JPH0144748Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a turbocharger for an internal combustion engine.
More specifically, the present invention relates to a failure detection device for wastegate valve devices of two mutually independent turbochargers (twin turbochargers).

[Prior art]

In a V-type engine, it is reasonable to provide one turbocharger for each cylinder group.
Also, in inline engines, in order to downsize the turbocharger and improve its response,
Preferably, the cylinders are divided into two groups, for example, and one turbocharger is provided for each cylinder group. Two turbochargers installed in one engine in this way are nicknamed twin turbochargers.

An example of a conventional twin-turbocharged engine is described in, for example, Japanese Utility Model Application No. 58-81324. Each turbocharger is provided with a wastegate valve device that bypasses a portion of the exhaust gas so that the boost pressure does not exceed a set value. This wastegate valve device includes an exhaust bypass that bypasses the exhaust turbine, a wastegate valve that controls the exhaust bypass, and an actuator that opens the wastegate valve in accordance with boost pressure.

[Problem that the invention attempts to solve]

In a turbocharged engine, if the wastegate valve device malfunctions or malfunctions, the rotational speed and supercharging pressure of the turbocharger will become abnormally high, which is undesirable. Therefore, it is necessary to detect abnormalities in the wastegate valve device at an early stage. In engines with twin turbochargers, conventional fault detection devices for wastegate valve systems route the boost pressures of both turbochargers to one pressure detector through a common signal path, and detect when the signal pressure exceeds a set value. It is designed to display an abnormality when Therefore, if only one wastegate valve device fails, the signal pressure does not rise sufficiently and cannot be distinguished from normal boost pressure, making it impossible to detect an abnormality and causing a delay in discovering the failure. It was hot.

[Purpose of invention]

An object of the present invention is to provide a wastegate valve device failure detection device that can quickly and accurately detect failures in each wastegate valve device in a twin-turbocharged engine.

[Means of solution and action]

The present invention provides a pressure system that operates in a twin turbocharged engine in response to the differential pressure between the incoming exhaust gas pressure to the exhaust turbine of one turbocharger and the incoming exhaust gas pressure to the exhaust turbine of the other turbocharger. The present invention is characterized in that a switch is provided, and a fault display device is operated in response to the operation of this pressure switch.

Since this pressure switch responds to the differential pressure,
If one of the wastegate valve devices fails and a pressure difference occurs, it will immediately operate. Therefore,
Abnormalities in the wastegate valve device can be detected reliably and early.

〔Example〕

An embodiment will be described with reference to the drawings. Although a V-type engine 10 is shown in the drawings, the present invention can also be applied to a row-type engine. The engine 10 has two left and right
The exhaust manifold 16L, which has cylinder rows 12R and 12L of the same group and is installed in the cylinder head 14L of the first cylinder row 12L on the left side, is connected to the turbine inlet of the turbine housing 22L of the first turbocharger 20L by an exhaust gas conduit 18L. . The suction side of the compressor housing 24L of the first turbocharger 20L is connected to an air cleaner 30, and the discharge side is connected to an intake manifold 32L via a throttle body 26 and a surge tank 28. The second cylinder row 12R on the right side also has a similar configuration, and in the drawing, each turbine housing 22L, 2
The exhaust side of 2R is joined by a pipe line 34 and further connected to a muffler 38 by an exhaust pipe 36.
1st and 2nd turbocharger 20L, 20R
operate independently of each other.

Each turbocharger 20L, 20R has an exhaust bypass 40L, 40R that bypasses the exhaust turbine.
are provided, and the respective exhaust bypasses are controlled by wastegate valves 42L and 42R. Each wastegate valve is connected to output rods 48L, 48R of diaphragm actuators 46L, 46R by links 44L, 44R, and the pressure acting on pressure chambers 52L, 52R defined by diaphragms 50L, 50R is a set value. When the exhaust gas exceeds the exhaust gas, the valve is opened so that the exhaust gas flow bypasses the exhaust turbine and is discharged to the exhaust bypasses 40L and 40R. Actuator 46L, 46R
The pressure chambers 52L and 52R are signal pipes 54L and 54R.
The compressor housings 24L and 24R are connected to the compressor housings 24L and 24R, so that the discharge pressure (supercharging pressure) of the compressor is reflected in the pressure chambers 52L and 52R. The above configuration is substantially the same as the conventional configuration.

