JPS594532B2 - Intake system for supercharged engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a supercharged engine, and more particularly to a supercharged engine equipped with a main intake passage for naturally inhaling fresh air and an auxiliary intake passage for supplying a supercharger. The present invention relates to an air intake device.

Conventionally, this type of supercharged engine has been equipped with an auxiliary intake port in addition to a main intake passage with a main intake valve at the main intake port, as disclosed in, for example, Japanese Unexamined Patent Publication No. 55-137314. An auxiliary intake passage equipped with an auxiliary intake valve is provided in the auxiliary intake passage, and a supercharger is provided in the auxiliary intake passage, and fresh air is supplied from the main intake passage by natural intake in a low load state below the set load of the engine, while When the load is higher than the set load of the engine, supercharging air is supplied from the auxiliary intake passage at least during the compression stroke in addition to fresh air from the main intake passage, and the supercharger driven by the engine A so-called partial supercharging system is known that allows intake supercharging to be performed with good responsiveness without causing insufficient supercharging even in the low rotation range of the engine.

However, in the conventional partial supercharging system described above, the supercharging timing is controlled by the auxiliary intake valve that functions as a shutoff valve, so the load on the valve mechanism that controls the opening and closing timing of the auxiliary intake valve is reduced. In addition, when the supercharging timing is variably controlled in accordance with engine operating conditions such as engine speed, the valve operating mechanism becomes extremely complex.

Moreover, since supercharging is controlled by the auxiliary intake valve, the lift amount of the auxiliary intake valve is restricted and the lift amount cannot be increased, so the auxiliary intake valve becomes a resistance to the passage of supercharging air.
There was a problem that supercharging efficiency deteriorated.

Therefore, the present invention has been made in view of the above-mentioned points, and the auxiliary intake passage is provided with a rotary timing valve that opens and closes in synchronization with the engine, separately from the auxiliary intake valve as a shutoff valve, and the timing valve is provided in the auxiliary intake passage. By providing an opening/closing timing variable means that varies the opening/closing timing of the valve according to the operating condition of the engine to control the supercharging timing, the valve operating mechanism of the auxiliary intake valve does not become larger or more complicated. , a supercharged engine that has a simple structure that allows for accurate supercharging control, and also enables the setting of a large lift amount of the auxiliary intake valve to improve supercharging efficiency. The purpose is to provide an intake device.

That is, the present invention provides an auxiliary intake passage having an auxiliary intake valve at an auxiliary intake port in addition to a main intake passage having a main intake valve at the main intake port, and a supercharger is provided in the auxiliary intake passage, and the engine In a supercharged engine that supplies supercharging air from an auxiliary intake passage at least during the compression stroke in addition to fresh air from the main intake passage under high load conditions, the auxiliary intake passage is opened and closed in synchronization with the engine. The supercharging timing is variably controlled according to the engine operating condition by means of an opening/closing timing variable means that changes the opening/closing timing of the timing valve according to the engine operating condition. It is something to do.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

In FIG. 1, reference numeral 1 denotes a reciprocating engine, in which a piston 3 fitted in a cylinder 2 reciprocates to inhale and compress air into a combustion chamber 4 defined by the cylinder 2 and piston 3. , explosion, expansion, and exhaust strokes in order, and the crankshaft 6 is connected via the connecting rod 5.
It is designed to be driven in rotation.

Further, 7 is an air cleaner, and 8 and 9 are a main intake system and an auxiliary intake system, respectively, which constitute the intake system of the engine 1.

The main intake system 8 is constituted by a main intake passage 10 whose upstream end is connected to the air cleaner 7 and whose downstream end is a main intake port 10a that opens into the combustion chamber 4.
0 is provided with a main throttle valve 11 that is interlocked with an accelerator pedal (not shown) and controls the amount of intake air from the main intake passage 10.

Further, a fuel injection valve 12 is disposed upstream of the main throttle valve 11 in the main intake passage 10, and a measuring plate type air flow sensor 13 for detecting the total intake air amount is disposed further upstream. A potentiometer 14 that detects the rotation angle of the measuring plate is connected to the sensor 13, and the output signal of the potentiometer 14, together with an engine rotation speed signal S1 from a rotation speed sensor 42 (described later), is used to control the fuel injection. The input is inputted to a control circuit 15 that controls the operation of the valve 12 , so that fuel is injected from the fuel injection valve 12 in an amount corresponding to the intake air amount of the engine 1 and the engine speed, and the fuel is injected into the engine 1 through the main intake passage 10 .
A fuel injection type fuel supply device 16 configured to supply fuel to
It consists of

On the other hand, the auxiliary intake system 9 has an upstream end connected to the main intake passage 1.
The auxiliary intake passage 17 communicates with the fuel injection valve 12 and the main throttle valve 11 downstream of the air flow sensor 13 of 0, and has an auxiliary intake port 17a as a downstream end open to the combustion chamber 4. A supercharger 18 made of, for example, a vane pump type supercharging pump is disposed in the middle.

