature sensor 32 is provided because the temperature of the intake air has an immediate effect on the control of the fuel injection amount. 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 the same as that of the atmospheric pressure sensor 31. Even when the intake air temperature sensor 32 is determined to be abnormal, the torque down control is not performed.

In addition to the above, a water temperature sensor 33 is provided on the jackets of the cylinder groups E1 and E2, a throttle sensor 34 is provided on the intake throttle valve 24, and an 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 abnormalities of these detected values are determined by the abnormality detecting means 3a according to the situation. With such a configuration, 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 satisfies a torque down condition based on information from each of the sensors. Whether or not the engine 2 is in operation is checked, and when the above condition is satisfied, a predetermined command signal for reducing the torque 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 constituting the FC signal 43 is set to 8 msec. If this cycle is measured and it is within the range of 8 msec ± 10%, the control corresponding thereto is performed, and If it is outside the range up to three times, it is ignored as a temporary defect, and if outside the above range occurs three times in a row, it is determined that there is an abnormality.

On the other hand, the drive wheel control means 4 is provided with a warning means 7 comprising a warning lamp. When the torque-down prohibition signal 44 is transmitted to the drive wheel control means 4, the warning means 7 is generated by this signal. Is configured to light up. If the slip control method is configured to brake the front wheels 11 and 12 as drive wheels under the control of the drive wheel control means 4 to reduce the torque, the torque reduction is prohibited. Signal 4
4, the braking may be released.

When an abnormality is found in the FC signal 43, it is determined that an abnormality has occurred in the drive wheel control means 4. First, the engine drive control means 3 sends the drive wheel control means 4
, A torque-down prohibition signal 44 is transmitted, and the drive-wheel control means 4 receiving this signal turns on the alarm means 7.
The driver can recognize that an abnormality has occurred in the slip control.

After a lapse of a predetermined time, 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 becomes the normal pulse signal from the slip response mode. The signal is switched to a signal so that the one in the slip correspondence mode is never transmitted. This state is configured to continue until the ignition switch is turned off.

In this embodiment, the engine torque control means 3b formed in the engine drive control means 3 functions as a slip control inhibiting means.

The operation of the present invention will be described below with reference to the flowchart shown in FIG. This flowchart is
Of the drive wheel control mainly performed by the drive wheel control means 4 and the drive control means 3 and the control of the rotational drive of the engine 2, the torque down control of the engine according to the present invention is extracted and shown. .

When the torque down control is started, it is first asked in step S1 whether the torque down control is possible. In response to this question, the detection values of the sensors related to the items to be checked, such as the atmospheric pressure sensor 31, the intake air temperature sensor 32, and the FC signal 43, are inspected, and it is determined whether or not they are abnormal. The number of revolutions of the engine 2 is checked from the detected values of Nos. 36 and
A determination is made as to whether it is within the rpm range.

If the result of the determination is NO, that is, if the torque down control is not possible, a predetermined torque down control prohibition process is performed in step S9, and then the normal engine Drive control is performed.

When the torque down control is possible in the above step S1 (YES), the next step S2 is executed to determine the torque down level (Ts). This torque down level (Ts) is determined by the slip detection means 41 based on the slip rate detected from the rotational speed difference between the front wheels 11 and 12 as drive wheels and the rear wheels 13 and 14 as driven wheels. 42, which is obtained by applying any of “1” to “12” shown in Table 1.

In the next step S3, it is determined whether or not the value of the torque down level (Ts) is larger than "0". When the determination is NO, that is, when it is not necessary to perform the torque down control (that is, when a slip is generated). If not, the normal engine drive control of step S10 is executed.

When the torque down level (Ts) is larger than "0" at step S3,
That is, the torque down level (Ts) is from “1” to
If any of "12", the next step S4 is executed. In this step S4, the engine water temperature (W) is asked. If the water temperature is higher than a predetermined α, the process proceeds to step S5, and if the water temperature is lower than the α, the process proceeds to step S6.

In step S5, various control charges corresponding to the torque down level when the engine water temperature is high are calculated. That is, first, referring to Table 1 above, the torque down level (Ts) and the engine water temperature,
Cylinder number control combination number (F) corresponding to engine speed
Is determined. Next, a fuel correction amount (C) is calculated based on a predetermined calculation method. In the calculation of the fuel correction amount (C), the torque down level (Ts) and the engine speed (n) are used as data. Then, in principle, the above-described control amounts are determined so that a lean air-fuel mixture is used during a warm period. Further, the ignition retard amount (R) is also determined with reference to Table 3 above.

In step S6, each control amount of the torque down control when the engine water temperature is lower than α is calculated. Each of the above control amounts is determined such that a rich fuel whose leaning is restricted is used.

When step S5 is executed, the torque reduction control in the warm state is executed in step S7 based on the respective control amounts determined there.
When step S6 is executed, the torque reduction control at the time of cold is performed in step S8 based on the control amounts determined in this step.

