JPH06212958A - Internal combustion engine with exhaust gas purifying mechanism - Google Patents

Abstract

PURPOSE:To provide an internal combustion engine with an exhaust gas purifying mechanism, by which a catalyst can be activated most efficiently and the catalyst can be easily activated in the shortest time. CONSTITUTION:A first control valve 8 and a second control valve 9 are disposed in an intake passage of a specific cylinder 1'. When the supply of a fuel to the cylinder 1' is stopped and fresh air is supplied to a catalyst 6 for purifying exhaust gas, the first control valve 8 is closed, and the opening of the second control valve 9 is controlled, whereby the supply quantity of fresh air can be controlled. The optimum catalyst activating condition can be kept by controlling the supply quantity of fresh air to the catalyst 6, so that at the time of starting an engine, the exhaust air purifying catalyst activation time can be reduced enough so as to produce a futher large effect for purifying exhaust gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder internal combustion engine having an exhaust gas purifying catalyst mechanism, and more particularly to an internal combustion engine with an exhaust gas purifying mechanism suitable for a fuel injection type automobile engine.

[0002]

2. Description of the Related Art It is an indispensable requirement to reduce the pollution of automobiles. Therefore, at present, an engine without an exhaust gas purifying catalyst mechanism is an exceptional entity. The mainstream of the catalyst for use is oxidation and reduction by a three-way catalyst, and therefore, the temperature is a predetermined value as one of the conditions for it to fulfill a predetermined exhaust gas purification function.
(About 300 ° C) or higher is required.

By the way, this condition is maintained in a substantially automatically satisfied state while the engine finishes the warm-up operation and continues to run, but the warm-up operation ends after the engine starts. Generally, the period until it is reached is not satisfied, so how to shorten this period is a major issue.

In the meantime, as a technique for solving this problem, an air pump is provided in an air passage bypassing the engine so that exhaust gas is exhausted, as originally proposed in US Pat. No. 4,893,995. Fresh air for purification catalyst
A method has been known in which (fresh air) is sent to burn the unburned fuel remaining in the exhaust gas in the catalyst, thereby rapidly raising the temperature of the catalyst and shortening the activation time of the catalyst. However, this method requires an additional air pump, which increases the cost and installation space, and also requires extra energy to drive the pump. For example, in Japanese Patent Laid-Open No. 2-19627, FIG. As shown, in an engine E having a plurality of cylinders 1 (six in this figure), by cutting off the fuel supply to a specific cylinder 1 ', the cylinder 1'behaves to act as an air pump. The prior art of accelerating the activation of the catalyst 6 is disclosed.

That is, when the fuel supply to the specific cylinder 1'is cut off, the air cleaner 4 and the throttle valve 3
Of the air taken into the intake manifold 2 from the atmosphere via the air, the air introduced into the specific cylinder 1 ′ is suction-compressed in the cylinder 1 ′ and then discharged to the exhaust manifold 5 as it is, so that the fresh air As a result, it is supplied to the catalyst 6, which promotes activation of the catalyst 6. In FIG. 6, 7 is an exhaust pipe.

[0006]

The prior art does not pay particular attention to the flow rate of air supplied to the catalyst as fresh air, and has a problem in activating the catalyst in the shortest time.

That is, the most efficient activation of the catalyst is
Naturally, there should be an optimum air flow rate value, but in the conventional technology, this is almost uniquely determined by the engine speed, so it becomes difficult to activate the catalyst in the shortest time. is there. An object of the present invention is to provide an internal combustion engine with an exhaust gas purifying mechanism that can most efficiently activate a catalyst and can easily activate the catalyst in the shortest time.

[0008]

SUMMARY OF THE INVENTION In a multi-cylinder type engine, the above object is to stop the supply of fuel to a specific cylinder among the plurality of cylinders and to selectively select only the intake air flow rate for the cylinder of this characteristic. And a flow control means for controlling the internal combustion engine, and the fuel control means and the flow control means are operated only during a period from the start of the internal combustion engine until a predetermined time elapses.

