JPH03107550A - Control device for engine - Google Patents

Abstract

PURPOSE:To suppress the drag-in of fuel into stop cylinders from operated cylinders in a device for stopping fuel supply to specific cylinders in the specific operating state by selecting as the stop cylinders, the longest in the distance of an intake system from the cylinders previously in the combustion strokes. CONSTITUTION:In case of a V-type twelve-cylinder engine provided with a first and a second banks 1a, 1b, disposed in a V-form, with six cylinders each disposed in series, and with the combustion stroke order (ignition order) of these cylinders C1-C12 being set in the order of C1 C12 C9 C4 C5 C8 C11 C2 C3 C10 C7 C6, the third, fourth, ninth, tenth cylinders C3, C4, C9, C10 are set as the stop cylinders for stopping fuel supply at the time of the engine operating state satisfying the thinning condition for the specified time, In other words, regartding the banks 1a, 1b respectively, the cylinders C3, C4, C9, C10, the longest in the distance of an intake system from the cylinders C11, C12, C1, C2 previously in the combustion strokes, are set as the stop cylinders.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device that deactivates a specific cylinder by cutting fuel in a specific operating state of an engine.

(Prior Art) Conventionally, when controlling the number of cylinders in this type of engine, as disclosed in Japanese Patent Publication No. 58-53180,
When the engine is under low load, by stopping the supply of intake air to a specific cylinder and supplying that intake air to the remaining cylinders, the pumping loss of the idle cylinders is reduced and fuel efficiency is improved. It is known.

(Problem to be Solved by the Invention) By the way, in order to reduce unburned components in engine exhaust gas, secondary air is supplied into the exhaust gas by a reed valve that utilizes exhaust pulsation to combust the unburned components. There is a technique to do this. However, it is difficult to supply a large amount of secondary air with this reed valve, and even if the number of engine cylinders increases and the amount of unburned components in the exhaust gas increases, the unburned components cannot be effectively combusted. There is a problem.

Therefore, when performing the above-mentioned conventional cylinder number control, only the fuel supply to the idle cylinders is stopped and air is sucked in as is, and the idle cylinders that do not burn due to this fuel cut are used as air pumps. There is an idea that a large amount of secondary air can be supplied by supplying discharged air as secondary air into the exhaust gas from other operating cylinders.

However, in this case, part of the fuel supplied to the light cylinder that was in the previous combustion stroke, for example, fuel that was not completely taken into the cylinder or fuel that was blown back into the intake passage due to the overlap of the intake/exhaust valves, is stopped. When carried into the cylinder, the fuel may be discharged as unburned gas without being combusted, and there is a risk that the original purpose may not be fully achieved due to the unburned gas being mixed into the secondary air.

The present invention has been made in view of the above, and its purpose is to identify a dormant cylinder that serves as an air pump, and to prevent fuel from being brought into the dormant cylinder from other operating cylinders. It is an object of the present invention to enable unburned components in exhaust gas to be effectively combusted using a large amount of secondary air.

(Means for Solving the Problem) In order to achieve the above object, the invention according to claim (1) sets the deactivated cylinder to the cylinder that is farthest in distance from the operating cylinder in the previous combustion stroke. , the distance between the cylinders reduces the amount of fuel carried into the idle cylinders.

That is, the present invention is an engine control device that stops the supply of fuel to a specific cylinder in a specific operating state, and the cylinder to which the fuel supply is stopped is replaced with the cylinder that was in the previous combustion stroke. The cylinder is characterized by having the longest distance from the intake system to the cylinder.

(Function) With the above configuration, in the invention according to claim (1), the deactivated cylinder is set to the cylinder that is farthest from the cylinder that was in the previous combustion stroke, so that the cylinder in the previous combustion stroke and the deactivated cylinder are The distance is the maximum in the intake system. For this reason, even if there is fuel left in the cylinder from the previous combustion stroke or fuel blown back into the intake passage, that fuel will be difficult to be sucked into the idle cylinder, and therefore the fuel from the operating cylinder will not flow into the idle cylinder. Bring-in items are reduced.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, 1 is a V-shaped 1 according to the first embodiment of the present invention.
It is a two-cylinder engine, and this engine 1 has first and second banks la and lb facing each other, and the first bank 1a has odd numbers, that is, the first cylinder C1, the third cylinder C3, and the fifth cylinder C5.
, the 7th cylinder C7, the 9th cylinder C9, and the 11th cylinder CI+, and the second bank 1b has even numbers, that is, the 2nd cylinder C2, the 4th cylinder C4, the 6th cylinder C6, and the 8th cylinder C8. , the 10th cylinder CIO, and the 12th cylinder CI2 are formed in a line in series from one end to the other end of the banks la and lb, respectively.