The supercharger 18 is connected to a pulley 21 which is transmitted to the crankshaft 6 by a belt 20 via an electromagnetic clutch 19.
The drive is connected to the

Further, the downstream side of the supercharger 18 in the auxiliary intake passage 17 is connected to the main throttle valve 11 via a linkage 22, and until the main throttle valve 11 is opened to a set opening degree, that is, the set load of the engine is An auxiliary throttle valve 23 is provided that remains closed in the following low load conditions, but opens when the main throttle valve 11 is opened beyond a set opening, that is, when the engine is in a high load state exceeding the set load. , the auxiliary throttle valve 23
is connected to an opening sensor 24 that detects the opening of the auxiliary throttle valve 23 and turns the electromagnetic clutch 19 ON-OFF. Therefore, when the auxiliary throttle valve 23 is opened (during high engine load) The electromagnetic clutch 19 is turned ON to operate the supercharger 18 using the pulley 21 (that is, the crankshaft 6 of the engine 1), while the electromagnetic clutch 19 is activated when the auxiliary throttle valve 23 is closed (during low engine load). The clutch 19 is turned off to stop the operation of the supercharger 18.

Further, the auxiliary intake system 9 has an auxiliary intake passage 1 at one end.
A bypass passage 25 is provided which opens upstream of the auxiliary throttle valve 23 downstream of the supercharger 18 of No. 7 and whose other end opens upstream of the supercharger 18 of the auxiliary intake passage 17.
An IJ valve 26 is provided, and when the supercharger 18 is in operation (supercharging), when the pressure (supercharging pressure) in the auxiliary intake passage 17 downstream of the supercharger 18 exceeds the set pressure, the above-mentioned IJ IJ-
The pressure is released to the auxiliary intake passage 17 upstream of the supercharger 18 through the bypass passage 25 by opening the valve 26,
The supercharging pressure is maintained at a set pressure.

Furthermore, a main intake valve 27 is provided at the main intake port 10a.
However, the above auxiliary intake port N? Auxiliary intake valves 28 are respectively disposed at a, and the valve timing of both intake valves 27 and 28 is such that the auxiliary intake valve 28 is partially overshot from the end of opening of the main intake valve 27, that is, from the latter half of the intake stroke to the compression stroke. It is set to wrap and open.

In addition, from the viewpoint of preventing backflow of intake air to each intake port tlOa, 17a, it is preferable to set the auxiliary intake valve 28 to open after the main intake valve 27 is closed, that is, during the compression stroke, without overlapping. .

As a result of the above, when the engine is under low load, the main intake passage 1
Engine 1 starts by naturally inhaling the air-fuel mixture as fresh air from 0.
On the other hand, when the engine is in a high load state, in addition to fresh air (mixture) from the main intake passage 10, at least during the compression stroke, pressurized air is supplied from the auxiliary intake passage 17 as supercharging air by the operation of the supercharger 18. A so-called partial supercharging system is configured to supply air to the engine 1.

In addition, 29 is a valve operating mechanism that controls the valve timing of the auxiliary intake valve 28, 30 is an exhaust port that opens into the combustion chamber 4, and 3
1 is an exhaust valve disposed at the exhaust port 30.

In addition to the above configuration, the present invention is characterized in that a rotary timing valve 32 that opens and closes in synchronization with the crankshaft 6 of the engine 1 is provided downstream of the auxiliary throttle valve 23 in the auxiliary intake passage 17. .

As shown in FIGS. 2 and 3, the timing valve 32 is attached to the outer wall of the engine 1, has an inlet 33a communicating with the upstream side of the auxiliary intake passage 17 on one end surface, and has a circumferential surface (in the figure, a lower surface). ), the casing 33 has an outlet 33b communicating with the downstream side (auxiliary intake port N?a) of the auxiliary intake passage 17, and is rotatably supported within the casing 33 via a bearing 34, and one end surface is connected to the flow. Entrance 33a
A hollow shaft-shaped shaft having an opening 35a on the circumferential side, which is open so as to be in communication with the crankshaft 6, and whose other end is closed, the inside of which forms a part of the auxiliary intake passage 17, and which has an opening 35a on the circumferential side. a rotary valve 35 rotatably fitted to the outer periphery of the rotary valve 35 and the casing 3
The opening of the rotary valve 35 rotates in synchronization with the crankshaft 6. When the opening 35a matches the opening 37a of the sleeve 37 on its outer periphery, it becomes an opening operation and opens the auxiliary intake passage 17, thereby supplying supercharged air from the supercharger 18 to the engine 1 via the auxiliary intake port 17a. Therefore, it is configured to control the supercharging timing.

