JP2000130261A - Control system for idling engine speed of multiple cylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system for the idling engine speed of a multiple cylinder internal combustion engine, capable of stably controlling the idling engine speed by one idling engine speed controller even if adopting a structure provided with independent throttle valves on respective cylinders. SOLUTION: In a control system for the idling engine speed of a multiple cylinder internal combustion engine, formed by providing an ISC (an idling engine speed controller) 3 for controlling the amount of intake air to be supplied to intake pipes 1 of respective cylinders while bypassing throttle valves in idling of a multiple cylinder internal combustion engine in which independent throttle valves are provided on respective cylinders, one air chamber 2 is installed near the intake pipes 1, one ISC 3 is attached to the air chamber, and the air chamber 2 and the intake pipes 1 of respective cylinders are connected to each other by rubber hoses (bypass pipes) 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control system for a multi-cylinder internal combustion engine having an independent throttle valve for each cylinder.

[0002]

2. Description of the Related Art In an idle speed control system for a multi-cylinder internal combustion engine in which idle speed (engine speed at idling) is controlled by electronic control, a bypass pipe bypassing a throttle valve and an intake pipe passing through a bypass pipe at idle are provided. For providing an idle speed control device (hereinafter abbreviated as ISC) for adjusting the amount of intake air supplied to the engine, and performing feedback control on the ISC based on a deviation between an actual engine speed and a target idle speed. Is used.

In a multi-cylinder internal combustion engine, the intake pipe of each cylinder is connected to one, and one intake pipe is connected to one intake pipe.
Generally, a system in which one throttle valve is provided and the idle speed is controlled by one ISC is employed.

However, when the intake pipes of a plurality of cylinders are connected to one as described above, a surge tank is required, which causes a problem that the entire intake system becomes large due to the surge tank.

Therefore, a configuration has been proposed in which an independent throttle valve is provided for each cylinder and the surge tank is omitted.

[0006]

However, if a configuration is adopted in which each cylinder is provided with an independent throttle valve, there arises a problem that ISCs are required by the number of cylinders and control thereof is complicated. That is, since the intake pressures at the time of idling of the respective cylinders are different, if the ISCs are provided by the number of the cylinders, a control map is required for each of the cylinders. Becomes unstable, or very complicated control is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to stably operate a single idle speed control device even if an independent throttle valve is provided for each cylinder. An object of the present invention is to provide an idle speed control system for a multi-cylinder internal combustion engine capable of controlling the idle speed.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a multi-cylinder internal combustion engine having an independent throttle valve for each cylinder. In an idle speed control system for a multi-cylinder internal combustion engine provided with an idle speed control device for controlling an amount of intake air supplied to an intake pipe of a cylinder, one air chamber is installed near the intake pipe and provided therein. One idle speed control device is attached, and the air chamber and the intake pipe of each cylinder are connected by a bypass pipe.

According to a second aspect of the present invention, in the first aspect of the present invention, an intake pressure sensor is attached to the air chamber.

According to a third aspect of the present invention, in the first aspect of the present invention, a regulator for controlling a fuel pressure is connected to the air chamber.

According to a fourth aspect of the present invention, there is provided the air rail according to the first aspect, wherein the air chamber is vertically long in the vicinity of intake pipes vertically arranged in the multi-cylinder internal combustion engine. And the idle speed control device is mounted above the air rail.

According to a fifth aspect of the present invention, there is provided the air rail according to the first aspect, wherein the air chamber is vertically long in the vicinity of an intake pipe arranged vertically in a multi-cylinder internal combustion engine. And the idle speed control device is mounted at an intermediate height position of the air rail.

According to a sixth aspect of the present invention, there is provided the air rail according to the first aspect, wherein the air chamber is vertically long in the vicinity of an intake pipe arranged vertically in a multi-cylinder internal combustion engine. And the idle speed control device is mounted below the air rail.