The order of combustion strokes (ignition order) of these 12 cylinders C1 to CI2 is as follows: 1st cylinder Cl-1 - 12th cylinder Cl2 - Node 9 cylinder C9 -
4th cylinder C4 - 5th cylinder C5 - 8th cylinder C8 - 11th cylinder CI+ = 2nd cylinder C, - 3rd cylinder C3 → 10th cylinder C
They are set in the order of IO → seventh cylinder C7 → sixth cylinder 6. Therefore, in the first bank 1a, the combustion stroke order of the six cylinders C+, C3, C5, C7, C9+C11 is as shown in FIG. ,CB,
The combustion stroke order of CRI and C12 is as shown in the same figure (b).

An intake port 3 and an exhaust port 4 are opened in each of the cylinders C1 to CI2, and an independent intake road 5 is connected to the intake port 3, and the independent intake passage 5 includes a collective intake passage 6a for each bank la and lb, 6b. The two collective intake passages 6a6b are gathered together at the upstream end and connected to an air cleaner (not shown), and a throttle valve 7 is disposed at the gathering portion. On the other hand, an independent exhaust passage 8 is connected to the exhaust port 4, and this independent exhaust passage 8 is connected to the exhaust port 4.
It is connected to collective exhaust passages 9a and 9b for each a and lb. Exhaust gas purification devices 10a and 10b each consisting of a catalyst are disposed in the middle of the collective exhaust passage 9a9b.

Further, each independent intake passage 5 is provided with an injector 11 that injects and supplies fuel, and each injector 11 opens its valve and injects fuel in response to a fuel injection command signal from a control unit 12. ing. This control unit 12 has an engine speed N
Various signals such as the amount of intake air per intake Q1, the cooling water temperature, the throttle opening, and the operating state of the idle switch are input. Then, the control unit 12 controls the number of cylinders to stop the fuel injection command signal to the injector 11 of a specific cylinder and stop the supply of fuel to the cylinder when the operating state of the engine 1 does not meet the thinning prohibition conditions described below. It is designed to do this.

The specific cylinders to which the fuel supply is stopped, that is, the thinning-out cylinders (paused cylinders), are set to four: the third cylinder C3, the fourth cylinder C4, the ninth cylinder C9, and the tenth cylinder CIO.

In other words, these thinning execution cylinders C3, C4, C9,
Coo is each bank la.

For each bank 1b, it is the cylinder whose intake system has the longest distance from the cylinder that was in the previous combustion stroke.For example, in the first bank 1a, the 9th cylinder C9 (3rd cylinder C3) is the cylinder that is the longest in the intake system from the cylinder that was in the previous combustion stroke. The distance between the cylinders is the greatest with respect to one cylinder C1 (the 11th cylinder C11). Similarly, in the second bank 1b, the 4th cylinder C4 (10th cylinder Cl0) is replaced by the 12th cylinder C12 (2nd cylinder C=) which was in the previous combustion stroke.
In contrast, the distance between the cylinders is the greatest.

Here, the procedure for controlling the number of cylinders performed by the control unit 12 will be explained with reference to the flowchart shown in FIG. First, in step S1, various signals such as intake air amount Q1, engine speed N1, cooling water temperature, throttle opening, and idle switch operating state are read, and in the next step S2, the final fuel injection amount Tj is calculated. This final injection ff1Ti is determined by TI - Tp X (1+C) + Tv Tp - (Q/N) xk k: constant, where various correction amounts such as cooling water temperature are 01 and invalid injection amount is Tv. The invalid injection ffi T v is a value set to compensate for the valve opening delay, since the valve does not open immediately even if the injection command signal is output to the injector 11. After that, in step S3, it is determined whether a thinning prohibition condition is satisfied in which the fuel supply to the third cylinder C3, the fourth cylinder C4, the ninth cylinder C9, and the tenth cylinder CIO is not stopped. Eight thinning prohibition conditions are set for the reasons shown below, and when the engine 1 is operating in a state other than these prohibition conditions, fuel supply to the thinning cylinders C3, C4, Cg, and CIO is prohibited. will be stopped.

■ When the cooling water temperature is lower than 20°C (if thinning operation is performed under this condition, combustibility will deteriorate).

