JPS626255Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas compression release type engine braking device for an engine equipped with an exhaust gas turbine supercharger.

Change the engine to an air compressor, open the exhaust valve near the top of the engine's compression stroke,
2. Description of the Related Art Gas compression release type engine braking devices are known that increase engine braking force by discharging compressed air through an exhaust system. In addition, in an engine equipped with an exhaust gas turbine supercharger, a waste gate is provided in the bypass passage that bypasses the turbine in the exhaust passage, and the exhaust gas is bypassed during high engine loads, so that the supercharging pressure is reduced by the straight line A shown in Figure 1.
An exhaust gas turbine supercharger with a waste gate is also well known in which an abnormal rise as shown in curve B is suppressed.

By the way, when a gas compression release type engine brake is used for an engine equipped with an exhaust gas turbine with a wastegate, the intake air amount is limited by the action of the wastegate, and the braking force is reduced compared to that of the engine without a wastegate as shown in Figure 2. For the straight line A in the case,
There is a problem of a decrease as shown by curve B.

This invention was developed to solve the above-mentioned problems, and the wastegate is opened during overpowering and closed during braking, so that both exhaust gas turbine supercharging and engine braking are effectively utilized. The purpose is to provide brake equipment.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 3, the exhaust passage 2 of the exhaust turbine supercharger 1 is provided with a bypass passage 4 that bypasses the turbine 3. It is adapted to be opened and closed by the end of the actuating rod 8 of the device 7.

The diaphragm device 7 is defined by the diaphragm 6 into a chamber B on the side of the actuating rod 8 and a chamber A on the opposite side, and a spring 9 interposed in the chamber B balances the boost pressure released later, 6 maintains the wastegate in the position where the operating rod 8 opens the wastegate.

The A chamber of the diaphragm device 7 is communicated with a three-way solenoid valve 12 through a passage 10 and the B chamber is communicated with a three-way solenoid valve 12 through a passage 11, while the B chamber can be opened to the outside air through a solenoid valve 13.

This three-way solenoid valve 12 communicates via a boost passage 17 in the middle of an air supply passage 16 that communicates the compressor 14 of the exhaust gas turbine supercharger 1 with the air intake valve 15 of the engine, and normally operates as indicated by the solid line arrow. The boost pressure is guided to the A chamber of the diaphragm device 7, but during braking, the switch is made so that the boost pressure is guided to both the A chamber and the B chamber as indicated by the chain arrow.

Switching of the three-way solenoid valve 12 and valve 13
The opening/closing is performed by means (not shown) that responds to the braking of the vehicle.

Next, the effect will be explained.

When the vehicle is running and the engine is producing power, the three-way solenoid valve 12 guides boost pressure to the A chamber of the diaphragm device 7 through the passage 10, while the solenoid valve 13 opens to expose the B chamber to the atmosphere. Therefore, the boost pressure and the biasing force of the spring 9 are balanced,
The actuating rod 8 is kept in the position where the wastegate 5 is opened by the diaphragm 6. As a result, even when the engine is under high load, the boost pressure is suppressed from becoming excessive as shown in curve B shown in FIG.

On the other hand, when the vehicle is braked, the solenoid valve 13 is closed by means not shown in response to this, and the three-way solenoid valve 12 is switched to guide boost pressure to both chambers A and B of the diaphragm device 7. .

As a result, the pressures in chambers A and B become equal to the boost pressure, and the balance between the boost pressure in the spring 9 and the chamber A is lost, and the actuating rod 8 is urged by the spring 9 to move to the right through the diaphragm. 6 is displaced to the right and its end closes the wastegate 5.

As a result, the braking force of the engine brake is
It is increased from curve B to straight line A shown in the figure.

As explained above, according to the present invention, the solenoid valve that guides boost pressure to the diaphragm device that opens and closes the wastegate is switched during braking, so that the wastegate opens during output and closes during braking. This has the effect of making it possible to utilize both exhaust gas turbine supercharging performance and engine braking performance.

[Brief explanation of the drawing]

Figure 1 is a graph of the relationship between engine speed and supercharging pressure, which explains the difference between the presence and absence of a wastegate, and Figure 2 is a graph showing the relationship between engine speed and braking force for a gas compression release type engine brake, which explains the difference between the presence and absence of a wastegate. FIG. 3 is an explanatory diagram showing an embodiment of the present invention. 1...Exhaust gas turbine supercharger, 2...Exhaust passage, 3...Turbine, 4...Bypass passage, 5...
...Wastegate, 7...Diaphragm device, 8
... Operating rod, 9 ... Spring, 12 ... Three-way solenoid valve, 13 ... Solenoid valve, 16 ... Air supply passage, 17
...boost passage.

Claims (1)

[Scope of utility model registration request] In a gas compression release type engine braking device equipped with a wastegate for an engine equipped with an exhaust gas turbine supercharger, a diaphragm device for opening and closing the wastegate is provided, and two chambers formed by sandwiching the diaphragm of the diaphragm device are provided. An engine braking device comprising a switching valve that selectively guides boost pressure, the switching valve being configured to switch the boost pressure of a diaphragm device and close a wastegate when braking a vehicle.