JPS63243461A - Movable glow plug of diesel engine - Google Patents

Abstract

PURPOSE:To improve the compression ratio in a swirl chamber and to prevent turbulence of the swirl by making a glow plug in such constitution in which a glow is mounted on the head of a glow piston and forming the head part of the glow piston into the same shape as that of the wall in the swirl chamber. CONSTITUTION:A combustion chamber 6 is formed by the top surface of a piston 1, the under surface 3a of a cylinder head 3 and a cylinder block 2 and the combustion chamber 6 is connected to a swirl chamber 4 through a jetting passage 7. And the swirl chamber 4 is provided with a nozzle 8 from which fuel F is injected and a glow plug 9. In this case, the glow plug 9 consists of a glow piston 11 which has a ring 10 around itself and a glow 12 which is mounted on the head of the glow piston 11. The head part 11a of the glow piston 11 is formed into the same shape as that of the wall of the swirl chamber 4 in order to form a part of the smooth wall of the swirl chamber 4 when the glow plug 9 is retracted.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a movable glow plug for a diesel engine, and more particularly to a movable glow plug with improved startability and thermal efficiency.

[Conventional technology]

Conventionally, regarding a movable glow plug, as shown in Japanese Patent Application Laid-Open No. 54-11"3735, a heat plug of the glow plug body is protruded into a vortex chamber to generate heat during cold starting, and during normal operation, the plug is heated. The method is to retreat from the vortex chamber.
In the device disclosed in Japanese Patent No. 7170, the glow plug is automatically pushed out of the swirl chamber after warm-up.

[Problems to be solved by the invention]

However, all of the above-mentioned conventional examples merely make the amount of protrusion of the glow plug variable, and there is a problem in that starting performance cannot be completely improved. The present invention was proposed to solve the above-mentioned problems, and by forming a glow plug at the tip of the glow piston and protruding the glow piston into the vortex chamber at the time of startup, the compression ratio in the vortex chamber is increased. The purpose of the present invention is to provide a glow plug for a diesel engine that directly injects fuel into the glow to ensure reliable ignition to improve startability, and that lowers the compression ratio after warm drilling to generate strong swirl. That is.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a diesel engine in which a glow plug that communicates with a main combustion chamber via a nozzle hole and that can freely move forward and backward in a vortex chamber equipped with an injection nozzle includes: It is composed of a glow piston having a glow piston ring and a glow formed at the tip of the glow piston, and the glow side surface of the glow piston has a shape of the wall surface of the swirl chamber when the glow piston is raised. The vortex chamber is configured to form a part of the wall surface of the vortex chamber in accordance with the above.

[For production]

Based on the above configuration, in the present invention, when a diesel engine is started, when a current flows through the glow, the driving means is turned on, the glow piston is pushed out and enters the vortex chamber, and the glow is heated. Since the portion of the glow piston that protrudes into the vortex chamber has a predetermined volume, the compression ratio increases. When the engine enters the compression stroke, air in the main combustion chamber flows into the swirl chamber through the nozzle holes, creating a swirl. When fuel is injected from an injection nozzle into this vortex, the fuel directly collides with the heated glow, ignites and burns. Then, when the glow is no longer energized, the drive means is turned off and the glow piston is retracted from the swirl chamber. Since the shape of the tip of the GLOBIS 1 hem matches the wall shape of the vortex chamber, the wall surface of the vortex chamber after the glow piston exits has a gentle wall shape, which does not interfere with swirl, and also reduces the compression ratio. can be kept.