According to a seventh aspect of the present invention, in the fourth, fifth or sixth aspect, the multi-cylinder internal combustion engine is an outboard engine having a plurality of cylinders arranged vertically.
The idle speed control device is arranged inside the intake pipe of each cylinder.

Therefore, according to the present invention, the intake air whose flow rate is controlled by one idle speed control device is introduced into one air chamber common to each cylinder, and from there to each intake pipe via a bypass pipe. I decided to introduce it,
The intake pressure of each cylinder becomes substantially equal, the amount of intake air to each cylinder can be controlled with a common control map, and even if an independent throttle valve is provided for each cylinder, one idle speed The control of the idling speed can be stably performed by the control device.

[0016]

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

<Embodiment 1> FIG. 1 is a block diagram of an idle speed control system according to Embodiment 1 of the present invention. This idle speed control system is provided in a multi-cylinder internal combustion engine for an outboard motor. Have been.

Here, a schematic configuration of the outboard motor will be described with reference to FIG.

FIG. 2 is a side view of the outboard motor 20. The outboard motor 20 is attached to a stern plate 50a of a hull 50 by a clamp bracket 21.
Swinging up and down with the cowling 23
A multi-cylinder internal combustion engine 24 is housed therein.

A propulsion device 25 is provided below the outboard motor 20. The propulsion device 25 includes a drive shaft 26 which is driven to rotate by the multi-cylinder internal combustion engine 24,
A forward / reverse switching mechanism 27 for changing the rotational direction of the drive shaft 26, a propeller 28 for transmitting rotation through the forward / backward switching mechanism 27, and the like are provided.

The multi-cylinder internal combustion engine 24 is a fuel injection type four-stroke in-line four-cylinder engine in which four cylinders (numbered from # 1 to # 4 from above) are arranged vertically. As shown in FIG. 1, the intake pipes 1 connected to the intake systems of the # 1 to # 4 cylinders are vertically arranged.

Although not shown, independent throttle valves are provided in the middle of each intake pipe 1, respectively.
An injector for injecting fuel into the intake passage at an appropriate timing is attached to a cylinder head of the engine for each cylinder.

Thus, in the idle speed control system according to the present embodiment, each of the # 1 to # 4 of the four-cylinder engine
One air chamber 2 common to the # 4 cylinder is the intake pipe 1
An idle speed control device (hereinafter abbreviated as ISC) 3 is attached to an upper portion of the air chamber 2, and an intake pressure sensor 4 is attached to a lower portion of the air chamber 2. ing. And IS
A large-diameter joint pipe 5 is attached to the inlet of C3, and a rubber hose 6 connected to a silencer (not shown) is connected to the joint pipe 5. IS
The C3 and the intake pressure sensor 4 are electrically connected to an unillustrated engine control unit (hereinafter abbreviated as ECU).

Further, two joint pipes 7 are attached to the opposite side surfaces of the air chamber 2, and a joint pipe 8 is attached to the lower surface of the air chamber 2. And joint pipe 8
Is connected to a rubber hose 9 connected to a regulator (not shown) for controlling fuel pressure. One end of a flexible rubber hose 10 constituting a bypass pipe is connected to each of the four joint pipes 7. The other end of each rubber hose 10 is connected to the intake pipe 1 of each of the # 1 to # 4 cylinders. In the present embodiment, the total cross-sectional area of the rubber hose 10 is set to be equal to or larger than the inlet cross-sectional area of the ISC 3, and the cross-sectional area of each rubber hose 10 is set to be larger than the cross-sectional area of each joint pipe 7.

As described above, when the throttle valves of each of the # 1 to # 4 cylinders are simultaneously opened and closed by the throttle operation during the load operation of the four-cylinder engine, the flow rate of the intake air (fresh air) drawn into the silencer (not shown) is increased. Adjusted.
The intake air passing through the throttle valve is applied to each intake pipe 1
Then, the fuel flows into each intake passage formed in the cylinder head through the passage, and is mixed with fuel injected from each injector at an appropriate timing to form a mixture having a predetermined air-fuel ratio. When the intake valve (not shown) is opened in each of the # 1 to # 4 cylinders, the air-fuel mixture is sucked into the cylinder for combustion.

