JPH08144803A - Engine controller - Google Patents

Abstract

PURPOSE: To prevent torque-down performance from being degraded due to generation of mis-fire in a working cylinder, in some cylinders to which fuel supply has been stopped after receiving a prescribed torque-down request, by promoting combustion of the working cylinder when the number of the cylinders which require fuel supply stop is numerous. CONSTITUTION: An ECU 23 which controls a fuel injection value 18 receives a torque down signal TCS from a traction control unit when slippage occurs in a driving wheel to perform ignition timing delay angle correction and traction control due to fuel stop for some cylinders. While fuel supply to some cylinders is stopping, the air-fuel ratio of mixture supplied to the cylinders working without requiring fuel stop is changed to fuel leaner side than the one when fuel supply is not stopped because of no request of torque-down. The more the number of the cylinders which require fuel supply stop is, the lean degree of the air-fuel ratio of the working cylinder is decreased more to promote combustion and restrain mis-fire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel control system for an engine, and more particularly, to a fuel control system for an engine, for example, by stopping fuel supply to some cylinders when a drive wheel of a vehicle is slipped. The present invention relates to an engine control device that reduces the output torque of an engine in response to a predetermined torque down request, such as reducing the output torque and suppressing slippage.

[0002]

2. Description of the Related Art During engine operation, a torque down request may occur due to various external conditions. For example,
In an engine that drives a vehicle, slippage may occur in the drive wheels during vehicle acceleration. When this slippage occurs, it is effective to reduce the output torque of the engine according to the slip level. Therefore, so-called traction control has been conventionally performed in which the output torque of the engine is reduced by delaying the ignition timing or stopping the fuel supply to some cylinders when a slip occurs.

By the way, when the traction control is performed by the method of stopping the fuel supply to some cylinders when a slip occurs, it is necessary to simply stop the fuel supply to some cylinders from the cylinders whose fuel supply is stopped. Since the air sent to the exhaust system reacts with the unburned components in the operating cylinders, the temperature of the exhaust system rises and the catalytic device is damaged, which causes a problem in the reliability of the exhaust system. Therefore, for example, Japanese Patent Laid-Open No. 3-670
As described in Japanese Patent Laid-Open No. 42-42, when the slip is detected and the fuel supply to some cylinders is stopped, the air-fuel ratio of the air-fuel mixture supplied to the operating cylinders is set to the fuel lean side as compared with the normal time. Is proposed to be changed.

[0004]

Changing the air-fuel ratio of the operating cylinders to the lean side when the fuel supply to some cylinders is stopped due to the occurrence of a torque down request such as slip suppression is to change the exhaust system. This is an effective means for suppressing the temperature rise, but on the other hand, if the air-fuel ratio is lean, the combustion temperature rises, so the temperature inside the combustion chamber may exceed the allowable temperature. This causes a problem in the reliability of the engine body.

Further, when the required torque down level is high and the number of cylinders for which fuel supply is stopped increases and the number of operating cylinders decreases, the combustion state of each operating cylinder greatly affects the generated torque. Therefore, if misfiring easily occurs by making the air-fuel ratio lean, the generated torque fluctuates due to misfiring, and the torque down amount often deviates, resulting in a problem that the torque down performance deteriorates.

For example, in a V-type engine having an exhaust manifold that forms an independent exhaust passage for each bank and collectively communicates the exhaust passages on the downstream side, the number of cylinders that stop and stop fuel supply In a state in which there is a plurality of cylinders and one bank has one idle cylinder, the temperature of the exhaust system rises remarkably, and the reliability of the exhaust system may not be ensured especially in the high rotation range. In the case of an engine having a plurality of cylinder rows, such as a V-type engine having a cylinder row in each of the left and right banks, in order to ensure the stability of the engine and to keep the sound level as low as possible, to secure the marketability. It is desirable to distribute the cylinders for which the fuel supply is stopped to each bank in a well-balanced manner. However, if the structure of the intake manifold is as described above, it is possible to distribute the cylinders for which the fuel supply is stopped to both banks. When the number of the idle cylinders becomes one, the air sent from the idle cylinders reacts particularly efficiently with the unburned components of the other operating cylinders, which causes the temperature of the exhaust system to rise significantly.

