JPS61272416A - Control device for new charge - Google Patents

Abstract

PURPOSE:To compensate a decrease of compression ratio when an intake timing control valve is early closed, by controlling the intake timing in accordance with an engine operative condition through the intake timing control valve, provided just in the upstream of an intake valve, while providing a compression ratio changing means in a combustion chamber. CONSTITUTION:A rotary type intake control valve 2, which rotates interlocking to an engine, is provided just in the upstream of an intake valve 1 in an intake port IP, and the engine constitutes the intake control valve 2 so as to close the intake port prior to closing of the intake valve 1 when the engine is in low load operation. The engine, arranging in its combustion chamber 12 a piston 14 loaded by a spring 15, variably forms volume of a subcombustion chamber 13. The earlier is the closing timing of the intake control valve 2, the smaller compression ratio in the combustion chamber 12 tends to decrease, but the engine, extruding the piston 14 by the spring 15 to decrease a capacity of the subcombustion chamber when the compression ratio decreases small, decreases the whole volume of the combustion chamber, thus a decrease of the compression ratio can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air supply control device, and more particularly, to an air supply control device that is provided with a valve member for air supply control in the vicinity of a mushroom valve for intake. The present invention relates to a control device.

(Prior Art) In a reciprocating engine equipped with a fuel injection device, fuel and air that are pressurized and injected into an intake passage are introduced into an engine combustion chamber by negative pressure when a piston descends.

At Tojiro, the amount of fuel injected under pressure into the intake passage is
The air-fuel ratio is set to be constant based on various factors such as air volume, intake air temperature, engine load, and amount of accelerator pedal depression. As long as the mushroom valve is open, it flows into the combustion chamber, so when the engine is in a low load and low rotation range, such as when idling, excess air-fuel mixture is sucked in until the piston reaches bottom dead center. This results in a pumping action that overwhelms the flow resistance of the air-fuel mixture, resulting in the inconvenience of depriving the engine of its output.

Therefore, in order to resolve this kind of military/cooperative relationship.

In the intake passage, near the intake mushroom valve, specifically in front of the intake mushroom valve in the intake direction.

A valve that opens and closes the intake path is installed separately from this mushroom valve.

It has been considered to reduce the power lost to the pumping action by stopping the supply of air-fuel mixture before the intake mushroom valve closes when the engine is idling.

The air supply control device described above in the drawings will now be explained as follows.

In Figure 3, the intake manifold and intake port IP
In the intake path IN connected between.

An intake mushroom valve 1 for opening and closing the intake port IP is disposed on the intake port IP side, and a freely rotatable rotary valve 2 is disposed in front of the intake mushroom valve 1 in the intake direction in the intake path IN.

The rotary valve 2 has a cylindrical shape as shown in FIG.
It is designed to be rotated in the direction of the arrow shown by the solid line during engine operation in conjunction with the operating cam drive system of the intake mushroom valve 1, and the peripheral wall has a discharge opening 2A that can communicate with the intake port side, and a discharge opening 2A that can communicate with the intake port side. An introduction opening 2B is formed at a position facing the opening and can communicate with the intake manifold side IM.

The peripheral wall connected to the above-mentioned discharge opening 2A has its length set for the first reason.

That is, in FIG. 4, which shows the lift of the cam using the coordinate axis showing the crank angle, line A indicates the intake mushroom valve 1.
Line B is the opening/closing timing and lift amount of rotary valve 2.
For example, if the intake air amount required during idling is 115 for the intake air amount S when the intake mushroom valve 1 is open, then from the opening time of the intake mushroom valve 1, Intake corresponding to the remaining intake amount of 415 is stopped. This state is indicated by the symbol B in FIG. 4, and the amount of intake air in the region (3) indicated by the horizontal line is supplied into the combustion chamber.

In this way, it becomes difficult to generate a pumping action of the piston until the piston reaches the bottom dead center (BDC), so that loss of engine output can be reduced.

Therefore, returning to FIG. 5, the length of the peripheral wall on the side of the discharge opening 2A is set to a length that can cut the intake air amount of 415 mentioned above, plus the length φ in the radial direction of the intake port. .

The discharge opening 2A of the rotary valve 2 is set such that the length in the circumferential direction of the valve matches or is slightly longer than the radial length φ of the intake port, and the discharge opening 2A of the inlet port 2B is set so that the length in the circumferential direction of the valve matches or is slightly longer than the radial length φ of the intake port. The length in the circumferential direction is set to allow communication with the intake manifold in a fully open state when polymerized.

Further, the discharge opening 2A of the rotary valve 2 is set such that the length in the circumferential direction of the valve matches the length φ in the radial direction of the intake port, or is set to be slightly longer than this.

The length of the inlet port 2B in the circumferential direction is set such that it can communicate with the intake manifold in a fully open state when the discharge opening 2A overlaps with the intake port.

This rotary valve 2 is designed to reduce the pumping action of the piston during idling.
The amount of air intake can be controlled according to the engine load.

That is, the rotary valve 2, like when idling,
In the low load and low rotation range of the engine, it is possible to supply 115 of the intake air amount obtained by the opening time of the intake mushroom valve l, but in response to the depression of the accelerator pedal, the intake port The degree of communication with the opening 2A can be changed.

Although the details are not shown, as the amount of depression of the accelerator pedal increases, the differential mechanism retards the rotary valve in the direction shown by the two-dot chain line in Fig. 5, and connects the intake port. As shown in FIG. 4, the amount of intake air to the intake mushroom valve is increased in the medium load range (vertical line area in the figure) and the high load area - (shaded area in the figure).

