JPS58197429A - Adjusting device of supercharge pressure - Google Patents

Abstract

PURPOSE:To prevent an internal-combustion engine from destructive damage or the like, by detecting a speed of the internal-combustion engine, bypassing exhaust gas flowing in an exhaust turbine at more than a permissible speed of the engine and preventively reducing an abnormal increase of thermal and mechanical loads on the internal-combustion engine. CONSTITUTION:When the speed of an internal-combustion engine 1 exceeds its permissible limit, a coil 26 in a solenoid valve 22 is excited by a control unit 28 through a detection signal from an engine speed detecting sensor 27, and a plunger 24 is attracted against resiliently pressing force of a spring 25 to open a valve 23, then exhaust gas flows out to a bypass passage 10. In this way, an amount of exhaust gas flowing in an exhaust passage 8 is decreased, and supercharge action by an exhaust turbine 13 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a boost pressure adjustment device for an internal combustion engine equipped with an exhaust gas-driven supercharger.

A supercharger for an internal combustion engine is a device that can increase the generated torque per unit volume of the cylinder by forcibly introducing the air-fuel mixture into the cylinder and combusting it in an overfilled state. It has the advantage of having a good acceleration feeling, being able to operate at low speeds and having a good overall fuel efficiency, and having the advantage of being able to use a smaller engine to obtain the same output.

However, on the other hand, it also has the disadvantage of reduced durability and reliability due to an increase in thermal and mechanical loads based on s4 compression combustion and an increase in abnormal vibrations due to knocking, especially when exceeding the allowable rotation speed. Operation at high speeds, so-called overrun operation, is the area where these loads reach their maximum values, so
If this was left unaddressed, there was a serious risk of causing major problems such as the destruction of the engine.

In view of these conventional drawbacks, this invention detects engine overrun, bypasses the exhaust gas that drives the exhaust turbine of the supercharger, and stops supercharging intake air to the engine. be.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a supercharging pressure regulating device according to the present invention will be described in detail below with reference to the accompanying drawings.

The drawing shows the general configuration of this example device, and in this drawing, the reference numeral (1) is the internal combustion engine (an intake duct connected to an air cleaner (not shown)), (3) is its intake passage, and (4) is the internal combustion engine. is a throttle valve provided in this passage to adjust the intake violet, (5) is an intake manifold, and (6) is located in this intake manifold to inject fuel at a constant rate to the intake violet. The controlled injector, (7) is an exhaust manifold, (8) is its exhaust passage, and (9) is an exhaust duct that guides exhaust gas to a muffler (not shown) and discharges it into the atmosphere.

(10) is a bypass passage that bypasses the exhaust manifold (7) to the exhaust duct (9); (U)
is driven by an intake turbine (12) that compresses intake air flowing in from the intake duct (2) and discharges it into the intake passage (3), and exhaust gas flowing out from the exhaust passage (8) to the exhaust duct (9). A supercharger consisting of an exhaust turbine (13), and a shaft (14) that connects both turbines, the exhaust passage (8) and the bypass passage (10).
A pulp (16) provided in between, a diaphragm (17) coupled to this pulp (16), a spring (18) that biases the pulp (16) in the valve closing direction, and a diaphragm (
Atmospheric chamber (1T) separated by 1T) and connected to the atmosphere side
9).

and a pressure chamber (20) communicating with the intake passage (3) via a passage (21); (η) a front exhaust manifold (7);
, a pulp (23) provided between the bypass passage (10),
a plunger (24) coupled to this pulp (23);
A spring (25) biases the pulp (23) in the valve closing direction.
), and the pulp (24) is suctioned.
3) a control valve consisting of an SJ magnetic coil 26) which opens the valve; (27) is a rotation speed detection sensor of the internal combustion engine;
28) The control valve (22) is activated by the output signal from the dovetail sensor.
This is a control unit that controls the

In the configuration of the above embodiment, the intake air flowing in from the intake duct (2) passes through the intake turbine (12) and the intake passage (3), is regulated by the throttle valve (4), and is then closed to the intake manifold (5). The mixture is mixed with fuel injected from an injector (6) within the internal combustion engine (1), and is sucked into the internal combustion engine (1) and combusted.
The exhaust gas after combustion is passed through the exhaust manifold (1), the exhaust passage (8), and the exhaust turbine (13).
) and then released into the atmosphere from the exhaust duct (9).