The present invention is for solving such a problem, and is a control for stopping the fuel supply to at least some cylinders and changing the air-fuel ratio of the operating cylinders to the lean side when a torque down request is generated. The purpose is to prevent the torque down performance from deteriorating, such as the occurrence of misfires in the operating cylinders, the generated torque fluctuates, the torque down amount deviates, and the operating state of the vehicle becomes unstable. And

Further, according to the present invention, the temperature in the combustion chamber is allowed when the control for stopping the fuel supply to at least some cylinders and changing the air-fuel ratio of the operating cylinders to the lean side when the torque down request is generated. The object of the present invention is to prevent the occurrence of a problem in the reliability of the engine body that exceeds the temperature and to ensure the reliability of the exhaust system and the reliability of the engine body at the same time.

Further, according to the present invention, in a V-type engine or the like, the reliability of the exhaust system can be ensured especially in a high rotation range by stopping the fuel supply and stopping the cylinder in one cylinder row. The purpose is to prevent disappearance.

[0010]

An engine control apparatus according to the present invention comprises a torque reducing means for reducing an output torque of an engine in response to a predetermined torque down request, and at least a part of the torque reducing means is required. Fuel stopping means for changing the pattern according to the torque down level to stop the fuel supply to some or all of the cylinders, and stopping the fuel supply to some of the cylinders by the fuel stopping means to suspend the cylinders. When changing the air-fuel ratio, the air-fuel ratio of the air-fuel mixture supplied to the cylinder operating without being subject to the fuel stop is changed to the fuel lean side with respect to the air-fuel ratio when the fuel supply is not stopped without the torque down request. In an engine fuel control device having an air-fuel ratio setting means, when the number of cylinders whose fuel supply is stopped by the fuel stop means is large, combustion of operating cylinders is promoted. And it is provided with a suppressing misfire suppression means misfire.

Further, in the engine control device of the present invention, as the misfire suppressing means, when the number of cylinders whose fuel supply is stopped by the fuel stopping means is large, the lean air-fuel ratio setting means is used as compared with when the number of cylinders is small. A lean degree reducing means for reducing the degree of change of the fuel ratio to the fuel lean side is provided. Here, the engine may have an exhaust system equipped with a catalyst device for purifying exhaust gas.

In the engine control device having each of the above-described configurations, the predetermined torque down request may be, for example, a request for suppressing a slip generated in the drive wheels of the vehicle driven by the engine.

Further, in the engine control device having each of the above-mentioned configurations, the engine has a plurality of cylinder rows, and an exhaust manifold that forms an independent exhaust passage for each cylinder row and collectively communicates the exhaust passages on the downstream side is provided. In the case where the engine rotation speed is equal to or higher than the determination rotation speed, the fuel stop pattern by the fuel stop means is set to one cylinder in any cylinder row for stopping the fuel supply. It is preferable to provide pattern changing means for changing so as not to create. Further, the engine control device in that case preferably sets the air-fuel ratio set by the lean air-fuel ratio setting means to the cylinder operating without being subject to fuel stop in the region where the engine speed is equal to or higher than the determination speed. A rich correction means for correcting the rich side is provided. Further, the engine in this case is, for example, a V-type engine having two cylinder rows and two banks constituting each cylinder row being arranged in a V-shape.

Further, in the engine control device having each of the above-mentioned configurations, the torque reducing means includes an ignition timing correcting means for retarding the ignition timing in addition to the fuel stopping means, and the torque reducing means is provided in accordance with the required torque down level. The correction of the ignition timing by the ignition timing correction means and the fuel stop by the fuel stop means may be selected or used together. When such ignition timing correction means is provided, a rich air-fuel ratio setting for setting the air-fuel ratio of the air-fuel mixture supplied to each cylinder to the fuel rich side when the output torque is reduced only by the ignition timing correction means. Means should be provided.

In the present invention, the misfire suppression means may be one that promotes combustion and suppresses misfire by forming an intake swirl in the cylinder, and the ignition energy for discharging by the spark plug is supplied. It may be one that promotes combustion and suppresses misfire by increasing the amount.

FIG. 1 is an overall configuration diagram of the present invention.