(Problem to be Solved by the Invention) When the above-mentioned rotary valve is used, it is possible to suppress the occurrence of pumping loss relative to engine output, which is noticeable in partial load ranges such as low engine load and low engine speed ranges. On the other hand, the following new problems arose.

In other words, since the rotary valve advances the intake end timing (hereinafter referred to as the intake closing timing) in the engine partial load range, the amount of air-fuel mixture introduced into the combustion chamber is also small, and as a result, the amount of air-fuel mixture that is introduced into the combustion chamber is small, resulting in less gain from the piston compression process. The compression pressure is low, which lowers the heat storage temperature during mixture compression, that is, the temperature of the mixed gas in the combustion chamber.
The swirl effect is also reduced, making it impossible to achieve proper combustion.

(Means for Solving the Problems) The present invention has been made in view of the above problems, and aims to provide an air supply control device that solves the above problems. The combustion chamber is equipped with a structure that can vary the compression ratio within the combustion chamber according to the amount of air supplied.

(Example) The present invention will be explained below with reference to illustrated embodiments.

In addition, in FIGS. 1 and 2, the same members as those shown in FIG. 3 and the subsequent drawings are given the same reference numerals.

In FIG. 1, reference numeral 10 indicates a piston, 11 a cylinder, 12 a main combustion chamber, 13 an auxiliary combustion chamber, 14 an auxiliary piston, and 15 a spring.

The auxiliary combustion chamber 13 communicates with the main combustion chamber 12, and inside it,
An auxiliary piston 14, which is given the habit of moving in the direction toward the main combustion chamber 12 by a spring 15, is slidably disposed.

The auxiliary piston 14 is designed to slide within the auxiliary combustion chamber 12 in response to the pressure generated during the compression process of the engine, thereby continuously increasing and decreasing the volume of the combustion chamber to increase or decrease the volume within the main combustion chamber 12. It is designed to control the gas pressure generated.

Therefore, if the intake half-close is performed by the rotary valve 2 in a low load region or the like, in other words, if the intake air amount is small, the volume of the main combustion chamber will decrease due to the sliding of the auxiliary piston 14. Therefore, the compression pressure inside the combustion chamber is increased.

On the other hand, in the high load range of the engine, the amount of mixed gas in the main combustion chamber increases, and the compression pressure increases when the piston rises, so the increase in compression pressure is suppressed by setting the auxiliary piston 14 to increase the combustion chamber volume. to prevent knocking.

FIG. 2 shows a modification of the auxiliary piston, in which the auxiliary piston 20 consists of two divided pistons 20 connected via a rod 21 within the auxiliary combustion chamber 13.
a, 20b, one of these split pistons 20
A slope is formed at a.

A slider 22 having an inclined surface corresponding to this inclined surface is brought into contact with this one piston 20b, and this slider 22 is connected to a load detection member (not shown) via a connecting member 23. ing.

The load detection member is, for example, a torque sensor activated by the amount of depression of the accelerator, and is configured to set the direction and amount of movement of the slider 22 depending on the load range of the engine.

In other words, in the high engine load range, the slider 22
slides to the right in the figure and pushes up one side of the auxiliary piston 20a, thereby pushing the other side of the auxiliary piston 20a upward.
b also slides upward to lower the gas pressure in the main combustion chamber, and in the low load range of the engine, the slider 22 slides to the left in the figure. The load sensing member is controlled so as to lower the gas pressure and increase the gas pressure in the main combustion chamber.

(Effects of the Invention) According to the present invention, this is caused by half-closing the intake by the rotary valve. Lowers the temperature of the mixed gas during compression in the combustion chamber and lowers the combustion temperature.

This can be suppressed by changing the volume within the combustion chamber due to the auxiliary piston, and furthermore, the reduction in the swirl effect can be suppressed by increasing the compression within the combustion chamber and increasing the squish obtained by this high compression.

Moreover, when high compression is achieved in the combustion chamber by the auxiliary piston, the combustion temperature of the mixed gas increases due to this high compression, which tends to increase NOx. Because the amount of air supply is controlled.

It is also possible to prevent the generation of NOx, so to speak, the shortcomings between the rotary valve and the auxiliary piston can be canceled out.
It is possible to obtain an engine that can suppress the expected occurrence of bombing loss, increase combustion efficiency, and reduce the residual rate of harmful components in exhaust gas and air.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a main part showing an embodiment of the present invention, FIG. 2 is a schematic diagram showing a modification of a main part of the embodiment of the present invention, and FIG. 3 is a schematic diagram showing a conventional example of an air supply control device. FIG. 4 is a diagram showing the operation of the conventional example shown in FIG. 3; FIG. 5 is a schematic diagram showing the main parts of the conventional example shown in FIG. 3. ]・・・Mushroom valve for intake, 2・・・Rotary valve, 1
2...Main combustion chamber, 13...Sub-combustion chamber, 14.2
0... Auxiliary piston, 15... Spring, IM...
...Intake manifold, IP...Intake port. 7 rice haku

Claims (1)

[Scope of Claims] A freely rotatable rotary valve, which is disposed at the connection between the intake port and the intake manifold and has a mixture discharge opening that can communicate with the intake port, is disposed near the intake mushroom valve, Air supply control that rotates the rotary valve at the same rotation ratio as the driving cam of the intake mushroom valve, and changes the degree of communication between the discharge opening of the rotary valve and the intake port side according to the load. In the apparatus, a main combustion chamber communicating with the intake port is provided with an auxiliary combustion chamber communicating with the main combustion chamber, and means for changing the combustion chamber volume in accordance with the amount of air supplied by the rotary valve in the auxiliary combustion chamber. An air supply control device characterized by being provided with.