JP4132299B2 - Idle speed control system for multi-cylinder internal combustion engine - Google Patents

Description

[0001]
BACKGROUND 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]
[Prior art]
In an idle speed control system of a multi-cylinder internal combustion engine that controls idle speed (engine speed at idling) by electronic control, intake air supplied to an intake pipe via a bypass pipe that bypasses a throttle valve and a bypass pipe at idle An idle speed control device (hereinafter abbreviated as ISC) for adjusting the amount is provided, and a method of feedback controlling the ISC based on the deviation between the actual engine speed and the target idle speed is used. .
[0003]
By the way, in a multi-cylinder internal combustion engine, a system is generally adopted in which the intake pipes of each cylinder are connected to one, one throttle valve is provided in one intake pipe, and the idle speed is controlled by one ISC. .
[0004]
However, as described above, when the intake pipes of a plurality of cylinders are connected to one, a surge tank is required, and the entire intake system becomes large due to the surge tank.
[0005]
In view of this, a configuration is proposed in which an independent throttle valve is provided for each cylinder and the surge tank is omitted.
[0006]
[Problems to be solved by the invention]
However, when a configuration in which an independent throttle valve is provided for each cylinder is adopted, there arises a problem that ISC is required for the number of cylinders and the control thereof becomes complicated. That is, since the intake pressure at idling of each cylinder is different, if the ISC is provided for the number of cylinders, a control map is required for each cylinder, and the idling speed is used to control the intake amount independently for each cylinder. Becomes unstable or requires very complicated control.
[0007]
The present invention has been made in view of the above problems, and the object of the present invention is to achieve a stable idling speed with a single idling speed control device even if a configuration is provided in which each cylinder is provided with an independent throttle valve. It is an object of the present invention to provide an idle speed control system for a multi-cylinder internal combustion engine capable of controlling the above.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, when idling a multi-cylinder internal combustion engine having an independent throttle valve for each cylinder, the throttle valve is bypassed and supplied to the intake pipe of each cylinder. In the idle speed control system for a multi-cylinder internal combustion engine provided with an idle speed control device for controlling the intake air amount to be provided, one idle speed control device is provided, and the intake pipe of each cylinder is provided from the idle speed control device. A bypass pipe connected to the idle hose is configured by a flexible hose connected to the idle speed control device via a joint pipe, and the total cross-sectional area of the flexible hose is controlled by the idle speed control. set above the inlet cross-sectional area of the device, the cross-sectional area of the flexible hose is set larger than the cross-sectional area of the joint pipe, before It is connected to the idle speed control system, the air rail to be connected to the respective flexible hose through the joint pipe provided in the air rail that was connected to a regulator for controlling the fuel pressure It is characterized by.
[0009]
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 rail .
[0010]
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the multi-cylinder internal combustion engine is an engine for an outboard motor in which a plurality of cylinders are arranged in the vertical direction, and the idle speed control device is provided for each engine. It is arranged inside the intake pipe of the cylinder.
[0011]
Therefore, according to the present invention, since the total cross-sectional area of the bypass pipe connected from one idle speed control device to the intake pipe of each cylinder is set to be equal to or larger than the inlet cross-sectional area of the idle speed control device, The intake air flowing through the pipe is decelerated so that the intake pressure of each cylinder becomes substantially equal, and the intake amount of each cylinder can be controlled with a common control map, and a configuration in which an independent throttle valve is provided for each cylinder is adopted. In addition, it is possible to control the idle rotational speed stably with one idle rotational speed control device.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0013]
<Embodiment 1>
FIG. 1 is a side view of the outboard motor, FIG. 2 is a side view of a multi-cylinder internal combustion engine mounted on the outboard motor, and FIG. 3 is a plan view of the multi-cylinder internal combustion engine.
[0014]
An outboard motor 1 shown in FIG. 1 is attached to a stern plate 50a of a hull 50 by a clamp bracket 2, which swings up and down around a tilt shaft 3, and has a multi-cylinder in a cowling 4 on the upper side. An internal combustion engine 5 is accommodated.
[0015]
A propulsion device 6 is provided at the lower portion of the outboard motor 1. The propulsion device 6 converts a drive shaft 7 driven to rotate by the multi-cylinder internal combustion engine 5, and changes the rotation direction of the drive shaft 7. A forward / reverse switching mechanism 8 and a propeller 9 to which rotation is transmitted via the forward / backward switching mechanism 8 are provided.
[0016]