[0017]

According to the engine control apparatus of the present invention, at least the output torque of the engine is reduced so as to receive the torque reduction request when the drive wheels of the vehicle driven by the engine are slipped. The torque reducing means including the fuel stopping means is activated, the fuel supply to some or all of the cylinders is stopped in a pattern according to the required torque down level, the cylinders are deactivated, and the output torque is reduced. As a result, slip of the vehicle drive wheels is suppressed, for example. Further, when the fuel supply to some of the cylinders is stopped in this way, the air-fuel ratio of the air-fuel mixture supplied to the operating cylinders is changed to the fuel lean side than normal. As a result, the temperature rise of the exhaust system due to the air sent out from the idle cylinder reacting with the unburned residue of the operating cylinder in the exhaust system is suppressed, and the reliability of the exhaust system is secured. Further, when the number of cylinders for which the fuel supply is stopped is large, the misfire suppression means is activated to promote the combustion of the operating cylinders and prevent misfire. As a result, torque fluctuations are suppressed, and stable operation is possible with a small number of operating cylinders.

Further, according to the engine control device of the present invention, when the fuel supply to some of the cylinders is stopped, the air-fuel ratio of the air-fuel mixture supplied to the operating cylinders is changed to a fuel lean side than normal. As a result, the unburned residue of the operating cylinders is reduced, and the temperature rise of the exhaust system due to the air sent from the idle cylinder reacting with the unburned residue of the operating cylinders in the exhaust system is suppressed, and the exhaust system including the catalyst device Reliability is ensured, and when the number of cylinders in which fuel supply is stopped and stopped is large, the degree of change of the air-fuel ratio to the lean side is reduced to prevent misfire of operating cylinders.
By reducing the degree of change in the air-fuel ratio of the operating cylinders when the number of deactivated cylinders is large, the temperature rise in the combustion chamber in the operating cylinders is suppressed, and the reliability of the engine body is ensured. In addition, when a large number of idle cylinders are used, a large amount of air flows into the exhaust system.In this state, reducing the degree of change to the lean side as described above causes the air-fuel ratio to become slightly rich and burns. Even if the remaining amount of emission becomes large, it has little influence on the temperature rise, and the reliability of the exhaust system including the catalyst device is secured.

Further, according to the engine control apparatus of the present invention, the engine is, for example, a V-type engine, has a plurality of cylinder rows, forms an independent exhaust passage for each cylinder row, and these exhaust passages are provided on the downstream side. When the engine is equipped with an exhaust manifold that communicates with each other, the fuel supply is stopped so that the cylinders that stop the fuel supply do not become one in any cylinder row in the region where the engine speed is higher than the determination speed. The pattern is changed, thereby preventing the temperature of the exhaust system from significantly increasing due to, for example, a V-type engine, the number of cylinders that stop and stop fuel supply is one in one bank or the like. The reliability of the exhaust system in the high speed range is secured. Further, in that case, the air-fuel ratio of the operating cylinders is corrected to the rich side in the region of the number of revolutions equal to or higher than the determination rotational speed, thereby increasing the combustion stability of the operating cylinders of the cylinder row on the side of increasing the number of idle cylinders and preventing the torque fluctuation. In addition, the temperature rise in the combustion chamber can be suppressed to ensure the reliability of the engine body.

Further, in the engine control apparatus of the present invention, when the ignition timing correction means for retarding the ignition timing is provided as the torque reducing means in addition to the fuel stopping means, the ignition timing is adjusted according to the required torque down level. Correction and fuel stop are selected or used together. Then, when the torque reduction is performed only by the ignition timing correction, the air-fuel ratio of the air-fuel mixture supplied to each cylinder is set to the fuel rich side, thereby suppressing misfire and suppressing an increase in combustion temperature. The reliability of the engine is secured.

Further, in the engine control device of the present invention, when the misfire suppression means is the swirl means, an intake swirl is formed in the cylinders to promote combustion when the number of idle cylinders is large, thereby causing misfire. Suppressed. When the misfire suppression means is the ignition energy increasing means, the ignition energy for discharging by the spark plug is increased so as to promote the combustion when the number of idle cylinders is large, thereby suppressing the misfire.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram of an embodiment of the present invention. In the figure, 1 is an engine body of a V-type 6-cylinder engine. This engine body is fixed to the upper part of the cylinder block 2 and a cylinder block 2 that forms a cylinder row of three cylinders in each of the V-shaped left and right banks, a piston 4 arranged in each cylinder 3 of the left and right banks. And a cylinder head 5. An intake manifold 6 is connected to the cylinder head 5 so that the inside of the left and right banks rises upward, and a variable intake pipe 7 forming a variable intake passage is connected to an inlet of the intake manifold 6. There is.