On the other hand, during idling when each throttle valve is in the fully closed state, the intake air sucked by the silencer is introduced into the air chamber 2 from the ICS 3 by bypassing each throttle valve.
Through the respective rubber hoses 10 to the intake pipes 1 and further through the respective intake pipes 1 to be supplied to the respective # 1 to # 4 cylinders to form an air-fuel mixture. At this time, an ECU (not shown)
Is based on the deviation between the actual engine speed detected by a rotation sensor (not shown) and the target idle speed.
The cylinders # 1 to # 1 are feedback-controlled to control the opening of the idle speed control valve (ISC valve) of C so that the actual engine speed matches the target idle speed.
The amount of intake air supplied to # 4 is controlled.

As described above, the engine speed during idling is controlled.
The intake whose flow rate is controlled by two ISC3
Since the air is introduced into the two air chambers 2 and then introduced into the respective intake pipes 1 via the rubber hoses 10, the intake pressures of the respective # 1 to # 4 cylinders become substantially equal, and the respective # 1 to # 4 cylinders are shared by a common control map. It is possible to control the amount of intake air to the # 4 cylinder and to adopt a configuration in which independent throttle valves are provided for each of the # 1 to # 4 cylinders as in the present embodiment.
One ISC 3 enables stable control of idle speed.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a configuration diagram of an idle speed control system according to Embodiment 2 of the present invention. In this figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals. Is omitted.

In this embodiment, one common to each of the # 1 to # 4 cylinders arranged in the vertical direction of the four-cycle four-cylinder engine is used.
The two air rails 11 are vertically long, the ISC 3 is mounted at an intermediate height position of the air rails 11, and the intake pressure sensor 4 is mounted therebelow. Further, a joint pipe 8 is mounted on the upper part of the air rail 11, and a rubber hose 9 connected to a regulator (not shown) for controlling the fuel pressure is connected to the joint pipe 8.

In this embodiment, the air rail 11 and each intake pipe 1 are directly connected by a metal pipe 12.

Therefore, also in the present embodiment, when the engine is idling, the intake air whose flow rate is controlled by one ISC 3 is introduced into one common air rail 11, and from there through a metal pipe 12 to each intake pipe 1. Therefore, the intake pressure of each of the # 1 to # 4 cylinders becomes substantially equal, and the same effect as in the first embodiment can be obtained.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram of an idle speed control system according to Embodiment 3 of the present invention. In this figure, the same elements as those shown in FIG. 1 and FIG. The description of them is omitted.

In this embodiment, the air rail 1
1 and each intake pipe 1 are connected by a flexible rubber hose 10, and other configurations are the same as those of the second embodiment.

Therefore, in the present embodiment, when the engine is idling, the intake air whose flow rate is controlled by one ISC 3 is introduced into one common air rail 11, from which it passes through the rubber hose 10 to each intake pipe 1. As a result, the intake pressure of each of the # 1 to # 4 cylinders becomes substantially equal, and the same effect as in the first embodiment can be obtained.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a configuration diagram of an idle speed control system according to Embodiment 4 of the present invention. In FIG. 5, the same elements as those shown in FIG. 4 are denoted by the same reference numerals. Is omitted.

In this embodiment, the air rail 1
1, an ISC 3 is attached to the upper part of the air rail 11, a joint pipe 8 is attached at an intermediate height position of the air rail 11, and a rubber hose 9 connected to a regulator (not shown) for controlling fuel pressure is connected to the joint pipe 8. Other configurations are the same as those of the third embodiment.

Therefore, in this embodiment, the same effect as that of the third embodiment can be obtained. However, in this embodiment, since the ISC 3 is particularly mounted on the upper part of the air rail 11,
A relatively low temperature and high density intake air close to the outside air temperature is ISC3
Is also obtained.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a configuration diagram of an idle speed control system according to Embodiment 5 of the present invention. In this figure, the same elements as those shown in FIG. 5 are denoted by the same reference numerals. Is omitted.