【Example】

Embodiments according to the present invention will be described below based on the drawings. In FIG. 1, reference numeral 1 indicates a piston, 2 a cylinder block, 3 a cylinder head, 4 a swirl chamber, and 5 a helad gasket. and the top surface of the piston 1 and the bottom surface 3 of the cylinder head 3.
A and the cylinder block 2 form a main combustion chamber e, and the main combustion chamber N6 and the swirl chamber 4 communicate with each other via a nozzle hole 7. Furthermore, an injection nozzle 8 for injecting fuel F and a glow plug 9 are installed in the swirl chamber 4.
The glow plug 9 is surrounded by a glow piston ring 10.
and a glow piston 11 having a predetermined volume;
A glow 12 attached to the tip of the glow piston 11
The glow 12 provided at the tip of the glow piston 11 includes a drive means (actuator) (not shown) that drives the glow piston 11 to move forward and backward into the vortex chamber 4. When being extruded, it is set so as to be placed on the extension line of the injection direction of the injection nozzle 8. The amount of protrusion of the glow 12 is set to be smaller than that of a conventional fixed glow. Furthermore, since the shape of the tip end 11a of the glow piston 11 matches the shape of the wall surface of the swirl chamber 4, when the glow plug 9 is retracted, a part of the gentle wall surface of the swirl chamber 4 is removed. It is supposed to form. In addition, code 13
is a valve, and 14 is a boat. Since this embodiment has the above-described configuration, when a current is applied to the glow 12 when starting the diesel engine at a low temperature, the actuator (not shown) is turned on, and the glow piston 11 is pushed out into the vortex chamber 4. Enter Glow 1
2 is heated, and the air in the swirl chamber 4 is also warmed. Since the glow piston 11 has a predetermined volume, the vortex i
The effective volume within chamber 4 becomes smaller and the compression ratio increases. In this way, when the temperature of the air in the swirl chamber 4 rises to the extent necessary to ignite the fuel, when the engine is started and enters the compression stroke, the piston 1 rises inside the cylinder block 2 and enters the main combustion chamber. The air in the chamber 6 passes through the nozzle hole 7 and enters the whirlpool chamber 4, creating a whirlpool and creating a high pressure kudzuyu. When fuel F is injected from the injection nozzle 8 into this vortex, the tip of the glow 12 is on the extension line of the injection direction of the injection nozzle 8, so
The injected fuel F directly collides with the glow 12 and ignites. Burn. Then, when the glow 12 is no longer energized, the actuator is turned off and the glow piston 11 is retracted from the swirl chamber 4. Since the shape of the tip 11a of the glow piston 11 matches the wall shape of the vortex chamber 4, the vortex chamber 4 has a gentle wall shape after the glow piston 11 exits, and the swirl generated within the vortex chamber 4 is suppressed. There will be no hindrance. Further, since the amount of protrusion of the glow 12 is smaller than that of the fixed glow, a strong swirl can be generated without disturbing the swirl in the vortex chamber 4.

【Effect of the invention】

As described above, according to the present invention, since the glow piston having a predetermined volume enters the vortex chamber at the time of starting, the effective volume in the vortex chamber becomes small, and therefore the compression ratio can be reduced, which improves starting performance. can be improved. In addition, the shape of the glow piston tip matches the shape of the wall of the vortex chamber, and when the glow plug is retracted, the tip of the glow piston forms part of the wall of the vortex chamber, and the wall of the vortex chamber becomes Since it has a gentle shape, the compression ratio after warm-up can be kept low, and the in-cylinder pressure can be lowered at full load, so the durability of the engine can be improved. Furthermore, since the compression ratio during operation is not increased more than necessary, the pumping loss is reduced and high output is possible. Furthermore, since the vortex chamber after warming up has a gentle wall surface and at the same time the amount of glow protrusion is reduced, the excellent effect of generating a strong swirl without disturbing the swirl in the vortex chamber can be achieved.

[Brief explanation of drawings]

The accompanying drawing is a partially cutaway vertical sectional view showing an embodiment of the present invention. 4... Vortex chamber, 6... Main combustion chamber, 7... Nozzle hole, 8
...Injection nozzle, 9...Glow plug, 11...
Glow piston, 11a... Tip of glow piston, 12... Glow.

Claims (1)

[Scope of Claims] A diesel engine in which a glow plug is provided in a vortex chamber that communicates with the main combustion chamber via an injection hole and is equipped with an injection nozzle and that can move forward and backward, a piston, and a glow formed at the tip of the glow piston, and the glow piston has a glow side surface that matches the wall shape of the vortex chamber when the glow piston is raised. A movable glow plug for a diesel engine, characterized in that it is formed so as to form a part of a wall surface of a swirl chamber.