The intake manifold 6 has independent left and right intake passages extending in the cylinder row direction so that the branch passages corresponding to the respective cylinders 3 are sequentially merged for each bank, and a collecting portion at which one end of each intake passage is collected. To form. The variable intake pipe 7 has one end connected to the upstream intake passage 9 connected to the air cleaner 8 and the other end connected to the intake manifold 6
It is connected to the inlet of the collecting part and is configured so that the open / close valve 10 can switch between a long path and a short path in a low rotation range and a high rotation range. The upstream intake passage 9 is provided with an air flow meter 11 for measuring the amount of intake air at the connection with the air cleaner 8, and the throttle valve 1 is provided at the downstream.
2 and 13 are arranged. Further, the cylinder head 5 is connected to an exhaust manifold 14 that extends independently to each bank and communicates with each other on the downstream side, and a catalytic converter 15 is connected to the outlet side of the exhaust manifold 14. Further, O ₂ sensors 16 and 17 for detecting the air-fuel ratio from the oxygen concentration in the exhaust gas are provided in the passage portion of each bank of the exhaust manifold 14, respectively.

A fuel injection valve 18 is provided for each cylinder in the vicinity of the connection portion of the intake manifold 6 with the cylinder head 5. Then, the spark plugs 1 are provided on the cylinder head 5 so as to be provided in the center of the combustion chamber space of each cylinder 3.
9 are arranged, and two of these 6 ignition plugs 19 are connected to separate ignition coils 20 in groups of two.

The engine body 1 is provided with various sensors such as a crank angle sensor 21 for detecting a crank angle and a water temperature sensor 22 for detecting a water temperature of engine cooling water. An engine control unit 23 composed of a microcomputer is provided, and detection signals of the air flow meter 11, the O ₂ sensors 16 and 17, the crank angle sensor 21, the water temperature sensor 22 and the like are input to the engine control unit 23 as information. It Further, the engine control unit 23 receives a signal (TCS signal) of a torque down execution command based on a rotation difference (slip amount) between the front wheels and the rear wheels from a TCS (traction control system) control unit of ABS (antilock brake system). . Then, the fuel injection amount is calculated based on these signals, the ignition timing is calculated, an injection pulse is output to each fuel injection valve 18, and an ignition pulse is output to each ignition coil 20.

In the calculation of the fuel injection amount, the basic injection amount is calculated based on the engine speed calculated from the output of the crank angle sensor 21 and the intake air amount detected by the air flow meter 11, and the water temperature based on the water temperature sensor 22 is calculated. Various corrections such as correction are added, and when the feedback execution condition that the water temperature is equal to or higher than a predetermined value in the predetermined feedback region of low and medium load is satisfied, the air-fuel ratio feedback correction based on the outputs of the O ₂ sensors 16 and 17 is added to the fuel. The injection amount is determined. Then, an injection pulse corresponding to the injection amount is output to the fuel injection valve 18, which drives the fuel injection valve 18.

The ignition timing is set by a map having the engine speed and the intake charge amount as parameters. And
An ignition signal is output corresponding to the ignition timing, and an ignition pulse is applied to each ignition coil 20.

Further, the engine control unit 23
Receives a torque down execution command signal (TCS signal) for traction control from the TCS control unit when a slip occurs on the drive wheels of the vehicle, and corrects the ignition timing retard according to the required torque down level based on the slip amount. And traction control is performed by stopping fuel in some cylinders.

The engine control unit 23 stores data for traction control as table values shown in Tables 1 to 4 below.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

Table 1 shows the Ig retard amount (ignition timing retard amount) for traction control according to FCL (function level) which displays the required torque down level in 11 stages in the low rotation range and the high rotation range, respectively. Is a table that defines Here, the low speed region is a region where the engine speed Ne is equal to or lower than a predetermined speed NB (for example, 4500 rpm), and the high speed region is a region where the engine speed Ne is higher than that. Ig retard amounts are set in the low rotation range and the high rotation range when the FCL is 1, 2 and in the low rotation range when the FCL is 5, 7, and 9, respectively.

