JPS6299630A - Suction device for engine - Google Patents

Abstract

PURPOSE:To take out stable negative pressure, by making the suction negative pressure for various controls over an engine turn to the converging negative pressure in a suction passage at the downstream of an on-off valve for a cylinder where firing order is uncontinued, in case of such an engine that installed the on-off valve to be closed earlier than suction valve close timing, in a suction passage at the upstream of a suction valve. CONSTITUTION:In a suction passage at the upstream of a suction port 7, there is provided with a timing valve 13 as an on-off valve making a suction quantity regulable by closing itself earlier than the close timing of a suction valve of each port, and it is opened or closed by a driving device 15 synchronously with an engine speed. Each hole 23 is installed at the downstream of the timing valve 13 in each suction pipe of cylinders 1b and 1c where firing order is uncontinued, interconnecting these holes with a pipe 24, and negative pressure in this pipe is used for suction negative pressure for various controls of fuel or the like of this engine.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a timing valve in the intake passage near the intake port, and controls charging by making the timing valve close timing earlier than the intake port closing timing. This invention relates to improvements to the intake system for engines that have been developed.

(Conventional Technique 16) Conventionally, in the case of an engine in which the intake air charge l14m is controlled by adjusting the opening degree of the throttle valve, there is a pumping loss due to throttling resistance, which is a major obstacle to improving the fuel efficiency of the engine. There is.

As an engine that reduces this pumping loss, a timing valve is provided in the intake passage near the intake port that is opened and closed at a predetermined timing, and the opening and closing timing of the timing valve is adjusted according to the operating condition of the engine. Engines have also been proposed in which the intake air filling amount is controlled by the length of the opening period of the timing valve, eliminating intake throttling resistance, reducing pumping loss, and improving fuel efficiency (for example, Showa 5
8-23245).

Of course, the engine equipped with the above timing valve,
When the load is low, the timing valve closes earlier than the intake port, and air is taken in during the short period when both are open to obtain less filling ω, eliminating the need for a throttle valve and reducing pumping loss. It is from et al.

Therefore, when performing various engine controls, such as controlling the fuel pressure injected from the fuel injection nozzle and controlling the opening/closing of the shutter valve, it is necessary to extract the intake pressure. J to the engine
5, the intake pressure changes greatly during the cycle, making it difficult to obtain a stable intake pressure.

However, when the intake port opens, the timing valve is in the open state, and this intake port opens and starts intake.
The intake passage is at atmospheric pressure until the timing valve closes, and as the timing valve closes, a sudden negative pressure is generated in the intake passage downstream of the timing valve due to volume expansion corresponding to the downward movement of the piston, causing the intake port to close. After that, a constant negative intake pressure is maintained between the timing valve and the intake port, and when the timing valve is activated again, it will rise to atmospheric pressure. Therefore, when taking the intake pressure from upstream of the timing valve, the period during which the timing valve is open is short, and even if the intake pressures of each cylinder are collected, stable negative pressure cannot be taken out.

On the other hand, when taking out the intake pressure on the downstream side of the timing valve, there are atmospheric pressures and sudden pressure fluctuations, so you cannot obtain stable intake pressure unless you take out the pressure at the right time. Control based on this is also unstable and has low accuracy. Also, if the intake pressure downstream of the timing valve of all cylinders is collected and extracted, negative pressure will be generated in one of the cylinders and stable intake pressure can be extracted, but in the case of a 4-cylinder engine, the timing valve installation The bombing loss reduction effect is halved.

The effect of reducing the pumping loss of the engine is that the timing valve closes in the latter half of the time when the intake air is heard at low load, and stops the supply of intake air. For example, if the ignition order of a 4-cylinder engine is 1-3-4-2 cylinders,
When the intake pressures downstream of the timing valves of the first and third cylinders, which have consecutive firing orders, are combined, when one cylinder is in a state where the above-mentioned pumping loss reduction effect is reduced by 1q, the timing valve of the other cylinder opens. The pressure becomes atmospheric pressure, and air is supplied from the intake pressure collecting passage to the other cylinder, thereby impairing the pumping loss reduction effect.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention provides an engine intake air supply system that allows stable intake pressure to be taken out without impairing the pumping loss reduction effect even in an engine in which a timing valve is provided in the intake passage near the intake port. The purpose is to provide a device.

(Description of the Invention) The intake device of the present invention is a four-cylinder cylinder in which a timing valve is provided in the intake passage near the intake port, and the filling amount is controlled by making the timing valve close timing earlier than the intake port closing timing. The engine is characterized in that the intake pressure for engine control is obtained by combining the intake pressures in the intake passages downstream of the timing valves of cylinders whose firing order is not consecutive.

(Effects of the Invention) According to the present invention, the intake pressure for engine control is combined and extracted from the intake passage downstream of the timing valve of the cylinders in which the firing order of the four-cylinder engine is not consecutive. Based on this, the intake pressure is continuously maintained in the intake passage between the cylinder timing valve and the intake port, and stable intake pressure with little pressure fluctuation can be extracted without timing. It is possible to improve 601 degrees of control.

