JP2000291454A - Engine brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine brake device which requires no new exhaust valve. SOLUTION: An engine brake device 100 is provided integrally with an injector 5. The engine brake device 100 is provided with a solenoid valve 3 for communicating or shutting off a space 6 surrounded with a head cover 2 and a cylinder head 1 and a combustion chamber 7, and a control unit 4 for electrically conducting the solenoid valve 3, when a piston 8 is positioned near the compression top dead center in order to releaser gas compressed by the piston 8 to the space 6 surrounded with the head cover 2 and the cylinder head 1 and then controlling the solenoid valve 3 so as to shut it off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine brake device for operating an electromagnetic valve near a compression top dead center to increase engine braking force.

[0002]

2. Description of the Related Art Japanese Patent Laying-Open No. 3-189309 discloses an engine brake device which operates an auxiliary exhaust valve near a compression top dead center to increase engine braking force.

[0003]

In recent years, the number of valves for each cylinder has been increasing (multi-valve). As the number of valves for each cylinder increases, the space for mounting an exhaust valve or the like in one cylinder on the cylinder head decreases. For this reason, it becomes difficult to attach a sub exhaust valve to the cylinder head in addition to the exhaust valve and the intake valve.

[0004] In view of the above problems, an object of the present invention is to provide an engine brake device that does not require a new exhaust valve.

[0005]

An engine brake device according to the present invention is an engine brake device provided integrally with an injector, which conducts or shuts off a combustion chamber from a space surrounded by a head cover and a cylinder head. In order to release gas compressed by an electromagnetic valve and a piston into a space surrounded by the head cover and the cylinder head, the position of the piston conducts the electromagnetic valve near a compression top dead center, and then the electromagnetic valve And a control unit that controls so as to shut off the power supply, thereby achieving the above object.

[0006] The control unit may control the electromagnetic valve to conduct when the piston position is near the bottom dead center, and then to shut off the electromagnetic valve.

[0007] The control unit may receive a signal from the injector in order to stop the operation of the electromagnetic valve when returning from fuel cut.

The operation will be described below.

In the electromagnetic valve according to the present invention, the position of the piston is conductive near the compression top dead center. The gas compressed by the piston escapes into a space surrounded by the head cover and the cylinder head, and the compression work performed by the piston is absorbed.
After the solenoid valve conducts, the solenoid valve shuts off and the piston performs expansion work. Pumping loss can be generated for each piston stroke.

When the control section controls the solenoid valve to conduct when the piston position is near the bottom dead center and then to shut off the solenoid valve, the pressure in the combustion chamber becomes close to the atmospheric pressure, and The compression work increases.

When the control section receives a signal from the injector, the operation of the electromagnetic valve can be reliably stopped when the fuel cut is restored.

[0012]

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

An engine brake device according to an embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a diagram showing an engine brake device 100 according to this embodiment.

The engine brake device 100 shown in FIG.
Has an electromagnetic valve 3 provided in a space 6 between the cylinder head 1 and the head cover 2, and a control circuit 4 for controlling the electromagnetic valve 3.

The engine brake device 100 is formed integrally with an injector 5 for injecting fuel. An injector 5 is provided in the cylinder head 1. Since the cylinder head 1 is not provided with an extra valve such as an auxiliary valve, the size of the engine brake device 100 according to the present embodiment can be reduced as compared with a conventional engine brake device.

The electromagnetic valve 3 is provided with a passage 3 a connecting the space 6 between the cylinder head 1 and the head cover 2 and the combustion chamber 7.
Is turned on or off. Since the electromagnetic valve 3 has the passage 3b, the valve can be opened and closed with a small operating force. Since the electromagnetic valve 3 allows the compressed gas to escape to the space 6 covered by the head cover 2, the compressed gas does not escape directly to the atmosphere. For this reason, in this embodiment, even if fuel is mixed with the compressed gas, there is no fear of damaging the environment.

In FIG. 1, for simplicity of explanation,
A passage for the injector 5 to inject fuel is omitted.

FIG. 2 and FIG. 3 show an example of the electromagnetic valve 3. FIG. 2 is a diagram illustrating the electromagnetic valve 3 in a normal state, and FIG. 3 is a diagram illustrating the electromagnetic valve 3 when releasing compressed air to the head cover. As shown in FIGS. 2 and 3, the electromagnetic valve 3 includes a fixed inner valve 11 and a movable outer valve 1.
2, a three-way solenoid valve 13 for driving the outer valve 12, a fixed orifice 14, and a hydraulic piston 15 are provided. Since the electromagnetic valve 3 shown in FIGS. 2 and 3 has the three-way electromagnetic valve 13, even if a high pressure is applied to the electromagnetic valve 3, the valve can be opened and closed with a small operating force.

Hereinafter, the operation of the engine brake device 100 will be described.

When the position of the piston 8 is near the top dead center of the compression, the control circuit 4 controls the electromagnetic valve 3 so that the passage 3a connecting the space 6 and the combustion chamber 7 becomes conductive. The gas compressed by the piston 8 escapes into the space 6, and the compression work performed by the piston 8 is absorbed.