Table 2 is a table that defines the allocation of the fuel stop pattern: FCPTN (fuel cut pattern) for traction control according to FCL.
Table 3 is a table that defines the aspects of each FCPTN as 8 aspects from 0 to 7 and 2 aspects of 2'and 3'as variants of 2 and 3. In Table 3, 1CYL on the horizontal axis
6CYL indicates the cylinders from the first cylinder to the sixth cylinder, ◯ indicates fuel supply, and x indicates fuel supply stop.

In the table of Table 2, FCPTN is defined separately in a low rotation range (Ne ≦ NB) and a high rotation range (Ne> NB). When the engine speed Ne is higher than the judgment speed NC (NC> NB) and the thermal reliability is a problem due to the structure of the exhaust manifold,
FCPTN with some modifications of CPTN2 and 3
2'and 3'are defined. In FCPTN2, the fuel-stopped cylinders are the first cylinder (left bank) and the fourth cylinder (right bank), and one fuel-stopped cylinder is provided for each bank. In FCPTN 3, the fuel-stopped cylinders are the first cylinder (left bank), the fourth cylinder (right bank), and the fifth cylinder (left bank).
Therefore, the right bank has only one fuel-stop cylinder. On the other hand, in FCPTN2 ′, the fuel-stopped cylinders are concentrated in the left bank with the first cylinder (left bank) and the fifth cylinder (left bank), and neither bank is a single fuel-stopped cylinder.
Further, in FCPTN3 ', the fuel-stopped cylinders are the first cylinder (left bank), the third cylinder (left bank), and the fifth cylinder (left bank), which are also concentrated in the left bank. Not individual.

Table 4 shows the value TCTCL of the fuel increase rate CTCS for lean setting at the time of executing the fuel stop (F / C),
Fuel increase rate CTC for rich setting when F / C is not executed
The value of S, TCTCL, and FCPTN, especially during F / C execution
It is a table which defines the value T'CTCL of the fuel increase rate CTCS in the case of 2 and 3 (changed to 2'and 3'at the judgment speed or more) according to the engine speed. TC
The table of TCL is set for FCPTN1, 4, 5, 6, 7 respectively, and the table of TCTCR is FCP.
Set for TN0. The table of T'CTCL is set for FCPTN2 (2 ') and 3 (3'), respectively. In the table, 1F, 1B, 1A, etc. mean that the digit of 1s differs depending on the FCPTN.

The relationship between the engine torque T and FCL indicating the required torque down level for traction control is as shown in FIG. In the figure, FCL0 is a state without traction, and the engine torque T in this FCL0 state
Corresponds to the torque reduction amount for each FCL. In the figure, the vertical axis represents the engine torque reduction T, and the horizontal axis represents the engine speed Ne. Further, NB is a rotation speed corresponding to NB in Tables 1 and 2, NC is a rotation speed corresponding to NC in Table 2, and NA is an upper limit rotation speed for engine protection.

FCL0 is in a state without traction, and neither Ig retard nor fuel stop is performed. At this time, the air-fuel ratio (A / F) is a normal setting, and the characteristics with respect to the engine speed Ne are as shown by the solid line in FIG.

When FCL1 and FCL2, FCPTN
Is 0, fuel stop is not performed, and I
Torque down only with g retard. Then, in this state, the air-fuel ratio is set to a richer side than normal as shown by the alternate long and short dash line in FIG.

In the case of FCL3 to 11, the fuel stop is executed according to the pattern defined in the table of Table 3 according to the FCPTN assigned by the table of Table 2, and the FCL
In the low rotation range of 5, 7 and 9, the torque is also reduced by using the Ig retard as well. Further, at this time, the air-fuel ratio is set to the lean side as shown by the broken line in FIG. 4, and the lean degree is made small in the pattern in which there are many fuel stopped cylinders.