In addition, when one cylinder is in a state where the timing valve closes in the latter half of the period when the intake port is open and the pumping loss reduction effect is achieved by stopping the supply of intake air, the timing valve of the other cylinder is in the open state. As a result, stable intake pressure can be obtained as described above without impairing this pumping loss reduction effect.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a sectional view of the second cylinder of a four-cylinder engine equipped with the intake system of the present invention, and FIG. 2 is a partially sectional plan view.

The engine body 1 has four cylinders from the first cylinder 1a to the fourth cylinder 1d.
An intake port 7 that is opened and closed by an intake valve 6 for a combustion chamber 5 formed above a piston 4 between a cylinder head 2 and a cylinder block 3 of each cylinder;
and 9 to the exhaust port 1 which is opened and closed by the exhaust valve 8.
are each opened.

2. The intake passage 10 that communicates with the intake port 7 of each cylinder 1a to 1d and supplies intake air has a high-load intake passage 10a with a large passage area, and is branched from this to form a narrow passage area for swirl generation. and a low-load intake passage 10b. Furthermore, fuel injection nozzles 11 for injecting fuel are arranged in the high-load intake passages 10a of each of the cylinders 1a to 1d.

A shutter valve 12 is interposed in each of the high-load intake passages 10a, while a low-load intake passage 1
A timing valve 13 common to each cylinder is interposed in the middle of 0b. This timing valve 13 is the sleeve 1
The timing valve 13 is formed into a cylindrical shape that is rotated in synchronization with the engine rotation within the timing valve 4, and the timing valve 13 is connected to each cylinder 1a to 1d.
Openings 13a are formed to open and close the low-load intake passages 10b, and the internal spaces communicate with the cylinders 1a to 1d. Further, the phase of the timing valve 13 relative to the crank angle is configured to be variable depending on the operating state.

That is, a planetary gear mechanism 15 is provided at one end of the timing valve 13, and the planetary gear mechanism 15 operates the camshaft 1 to open and close the intake valve 6 and the exhaust valve 8.
6 is driven by a cam pulley 17 fixed to one end of the timing belt 18. The above planetary gear II
In the structure 15, a central driving gear 21 is rotated via three planetary gears 20 inside an external gear 19 driven by the timing belt 18, and the timing valve 13 to which the driving gear 21 is fixed is rotated. It is driven.

The operating rod 22, which moves in the opposite direction as the load increases in conjunction with the Akbil, is linked to the planetary gear 20 to change the phase angle of the planetary gear 20 with respect to the timing valve 13, thereby changing the timing when the load increases. Valve 13
The opening/closing timing is configured to be delayed. A lever 12a of the shutter valve 12 is connected to the operating rod 22 through a notch hole 22a, so that the shutter valve 12 starts opening when the operating rod 22 is loaded with a predetermined load or more. It is composed of

With the above structure, in the low-load operating state, the shutter valve 12 of the high-load intake passage 10a is opened, and the opening/closing timing of the timing valve 13 is controlled to the delayed side as the load increases, so that the intake valve 6 The overlap period with the opening timing of the port 7 is increased to lengthen the intake period, and the filling amount is increased depending on the operating state. The load increases further and timing valve 1
3 reaches a predetermined delay state and the intake air amount adjustment by opening/closing control of the timing valve 13 reaches its limit, the shutter valve 12 is opened this time to supply intake air from the high-load intake passage 10a to adjust the filling amount. In this state, the opening degree of the shutter valve 12 is increased to increase the intake air amount in response to an increase in the load.

Then, for example, in order to introduce the intake pressure to a pressure V-regulator (not shown) that controls the fuel pressure supplied to the fuel injection nozzle 11 to maintain a predetermined differential pressure with respect to the intake pressure, Or EGR the intake negative pressure
In order to use it as an operating source for actuators such as valves, a pressure outlet 23 is provided in the low-load intake passage 10b downstream of the timing valve 13 for the second cylinder 1b and the third cylinder 1C in which the firing order is not consecutive. has been done.

The outlet passages 24 connected to the pressure outlet ports 23 of both cylinders 1b and 1c are combined, and the combined intake pressure is extracted. J3, the ignition order of the four-cylinder engine is 1-3-4-2 cylinders.

FIG. 3 shows the relationship between the opening/closing timing of the intake port 7 by the intake valve 6 (indicated by a chain line) and the opening/closing timing of the timing valve 13 (indicated by a broken line) during low load when the shutter valve 12 is closed. It shows pressure fluctuations (negative pressure) in the low-load intake passage 10b on the downstream side of the timing valve 13 for air rgU1a to 1d.

The opening/closing timing of the intake port 7 by the intake valve 6 is constant with respect to the crank angle, whereas the timing valve 13 opens earlier than the intake port 7 and closes earlier. At this time, intake air is supplied to the combustion chamber 5 during the period when both the timing valve 13 and the intake port 7 are inquired, and the opening/closing timing of the timing valve 13 is delayed as the load increases depending on the engine operating state. The filling port is increased by lengthening the overlap period (between b and c in FIG. 3) in which the intake port 7 and timing valve 13 are open, that is, the intake period.