The multi-cylinder internal combustion engine 5 is a fuel injection type four-cycle in-line four-cylinder engine, and its crankshaft 10 is long in the vertical direction (the vertical direction in FIG. 3), and four cylinders in the vertical direction. (Reference numerals # 1 to # 4 from the top) are arranged in parallel. Although not shown, pistons are fitted in the cylinders of the respective cylinders # 1 to # 4 so as to be slidable in the horizontal direction, and each piston is connected to the crankshaft 10 via a connecting rod.
[0017]
Further, as shown in FIGS. 2 and 3, between the small-diameter pulley 11 attached to the upper portion of the crankshaft 10 and the large-diameter pulleys 14 and 15 attached to the upper ends of the camshafts 12 and 13. An endless cam belt 16 is horizontally wound around. A flywheel magneto 17 is attached to the upper end of the crankshaft 10, and the drive shaft 7 (see FIG. 1) is connected to the lower end of the crankshaft 10.
[0018]
Thus, four intake pipes 19 extend horizontally from the silencer 18 arranged on one side of the engine 5 toward the rear (right side in FIG. 2). A throttle body 20 provided independently for each of the cylinders # 1 to # 4 is attached. The intake pipe 21 connected to each throttle body 20 is connected to an intake passage (not shown) formed in the cylinder head 22 for each of the cylinders # 1 to # 4. The two intake pipes 21 and the lower two cylinders # 3 and # 4 are joined to each other on the way.
[0019]
Further, as shown in FIG. 2, a single common valve shaft 23 penetrates through each throttle body 20 in the vertical direction, and the valve shaft 23 is accommodated in each throttle body 20 (not shown). The throttle valve is installed. A throttle opening sensor 24 is attached to an upper end portion of the valve shaft 23, and a throttle wire 28 is connected to an intermediate portion of the valve shaft 23 via a rod 25, levers 26, 27, and the like. In FIG. 2, 29 is a shift wire for operating the forward / reverse switching mechanism 8 to switch forward / reverse.
[0020]
Incidentally, as described above, the four-cylinder engine 5 according to the present embodiment is a fuel injection engine, and the cylinder head 22 is provided with an injector 30 for each cylinder # 1 to # 4 (see FIG. 3). ) The fuel supplied from the delivery pipe 31 arranged in the vertical direction is injected into the intake passages of the cylinders # 1 to # 4 at appropriate timing by the injectors 30.
[0021]
Thus, as shown in the figure, an idle speed control device (hereinafter abbreviated as ISC) 32 is disposed inside the upper two intake pipes 21, and an idle speed control (not shown) is provided in the ISC 32. A valve (hereinafter abbreviated as ISC valve) is provided. The opening of the ISC valve is controlled by an unillustrated engine control device (hereinafter abbreviated as ECU).
[0022]
The inlet of the ISC 32 is connected to the silencer 18, and two flexible rubber hoses 33, 34 constituting a bypass pipe are led out from the outlet of the ISC 32. The other rubber hose 34 is connected to the merging portion of the intake pipe 21 of the third cylinder # 3 and the fourth cylinder # 4, and is connected to the merging portion of the intake pipe 21 of the first cylinder # 1 and the second cylinder # 2. .
[0023]
As described above, when the throttle wire 28 is operated during the load operation of the four-cylinder engine 5, the throttle valves in the throttle bodies 20 are simultaneously opened and closed, and the flow rate of the intake air (fresh air) sucked into the silencer 18 is adjusted. Then, the intake air that has passed through the throttle valve flows to each intake passage formed in the cylinder head 22 through each intake pipe 21 and is mixed with fuel injected at an appropriate timing from each injector 30 to have a predetermined air-fuel ratio. An air-fuel mixture is formed. When the intake valve (not shown) is opened in each of the cylinders # 1 to # 4, the air-fuel mixture is sucked into the cylinder, compressed by the piston, and used for combustion in the combustion chamber.
[0024]
Thus, when the four-cylinder engine 5 is operated and the crankshaft 10 is rotationally driven at a predetermined speed as described above, the rotation is transmitted to the propulsion device 6 via the drive shaft 7, and the pulley 11, It is transmitted to the camshafts 12 and 13 via the cam belt 16 and the pulleys 14 and 15, and the propeller 9 of the propulsion device 6 is rotationally driven to generate a required propulsive force. The intake valve and the exhaust valve are opened and closed at an appropriate timing, whereby gas exchange is performed in the cylinders of the cylinders # 1 to # 4.
[0025]
On the other hand, during idling when each throttle valve is in the fully closed state, the intake air sucked into the silencer 18 bypasses each throttle valve and is introduced from the ICS 32 through the rubber hoses 33 and 34 into the intake pipe 21, and The gas is supplied to each cylinder through 21 to be used for air-fuel mixture formation. At this time, the ECU (not shown) feedback-controls the opening of the ISC valve of the ISC 32 based on the deviation between the actual engine speed detected by the rotation sensor (not shown) and the target idle speed, and the actual engine speed. Controls the amount of intake air supplied to each of the cylinders # 1 to # 4 so as to match the target idle speed.
[0026]
As described above, the engine speed during idling is controlled. In this embodiment, one ISC 32 is provided, and the total cross-sectional area of the rubber hoses 33 and 34 connected from the ISC 32 to the intake pipe 21 is determined by the ISC 32. It is set to be larger than the inlet cross-sectional area.
[0027]