Even if FCL3 to 11 are used, FCP
When TN2 and FCPTN3, the engine speed is NC
The fuel stop patterns are FCPTN2 'and F, respectively.
Change to CPTN3 'and correct the air-fuel ratio to the rich side as shown by the chain double-dashed line in FIG. 5 to 7 are flowcharts showing the processing procedure of the traction control. This flowchart consists of steps S1 to S24. When started, first at step S1, the engine speed Ne is reached.
Initial setting of various parameters such as the following, then in step S2 the rotation difference between the front wheels and the rear wheels, that is, the slip amount is calculated (processing of the ABS control unit), and whether or not to perform traction in step S3 based on this slip amount Is determined (processing of the TCS control unit). When the traction is not executed, the process ends. When the traction is executed, the process proceeds to step S4, and the required torque down level FCL based on the slip amount is read.

Next, in step S5, it is checked whether FCL is within the range of 1 to 11 to prevent erroneous determination. And
If the FCL is not within this range, the process is terminated as it is, and if it is within this range, the process proceeds to step S6.

In step S6, it is determined whether the engine speed Ne is less than or equal to the upper limit engine speed NA for engine protection. If Ne is equal to or less than NA, step S7
Proceed to and enter the traction control process. If Ne exceeds NA, fuel is cut off from all cylinders in step S8, and the process ends.

In step S7, air-fuel ratio feedback based on the output of the O ₂ sensor is stopped in preparation for execution of traction control, and EGR (exhaust gas recirculation) is stopped. Then, the process proceeds to step S9, and the rotation region for setting the Ig retard amount and allocating the FCPTN is determined by whether the engine speed Ne is NB or less.

When it is determined in step S9 that the Ne is in the low speed range equal to or lower than NB, the Ig retard amount at the time of low speed specified in the table of table 1 is read in step S10, and the table of table 2 is specified in step S11. FC at low speed
Select PTN. Then, the process proceeds to step S14.

When it is determined in step S9 that the Ne exceeds the NB in the high speed range, the Ig retard amount at the time of high rotation specified in the table of table 1 is read in step S12, and the table of table 2 is read in step S13. Select FCPTN at the specified high speed. Then, the process also proceeds to step S14.

In step S14, it is determined whether the fuel stop (F / C) is executed or not, depending on whether FCL is 3 or more. When FCL is 3 or more, F / C
At the time of execution, the fuel increase table value TGT at the time of execution of F / C defined in the table of Table 4 in step S15
Read CL, go to step S17, and FC
When L is not 3 or more, it means that the F / C is not executed, and therefore F / C defined in the table of Table 4 in step S16.
The fuel increase table value TGTCR when C is not executed is read, and the process also proceeds to step S17.

In step S17, the engine speed Ne
Is greater than or equal to the determination rotational speed NC (the same as NC in FIG. 4), and if Ne is greater than or equal to NC, step S18
Then, the FCPTN that defines the mode of the fuel stop pattern is read from the table of Table 3. Then, in step S19, the FCPTN is determined to determine whether to change the pattern.
If FCPTN is 2, it is determined whether FCPTN2 is FCP in the table of Table 3 in step S20.
Change to TN2 'and proceed to step S23, FC
If PTN is not 2, it is checked in step S21 if FCPTN is 3, and if FCPTN is 3, step S21 is performed.
FPTTN3 in 22 is the FCPT in the table of Table 3
Change to N3 'and proceed to step S23.

Next, in step S23, the fuel increase table value is switched to T'GTCL in the table of Table 4,
It proceeds to step S24. Also, in step S21, the FCP
If the TN is not 3, the fuel increase table value is not switched and the process directly proceeds to step S24.

If Ne is not equal to or more than NC in step S17, the pattern is not changed and the fuel increase table value is not changed, and therefore the process directly proceeds to step S24.

At step S24, traction control is executed.

Although the V-type engine has been described in the above embodiment, the present invention is not limited to the V-type engine and can be applied to engines other than the V-type having a plurality of cylinder rows, and can be connected in series. It can also be applied to engines.

Further, in the above-mentioned embodiment, the lean degree of the air-fuel ratio is made small in order to suppress the misfire of the operating cylinders when there are many fuel-stopped cylinders, but swirls are generated for suppressing the misfire. A means for increasing the ignition energy may be adopted.

Although the above embodiment relates to traction control, the present invention can also be applied to control for a torque down request other than traction such as gear shift torque down.