[0009]

[Function] Since the supply amount of fresh air from a specific cylinder can be controlled independently of the engine speed, it is possible to easily obtain the optimum conditions for activating the catalyst during warm-up operation, and in the shortest time. The catalyst can be activated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An internal combustion engine with an exhaust gas purifying mechanism according to the present invention will be described below in detail with reference to the illustrated embodiments.
FIG. 1 shows an embodiment of the present invention, in which 2'is a branch pipe for fresh air, 8 is a first control valve, 9 is a second control valve, 10
Is an air cleaner for fresh air. A multi-cylinder engine E having six cylinders 1, a specific cylinder 1 ′, an intake manifold 2, a throttle valve 3, an air cleaner 4, an exhaust manifold 5, an exhaust pipe 7, etc. are the same as those in the prior art shown in FIG. 6. Is. The fresh air branch pipe 2 ′ branches into a specific cylinder 1 ′ of the intake manifold 2, further branches from a passage leading to the specific cylinder 1 ′, and communicates with the atmosphere via a fresh air cleaner 10.

The first control valve 8 is of a butterfly valve type similar to the throttle valve 3, for example, and is made openable and closable by a predetermined actuator (not shown). It is provided upstream of the position where the fresh air branch pipe 2'is provided in the passage to the specific cylinder 1 '. And this first
The control valve 8 is configured to remain in the fully opened state when nothing is controlled.

The second control valve 9 is of a butterfly valve type similar to the first control valve 8 and is made openable and closable by a predetermined actuator (not shown). It is provided in the middle of the branch pipe 2 '. Then, the second control valve 9 is configured to remain in the fully closed state when nothing is controlled.

Next, the control operation of the embodiment of FIG. 1 will be described with reference to the flow chart of FIG. engine
When the (internal combustion engine) E is started, the start processing 101 is set in the control processing by a microcomputer in the engine control device (not shown), and the processing according to the flowchart of FIG. 2 is started.

When the processing of FIG. 2 is started in this way, it is first checked in a judgment processing 102 whether or not the accelerator pedal is operated, and if the result is NO (negative), then in the next judgment processing 103, after the engine is started. Then, it is checked whether or not a predetermined time set in advance has elapsed, and if the result also becomes NO here, the processes 104 and 105 are executed, the process returns to the judgment process 102 again, and the process is repeated.

On the other hand, while the processing is being repeated in this way, if the result of the judgment in either of the judgment processings 102 and 103 is YES (affirmative), the processing advances to end processing 106, and the processing according to this flowchart is ended. Of.

Next, in process 104, the supply of fuel to the specific cylinder 1'is cut off. Specifically, each cylinder 1
Of the six fuel injection valves (not shown) provided for each, only the injection pulse signal for the fuel injection valve supplying fuel to this specific cylinder 1'is stopped. At this time, the ignition for this specific cylinder 1'may also be stopped.

Subsequently, in step 105, the respective actuators are operated to close the first control valve 8 to a fully closed state and to open the second control valve 9 to a predetermined opening. is there.

As a result, according to this embodiment, after the engine is started, the fuel supply to the cylinder 1'is cut off and the predetermined time elapses or the accelerator pedal is depressed. The intake side of the cylinder 1'is shut off from the intake manifold 2 and the throttle valve 4 side by the first control valve 8, and is brought into a state of being communicated with the atmosphere via the air cleaner 10 by the second control valve 9. .

Even in this state, fuel is supplied to the cylinders 1 other than the specific cylinder 1 ', so that the engine E continues to rotate, and as a result, the specific cylinder 1'has air. It functions as a pump, sucks air from the atmosphere through the air cleaner 10, compresses it, sends it to the exhaust manifold 5, and supplies it to the catalyst 6 as fresh air.

On the other hand, since the exhaust gas is sent out from the cylinders 1 other than the specific cylinder 1'and flows into the catalyst 6, the unburned fuel existing in the exhaust gas is present in the catalyst 6. The combustion is performed by the fresh air supplied from the specific cylinder 1 ', and as a result, the catalyst 6 is heated.

Accordingly, the activation of the catalyst 6 is greatly promoted, the activation is completed in a short time, and the exhaust gas purification from the warm-up operation to the normal operation is incomplete. Can be minimized.

According to this embodiment, the amount of fresh air supplied from the specific cylinder 1'at this time is determined by the opening degree of the second control valve 9 and the opening degree of the throttle valve 3. Since it can be controlled independently, it can always be controlled to the optimum fresh air amount,
The activation efficiency of the catalyst 6 can be sufficiently increased.

Although a detailed description of the opening control of the second control valve 9 will be omitted, the opening may be controlled according to the temperature of the engine E (cooling water temperature), the temperature of the catalyst 6 and the like. You can do it.