In low-load operation where the opening of the throttle valve (4) is small, the amount of exhaust gas is small and the speed of the exhaust gas passing through the exhaust passage (8) is low, so the exhaust turbine (13) can only rotate at a sluggish rate. Therefore, the intake turbine (12) does not have the ability to compress and supply intake air, and the internal combustion engine (1) continues normal operation. On the other hand, during load operation with the throttle valve (4) open, the exhaust gas turbine (13) is accelerated by the increase in exhaust flow velocity due to the increase in exhaust gas violet, and the intake turbine (12) connected to this exhaust turbine (13) is accelerated. Then, the intake air is forcibly sent to the intake passage (3) to start supercharging, and along with this, the exhaust gas pressure further increases and the exhaust turbine (13) is further accelerated.

The boost pressure rapidly increases due to such a positive feedback loop and reaches a constant value determined by the strength conditions of the internal combustion engine (1), but at this time, the pressure in the intake passage (3) K, M (20 ) and the atmospheric chamber (19), the diaphragm (17) moves against the elastic force of the swivel (18), and the pulp (16) opens to direct the exhaust gas to the bypass passage (10). ), and the driving force of the exhaust turbine (13) is lowered to maintain a constant pressure.This allows the internal combustion engine (1) to generate high torque at the limit boost pressure determined by the strength conditions. will occur.

In this embodiment, when the internal combustion engine (1) exceeds the allowable rotation speed in this state, the control 22 (2B) is activated by the detection signal from the 1 rotation speed detection sensor (21).
The coil (26) of η) is connected to wJ, and the plunger (24
) is sucked against the elastic force of the spring (25) and the valve 7' (23) is opened, thereby allowing the exhaust gas to flow out into the bypass passage (10). ), and the supercharging action by the exhaust turbine (13) is stopped.

In addition, in the above-mentioned embodiment, 1! is used as a 7-piece pulp duct for bypassing exhaust gas to the bypass passage when the engine speed is higher than the permissible rotation speed of the internal combustion engine. Although a magnetic valve is used, a motor, pneumatic pressure, hydraulic cylinder, etc. may also be used for this actuator.

As detailed above, according to the present invention, the rotation speed of the internal combustion engine is detected, and when the rotation speed exceeds the allowable rotation speed, the actuator is operated to bypass the flow of exhaust gas passing through the exhaust turbine of the supercharger. However, since the supercharger is virtually not activated, abnormal increases in thermal and mechanical loads on the internal combustion engine can be reduced in advance, which protects the internal combustion engine from damage. This greatly contributes to improving reliability, especially during rapid starts, where a sudden increase in rotational speed causes a delay in gear shifting, causing the internal combustion engine to reach a chain reaction speed that exceeds the allowable rotational speed. The structure is simple and can be easily implemented.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing an embodiment of the supercharging pressure adjusting device according to the present invention. (1)...Internal combustion engine, (3)...Intake passage, (
4)・511e throttle palf, (5)・・e・inf-kumamani hold, (6)・・・・injector,
(7)...Exhaust manifold, (8)...
...Exhaust passage, (10)...Bypass passage, (11
)...supercharging m, (12)...intake turbine, (
13)...Exhaust turbine, (η)...Solenoid valve (
Acti (28)... Control unit. Agent Shin Tameno

Claims (1)

[Claims] In an internal combustion engine equipped with an exhaust gas-driven supercharger, a rotation speed detection sensor detects the rotation speed of the internal combustion engine, and outputs a drive signal when the detection signal from the sensor exceeds the allowable rotation speed. 1. A supercharging pressure regulating device comprising: a control unit that controls the flow of exhaust gas; and an actuator that bypasses the flow of exhaust gas passing through an exhaust turbine of a supercharger in response to the drive signal.