[0057]

According to the engine control apparatus of the present invention, when a torque reduction request is received when, for example, a drive wheel of a vehicle driven by the engine slips, a torque reduction means including at least a fuel stop means is provided. Activate it,
By stopping the fuel supply to some or all of the cylinders in a pattern according to the required torque down level and suspending those cylinders, it is possible to reduce the output torque and suppress the slip of the vehicle drive wheels, for example. In this way, when the fuel supply to some of the cylinders is stopped, by changing the air-fuel ratio of the air-fuel mixture supplied to the operating cylinders to a fuel lean side than normal, the air sent from the idle cylinders is exhausted in the exhaust system. It is possible to suppress the temperature rise of the exhaust system due to reaction with the unburned residue of the operating cylinders, to ensure the reliability of the exhaust system, and to activate the misfire suppression means when the number of cylinders where fuel supply is stopped is large. By letting
It is possible to promote combustion in the operating cylinders, suppress misfires, suppress torque fluctuations, and stabilize the operating state when there are few movable cylinders, and to supply fuel to at least some cylinders when a torque down request occurs. When control is performed to stop and to change the air-fuel ratio of the operating cylinder to the lean side, a misfire occurs in the operating cylinder, the generated torque fluctuates, and the torque reduction amount deviates, making the operating state of the vehicle unstable. It is possible to achieve the purpose of preventing the torque reduction performance from being deteriorated.

In addition, the engine control system of the present invention is stopped by changing the air-fuel ratio of the air-fuel mixture supplied to the operating cylinders to the fuel lean side than normal when the fuel supply to some of the cylinders is stopped. It is possible to suppress the temperature rise of the exhaust system due to the air sent out from the cylinder reacting with the unburned residue of the operating cylinder in the exhaust system, to ensure the reliability of the exhaust system including the catalyst device, and to stop the fuel supply. When the number of cylinders that are in the deactivated state is large, the degree of change of the air-fuel ratio to the lean side is reduced to promote combustion of operating cylinders and suppress misfire to suppress torque fluctuations. Can be stable,
Furthermore, by reducing the degree of change in the air-fuel ratio of the operating cylinders in this way when the number of idle cylinders is large, the temperature rise in the combustion chamber of the operating cylinders is suppressed while avoiding the effect on the temperature rise of the exhaust system. The temperature inside the combustion chamber can be ensured by ensuring the reliability of the main body and stopping the fuel supply to at least some cylinders when a torque down request is generated and controlling the air-fuel ratio of the operating cylinders to the lean side. It is possible to achieve the purpose of ensuring the reliability of the exhaust system and the reliability of the engine body at the same time by preventing the engine from exceeding the allowable temperature and causing a problem in the reliability of the engine body.

Further, in the engine control device of the present invention, the engine is, for example, a V-type engine, and has a plurality of cylinder rows,
A cylinder that forms a separate exhaust passage for each cylinder row and has an exhaust manifold that collectively communicates the exhaust passages on the downstream side, and stops fuel supply in a region where the engine speed is equal to or higher than the determination speed. By changing the fuel stop pattern so that the number of cylinders does not become one in any one of the cylinder rows, for example, in the case of a V-type engine, the number of cylinders that stop and stop the fuel supply is 1 in one cylinder row.
It is possible to prevent the temperature of the exhaust system from significantly increasing due to the individual state, to ensure the reliability of the exhaust system in the high speed region, and to stop and suspend the fuel supply in the V-type engine or the like. It is possible to achieve the purpose of preventing the reliability of the exhaust system from becoming unreliable because the number of cylinders is one in one bank or the like. By correcting the air-fuel ratio of the operating cylinders to the rich side, the combustion stability of the operating cylinders in the cylinder row where the number of idle cylinders increases is increased to prevent torque fluctuations and the temperature rise in the combustion chamber is suppressed to suppress the engine body. The reliability of can be secured.

Further, the engine control system according to the present invention selects or uses the ignition timing correction and the fuel stop depending on the required torque down level, thereby suppressing the influence on the combustion stability and reducing the required torque. It can be executed, and by setting the air-fuel ratio of the air-fuel mixture supplied to each cylinder to the fuel-rich side when torque reduction is performed only by ignition timing correction, misfiring is suppressed and the combustion temperature is increased. It can be suppressed to ensure engine reliability.

