JPS61126325A - Multi-cylinder type internal combustion engine provided supercharger - Google Patents

Abstract

PURPOSE:To aim at enhancing the output responsive characteristic of an engine, by providing a throttle valve in a branch pipe so that intake air which has been adjusted by the operation of the throttle valve is directly introduced into a cylinder. CONSTITUTION:Upon low load operation of an engine 1, an electromagnetic clutch 8 is disengaged so that a supercharger 7 will not be driven. Upon high load operation of the engine 1 the electromagnetic clutch 13 is engaged to drive the supercharger 7 so that intake-air is supercharged. The thus supercharged air is introduced into a throttle valve 6 through a surge tank 3 and is then introduced into an engine cylinder 1a so that there is offered substantially no delay.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a multi-cylinder internal combustion engine equipped with a supercharger, and particularly relates to a multi-cylinder internal combustion engine suitable for use with an engine-driven supercharger. be.

[Prior art]

In a multi-cylinder internal combustion engine, a large-capacity surge tank is provided between the throttle valve and the manifold in order to uniformly distribute the intake air adjusted by the throttle valve to a plurality of cylinders.

However, such a multi-cylinder internal combustion engine
When equipped with a supercharger as disclosed in Publication No. 167817, the intake air supercharged by the supercharger enters a large-capacity surge tank, and then passes through each branch pipe of the manifold to each cylinder. As a result, the time it takes for the intake air regulated by the throttle valve to reach the cylinder is delayed compared to a single-cylinder internal combustion engine. Therefore, in a multi-cylinder internal combustion engine equipped with a supercharger, there is a problem in that the response characteristics to the engine output deteriorate.

[Purpose of the invention]

An object of the present invention is to provide a multi-cylinder internal combustion engine with a supercharger that can improve output response characteristics to throttle valve operation.

[Structure of the invention]

The present invention achieves the above object in a multi-cylinder internal combustion engine in which a manifold pipe is provided downstream of an intake passage provided with a supercharger via a surge tank, and a cylinder is connected to each branch pipe of the manifold pipe. The present invention is characterized in that a throttle valve for adjusting the amount of intake air is provided in each of the branch pipes.

〔Example〕

Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

In the figure, l is a multi-cylinder engine having a plurality of cylinders 1a. Each branch pipe 2 of a manifold pipe is connected to each of the plurality of cylinders 1a, and the plurality of branch pipes 2 are connected to an intake passage 4 via a surge tank 3 having a large capacity. Each branch pipe 2 on the downstream side of the surge tank 3 is provided with a fuel injection nozzle 5 and a throttle valve 6 for adjusting the amount of intake air.

The intake passage 4 is provided with a supercharger 7, which is a positive displacement pump and includes a pair of rotors 7a, 7a. This supercharger No. 7 is connected to the crankshaft 10 of the engine 1 via an electromagnetic clutch 8 and a belt 9, and is driven to rotate by the power of the crankshaft 10.

Further, the intake passage 4 is provided with a bypass 11 that bypasses the supercharger 7, and this bypass 11 includes a main passage 11.
a and the sub passage 11b are formed parallel to each other. The main passage 11a is provided with a normally closed throttle valve 12, and the sub passage 11b is provided with an electromagnetic valve 13 that is alternately switched between fully open and fully closed.

The throttle valve 12 is connected to a drive section 15 via a loft 14. This drive unit 15 connects the lower end of the loft 14 to an internal diaphragm 16, and the loft 14
The throttle valve 12 is kept in a normally closed state by being pulled by the elastic force of the compression spring 17. The diaphragm chamber 18 in the drive unit 15 communicates with the downstream side of the bypass 11 via a connecting pipe 19, and when the supercharging pressure of the supercharger 7 becomes too high, the supercharging pressure is transferred to the diaphragm 1.
6, the loft 14 is pushed back against the elastic force of the compression spring 17, and the throttle valve 12 is opened.