■ When the cooling water temperature is higher than 50°C (at this time, unburned carbide HC is difficult to generate and the effect of secondary air supply is small).

■ Engine idling condition (idling stability worsens due to thinning operation).

■ When the engine accelerates (because engine power is required).

■ When starting the engine (ensuring startability).

■ When the engine is under high load (engine output is required)
.

■ When various sensors fail (normal control is not executed).

■ Engine deceleration until a certain period of time has passed since the fuel cut (in this state, the engine speed drops significantly and stability deteriorates due to thinning operation).

Then, if such a thinning prohibition condition is satisfied, the determination is Y.
When ES is reached, the flag F is set to F=0 in step S4. This flag F identifies whether the operating state of the engine 1 has once entered the thinning execution zone, and is set to F=O once the operating state of the engine 1 has entered the thinning execution zone. Next, in step S5, the fuel injection amount T of each cylinder C1 to C12 is set to the final injection amount T1, and the signal thereof is output to the injector 11.

On the other hand, when the determination is No, in which the thinning prohibition condition is not satisfied, it is determined in step S6 whether the cylinders in the combustion stroke at that time are the thinning execution cylinders C3, C4, C9, CIO. If this determination is YES, the process advances to step S9, and the thinning execution cylinders C3, C4, C9, C
IG fuel injection amount 0 T is multiplied by the coefficient α to the final injection amount Ti, which is T-T1×α
Then, the signal is sent to the thinning execution cylinder C3°C4, c, .
, I Output to the injector 11 of the CIO to execute a thinning operation.

Further, when the determination in step S6 is NO, it is determined in step S7 whether the flag F is F-0, and when this determination is No (F=1), the process proceeds to step S5. Further, when the determination is YES in F-0, the process proceeds to step S8, and after setting the flag F to F=1, step S
At step 9, thinning operation is executed. This step S6.
According to the flow of Sy and S8, when the operating state of engine 1 enters the thinning execution zone for the first time, flag F is set to F.
= 0, so even if the cylinder is not supposed to be thinned out, the fuel supply to that cylinder is stopped and thinned out operation is executed, and this allows the cylinder to be used as an air pump to quickly supply secondary air. We are trying to supply the following. Further, the coefficient α is changed depending on the cooling water temperature, for example, and when the cooling water temperature is low in the range of 20 to 50°C, α= 0
When it is high, α is set so that the air-fuel ratio or combustion limit is lean, and the thinning cylinders C3, C4, C9, and C
1l+ is burned to prevent the wall temperature from decreasing and to ensure combustibility.

Therefore, in the above embodiment, when the engine 1 is operated and the operating state is in the thinning prohibition condition, the thinning operation is not executed and fuel is injected and supplied from the injector 11 to each cylinder C1 to CI2. On the other hand, when the thinning prohibition condition is not satisfied, the specific third cylinder C3
, the fuel supply to the fourth cylinder C4, the ninth cylinder C9, and the tenth cylinder CIO is stopped, and the fuel supply to the cylinders C3, C4, C9, CI
O is an air pump that sucks intake air and discharges it directly into the U1 air passage.This pump supplies a large amount of secondary air into the exhaust gas, which can burn the unburned components and improve emission performance. be able to.

At that time, the thinning execution cylinder C in each bank 1a, 1b
3.C4, C9, and CIO are set to the cylinders furthest from the cylinder that was in the previous combustion stroke, so
The cylinder in the previous combustion stroke and the cylinder in which thinning was performed C3rC
4+ C9+ The distance from C1o is each bank la.

Maximum within lb. Therefore, even if there is fuel left in the cylinders from the previous combustion stroke or fuel blown back into the intake passage 5, that fuel is transferred to the thinned-out cylinders C3, C4+C9.
, CIO, and therefore the fuel from the operating cylinder is thinned out in the cylinder c3. C4, C9, and CIO are reduced, thereby preventing the fuel from being discharged as unburned components, and improving and maintaining emission performance.

Furthermore, when the above-mentioned thinning prohibition condition is canceled and the operating state of engine 1 enters the thinning execution zone for the first time,
Thinning-out cylinders C3, C4, c, .

Fuel supply to the cylinders other than the CIO is also stopped. Therefore, that cylinder becomes an air pump in the same way as above, and at the same time the thinning prohibition condition is canceled, the thinning execution cylinders C3+C4 and C9+CI.