Although the air cleaner 4 and the air cleaner 10 are separate bodies in the embodiment of FIG. 1, the air cleaner 4 and the fresh air branch pipe 2'of the second control valve 9 are connected by a pipe line. Therefore, a configuration in which the air cleaner 4 is shared with the air cleaner is also conceivable.

As a matter of course, it is also conceivable that the air cleaner 10 is shared by the air cleaner 10 and the air cleaner 10 which are communicated with each other through the conduit.

Further, the second control valve 9 and the branch pipe 2'are
A configuration in which each of the fixed cylinders in the plurality of cylinders that stops the supply of the fuel is individually provided, and the branch pipes 2 ′ from each of the fixed cylinders in the plurality of cylinders are merged, and the merged portion and the air cleaner 10 are combined. The same effect can be obtained with any structure such as the structure in which the second control valve 9 is provided therebetween.

Next, FIG. 3 is a flow chart showing another embodiment of the control operation of the embodiment of FIG. 1, only the content of the processing 203 is different from that of the embodiment of FIG.

When the engine (internal combustion engine) E is started, the start processing 201 is set in the control processing by the microcomputer in the engine control device (not shown) and the processing is started.

First, in the judgment processing 202, it is checked whether or not the accelerator pedal is operated. If the result is NO (negative), then in the next judgment processing 203, the catalyst 6
Of temperature Tc is checked to determine whether it is higher than a preset predetermined temperature Tset for determination. Then, when the temperature Tc of the catalyst 6 is lower than the temperature Tset for determination, the control processes 204 and 205 are executed, the process returns to the determination process 102 again, and the process is repeated.

On the other hand, while the processing is being repeated in this way, if the determination result of either the determination processing 202 or 203 is YES (affirmative), the processing proceeds to termination processing 206, and the processing according to this flowchart is terminated. Of.

Next, in the control process 204, the fuel supply to the specific cylinder 1'is cut off. Specifically, six fuel injection valves (not shown) provided for each cylinder 1
Among them, only the injection pulse signal to the fuel injection valve supplying the fuel to this specific cylinder 1'is stopped. At this time, the ignition for this specific cylinder 1'may also be stopped.

Subsequently, in step 205, the respective actuators are operated to close the first control valve 8 to the fully closed state and open the second control valve 9 to a predetermined opening. is there.

Therefore, according to the embodiment shown in FIG.
As in the case of the above embodiment, the activation of the catalyst 6 is greatly promoted, the activation is completed in a short time, and the exhaust gas purification from the warm-up operation to the normal operation is incomplete. The period can be minimized, and the amount of fresh air supplied from a specific cylinder 1'can be controlled by the opening of the second control valve 9 regardless of the opening of the throttle valve 3. Therefore, it is possible to constantly control the optimum fresh air amount and sufficiently enhance the activation efficiency of the catalyst 6. Further, according to this embodiment, the control is performed while directly monitoring the temperature of the catalyst 6. Therefore, it is less affected by the outside air temperature, etc., and more accurate control can be performed.

Next, FIG. 4 is a flow chart showing another embodiment of the present invention. In the embodiment of FIG. 4, the processing 303 for judging the temperature of the engine is added to the embodiment of FIG. The other parts have the same structure.

In the judgment processing 303, the cooling water temperature Tw of the engine E is checked, and the temperature is set beforehand for judgment.
(Water temperature) It is determined whether it is higher than Tset1. Then, when the engine cooling water temperature Tw is lower than the water temperature Tset1, the process proceeds to the catalyst temperature determination process 304. On the other hand, when the cooling water temperature Tw is higher than the water temperature Tset1, the process proceeds to the ending process 307 and the ending process is performed.

In the catalyst temperature judgment processing 304, the temperature Tc of the catalyst 6 is set beforehand, and the judgment temperature Tset2 (= Ts) is set.
It is better than et)). Subsequent processing is the same as in the case of FIG.

FIG. 5 shows another embodiment of the present invention. In this embodiment, instead of the first control valve 8 and the second control valve 9 in the embodiment of FIG. The control valve 11 is provided in a portion of the exhaust pipe up to the exhaust manifold 5.