Further, the engine control device of the present invention can promote combustion and suppress misfire by forming an intake swirl in each cylinder when the number of idle cylinders is large,
Further, by increasing the ignition energy when the number of idle cylinders is large, combustion can be promoted and misfire can be suppressed.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of the present invention.

FIG. 2 is a system diagram of an embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the required torque down level and the engine speed in traction control according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram of an air-fuel ratio in traction control according to an embodiment of the present invention.

FIG. 5 is a flowchart (No. 1) for executing the traction control according to the embodiment of the present invention.

FIG. 6 is a flowchart (No. 2) for executing the traction control according to the embodiment of the present invention.

FIG. 7 is a flowchart (No. 3) for executing the traction control according to the embodiment of the present invention.

[Explanation of symbols]

 1 Engine Body 14 Exhaust Manifold 15 Catalytic Converter 18 Fuel Injection Valve 19 Spark Plug 20 Ignition Coil 23 Engine Control Unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location F02D 17/02 V 29/02 311 A 41/02 301 C 41/22 330 S 43/00 301 B E HU F02P 3/045 303 F 5/15

Claims (11)

[Claims] 1. A torque reducing means for reducing an output torque of an engine in response to a predetermined torque down request, wherein at least a part of the torque reducing means changes a pattern according to a required torque down level, or a part or all of the pattern is changed. Fuel stopping means for stopping the fuel supply to the cylinders, and when the fuel stopping means stops the fuel supply to some of the cylinders and suspends those cylinders, it operates without being subject to the fuel stop. In a fuel control apparatus for an engine, the lean air-fuel ratio setting means changes the air-fuel ratio of an air-fuel mixture supplied to a cylinder to a fuel lean side with respect to the air-fuel ratio when there is no torque down request and fuel supply is not stopped. And a misfire suppression means for suppressing the misfire by promoting the combustion of the operating cylinders when the number of cylinders whose fuel supply is stopped by the fuel stop means is large. Engine control device to collect. 2. The degree of change of the air-fuel ratio by the lean air-fuel ratio setting means to the fuel lean side as compared with when the number of cylinders whose fuel supply is stopped by the fuel stop means is large, as the misfire suppression means. 2. The engine control device according to claim 1, further comprising lean degree reducing means for reducing the amount. 3. The engine control device according to claim 2, wherein the engine has an exhaust system provided with a catalyst device for purifying exhaust gas. 4. The engine control device according to claim 1, wherein the predetermined torque down request is for suppressing a slip that has occurred in a drive wheel of a vehicle driven by the engine. 5. The engine has a plurality of cylinder rows, an independent exhaust passage is formed for each cylinder row, and an exhaust manifold is provided for collecting and communicating the exhaust passages on a downstream side. Is a region where the number of revolutions is equal to or higher than the determination speed, the pattern of fuel stop by the fuel stop means
The engine control device according to claim 1, 2, 3 or 4, further comprising pattern changing means for changing the number of cylinders for which fuel supply is stopped so as not to become one in any one of the cylinder rows. 6. A rich correction means for correcting the air-fuel ratio set by the lean air-fuel ratio setting means to a rich side for a cylinder that operates without being subject to fuel stop in a region where the engine speed is equal to or higher than the determination speed. The engine control device according to claim 5, further comprising: 7. The engine has two rows of cylinders,
V in which two banks forming each cylinder row are arranged in a V-shape
7. The engine control device according to claim 5, which is a type engine. 8. The torque reducing means includes ignition timing correcting means for retarding the ignition timing in addition to the fuel stopping means, and the ignition timing correcting means corrects the ignition timing according to a required torque down level. The fuel stop by the fuel stop means is selected or used together.
An engine control device according to 2, 3, 4, 5, 6 or 7. 9. The rich air-fuel ratio setting means for setting the air-fuel ratio of the air-fuel mixture supplied to each cylinder to the fuel rich side when the output torque is reduced only by the ignition timing correction means. Engine controller. 10. The engine control device according to claim 1, wherein the misfire suppressing means forms combustion swirl in the cylinder to promote combustion and suppress misfire. 11. The engine control device according to claim 1, wherein said misfire suppressing means increases combustion energy to suppress misfire by increasing ignition energy for discharging by a spark plug.