KR100412880B1 - a preventing device for the second explosion in the key-off stage of diesel engine - Google Patents

Abstract

The present invention relates to a secondary explosion prevention device for the key-off of the diesel engine, the electronic control unit 11 receives an off signal from the start switch 12 opens the solenoid valve 10, As a result, the negative pressure of the intake manifold 2 is transmitted to the actuator 9, and the actuator 9 closes the throttle valve 8a of the throttle body 8 provided in the intake manifold 2, thereby closing the key. Immediately after the off-off, the residual air of the intake machine is not allowed to enter the cylinder.

Therefore, the secondary explosion due to residual air compression and fuel injection does not occur after the engine stops, so that the engine shock caused by the secondary explosion and the body vibration problem occurring after the vehicle stop are solved.

Description

{A preventing device for the second explosion in the key-off stage of diesel engine}

The present invention relates to a secondary explosion prevention device for the key-off of the diesel engine that can prevent the vehicle body from vibrating significantly due to the secondary explosion occurs when the key-off (key-off) after stopping the vehicle equipped with the diesel engine will be.

Generally, as shown in FIG. 1, an intake and exhaust manifold of an engine mounted vehicle includes an intake manifold 2 and an exhaust manifold 3 mounted on an engine 1, and the intake manifold 2 and an exhaust manifold. The inlet pipe 4 and the exhaust pipe 5 are connected to the fold 3, respectively, and both the intake pipe 4 and the exhaust pipe 5 are opened to the atmosphere through the turbocharger 6, and the turbocharger 6 ) Between the intake manifold 2 and the intercooler 7. In addition, an air cleaner (not shown) is provided in the portion before the turbocharger 6 of the intake pipe 4.

Therefore, when the outside air flows through the intake pipe 4 and the intake manifold 2, the compressor is charged by the compressor of the turbocharger 6, thereby increasing the combustion chamber charging efficiency and improving the output of the engine. By rotating the turbine of the turbocharger 6 via the exhaust pipe 5, the intake and exhaust machine is circulated in such a manner as to interlock the compressor, and the intercooler 7 passes the turbocharger 6 while the temperature rises. By lowering the temperature of the to increase the density serves to prevent the charging efficiency is lowered.

On the other hand, in a diesel engine, fuel is burned by inhaling only air in the combustion chamber and then spontaneously igniting by injecting fuel into the compressed air which has become hot, and the engine operates normally by circulating a series of combustion processes. .

However, in a vehicle equipped with the diesel engine as described above, when the engine is stopped after the vehicle is stopped (turn the key from the key cylinder to the off position → key off). Outside air remaining in the suction system is sucked and compressed, and fuel is injected into the compressed air by the piston lift, causing an unstable secondary explosion (combustion) phenomenon. In addition to the impact on the vehicle was delivered to the vehicle body of the stationary state, because the phenomenon occurs, causing the discomfort to the occupants.

2A and 2B are graphs showing vibration characteristics of the engine and the vehicle body at the time when the engine is stopped after the vehicle is stopped, respectively. This appears, and can be confirmed that the state is reduced after the vibration does not occur. In this graph, the portion in which the amount of vibration suddenly increases is the portion in which the vibration caused by the second explosion occurs immediately after the key-off.

Therefore, in the related art, the vibration problem caused by the secondary explosion has been tried to be solved by properly tuning the vibration characteristics of the engine mount used when the power train is mounted, but the reduction of the body vibration due to this was limited, and it also caused the secondary explosion itself. It was not a fundamental solution to the problem.

Accordingly, the present invention has been made to solve the above problems, to prevent the engine shock by preventing the secondary explosion in the engine when the key-off, and also to prevent the passengers from feeling uncomfortable by not vibrating the vehicle. It is an object of the present invention to provide a secondary explosion prevention device in the key-off of a diesel engine.

