JPS6228290B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an intake system for a supercharged engine.

Conventionally, as an intake system for a supercharged engine, a supercharger driven by the engine is installed in the intake passage, and fresh air is supplied by natural intake when the engine load is lower than the set load, and when the load exceeds the set load, the supercharger is In addition to those that supply supercharged air from a charger or the main intake system that supplies fresh air using the engine's intake negative pressure, there are auxiliary intake systems that are equipped with a supercharger driven by the engine. and supply fresh air from the main intake system when the engine's set load is below, and supply supercharging air from the auxiliary intake system at least during the compression stroke in addition to fresh air from the main intake system when the engine's set load is higher than the engine's set load. (for example, Japanese Patent Application Laid-Open No. 1983
137314) has been proposed.

However, a throttle valve is provided in the intake passage downstream of the supercharger to supply supercharging air according to load fluctuations, but the supercharger is driven by the engine and its discharge pressure is Because it simply changes depending on the engine speed, regardless of the engine load condition,
In a transient state of the engine transitioning from the non-supercharged region to the supercharged region, at the start of supercharging when the throttle valve begins to open, the supercharging pressure between the turbocharger and the throttle valve increases rapidly, causing the turbocharger to This increases the driving resistance of the engine, causing a shock in the engine, and also causes a shock in which a large amount of supercharging air is supplied at once, causing a large change in the operating state of the engine.

The present invention has been made in view of the above problems, and provides a supercharging system that prevents engine shock due to an increase in drive resistance of a supercharger during a transient state of the engine, and shock due to a sudden change in operating conditions caused by a sudden increase in supercharging air. The purpose of the present invention is to provide an air intake system for a motorized engine.

In order to achieve the above object, the present invention provides an engine intake system with a supercharger driven by the engine, and supplies supercharged air from the supercharger to the engine at a load equal to or higher than the set load of the engine. The supercharged engine is characterized by being provided with a control device that gradually increases the supercharging pressure of the supercharger in a transient state of the engine transitioning from a non-supercharged region to a supercharged region.

That is, the above-mentioned supercharged engine has a relief passage that bypasses the supercharger, a relief valve that is interposed in the relief passage, and operates the relief valve to open in the non-supercharged region and to open the relief valve in the supercharged region. The relief valve includes an actuation means for operating in the closing direction, and a delay means for delaying the closing operation of the relief valve in a transient state of the engine transitioning from a non-supercharging region to a supercharging region. Therefore, even if pressurized air is supplied from the turbocharger immediately after transitioning from the non-supercharging region to the supercharging region, the relief passage has not yet been closed, so the supercharging pressure will not suddenly increase. The relief valve closes with a delay, and the supercharging pressure increases, thereby preventing the supercharging pressure from rising rapidly during a transient state of the engine. Furthermore, since the relief valve is fully closed after the delay means is activated, the required output can be obtained by directly utilizing supercharging from the supercharger when the engine load is higher than the set load of the engine.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an engine, 2 is a main intake system that supplies fresh air to the engine 1 through a main intake port 4 that opens into the combustion chamber 3 of the cylinder head 1a of the engine 1, and 5 is the combustion chamber 3. 7 is an auxiliary intake system that supplies supercharging air to the engine 1 through an auxiliary intake port 6 that opens into the combustion chamber 3, and an exhaust system that discharges exhaust gas from the engine 1 through an exhaust port 8 that also opens into the combustion chamber 3. be.

In the main intake system 2, 9 is a main intake valve that opens and closes the main intake port 4 at predetermined timing, 10 is a main throttle valve that is interposed in the middle of the main intake passage 11 and controls the intake flow rate, and 12 is a fuel injection type valve. The fuel supply device 12 includes a fuel injection nozzle 13 that injects fuel upstream of the main throttle valve 10 and an injection control device 14 that controls the fuel injection amount.

The injection control device 14 includes an air flow meter 15
The intake air amount signal and rotation sensor 1 detected by
6 receives the engine rotational speed signal detected by 6, calculates the fuel injection amount according to the operating state of the engine 1 based on these signals, and issues a control signal to the fuel injection nozzle 13 to inject a predetermined amount of fuel into the main intake system 2. It is configured to inject.

In the auxiliary intake system 5, 17 is an auxiliary intake valve that opens and closes the auxiliary intake port 6 at a predetermined timing (see FIG. 2) by a timing cam 18, and 19 is a vane-shaped air pump interposed in the middle of the auxiliary intake passage 20. This is a supercharger consisting of:

The supercharger 19 is driven by the engine 1 via an electromagnetic clutch 21. That is, due to the reciprocating movement of the piston 22 in the engine 1, the connecting rod 2
The supercharger 19 is rotationally driven by the driving force of the crankshaft 24, which is rotationally driven through the crankshaft 24, transmitted through the drive device 25. Stopping is controlled.

The electromagnetic clutch 21 is connected or disconnected depending on the load of the engine 1, and is connected, for example, to the main throttle valve 1.
When the load of the engine 1 exceeds a set value, the electromagnetic clutch 21 is connected and the supercharger 19 is It is configured to drive.

Reference numeral 26 denotes an auxiliary throttle valve interposed in the auxiliary intake passage 20 downstream of the supercharger 19. The auxiliary throttle valve 26 is linked to the main throttle valve 10 by a link mechanism or the like, so that the main throttle valve 10 In conjunction with the opening to a predetermined opening degree or more, a linked operation is performed to open from the closed state.

Further, 27 is a relief passage that bypasses the supercharger 19, and 28 is a relief valve provided in the relief passage 27. The opening and closing operation of the relief valve 28 is controlled by a control device 29, and the It is configured such that the supercharging pressure by the supercharger 19 gradually increases during a transient state of the engine 1 moving from a charging region to a supercharging region.