In the present embodiment, the air rail 1
1, the ISC 3 is attached to the lower part, and the intake pressure sensor 4 is attached to the upper part of the air rail 11, and the other configuration is the same as that of the fourth embodiment.

Therefore, in this embodiment, the same effect as that of the third embodiment can be obtained. However, in this embodiment, since the ISC 3 is particularly attached to the lower part of the air rail 11,
This ISC3 does not protrude above the engine,
The effect that the engine can be downsized can also be obtained.

[0041]

As is apparent from the above description, according to the present invention, the intake air whose flow rate is controlled by one idle speed control device is introduced into one air chamber common to each cylinder, from which it is introduced. Since the intake pressure is introduced into each intake pipe through the bypass pipe, the intake pressure of each cylinder becomes substantially equal, the intake amount to each cylinder can be controlled with a common control map, and the independent throttle for each cylinder Even when the configuration in which the valve is provided is employed, an effect is obtained in which the idle speed control can be stably performed by one idle speed control device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an idle speed control system according to a first embodiment of the present invention.

FIG. 2 is a side view of the outboard motor.

FIG. 3 is a configuration diagram of an idle speed control system according to Embodiment 2 of the present invention.

FIG. 4 is a configuration diagram of an idle speed control system according to Embodiment 3 of the present invention.

FIG. 5 is a configuration diagram of an idle speed control system according to Embodiment 4 of the present invention.

FIG. 6 is a configuration diagram of an idle speed control system according to Embodiment 5 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intake pipe 2 Air chamber 3 ISC (idle speed control device) 4 Intake pressure sensor 7, 8 Joint pipe 9 Rubber hose 10 Rubber hose (bypass pipe) 11 Air rail (air chamber) 12 Metal pipe (bypass pipe)

Claims (7)

[Claims] 1. An idle speed control device for controlling the amount of intake air supplied to an intake pipe of each cylinder by bypassing a throttle valve at the time of idling of a multi-cylinder internal combustion engine having an independent throttle valve for each cylinder. In the idle speed control system for a multi-cylinder internal combustion engine, one air chamber is installed near the intake pipe, one idle speed control device is attached thereto, and the air chamber and the intake pipe of each cylinder are provided. And an idle speed control system for a multi-cylinder internal combustion engine, wherein the system is connected by a bypass pipe. 2. An idle speed control system for a multi-cylinder internal combustion engine according to claim 1, wherein an intake pressure sensor is attached to said air chamber. 3. A regulator for controlling fuel pressure is connected to the air chamber.
An idle speed control system for a multi-cylinder internal combustion engine according to the above description. 4. The multi-cylinder internal combustion engine includes a plurality of air rails extending vertically in the vicinity of intake pipes arranged vertically in the multi-cylinder internal combustion engine. The idle speed control system for a multi-cylinder internal combustion engine according to claim 1, further comprising a control device. 5. The multi-cylinder internal combustion engine includes an air rail that is long in the vertical direction in the vicinity of intake pipes that are vertically arranged in the multi-cylinder internal combustion engine. 2. The idle speed control system for a multi-cylinder internal combustion engine according to claim 1, further comprising an idle speed control device. 6. The multi-cylinder internal combustion engine includes an air rail extending vertically in the vicinity of intake pipes arranged vertically in a multi-cylinder internal combustion engine, and an idle speed below the air rail. The idle speed control system for a multi-cylinder internal combustion engine according to claim 1, further comprising a control device. 7. The outboard motor according to claim 7, wherein the multi-cylinder internal combustion engine is an outboard engine having a plurality of cylinders arranged in a vertical direction, wherein the idle speed control device is arranged inside an intake pipe of each cylinder. 7. An idle speed control system for a multi-cylinder internal combustion engine according to claim 4, 5 or 6.