JPS603309Y2 - Diesel engine with subchamber - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a diesel engine with a sub-chamber in which a sub-chamber is formed by inserting a mouthpiece into a recess provided inward from the lower surface of the cylinder head.

Conventionally, this type of diesel engine with a pre-chamber is equipped with a glow plug to facilitate starting in cold weather, but because a part of the heater of this glow plug is placed protruding into the pre-chamber, Although it has the effect of accelerating starting, it has the disadvantage of inhibiting the vortex flow in the pre-chamber and the propagation of flame at times other than during a cold start.

For example, Japanese Utility Model Publication No. 50-7382-W attempts to eliminate the drawbacks of glow plugs.

The bulletin states that the glow plug is abolished and a heating wire is attached to the auxiliary combustion chamber mouthpiece or a part of the side wall member close to the mouthpiece in order to obtain the same starting promotion effect as the glow plug. It is shown.

However, with this method, since the cap is made of metal, it is difficult to insulate the heating wire sufficiently, and if the insulation is sufficient, there are problems such as poor heat conduction from the heating wire to the cap or side wall member. However, since the cap or side wall member is attached in contact with the cylinder head in the vicinity, there are problems such as the inability to ignite the spray even if a large amount of energy is input to the heating wire.

The present invention eliminates the cause of vortex flow inhibition in the pre-chamber by eliminating the glow plug, and is equipped with a heater that can sufficiently exhibit the starting promotion effect in place of the glow plug, and does not have the drawbacks of the preceding publication. To provide a diesel engine with a pre-chamber with a relatively simple structure and at low cost.

The present invention provides a diesel engine with a sub-chamber in which a sub-chamber is formed by inserting a mouthpiece into a recess provided inward from the lower surface of the cylinder head. A heater having a heating element embedded in the part thereof is disposed above the cap so that its inner peripheral surface is concave with respect to the inner wall surface of the auxiliary chamber, and the heater has a heating element embedded in the part thereof that contacts the cap and the cylinder head. A heat insulating gasket is inserted.

It is generally known that in a sub-combustion chamber type engine, the mouthpiece and its nozzle through which combustion gas passes are at the highest temperature.

However, if this mouthpiece is attached closely to the cylinder head as in the previous example, the temperature of the mouthpiece will rise only to about 350-450°C due to heat conduction, and the fuel injected from the injection nozzle will not reach the same position. It has also been confirmed that air and fuel do not mix quickly without vaporization.

Therefore, in the present application, as in the above structure, a heater made of a ceramic material with a heat insulating packing inserted and a heating element buried close to the inner peripheral surface is disposed above the cap, and this is used as an ignition source. By doing so, it is an attempt to obtain a diesel engine with a pre-chamber which eliminates the drawbacks of the preceding publications.

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

1 is made of a refractory material such as ceramic that has high insulation and heat insulation properties, and the portion close to the inner circumferential surface, for example,
．． It is a ring-shaped heater in which the heating element material 1a is embedded by printing etc. in the part of 2 to 0.6 rra, and the material is ceramic, so it is suitable for use in harsh atmospheres such as the above-mentioned repeated oxidation-reduction at high temperatures. In addition to being durable, since the heating element material is provided as close as possible to the inner circumferential surface with which the fuel spray comes into contact, the fuel spray quickly vaporizes and burns.

2.2a is an electrode rod for energizing the heating element material,
One end is integrally attached to the heater 1, and the other end projects outward from the cylinder head 3 and is connected to a terminal 4a of a conductive wire 4 led from a power source and a preheating circuit (not shown). Further, a screw 5 is cut at the tip thereof, and a cap nut 6 can be screwed thereto.

On the other hand, the cylinder head 3 is provided with a recess 8a into which the mouthpiece 7 is inserted from the lower surface to form a sub-chamber 8, and an injection nozzle 9 is arranged facing the recess 8a. A through hole 10 through which the electrode rod 2.2a passes is formed from the recess 8a to the upper end 3a of the head 3.

The mouthpiece 7 is provided with a nozzle hole 7a facing a main chamber 12a formed at the top of the piston 12 fitted into the cylinder body 11.

Further, numeral 13 indicates an exhaust passage in a longitudinal section different from the subchamber 8, and numeral 14 indicates an exhaust valve for opening and closing the exhaust passage.

To set the heater 1 in the auxiliary chamber 8 of such a head 3, fit the heater 1 into the recess 8a from the bottom surface of the head 3 while inserting the electrode rods 2, 2a integrated with the heater 1 into the through hole 10. , into which the base 7 is inserted.

Further, when the heater 1 is disposed above the base 7, its inner circumferential surface is concavely pressed against the inner wall surface of the auxiliary chamber 8 to form an air pocket P.