The relief valve 28 is composed of a butterfly-shaped valve that opens and closes the relief passage 27.
A rod 31a of an actuator 31 as an actuating means is connected to the tip of the rotating lever 30.
In this actuator 31, the base end of a rod 31a is supported by a diaphragm 31b, and a spring 31d that biases the relief valve 28 in the opening direction is compressed in a negative pressure chamber 31c at the back of the diaphragm 31b. One end is connected,
The other end of the negative pressure passage 32 opens into the main intake passage 11 downstream of the main throttle valve 10, and intake negative pressure is introduced into the negative pressure chamber 31c as a source for closing the relief valve 28.

Further, a three-way valve 33 is interposed in the negative pressure passage 32. This three-way valve 33 is operated by a signal from an auxiliary throttle valve operation detection device 34 that detects the opening degree of the auxiliary throttle valve 26, and when the auxiliary throttle valve 26 is closed and there is no supercharging, the negative pressure chamber 31c of the actuator 31 is closed. The three-way valve 33 is operated to open the relief valve 28 to open the air to the atmosphere, while the three-way valve 33 is operated to introduce intake negative pressure into the negative pressure chamber 31c of the actuator 31 during supercharging when the auxiliary throttle valve 26 is open. The relief valve 28 is then closed.

Further, a throttle 35 as a delay means is provided downstream of the three-way valve 33 in the negative pressure passage 32, and the intake negative pressure is gradually introduced by delaying the introduction of the intake negative pressure into the negative pressure chamber 31c. It is configured to gradually close the relief valve 28.

On the other hand, in the exhaust system 7, 36 is an exhaust valve that opens and closes the exhaust port 8 at a predetermined timing;
is an exhaust passage communicating with the exhaust port 8.

The relationship between the opening and closing timings of the main intake valve 9 and the auxiliary intake valve 17 is as illustrated in FIG.
7 opens from the end of the intake stroke to the compression stroke,
It closes at a later time than the main intake valve 9,
Pressurized air is supplied from the auxiliary intake system 5 at least during this compression stroke.

Next, to explain the operation of the above embodiment, when the engine 1 is under low load, the supercharger 19 is not driven and fresh air is supplied to the combustion chamber 3 only from the main intake system 2 by natural intake. Ru. At this time, the auxiliary throttle valve 26 closes the auxiliary intake passage 20.

When the load of the engine 1 rises above the set load and the engine enters a transient state in which the main throttle valve 10 is wide open, the electromagnetic clutch 21 is connected and the supercharger 19 is driven. As pressurized air is discharged, the auxiliary throttle valve 26 starts to open in conjunction with the opening operation of the main throttle valve 10, but the relief valve 2
8 is large, pressurized air from the supercharger 19 returns via the relief passage 27, and the supercharging pressure is low.

Subsequently, the detection device 34 detecting the opening operation of the auxiliary throttle valve 26 operates the three-way valve 33 to introduce intake negative pressure into the negative pressure chamber 31c of the actuator 31.
Close the relief valve 28. At this time, the intake load is gradually introduced into the negative pressure chamber 31c by the action of the throttle 35, and as a result, the relief valve 28 gradually closes, the supercharging pressure gradually increases, and the main intake system In addition to the fresh air from 2, supercharging air is gradually supplied from the auxiliary intake system 5.

After the delay effect by the throttle 35 is eliminated, the relief valve 28 remains fully closed, so that the supercharging by the supercharger 19 is directly used for the operation of the engine 1.

In the above embodiment, the relief valve 28 is gradually closed using the throttle 35 as the control device 29 to gradually increase the supercharging pressure in the transient state. A control device that gradually increases the number may be adopted, and the boost pressure is increased continuously or in stages in a transient state.

Further, in the above embodiment, fuel is supplied only to the main intake system 2, but fuel may also be supplied to the auxiliary intake system 5 in addition to the main intake system 2, and furthermore, fuel can be supplied to the auxiliary intake system 5. Instead of the nozzle 13, a fuel supply device using a carburetor may be used.

Further, in addition to reciprocating engines, the above-mentioned intake device can also be applied to, for example, rotary piston engines.

Therefore, according to the present invention, since the closing operation of the relief valve in the relief passage is delayed to suppress a sudden increase in supercharging pressure, engine shock and sudden increase in driving resistance of the supercharger at the start of supercharging can be prevented. Sudden changes in engine operating conditions due to excessive supercharging can be reliably prevented, and there is no need to control the rotational speed of the supercharger itself, making it possible to obtain excellent durability or reliability with a simple configuration. After the non-supercharging region is completely shifted to the supercharging region, the relief passage is closed, so that the required output can be obtained by directly utilizing the supercharging of the supercharger.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall configuration diagram of a supercharged engine, and FIG. 2 is a curve diagram showing valve opening/closing timing. DESCRIPTION OF SYMBOLS 1...Engine, 2...Main intake system, 5...Auxiliary intake system, 11...Main intake passage, 12...Fuel supply device, 19...Supercharger, 29...Control device, 31
...actuator, 35...aperture.

Claims (1)

[Claims] 1. A supercharged engine in which a supercharger driven by the engine is provided in the intake system of the engine, and supercharged air from the supercharger is supplied to the engine at a load equal to or higher than the set load of the engine, A relief passage that bypasses the supercharger, a relief valve interposed in the relief passage, an actuating means that opens the relief valve in a non-supercharging area and closes the relief valve in a supercharging area, and a non-supercharger. An intake system for a supercharged engine, comprising a delay means for delaying the closing operation of a relief valve in a transient state of the engine transitioning from a supercharging region to a supercharging region.