Next, after a predetermined period of time has passed since the electromagnetic valve 3 is turned on, the control circuit 4 controls the electromagnetic valve 3 so that the passage 3a connecting the space 6 and the combustion chamber 7 is shut off. For this reason, the piston 8 performs expansion work until it reaches the bottom dead center.
When the electromagnetic valve 3 is turned on and a predetermined period has elapsed, the piston 8 is located near the top dead center. That is, the electromagnetic valve is turned on before the piston 8 reaches the top dead center or when the piston 8 reaches the top dead center, and the electromagnetic valve is shut off after a predetermined period has elapsed.

As described above, since the electromagnetic valve 3 operates, in this embodiment, a pumping loss can be generated for each piston stroke, and the engine brake is strengthened.

Further, when the position of the piston 8 is near the bottom dead center, the control circuit 4 controls the electromagnetic valve 3 and
a is turned on, and when a predetermined period has elapsed, the control circuit 4
It is preferable to control the electromagnetic valve 3 and shut off the passage 3a. When such control is performed, the pressure in the combustion chamber 7 approaches the atmospheric pressure, and the compression work of the piston 8 increases.

When the control circuit 4 receives a signal indicating the cut or supply of fuel from the injector 5, the operation of the electromagnetic valve 3 can be reliably inhibited when the fuel cut is restored. In the operation prohibited state, the electromagnetic valve 3
Is closed.

FIG. 4 is a diagram showing an operation inhibition flag of the electromagnetic valve 3 when the control circuit 4 receives a fuel cut signal and the engine speed reaches the return speed.

As shown in FIG. 4, when the fuel cut signal changes from the OFF state to the ON state at time t1, the operation inhibition flag of the electromagnetic valve 3 changes from the ON state to the OFF state. For this reason, the electromagnetic valve 3 becomes operable.

At time t2, when the engine speed reaches the return speed, the fuel cut signal changes from the ON state to the OFF state, and the operation inhibition flag of the electromagnetic valve 3 changes from the OFF state to the ON state. For this reason, the electromagnetic valve 3 cannot operate.

Since the engine brake device 100 is formed integrally with the injector 5, noise is less likely to be applied to the signal from the injector 5. As a result, malfunctions are less likely to occur.

The embodiment may have a time lag so that the fuel is actually injected after the operation of the electromagnetic valve 3 is prohibited. Further, embodiments may have a time lag so that the solenoid valve 3 is activated after the fuel has been cut and there is no more fuel to be injected.

[0031]

According to the engine brake device of the present invention, the position of the piston is conducted near the compression top dead center, the electromagnetic valve is conducted, and then the electromagnetic valve is shut off. With the engine brake device of the present invention, a pumping loss can be generated.

The engine brake device of the present invention is provided integrally with the injector, and there is no need to provide an extra valve such as a sub exhaust valve in the cylinder head.
The engine brake device of the present invention can be downsized as compared with a conventional engine brake device.

In the engine brake device according to the present invention, the electromagnetic valve can connect the space surrounded by the head cover and the cylinder head to the combustion chamber. Since the electromagnetic valve can release the compressed gas to the space, the compressed gas does not directly escape to the atmosphere. For this reason,
In the engine brake device of the present invention, even if fuel is mixed with the compressed gas, there is no possibility of damaging the environment.

According to another control unit of the present invention, when the piston is controlled so as to conduct the electromagnetic valve near the bottom dead center and then to shut off the electromagnetic valve, the pressure in the combustion chamber is close to the atmospheric pressure. The compression work of the piston increases.

When another control unit of the present invention receives an injector signal from the injector, the operation of the electromagnetic valve can be reliably stopped at the time of returning from the fuel cut.

[Brief description of the drawings]

FIG. 1 is an engine brake device 10 according to an embodiment.
FIG.

FIG. 2 is a diagram showing the electromagnetic valve 3 in a normal state.

FIG. 3 is a diagram showing the electromagnetic valve 3 in a case where compressed air is released to a head cover.

FIG. 4 is a diagram showing an operation prohibition flag of the electromagnetic valve 3 when the control circuit 4 receives a fuel cut signal and the engine speed reaches the return speed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Head cover 3 Electromagnetic valve 3a Passage 3b passage 4 Control circuit 5 Injector 6 Space 7 Combustion chamber 8 Piston 100 Engine brake device

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) F02M 61/16 F02M 61/16 Z

Claims (3)

[Claims] 1. An engine brake device provided integrally with an injector, comprising: an electromagnetic valve that conducts or shuts off a space surrounded by a head cover and a cylinder head and a combustion chamber; and a gas that is compressed by a piston. To escape to the space surrounded by the head cover and the cylinder head,
A control unit that controls the electromagnetic valve to conduct when the position of the piston is near the compression top dead center, and then to shut off the electromagnetic valve. 2. The engine brake device according to claim 1, wherein the control unit controls the solenoid valve to be conductive when the piston position is near bottom dead center, and thereafter to shut off the solenoid valve. 3. The engine brake device according to claim 1, wherein the control unit receives a signal from the injector to stop the operation of the electromagnetic valve when returning from fuel cut.