1 is a configuration diagram of the intake and exhaust pipe of a conventional diesel engine,

2a and 2b is a vibration diagram of the engine and the vehicle body showing that the secondary explosion occurred during the key-off in the conventional diesel engine,

3 is a configuration diagram of the intake and exhaust pipe of the diesel engine to which the secondary explosion prevention apparatus according to the present invention is applied;

4 is a sectional view showing main components of the present invention, in which the throttle body and the actuator are installed in cross-sectional view;

5A and 5B are diagrams corresponding to FIGS. 2A and 2B, wherein the engine and vehicle body vibrations show that secondary explosion did not occur during key-off in the diesel engine to which the secondary explosion prevention apparatus according to the present invention is applied. Is leading.

* Description of the symbols for the main parts of the drawings *

1: engine, 2: intake manifold,

3: exhaust manifold, 4: intake pipe,

5: exhaust pipe, 6: turbocharger,

7: intercooler, 8: throttle body,

8a: Throttle Valve, 9: Actuator,

9a: housing, 9b: spring,

9c: diaphragm, 9d: rod,

9e: lever, 10: solenoid valve,

11: Electronic control unit, 12: Start switch.

The present invention for achieving the above object, a throttle body having a throttle valve inside and mounted to an intake manifold, an actuator for operating the throttle valve of the throttle body, and for transmitting a working pressure to the actuator And a solenoid valve and an electronic control unit which receives the off signal of the start switch and controls the operation of the solenoid valve.

Accordingly, when the key is turned off, the actuator is operated by the intake negative pressure to close the throttle valve momentarily, so that no outside air flows into the combustion chamber, thereby preventing the secondary explosion.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

3 is a configuration diagram of an intake and exhaust pipe of a diesel engine to which a secondary explosion prevention apparatus according to the present invention is applied. The present invention is provided with an intake manifold 2 and an exhaust manifold 3 mounted on an engine 1. An intake pipe 4 and an exhaust pipe 5 are respectively connected to the manifold 2 and the exhaust manifold 3, and both of the intake pipe 4 and the exhaust pipe 5 are introduced into the atmosphere through the turbocharger 6. In the intake and exhaust pipe of a diesel engine having an opening, and having an intercooler 7 in the intake pipe 4 between the turbocharger 6 and the intake manifold 2, the intake manifold 2 is provided. A throttle body (8) having a throttle valve is installed, and an actuator (9) for operating the throttle valve of the throttle body (8) is provided, and a solenoid valve for supplying or interrupting the operating pressure of the actuator ( 10) is installed, the electromagnetic air unit 11 for controlling the opening or closing action of the solenoid valve (10) Is provided, and the start switch 12 is connected to the electronic control unit 11 is made of a structure.

Here, the throttle body 8 is installed in the intake manifold 2 as in the gasoline engine, and is provided with a throttle valve 8a as shown in FIG. 4.

The throttle valve (8a) is operated by the actuator (9), the actuator (9) is provided with a diaphragm (9c) carried by a spring (9b) inside the housing (9a), this diaphragm ( A rod 9d having one end connected to the center of 9c extends to the outside of the housing 9a, and the other end of the rod 9d is inserted into the throttle body 8 to the throttle valve 8a. One end is hinged to the other end of the fixed lever (9e), the lower space of the diaphragm (9c) of the housing (9a) is made of a structure that is connected to the solenoid valve 10 via a pipe.

The operation of the present invention will be described below.

When the vehicle is stopped and the driver turns the key from the key cylinder to the off position, the start is turned off. At this time, the connection state of the start switch 12 is disconnected and the signal is transmitted to the electronic control unit 11.

The electronic control unit 11 that recognizes the off state of the start switch 12 sends an operation signal to the solenoid valve 10 to open the solenoid valve 10.

When the solenoid valve 10 is opened, the negative pressure of the intake manifold 2 is transmitted to the actuator 9, and the throttle valve 8a is closed by pulling the rod 9d.