Secondary air can be immediately supplied even if the combustion engine is not in the combustion process.

3 Furthermore, when the cooling water temperature is high in the range of 20 to 50°C, fuel is injected and supplied so that the air-fuel ratio becomes lean at the combustion limit even in the thinned out cylinders C3, C4, and C9° CIO. . For this reason, the thinning execution cylinder C3,
By combusting C4, C9, and CIO, it is possible to prevent a decrease in the wall surface temperature and ensure combustibility.

FIGS. 4 and 5 show a second embodiment of the present invention, in which the same parts as in FIG. This is what I did.

That is, in this embodiment, the first bank 1a' of the engine 1' includes the first cylinder C1, the third cylinder C3, and the fifth cylinder C.
5, and the second bank lb' has the second cylinder C2 and the fourth cylinder C2.
A cylinder C4 and a sixth cylinder C6 are respectively formed,
The combustion strokes of these six cylinders C1 to C6 proceed according to the cylinder numbers.

The first cylinder C1 and the second cylinder C1 of the first bank la' are
The second cylinder C2 of the bank 1b' is the cylinder that was in the previous combustion stroke in each bank 4 1a'lb' (the fifth cylinder C5 for the first cylinder C1, and the sixth cylinder C for the second cylinder C2).
G), and these cylinders C1 and C2
It is said to be a thinning execution cylinder.

In FIG. 4, 3 is a cylinder block of the engine 1', 14a, 4b are cylinder heads assembled to the cylinder block 13, and 15 is a piston that reciprocates within each cylinder C1 to C6. Also, 16 is bank la'
, lb', 17 is an air cleaner, 18 is an air flow meter that detects the amount of intake air, 19 is an idle switch that detects the idle state of the engine 1', and 20 is a crank angle sensor that detects the crank angle. , 21 is an 02 sensor that detects the oxygen concentration in exhaust gas.

Therefore, in this embodiment, when the engine 1' is operated and its operating state is not in the thinning prohibition condition,
The fuel supply to specific first cylinder C1 and second cylinder C2 is stopped and the cylinders C, , C.

The pump serves as an air pump, and by supplying a large amount of 25th order air by this pump, the unburned components can be combusted and the emission performance can be improved.

At this time, the cylinders cl and c2 in each bank engine a' and 1b' are the cylinders c1 and c2 which were in the previous combustion stroke, respectively.
5. Since it is set to the cylinder farthest from cG, the cylinder C5°C6 of the previous combustion stroke and the cylinder C1 where thinning is performed
, C2 is maximum within each bank 1a'lb', and the distance from cylinders c5 . Even if there is uninhaled fuel or fuel blown back into the intake passage at c6, the amount of that fuel carried into the thinning cylinders C1 and C2 is reduced, making it possible to improve and maintain emission performance.

It goes without saying that the present invention can also be applied to in-line engines other than V-type.

(Effect of the invention) As explained above, according to the invention according to claim (1),
When controlling the number of cylinders by stopping the fuel supply to a specific cylinder of the engine and using the inactive cylinder as an air pump for supplying secondary air, the inactive cylinder 6 is set at the distance of the intake system from the cylinder that had the previous combustion stroke. By setting this to the longest cylinder, it is possible to maximize the distance between the operating cylinder that was in the previous combustion stroke and the inactive cylinder, effectively suppressing the carry-over of fuel from the operating cylinder to the inactive cylinder, and thus reducing the V1 gas The unburned components inside can be effectively combusted by a large amount of secondary air.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a schematic plan view of the engine, FIG. 2 is an explanatory diagram showing the order of combustion strokes of cylinders for each bank, and FIG. FIG. 2 is a flowchart showing a control procedure for performing fuel supply stop control. FIG. 4 is a schematic perspective view of an engine showing a second embodiment, and FIG. 5 is a view corresponding to FIG. 1. 1.1'...Engine 1 a, 1 b + 1 a' + 1 b
'...Bank 01 to CI2...Cylinder C3, C4, C9, CIO (CI, C2)...Cylinder to be thinned out (specific cylinder) 7 11...Injector 12...Control unit 8 Station Tokukaihei 3 107550 (6) -350- Ward U-tsu clothes

Claims (1)

[Claims] (1) An engine control device configured to stop the supply of fuel to a specific cylinder in a specific operating state, wherein the cylinder to which the fuel supply is stopped is connected to the intake system from the cylinder that was in the previous combustion stroke. An engine control device characterized in that the cylinder has the longest distance.