JPS58122333A - Diesel engine intake throttle device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to an intake throttle device for a diesel engine.

Diesel engines generate large vibrations and noise during no-load operation and when the engine is stopped.1 The applicants installed an intake passage FC @ air throttle valve and used the same throttle valve as an excuse to control intake air during no-load operation. We have proposed an air intake throttling device for a diesel engine that is configured to fully close the O throttle P valve to shut off intake air when the engine is stopped. However, in the intake throttle device with the above configuration, there was room for modification depending on the operating conditions 11 before and after driving the throttle valve to the open position IK. When bringing the valve to the open position, a large negative pressure may be generated in the intake pipe. For this reason, even if the throttle valve is fully opened when accelerating again after deceleration, the intake pipe is filled with fresh air until the intake pipe is filled with air.
It is presumed that if the air density sucked into the cylinder is low, the compression pressure will decrease, leading to a failure in furnace firing. If combustion is not complete, white smoke will be generated from the exhaust pipe. ζ
A negative pressure delay valve is placed at the 9th position, but when driving downhill for a very long time, the engine speed is high even when the engine is running without load, so negative pressure is generated in the intake pipe.

An object of the present invention is to provide an intake throttling device for a diesel engine in which the intake negative pressure does not become larger than a set value even if the intake throttling is performed during no-load operation by improving the intake throttling device configured as described above. shall be.

A detailed explanation will be given below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of a diesel engine O intake throttle device 01 to which the present invention is applied. flows from right to left. The intake pipe IK is provided with a butterfly valve 3 that is rotatable about a valve shaft 4. One end of a lever 5 is connected to the valve shaft 4, and the other end of the lever 5 is connected to a lid 6. This rod 6 is connected to a negative pressure diaphragm device 7. With this negative pressure diaphragm device 7, the butterfly valve 3 is in the fully open position shown in the figure, imaginary line!
It is driven to the open position shown by and the fully closed position shown by virtual III.

The negative pressure diaphragm device γ is a two-stage type consisting of a first diaphragm chamber 8 and a second diaphragm chamber 9. When no negative pressure is applied to both diaphragms 11g and 9, the butterfly valve 3 is in the fully open position, and the butterfly valve 3 is in the fully open position. When negative pressure is applied to the diamond chamber 8KO, the butterfly valve 3 is in the open position.
When negative pressure is applied to both diaphragm chambers 8 and 9, the butterfly valves 3 are each driven to the fully closed position.
Negative pressure is introduced into the diaphragm chamber 8 via a conduit lO (not shown).
From, conduit 12, negative pressure switching valve 13, conduit 14, negative pressure control valve 1Is1 dedicated pipe 16, negative pressure delay valve 17, and conduit 1B
It is done through. Negative pressure is introduced into the second diaphragm 5 chamber 9 from the Okaji negative pressure tank 11 through the conduit 19 and the negative pressure switching valve 2.
0. A conduit 22 is branched from the conduit 21 via the conduit 21, and the conduit 21 is connected to the remaining boat C of the negative pressure control valve 15. A hole 23 is bored in the intake passage 2, and the negative pressure in the intake passage is introduced to the negative pressure control valve 15 via a conduit 24. Negative pressure switching valves 13 and 20 are connected to port A and port C, which is open to the atmosphere, when energized (to be described later), and connected to port 8, which feeds into the negative pressure tank 11, when not energized.

The negative pressure switching valve 13, 20d is electrically connected to the key switch 26 and the relay switch 27, and the negative pressure control valve 15 is a negative pressure switching valve connected to the intake negative pressure in the intake passage 2 and communicating with the second diaphragm chamber 9. 20 is connected to nine parts via a key switch 26 from a battery power supply 25, and therefore,
The negative pressure switching valve 20 is energized when the key switch 26 is on, and is de-energized when the key switch 26 is off. The negative pressure switching valve 13 communicating with the first diaphragm chamber has a power supply 25, a key switch 2
6. It is connected through a series circuit of a relay switch 27, and the relay switch 27 opens IK when the accelerator switch 2B is closed, and closes when the accelerator switch 2B is open. Therefore, the negative pressure switching valve 13 is energized only when the key switch 26 is on and the accelerator switch 28 is off. In the negative pressure control valve 16, when the negative pressure in the intake passage is smaller than a set value, the ports B and B are connected, and when the negative pressure is greater than the set value, ports A and C are connected.

With the above configuration, the intake throttle device for a diesel engine operates as follows.

When the engine is started, the key switch 26 is closed. When the negative pressure switching valve 20 is energized and atmospheric pressure is introduced into the second diaphragm 119 from BO C, when the accelerator pedal is depressed or when the accelerator is moved to the opening side due to an increase in fuel at low temperature, Since the accelerator switch 28 is forced into the open state, the negative pressure switching valve 13 is energized. At this time, if the zero negative pressure in the intake passage 2 is below the set value (in most cases it is below the set value), the port of the negative pressure control valve 15 and bow) B are connected. Atmospheric pressure is introduced from the pressure switching valve lsO boat 13 to the first diaphragm 5lE8. As a result, the butterfly valve 3 is brought to the fully open position shown in the figure.