The pressure fluctuation in the low-load intake passage 10b on the downstream side of the timing valve 13 due to the opening and closing of the intake port 7 and the opening and closing of the timing valve 13 as described above first occurs when the opening 13a of the timing valve 13 is connected to the intake port 7 at point a. It opens in communication with the downstream low-load intake passage 10b, and air flows from the internal space of the timing valve 13 into the downstream low-load intake passage 10b. Note that the internal space of this timing valve 13 also communicates with the opening 13a for other cylinders, and when the opening 13a of one cylinder is in the open state communicating with the downstream low-load intake passage 10b, the internal space The space is communicated with the second-stream low-load intake passage 10b through the opening 13a of another cylinder, and is supplied with intake air from upstream.

As described above, when the timing valve 13 is activated at point a, the downstream low-load intake passage 10b becomes atmospheric pressure due to the introduction of intake air. When the intake port 7 is opened at point b near the top dead center T, the supply of intake air to the combustion chamber 5 starts, but even when the piston 4 descends, the intake air is supplied without resistance and combustion occurs at atmospheric pressure. Air intake into chamber 5 takes place. Subsequently, when the timing valve 13 closes at the 0 point, the upper limit of negative pressure (pressure decrease) due to the volume expansion accompanying the descent of the piston 4 of the combustion chamber 5
acts on the low-load intake passage 10b through the intake port 7, and its negative pressure suddenly rises. Then, this negative pressure reaches its maximum at bottom dead center B, and after passing this bottom dead center B, the negative pressure decreases a little, but at point d, the intake port 7
After closing, the intake port 7, timing valve 13, and shutter valve 17 are opened, so that this negative pressure is maintained.

The pressure fluctuations occur sequentially with a crank angle shift of 180° in accordance with the ignition order. Then, by combining the intake pressures of the second cylinder 1b and the third cylinder 1C through the derivation passage 24, the negative pressure generation period and the negative pressure holding period are continuous, and stable intake negative pressure can be taken out. Moreover, in the second cylinder 1b or the third cylinder 1C,
During the c-d period during which the pumping loss reduction effect is obtained after the 0 point when the timing valve 13 is closed to the d point when the intake port 7 is open, the third cylinder 1C or the second cylinder 1
Since the a-C periods heard by the fllb timing valve 13 do not overlap, the pumping loss reduction effect is not impaired even if the intake pressures of both cylinders are combined.

In the above embodiment, the intake pressures of the second cylinder 1b and the third cylinder 1C are combined;
It is also possible to combine the intake pressure with d.

Further, in the above embodiment, the intake passage 10 is configured with a high-load intake passage 10a and a low-load intake passage 10b,
A timing valve 13 is interposed in the low-load intake passage 10b to reduce pumping loss in the low-angle Vi range, and
The timing valve 13 is made smaller to improve its reliability, and the low-load intake passage 10b has a passage structure suitable for generating swirl to improve combustibility. The total amount of intake air supplied to the combustion chamber 5 may be controlled by the timing valve 13 as described above even under high load. In addition, the intake air volume during high loads is adjusted using the shutter valve 12 provided for each cylinder, but the intake air volume is further adjusted by providing a throttle valve common to all cylinders on the upstream side. The air intake passage 10b may be simply provided with a shutter valve that closes when the load is low.

On the other hand, the control of the opening timing of the timing valve 13 and the adjustment of the opening of the shutter valve 12 according to the operating state are controlled by the output of a control unit that is provided with an actuator for each and receives a signal that detects the operating state of the engine. Control may be performed using characteristics similar to those described above.

Furthermore, the intake pressure extracted as described above can be used, for example, to control the fuel pressure to the fuel injection nozzle in accordance with the detected value depending on the level of the pressure, and also to be used as an operating state detection signal related to the load. Alternatively, the pressure may be used as the operating source pressure of the actuator of each engine control m+ mechanism.

[Brief explanation of drawings]

FIG. 1 shows a four-wheel drive system equipped with an intake device according to an embodiment of the present invention.
Fig. 2 is a cross-sectional view of the second cylinder of the engine, Fig. 2 is a plan view of the engine partially cut away, and Fig. 3 shows the pressure changes in the intake passage downstream of the timing valve due to the opening and closing of the intake port and timing valve in each cylinder. FIG. 1...Engine body 1a-1d...
...Cylinder 6...Intake valve 7...
...Intake port 10...Intake passage 10a...High load intake passage 10b...Low load intake passage 12...Shutter valve 13... ...Timing valve 13a...Opening 15...Planetary gear mechanism 23...Pressure outlet 24...
...Outlet passage tube 21■

Claims (1)

[Claims] (1) In a four-cylinder engine in which a timing valve is provided in the intake passage near the intake port and the filling amount is controlled by making the timing valve close timing earlier than the intake port closing timing, the intake pressure for engine control is of,
An intake system for an engine, characterized in that intake pressures in intake passages downstream of timing valves of cylinders whose firing order is not consecutive are combined and extracted.