Further, the timing valve 32 is provided with a variable mechanism 38 that changes and controls the timing when the opening 35a of the low-resolution valve 35 and the opening 37a of the sleeve 37 match, that is, the opening timing of the timing valve 32.

The variable mechanism 38 is fixed to a servo motor 39 and a rotating shaft 39a of the servo motor 39, and has a pin 40a at its tip.
The rotary arm 40 has a rotary arm 40 projecting therefrom, and a variable operation rod 41 that has a long hole 41a into which the pin 40a is slidably engaged and is erected on the circumferential surface of the sleeve 37. The rotating arm 40 is rotated by the operation of the servo motor 39,
Through engagement between the pin 40a of the rotating arm 40 and the elongated hole 41a of the variable operating rod 41, the variable operating rod 41 and the sleeve 37 engaged therewith are rotated to open the opening 37a of the sleeve 37. By rotating the position of the opening of the low-return valve 35, the valve opening timing can be changed.

On the other hand, the control circuit 15 receives a detection signal (engine rotation speed signal S) from a rotation speed sensor 42 that detects the engine rotation speed.
+) and the detection signal (supercharging pressure signal S2) of the supercharging pressure sensor 43 that detects the pressure (supercharging pressure) downstream of the supercharger 18 in the auxiliary intake passage 17, and the control circuit. 15 is connected to a servo motor 39 of a variable mechanism 38 in the timing valve 32.

As shown in FIG. 4, the control circuit 15 outputs an advance amount signal that determines the advance amount of the valve opening timing in accordance with the engine rotation speed signal S1 of the rotation speed sensor 42. The amount determining circuit 44 compares the boost pressure signal S2 from the boost pressure sensor 43 with a set pressure signal corresponding to the set boost pressure, and the valve is opened when the set pressure signal indicates an abnormal boost pressure. A comparator 45 outputs a retard correction signal for retarding the timing, and receives an advance amount signal from the advance amount determining circuit 44 and a retard correction signal from the comparator 45 to drive the above-mentioned motor 39 to the drive side. and a motor drive circuit 46,
The operation of the servo motor 39 is controlled to increase the advance amount of the valve opening timing in accordance with an increase in engine speed, and to retard the advance amount in the event of abnormal boost pressure, thereby causing the timing valve 32 to open. The valve timing is controlled according to the operating state of the engine.

Next, to explain the operation of the above embodiment, when the engine is in a low load state and is not supercharged, supercharging air is not supplied from the auxiliary intake passage 17, and the combustion chamber 4 of the engine 1 is supplied to the main intake passage. Air-fuel mixture as fresh air is supplied from No. 10, ensuring good operating performance like a normal engine.

On the other hand, during supercharging when the engine is under high load, the engine 1
In the combustion chamber 4, pressurized air as supercharging air is supplied from the auxiliary intake passage 17 with good response to the air-fuel mixture as fresh air from the main intake passage 10, at least in the compression stroke, so that insufficient supercharging can be avoided. It is possible to increase the charging efficiency and improve the output performance of the engine without causing any problems.

At this time, the supercharging timing is controlled by the timing valve 32, and the auxiliary intake valve 28 only functions as a shutoff valve, so the load on the valve mechanism 29 that controls the operation of the auxiliary intake valve 28 is small, and the The valve mechanism 29 can be made compact and can have a simple structure without requiring a complicated variable mechanism.

Moreover, since the auxiliary intake valve 28 can set its lift amount to a large value simply by acting as a shutoff valve, the supercharging resistance caused by the auxiliary intake valve 28 can be reduced and the supercharging efficiency can be improved. I can do it.

Further, the variable mechanism 38 that controls the opening/closing timing of the timing valve 32 has an opening 37a in the sleeve 37.
The opening/closing timing can be changed by a simple operation of rotationally changing the position of the supercharging timing, so the supercharging timing can be controlled according to engine operating conditions such as engine speed with a simple structure. .

Furthermore, in the above embodiment, the timing valve 32
The servo motor 39 of the variable mechanism 38, which governs the opening/closing timing of the As a result, the amount of advance of the valve opening timing of the timing valve 32 increases, and the amount of advance of the valve opening timing is retarded in the event of abnormal boost pressure.

Therefore, in the low rotational speed range of the engine, the opening timing of the timing valve 32 is hardly advanced, and the difference between the main intake hole HOa and the auxiliary intake port H? The overlap period with the main intake port 10a is made as short as possible, preventing intake air from flowing back into the main intake port 10a, and maintaining a good supercharging effect.