During no-load operation when the fuel increase at low temperature is released and the accelerator pedal is not depressed, the accelerator switch 28 closes and the relay switch 27 opens, so the negative pressure switching valve 13
Since no current is applied to the diaphragm, the port is connected to BK, and negative pressure is introduced into the first diaphragm chamber. Therefore,
The butterfly valve 3 is brought to the open position indicated by the phantom line l. Therefore, in the engine state, the rotation speed is low because it is in the no-load operating state 11 where intake throttling is performed, and the rotation speed is about lθ~30%.
By throttling the intake air, it is possible to prevent the compression pressure from rising excessively in a diesel engine with a high compression ratio. Therefore, it is possible to suppress vibration and noise during idle operation and no-load operation. In addition, since a negative pressure delay valve 15 is disposed in the middle of the conduit leading to the first diaphragm lI8, when the engine speed is suddenly decelerated from a high speed state, the first butterfly valve 3 is slowly moved from the fully open position to the fully open position. Conversely, they are continuously driven from the fully open position to the fully open position.

However, when the speed is suddenly reduced from high speed to high speed, or when rotating at high speed on a long downward slope with the intake throttle closed, it is assumed that the negative pressure in the intake pipe will increase due to the 1 intake throttle at the cape. Ru. If the negative pressure in the intake pipe becomes too high, it will cause a decrease in output due to poor combustion during re-acceleration and the generation of white smoke.In the illustrated example, when the negative pressure in the intake pipe becomes larger than the set value, Bow) A of the control valve 15 and port C are connected. Port C is connected to the second diaphragm chamber 9 by a conduit 21. During operation, the key switch 26 is naturally closed, so the negative pressure switching valve 20 is energized, and atmospheric air is introduced into the conduit 21 from the port C of the negative pressure switching valve 20.

Therefore, the first diamond! 17 has conduit 22 and conduit 1
Atmospheric air is introduced via 6, negative pressure delay valve 17, and conduit 18. When the atmosphere is introduced into the first diaphragm chamber 8, the butterfly valve 3 is in the fully open position, the intake air is no longer throttled, and the negative pressure in the intake pipe is reduced. During no-load operation, when the intake pipe negative pressure becomes smaller than the set value, the negative pressure control valve 15t! .

B) A is connected to port Bt, so that negative pressure from the negative pressure tank 11 is introduced into the first diamond 7 diaphragm chamber 8, and the butterfly valve 3a is again brought to the open position of the imaginary line l. Therefore, when the engine is running low, the negative pressure control valve 15 is repeatedly turned on and off, and the intake pipe negative pressure is kept at a constant rate near the set value, so that no large negative pressure is applied to the intake pipe.

When the engine is stopped, when the key switch 26 is turned off, fuel injection is stopped and the negative pressure switching valves 13 and 20 are both de-energized, so that port A and port B are turned off.
The negative pressure from the negative pressure tank 11 is introduced into the first diaphragm chamber 8 and the second diaphragm chamber 9. Therefore, the butterfly valve 3 is driven to the fully closed position shown by the imaginary line L. Therefore, the intake passage is completely blocked and fuel and air are not supplied at the same time, causing the engine to generate large vibrations and noise. Stop without any trouble.

As explained above, according to the present invention, it is possible to prevent vibration and noise during no-load operation and when the engine is stopped, and also to prevent the generation of white smoke when transitioning from deceleration to acceleration. .

[Brief explanation of the drawing]

The figure is a schematic configuration diagram showing one embodiment of an intake throttle device for a diesel engine to which the present invention is applied.1.2 Intake passage, 3 Butterfly valve, 7 Negative pressure diamond Device, 8.9...Diaphragm chamber, 11...Negative pressure tank,
13.20... Negative pressure switching valve, 15... Negative pressure control valve, 23-... Intake pipe negative pressure adjustment hole, 26... Key switch, 27... Relay switch,
28... Accelerator switch, Patent applicant: Tosei Jidosha Kogyo Co., Ltd. Patent agent: Akira Aoki, patent attorney: Kazuyuki Tate, patent attorney: Kyosuke Tsuchinakayama, patent attorney: Akira Yamaguchi

Claims (1)

[Claims] An intake throttle valve is installed in the intake passage, and the intake throttle valve is driven by negative pressure. It is equipped with a two-actuator evaporator, a conduit that connects the two actuator evaporators to a negative pressure source, and a control device that controls the operation of the two activator evaporators. A diesel engine that is driven completely open when negative pressure is introduced to the actuator, fully closed when negative pressure is introduced to both actuators, and fully open when negative pressure is not introduced to both actuators. intake throttle J)
III! tc, two passages of the three-passage negative pressure control valve which switches the passage depending on the magnitude of the intake negative pressure O are connected in the middle of the conduit leading to the first actuator, and the isthmic negative pressure control valve O* is connected. The OX passage is connected to a conduit leading back to the second actuator every week, and when the intake negative pressure becomes larger than the set running value, the throttle valve is driven from the fully open position to the fully open position during running. Intake throttle device for diesel engines.