That is, when the negative pressure of the intake manifold 2 is transmitted to the lower space of the housing 9a of the actuator 9, the center portion of the diaphragm 9c is lowered while compressing the spring 9b, thereby holding the rod 9d. By pulling and rotating the lever 9e clockwise, the throttle valve 8a is rotated in the same direction to block the air passage of the throttle body 8.

In this way, the throttle valve 8a is blocked by the driver's key-off operation to prevent the inflow of outside air so that the residual air of the intake manifold 2 does not flow into the cylinder, thereby raising the piston by engine inertia. Even if the fuel is injected, the secondary explosion does not occur even though sufficient heat of compression is not generated.

Therefore, the engine shock caused by the second explosion after the engine stops disappears, and vibration does not occur in the vehicle body. Thus, the phenomenon in which the occupants feel uncomfortable by the vibration of the vehicle body immediately after the vehicle stops is eliminated.

Meanwhile, the electronic control unit 11 is configured to close the solenoid valve 10 again when the set solenoid valve 10 opening time elapses.

That is, after the set solenoid valve opening time (approximately 2 to 3 seconds is sufficient), the solenoid valve 10 is closed by the signal of the electromagnetic air unit 11, and the negative pressure transfer of the intake manifold 2 is interrupted. Thus, the diaphragm 9c is returned to its original position by the restoring force of the spring 9b, and the rod 9d is re-raised so that the throttle body 8 is closed while the throttle valve 8a is closed as the lever 9e rotates counterclockwise. The air passage of the) is reopened so that subsequent vehicle starting does not interfere.

That is, the throttle valve 8a of the present invention operates only for a predetermined time after the engine stops to prevent the inflow of external air into the engine immediately after the engine stops, and in other states, the engine operates normally. It is not to affect.

5A and 5B, when the vibration characteristics of the diesel engine to which the secondary explosion preventing device according to the present invention is applied are examined for the key-off vibration, both the engine and the vehicle body maintain a constant vibration according to the idle operation of the engine after the vehicle is stopped. It can be seen that it decreases and reaches a vibration free state.

That is, as shown in the conventional case of FIGS. 2A and 2B described above, the sudden vibration does not appear immediately after the key-off, indicating that the secondary explosion did not occur.

As described above, according to the present invention, since the residual air of the intake machine cannot be introduced into the cylinder immediately after the key-off after the vehicle is stopped, the possibility of the secondary explosion is eliminated. Therefore, the engine shock due to the secondary explosion does not occur, the shock vibration caused by the secondary explosion during the key-off is transmitted to the vehicle body has the effect that the phenomenon that the passengers feel uncomfortable is eliminated.

Claims (3)

The electronic control unit 11 receives the key-off signal of the start switch 12 to operate the solenoid valve 10, and receives the operation signal from the electronic control unit 11 to open the intake manifold 2. The throttle valve 8a is rotated by pulling the rod 9d by the negative pressure of the solenoid valve 10 for transmitting the negative pressure to the actuator 9 and the negative pressure of the intake manifold 2 transmitted through the solenoid valve 10. The actuator 9 which blocks the air passage of the throttle body 8 and the throttle body 8 installed to be rotatable inside the throttle body 8 are mounted to the intake manifold 2. Secondary explosion prevention device in the key-off of the diesel engine comprising a. 2. The actuator (9) according to claim 1, wherein the actuator (9) is provided with a diaphragm (9c) carried by a spring (9b) inside the housing (9a), and a rod (9d) having one end connected to the center of the diaphragm (9c). Extends to the outside of the housing 9a, and the other end of the rod 9d is inserted into the throttle body 8 and hinged to the other end of the lever 9e having one end fixed to the throttle valve 8a. The lower space of the diaphragm (9c) of the housing (9a) is connected to the solenoid valve (10) via a pipe structure, characterized in that the secondary explosion prevention device when the key-off of the diesel engine. The throttle valve (8a) according to claim 1, wherein the electronic control unit (11) opens the solenoid valve (10) and then closes the solenoid valve (10) again after the set time has elapsed. Secondary explosion protection device when the diesel engine is off.