On the other hand, in the high speed range of the engine, the timing valve 32
Since the valve opening timing is advanced by rotating the sleeve 37 in the direction of arrow Y in FIG. 3 (that is, in the direction opposite to the rotational direction X of the rotary valve 35), the supercharging efficiency can be improved.

In this case, the intake air does not blow back into the main intake port NOa due to an increase in the inertial action of the fresh air from the main intake passage 10.

Furthermore, when the supercharging pressure increases abnormally due to a failure of the relief valve 26, etc., the advance amount of the opening timing of the timing valve 32 is retarded and the supercharging efficiency decreases.
Damage to the engine 1 due to an abnormal increase in intake pressure can be prevented.

Note that the present invention is not limited to the above-mentioned embodiment, and includes various other modifications. For example, in the above-mentioned embodiment, a fuel injection system is used as the fuel supply device 16 provided in the main intake system 8. Although the description has been made regarding a vaporizer type, the present invention is also applicable to a vaporizer type.

However, in the case of this carburetor system, since the fuel is sucked in by the venturi negative pressure caused by the intake air flow, the fuel is vaporized at a position upstream of the opening at the upstream end of the auxiliary intake passage 17 of the main intake passage 10 through which all the intake air flows. This method is suitable for the fuel injection method as in the above embodiment, since fuel needs to be installed in the auxiliary intake passage 17 and there is a risk that fuel will flow into the supercharger 18 in the auxiliary intake passage 17 and contaminate the supercharger 18.

Further, the fuel supply device 16 may be provided in the auxiliary intake system 9 as well as the main intake system 8.

Further, in the above embodiment, the supercharger 18 is connected to the pulley 21 that rotates synchronously with the engine 1 via the electromagnetic clutch 19, and is driven only during supercharging. In addition to being directly connected to and constantly driven, by providing a control valve in the bypass passage, the supercharged air from the supercharger 18 is passed through the bypass passage by operating the control valve when not supercharging, while Supercharger 18 during supercharging
The supercharger may be supplied to the engine 1 via the auxiliary intake passage 17.

Furthermore, the electromagnetic clutch 19 is operated 0N-OFF based on the output of the opening sensor 24 that detects the opening of the auxiliary throttle valve 23, but the opening of the main throttle valve 11 linked to the auxiliary throttle valve 23 is Or 0N- depending on the amount of intake air etc.
It may also be controlled to be OFF.

As explained above, according to the present invention, in a partially supercharged supercharged engine, in addition to the auxiliary intake valve as a shutoff valve, the auxiliary intake valve is provided in the auxiliary intake passage with a rotary type timing valve that opens and closes in synchronization with the engine. In addition to providing a valve, a variable opening/closing timing means for varying the opening/closing timing of the timing valve depending on the operating status of the engine is provided to variably control the supercharging timing according to the operating status of the engine. It is possible to perform supercharging control accurately with a simple structure without requiring a valve mechanism, and it is also possible to improve supercharging efficiency by setting the lift amount of the auxiliary intake valve to the dog level. It is.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which FIG. 1 is a general schematic diagram, FIG. 2 is an enlarged vertical sectional view of a timing valve portion, FIG. 3 is a sectional view taken along the line III--III in FIG. 2, and FIG. The figure is a block diagram of the control circuit. 1...Engine, 4...Combustion chamber, 6.
...Crankshaft, 10...Main intake passage, 10a...Main intake boat, 11...
...Main throttle valve, 15...Control circuit, 16...
...Fuel supply device, 17...Auxiliary intake passage,
17a...Auxiliary intake port, 18...
Supercharger, 23... Auxiliary throttle valve, 27...
・Main intake valve, 28... Auxiliary intake valve, 29...
... Valve mechanism, 32... Timing valve,
35...Rotary valve, 37...Sleeve, 38...Variable mechanism.

Claims (1)

[Claims] 1. In addition to the main intake passage with a main intake valve at the main intake port, an auxiliary intake passage with an auxiliary intake valve at the auxiliary intake port is provided, and a supercharger is installed in the auxiliary intake passage, and the engine is operated under high load conditions. In a supercharged engine that supplies supercharging air from an auxiliary intake passage at least during the compression stroke in addition to fresh air from the main intake passage, a Rokuri timing valve that opens and closes in synchronization with the engine in the auxiliary intake passage. and an opening/closing timing variable means for varying the opening/closing timing of the timing valve according to the operating condition of the engine, and the supercharging timing is variably controlled according to the operating condition of the engine. Intake system for a fed engine.