This air pocket is extremely difficult to generate an initial flame kernel when the air-fuel mixture starts to burn in a vortex field where the air velocity is high, such as a vortex chamber, and in many cases it occurs near the center where the influence of the vortex is less.

When the spray ignition heat source is provided at a location near the periphery of the vortex chamber where the flow velocity is high as in the present invention, the air pocket creates a part unaffected by the flow velocity and stabilizes the initial flame kernel generation. It is important not to reduce the temperature of the air by air cooling.

Here, 15 is a heat insulating gasket interposed on the upper and lower surfaces of the heater 1.

The heat insulating gasket 15 is necessary to quickly heat the heater 1 and maintain the temperature of the heater 1 at a high temperature with minimum electrical energy as in the present invention, and is made of ceramic fiber or a ceramic material with low thermal conductivity. be done.

That is, in order to maintain the heater 1 at a high temperature, it is necessary to supply a large current or reduce the heat dissipation energy, but since there is a limit to the electric power of an internal combustion engine that uses a battery as a heat source, heat dissipation is prevented by the heat insulating packing 15. is important.

Further, an electrode rod 2.2a protruding from the upper end 3a of the head 3
A sealing member 17 is installed inside the head cover 16 on either side of the head cover 16.
The terminal 4a of the conductive wire 4 introduced through the packing 18
．． It is connected via an insulating member 19, and a packing 2 is placed above it.
0 is inserted, and the bag dot 6 is screwed and fixed to the threaded portion 5.

Among the electrode rods 2 and 2a, the other electrode rod that is not connected to the terminal 4a of the conductive wire 4 serves as a herad earth.

When starting a diesel engine with a pre-chamber configured as described above in cold weather, etc., if the preheating circuit (not shown) is closed, the current from the power source is passed through the conductive wire 4, electrode rod 2 (or 2).
a) to the heating element material 1a, the inner circumferential surface of the heater 1 made of a ceramic material with a heat insulating packing inserted and the heating element buried close to the inner circumferential surface is rapidly heated, and the injection nozzle An atmosphere that facilitates ignition is formed over the entire inner circumferential surface of the auxiliary chamber 8 including the vicinity of the wall surface where the fuel spray from the auxiliary chamber 9 reaches.

Therefore, the problems of the preceding publication mentioned above are eliminated, and the sub-chamber 8
Ignition and combustion inside the tank are extremely promoted.

In addition, since the glow plug does not protrude into the pre-chamber unlike in conventional pre-chambers, the generation of vortices in the pre-chamber and the propagation of flame are not inhibited, so ignition combustion is further promoted and the exhaust gas It has the effect of reducing harmful components such as HC and CO inside, and also has the effect of eliminating flame propagation at low temperatures due to the short distance between the injection nozzle and the glow plug, and the difficulty of maintaining the plug itself at a high temperature. .

Furthermore, the inner circumferential surface of the heater 1 is formed into a subchamber 8 as shown in FIG.
By forming an air pocket P in a concave shape with respect to the inner wall surface of the auxiliary chamber 8, a part of the spray from the injection nozzle 9 stays in the pocket P, and a so-called . Since the flame is prevented from blowing out, it can be used as an extremely effective ignition source.

As described above, in this invention, the heater is placed in the middle of the inner wall of the auxiliary chamber, and the preheating circuit for the glow plug is connected to the electrode rod of the heater, without changing the conventional preheating circuit. Since there is no need to install a glow plug, the structure is relatively simple, manufacturing is inexpensive, maintenance is easy, and the above-mentioned problems associated with glow plugs are eliminated, creating an ideal ignition and combustion system. This has the effect of providing a diesel engine with a pre-chamber having the following characteristics.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a perspective view of a heater in the same embodiment. 1... Heater, 1a... Heat generating element material, 2, 2a... Electrode rod, 3... Cylinder head, 4... Continuity Line, 7...cap, 8...subchamber, 9...injection nozzle,
10...Through hole, 15...Insulation gasket.

Claims (1)

[Scope of utility model registration request] In a diesel engine with an auxiliary chamber, in which the auxiliary chamber is formed by inserting a mouthpiece into a recess provided inward from the bottom surface of the cylinder head, heat is generated in a portion of the ring-shaped ceramic material that is close to the inner peripheral surface of the ring. A heater with an embedded element is disposed above the cap so that its inner peripheral surface is concave with respect to the inner wall surface of the auxiliary chamber, and a heat insulating packing is provided at the portion where the heater contacts the cap and the cylinder head. A diesel engine with a pre-chamber, which is characterized by an intervening chamber.