That is, the throttle valve 12 acts as a relief valve.
(This is to prevent damage to the engine 1 due to excessive boost pressure.

On the other hand, the electromagnetic valve 13 provided in the auxiliary passage 11b and the electromagnetic clutch 8 provided in the supercharger 7 are simultaneously operated by a switch 21 that is activated according to the load of the engine 1. The drive unit 20 of the switch 21 is composed of a diaphragm 22 made of an elastic material and a diaphragm chamber 23, and the diaphragm 22 is connected to a piston 21a to which a contact of the switch 21 is attached. Further, the diaphragm chamber 23 communicates with the downstream side of the throttle valve 6 via a connecting pipe 24 . This connecting pipe 24 includes an intake balance pipe 25 which communicates the branch pipes 2 connected to each cylinder 1a with each other.
It communicates with the downstream side of the throttle valve 6 via.

When the engine 1 is operating at a low load, the diaphragm 22 of the drive unit 20 configured in this way is sucked by the high negative intake pressure downstream of the throttle valve 6, so that the piston 21
Pull a to turn off the switch 21. On the other hand, when the load on the engine 1 exceeds a predetermined value and the negative pressure of the intake pressure becomes small, the diaphragm 22 pushes back the piston 21a by its own elastic force and turns on the switch 21.

As described above, when the switch 21 is off, the electromagnetic clutch 8 is disconnected, the power of the crankshaft 10 is not transmitted to the supercharger 7, and the electromagnetic valve 13 is fully open.

On the other hand, when the switch 21 is turned on, the electromagnetic clutch 8 is connected and the power from the crankshaft 10 is transferred to the supercharger 7.
, and the solenoid valve 13 is switched to fully closed.

Now, according to the multi-cylinder internal combustion engine described above, when the engine 1 is operated in a high load range, the electromagnetic clutch 13 is connected, so the supercharger 7 is driven to supercharge the intake air. This supercharged intake air passes through the surge tank 3 and reaches the throttle valve 6 of the branch pipe 2, and in this state, the intake air regulated by the throttle valve 6 is sucked into each cylinder 1a, so there is almost no time delay. That is, there is no time lag like in conventional systems where the intake is adjusted by a throttle valve, passed through a surge tank, and then entered into a cylinder, and it is possible to generate response characteristics as high as a single cylinder internal combustion engine.

In addition, in the above-mentioned embodiment, the case where the supercharger 8317 is an engine-driven type driven by engine output has been described, but the present invention is a multi-engine supercharger equipped with an exhaust turbo-type supercharger that is driven using exhaust gas. It is also applicable to cylinder internal combustion engines.

(Effects of the Invention) As described above, the present invention provides a manifold pipe downstream of an intake passage in which a supercharger is provided via a surge tank, and a multiplicity pipe in which a cylinder is connected to each branch pipe of the manifold pipe. In a cylinder internal combustion engine, a throttle valve for adjusting the amount of intake air is provided in each of the branch pipes, so that the intake air adjusted by the throttle valve operation can be immediately drawn into the cylinder, which is different from the conventional multi-cylinder internal combustion engine. In comparison, the output response characteristics can be improved.

[Brief explanation of drawings]

FIG. 1 is a plan view schematically showing a multi-cylinder internal combustion engine according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view schematically showing the same internal combustion engine. 1...Engine, la...Cylinder, 2
... (manifold) branch pipe, 3... surge tank,
4... Intake passage, 5... Fuel injection nozzle,
6... Throttle valve, 7... Supercharger.

Claims (1)

[Claims] In a multi-cylinder internal combustion engine in which a manifold pipe is provided downstream of an intake passage provided with a supercharger via a surge tank, and a cylinder is connected to each branch pipe of this manifold, a throttle valve that adjusts the amount of intake air is installed. A multi-cylinder internal combustion engine with a supercharger, characterized in that each of the branch pipes is provided with a supercharger.