Thus, if the total cross-sectional area of the rubber hoses 33 and 34 is set to be equal to or larger than the inlet cross-sectional area of the ISC 32 as described above, the intake air flowing through the rubber hoses 33 and 34 is decelerated during idling, and the suction of the cylinders # 1 to # 4 is reduced. The air pressure becomes substantially equal, and the intake air amount to each cylinder # 1 to # 4 can be controlled by a common control map. As in this embodiment, an independent throttle valve is provided for each cylinder # 1 to # 4. Even if the provided configuration is adopted, it is possible to stably control the idling speed with one ISC 32.
[0028]
<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram of the idle speed control system according to the second embodiment of the present invention.
[0029]
In the present embodiment, a common air rail 35 is provided for each cylinder # 1 to # 4 of a four-cycle four-cylinder engine, and an ISC 32, an intake pressure sensor 36, and joint pipes 37 and 38 are attached to the air rail 35. Yes. A large-diameter joint pipe 39 is attached to the inlet of the ISC 32, and a rubber hose 40 connected to a silencer (not shown) is connected to the joint pipe 39. The ISC 32 and the intake pressure sensor 36 are electrically connected to an ECU (not shown).
[0030]
The joint pipe 37 is connected to a rubber hose 41 connected to a regulator (not shown) for controlling the fuel pressure.
[0031]
Further, one end of a rubber hose 42 constituting a bypass pipe is connected to each of the four joint pipes 38, and the other end of each rubber hose 42 is connected to the intake pipe 21 of each cylinder # 1 to # 4. .
[0032]
Thus, in the present embodiment, the total cross-sectional area of the rubber hose 42 is set to be equal to or larger than the inlet cross-sectional area of the ISC 32, and the cross-sectional area of each rubber hose 42 is set to be larger than the cross-sectional area of each joint pipe 38. .
[0033]
Therefore, also in the present embodiment, the intake air flowing through each rubber hose 42 is decelerated during idling, and the intake pressures of the cylinders # 1 to # 4 are substantially equal, and the common control map is used to supply the cylinders # 1 to # 4. The intake air amount can be controlled, and the same effect as in the first embodiment can be obtained.
[0034]
【The invention's effect】
As is apparent from the above description, according to the present invention, when idling a multi-cylinder internal combustion engine having an independent throttle valve for each cylinder, the throttle valve is bypassed and supplied to the intake pipe of each cylinder. In the idle speed control system for a multi-cylinder internal combustion engine provided with an idle speed control device for controlling the intake air amount to be provided, one idle speed control device is provided, and the intake pipe of each cylinder is provided from the idle speed control device. Since the total cross-sectional area of the bypass pipe connected to the inlet cross-sectional area of the idle speed control device is set to be larger than the intake cross-section area, the intake air flowing through each bypass pipe during idling is decelerated and the intake pressure of each cylinder becomes substantially equal. It is possible to control the intake air amount of each cylinder on the map and adopt a configuration in which each cylinder has an independent throttle valve. Also, the effect that a stable idle speed control in one of the idle speed control device can be obtained.
[Brief description of the drawings]
FIG. 1 is a side view of an outboard motor.
FIG. 2 is a side view of a multi-cylinder internal combustion engine mounted on an outboard motor.
FIG. 3 is a plan view of a multi-cylinder internal combustion engine mounted on an outboard motor.
FIG. 4 is a configuration diagram of an idle speed control system according to a second embodiment of the present invention.
[Explanation of symbols]
5 4-cycle 4-cylinder engine (multi-cylinder internal combustion engine)
20 Throttle body 21 Intake pipe 32 ISC (idle speed controller)
33, 34 Rubber hose (flexible hose: bypass pipe)
38 Joint pipe 42 Rubber hose (flexible hose: bypass pipe)

Claims (3)

An idle speed control device is provided that controls the amount of intake air supplied to the intake pipe of each cylinder by bypassing each throttle valve during idling of 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,
One idle speed control device is provided, a bypass pipe connected from the idle speed control device to the intake pipe of each cylinder is provided, and the bypass pipe is connected to the idle speed control device via a joint pipe. The total cross-sectional area of the flexible hose is set to be equal to or larger than the inlet cross-sectional area of the idle speed control device, and the cross-sectional area of the flexible hose is larger than the cross-sectional area of the joint pipe. A regulator for controlling the fuel pressure on the air rail, which is set large and provided with an air rail connected to the flexible hose via the joint pipe and connected to the idle speed control device idle speed control system for a multi-cylinder internal combustion engine, characterized in that connected to. The idle speed control system for a multi-cylinder internal combustion engine according to claim 1, wherein an intake pressure sensor is attached to the air rail .   The multi-cylinder internal combustion engine is an engine for an outboard motor in which a plurality of cylinders are arranged in a vertical direction, and the idle speed control device is arranged inside an intake pipe of each cylinder. 3. An idle speed control system for a multi-cylinder internal combustion engine according to 1 or 2.

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