The wastegate valve failure detection device of the present invention includes a differential pressure responsive pressure switch 56. The housing 58 of the pressure switch 56 is partitioned into a first pressure chamber 62L and a second pressure chamber 62R by a diaphragm 60, which is normally held in a neutral position by opposing springs 64L and 64R. . Each pressure chamber 62L, 62R is connected to exhaust gas conduit 18L, 1 by signal pipe 66L, 66R.
8R, and the exhaust gas pressure (back pressure) entering each exhaust turbine is transferred to each pressure chamber 62.
It is designed to be able to be introduced into L and 62R. The diaphragm of the pressure switch 56 has an output rod 68.
L and 68R are fixed, and movable contacts 70L and 70R are attached to their free ends. Each movable contact cooperates with fixed contacts 72L and 72R to form a normally open switch. Each switch is connected in series with a fault indicator, such as a warning lamp 74L, 74R, respectively, to a battery 76, forming first and second warning circuits 78L, 78R. The signal of the alarm circuit can be input to the control device 80.

Next, to explain the operation of this failure detection device,
If a failure occurs in any of the wastegate valve devices due to damage or falling off of the signal tube 54, damage to the diaphragm 50, sticking of the link 44, disconnection of the link 44 and output rod 48, etc.,
Since either waste gate valve 42L or 42R does not open even if the supercharging pressure exceeds the set value, the incoming exhaust gas pressure at the turbine inlet of the first turbocharger 22L and the second turbocharger 2
A pressure difference occurs between the incoming exhaust gas pressure at the turbine inlet of 2R. This differential pressure is the signal pipe 66L,
66R, the pressure chamber 62L of the pressure switch 56,
62R, the diaphragm 60 moves in either the left or right direction against the action of either one of the springs 64L or 64R, and brings one of the movable contacts 70L or 70R into contact with the fixed contact.
Therefore, if the wastegate valve device of the first turbocharger 20L fails, the first alarm circuit 78L is formed and the first alarm lamp 74L lights up to indicate the failure, and the second turbocharger 20R
In this case, the second alarm lamp 74R lights up. Further, the signal from the pressure switch 56 is transmitted to the control device 80.
The control device 80 stops the fuel supply device 82 consisting of an injector or a carburetor to cut off the fuel. Since the engine stops due to fuel cut and a warning lamp lights up, the driver can be informed of an abnormality in the wastegate valve device. Therefore, the fuel cut device can also be used as a fault indicator.

[Effect of idea]

As is clear from the above, the failure detection device of the wastegate valve device of the present invention detects the differential pressure between the incoming exhaust gas pressure of one exhaust turbine of the twin turbocharger and the incoming exhaust gas pressure of the other exhaust turbine. Since it uses a pressure switch that responds to
Failure of only one wastegate valve device can be detected quickly and reliably.

[Brief explanation of the drawing]

The accompanying drawing is a schematic partially cutaway front view of a twin-turbocharged engine equipped with a failure detection device for a wastegate valve device according to the present invention. 10...Engine, 12...Cylinder row, 16...
Exhaust manifold, 18...Exhaust gas pipe, 20
L...first turbocharger, 20R...second turbocharger, 22...turbine housing,
32... Intake manifold, 40... Exhaust bypass, 42... Waste gate valve, 46... Waste gate valve actuator, 56... Differential pressure responsive pressure switch, 74... Warning lamp.

Claims (1)

[Scope of Claim for Utility Model Registration] The cylinders of a multi-cylinder internal combustion engine are divided into at least two cylinder groups, each cylinder group is provided with an independent turbocharger, and each turbocharger is provided with:
an exhaust bypass that bypasses the exhaust turbine; a wastegate valve that controls opening and closing of the exhaust bypass;
In a multi-cylinder internal combustion engine with a twin turbocharger equipped with a wastegate valve device including an actuator that opens the wastegate valve in accordance with boost pressure, the exhaust gas inflows to the exhaust turbine of one turbocharger. A pressure switch is provided that operates in response to a differential pressure between the gas pressure and the incoming exhaust gas pressure to the exhaust turbine of the other turbocharger, and operates a wastegate valve system failure indicating device in response to the operation of the pressure switch. It is characterized by
Failure detection device for wastegate valve device of twin turbo charger.