As described in detail above, in the engine control apparatus of this embodiment, when a slip occurs in the vehicle, the slip is suppressed by controlling the torque of the engine by controlling the number of cylinders. When the combustion of the engine is unstable, specifically, when the number of cylinders is controlled in one bank, the leaning of fuel is restricted, so that the instability of the engine drive is eliminated, For example, when the three cylinders are to be deactivated, when the temperature is low and the rotation speed is low (that is, combustion is unstable), the single- bank operation (operation of the combination number “4” in Table 2) is performed, and the first bank group E1 is connected. The first exhaust pipe 23a and the second exhaust pipe 23b for the second cylinder group E2 do not mix with each other, so that the unburned component exhausted from the operating cylinder is rich in exhaust, and cylinder Not occur afterburning of the exhaust pipe due to mixing with the oxygen to be al discharged, therefore, the first purifier K1 and a second clarifier provided their K2
High temperature deterioration of the catalyst filled in the inside can be prevented.

[0071]

As described in detail above, the engine control apparatus of the present invention cuts the fuel for a preset cylinder when a predetermined torque-down condition is satisfied, and supplies the air-fuel mixture supplied to the remaining operating cylinders. In the engine control device configured to perform lean control, when the combustion of the engine is unstable, the lean air-fuel ratio of the fuel is increased.
To reduce the number of cylinders for fuel cut
Focus on one cylinder group of cylinder group or cylinder group 2
Engine torque control means for controlled so that those are thus provided.

[0072] Therefore, when the combustion state of the engine is unstable, the air-fuel mixture is suppressed lean into operating cylinders (residual cylinder) by the action of the engine torque control means is supplied Rutotomoni, each cylinder group In each of the connected exhaust pipes, since the exhaust of the oxygen-rich working cylinder group and the exhaust of the stopped cylinder group in which unburned components remain do not mix with each other, the exhaust pipe connected to the working cylinder group does not mix. The unburned components do not burn and the temperature does not rise. Therefore, by providing an exhaust gas purifying device in which each of the exhaust pipes is filled with a catalyst, deterioration of the catalyst at high temperatures can be effectively suppressed.

[0073] Further, the engine torque control means, Ri cold der than the temperature at which the cooling water is set in advance of the engine,
In addition , if the engine is configured to determine that the combustion of the engine is unstable when the engine is rotating at a lower rotation speed than a preset rotation speed, the unstable combustion of the engine can be easily detected. It is possible, and the torque down control of the engine can be appropriately performed by this detection.

In addition, if the engine torque control means is configured to determine that the above-described torque-down condition is satisfied when the vehicle slips, the engine torque-down control based on the fact that the torque-down condition is satisfied when the vehicle slips is provided. Is executed, the torque of the driving wheel that is eventually slipping and driving and rotating is reduced, and the slip is effectively suppressed.

[Brief description of the drawings]

FIG. 1 is a system diagram illustrating 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 using a lean air-fuel mixture, and the other cylinder group is a paused cylinder group.

FIG. 3 is an explanatory diagram for explaining a state in which an operating cylinder and a stopped cylinder are mixed in both cylinder groups.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle 1a Right drive wheel speed sensor 1b Left drive wheel speed sensor 1c Right driven wheel speed sensor 1d Left driven wheel speed sensor 11, 12 Front wheels 13, 14 Rear wheel 2 Engine E1 First cylinder group E11, E12, E13 Unit cylinder (of first cylinder group) E2 Second cylinder group E21, E22, E23 Unit cylinder 21 (of second cylinder group) 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 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 44 Prohibition signal 5 Fuel injection nozzle 51 Pulse signal 6 Ignition coil 61 Electric 7 alarm means

Continuation of the front page (56) References JP-A-2-233855 (JP, A) JP-A-4-171245 (JP, A) JP-A-63-263243 (JP, A) JP-A-61-89936 (JP) JP-A-2-176138 (JP, A) JP-A-55-131540 (JP, A) JP-A-59-170431 (JP, A) JP-A-63-186937 (JP, A) 3-67042 (JP, A) JP-A-7-133716 (JP, A) JP-A-1-88016 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 17/02 F02D 29/02 F02D 41/00-41/40 F01N 3/20

Claims (3)

(57) [Claims] A first cylinder group and a second cylinder group;
First exhaust pipe connected to the first cylinder group and connected to the second cylinder group
Second exhaust pipe and a first purifier provided in the first exhaust pipe
And an engine having a second purifier provided in the second exhaust pipe.
A gin, performs fuel cut preset cylinders when a predetermined torque reduction condition is satisfied, configured control of the engine to perform control of the mixture supplied to the remaining operating cylinders to lean In the system, when the combustion of the engine is unstable, the lean air-fuel ratio
To reduce the number of cylinders for fuel cut
Focus on one cylinder group of cylinder group or cylinder group 2
The engine control apparatus, wherein the engine torque control means is provided for controlled so. Wherein Ri cold der than the temperature at which the cooling water is set in advance of the engine, and unstable combustion engine when the engine is rotating at a low rotational speed than the rotational speed that has been set in advance control device according to claim 1, wherein the engine, characterized in that the engine torque control means is provided determining the. 3. The engine control device according to claim 1, further comprising engine torque control means for determining that the torque-down condition is satisfied when the vehicle slips.