The control valve 11 is, for example, of the same butterfly valve type as the throttle valve 4, is made openable and closable by a predetermined actuator (not shown), and is controlled to a fully open state during normal operation. The fuel supply to the specific cylinder 1'is stopped, and the catalyst 6 is transferred from this specific cylinder 1 '.
In the state where fresh air is being supplied, it is configured to be moved to a predetermined opening degree in a closing direction to control the supply amount of fresh air.

Therefore, as for the control operation of the embodiment of FIG. 5, one of the controls of FIGS. 2 to 4 may be applied as in the case of the embodiment of FIG.

In this case, the control processing 105, 20
5, and the contents of processing in 306 are respectively the control valve 11
Needless to say, the process is to control the valve to close to a predetermined opening.

The control valve 11 in this embodiment is provided at a position where the exhaust manifold 5 communicates with the outside air, and the fresh air supplied to the exhaust manifold 5 is discharged to the outside air to be supplied to the exhaust manifold 5. A mechanism for adjusting the amount of fresh air is also possible.

Further, each control valve 8 in the above embodiment,
Any of an electromagnetic motor, an ultrasonic motor, a hydraulic motor, and a diaphragm actuator that uses negative intake pressure of the engine may be used as the actuator used to drive 9 and 11.

[0043]

According to the present invention, the exhaust purification catalyst activation time at the time of engine start can be shortened, so that it has a great effect on purification of engine exhaust gas.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of an internal combustion engine with an exhaust gas purifying mechanism according to the present invention.

FIG. 2 is a flowchart showing an example of a control operation in the present invention.

FIG. 3 is a flowchart showing another embodiment of the control operation in the present invention.

FIG. 4 is a flowchart showing still another embodiment of the control operation in the present invention.

FIG. 5 is an explanatory diagram showing another embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a conventional example of an internal combustion engine with an exhaust gas purification mechanism.

[Explanation of symbols]

 1 cylinder 1'specific cylinder 2 intake manifold 3 throttle valve 4 air cleaner 5 exhaust manifold 6 exhaust purification catalyst 7 exhaust pipe 8 first control valve 9 second control valve 10 air cleaner 11 control valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI technical display location F02D 13/06 ZAB B 7049-3G (72) Inventor Hidefumi Adachi 2520 Takaba, Katsuta City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division (72) Inventor Hidefumi Iwaki 2520 Takaba, Katsuta City, Ibaraki Prefecture Hitachi Automotive Equipment Division

Claims (7)

[Claims] 1. In a multi-cylinder internal combustion engine having an exhaust gas purifying catalyst mechanism, fuel control means for selectively stopping only fuel supply to a specific cylinder among the plurality of cylinders, and to the specific cylinder. A flow rate control means for selectively controlling only the intake air flow rate is provided, and the fuel control means and the flow rate control means are operated only during a period from the start of the internal combustion engine until a predetermined time elapses. An internal combustion engine with an exhaust gas purification mechanism characterized by: 2. The internal combustion engine with an exhaust gas purifying mechanism according to claim 1, wherein the flow rate control means is composed of a valve mechanism that controls an opening degree of an intake passage of the specific cylinder. . 3. The invention according to claim 1, wherein the flow rate control means controls a first valve mechanism for controlling an opening degree of an intake passage of the specific cylinder, and the first valve mechanism controls the opening of the specific cylinder. The second that connects the intake passage up to the intake inlet to the atmosphere
Internal combustion engine with an exhaust gas purifying mechanism. 4. The internal combustion engine with an exhaust gas purifying mechanism according to claim 1, wherein the flow rate control means is composed of a valve mechanism that controls an opening degree of an exhaust passage of the specific cylinder. . 5. The invention according to any one of claims 1 to 4,
An internal combustion engine with an exhaust gas purifying mechanism, wherein a period from a start of the internal combustion engine until a predetermined time elapses is a constant period controlled by a timer. 6. The invention according to any one of claims 1 to 4,
The period from the start of the internal combustion engine until a predetermined time elapses is configured to be a period after the start of the internal combustion engine until the temperature of the exhaust gas purification catalyst reaches a predetermined value. An internal combustion engine with a characteristic exhaust gas purification mechanism. 7. The invention according to any one of claims 1 to 4,
It is characterized in that the period from the start of the internal combustion engine until a predetermined time elapses is a period until the temperature of the internal combustion engine reaches a predetermined value after the internal combustion engine is started. Internal combustion engine with exhaust gas purification mechanism.