JPH0460166A - Six-cycle diesel engine - Google Patents

Abstract

PURPOSE:To warm a wall surface of a supply air chamber by heat of exhaust gas so as to reduce a cooling loss of heat in compressed air, with which the supply air chamber is charged, by forming an exhaust passage in the vicinity of the supply air chamber while forming the exhaust passage and the supply air chamber in a cylinder head. CONSTITUTION:A subcombustion chamber 9, supply air chamber 10 and a cooling water jacket 11 are formed while forming intake and exhaust passages 7, 8, connected to a main combustion chamber 6 in a cylinder l, in a cylinder head 5. The subcombustion chamber 9 communicates with the main combustion chamber 6 by an injection port 13 formed in an insert 12, and the supply air chamber 10 communicates with the main combustion chamber 6 by a communication port 14. Here, the exhaust passage 8 and the cooling water jacket 11 are formed in a position in the vicinity of the supply air chamber 10 to cause its wall surface to be warmed by heat of combustion gas discharged through the exhaust passage, and activation of an activated premixture, produced in the supply air chamber. is promoted by reducing a cooling loss of heat in compressed air with which the supply air chamber 10 is charged.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a six-stroke diesel engine.

Conventional technology Six-stroke diesel engines have been developed that aim to improve output by increasing the weight of air entering the combustion chamber.The cylinder head of a six-stroke diesel engine has an air supply chamber, an intake passage, and an exhaust passage. is formed.

Here, a sub-injection nozzle is provided facing the air supply chamber, and fuel is injected into the compressed air filled in the air supply chamber in the first compression stroke to generate an activated premixture. The 6-cycle diesel engine is designed to increase the amount of fuel consumed during combustion to improve engine output, improve startability, and reduce harmful exhaust gas components such as smoke, Co, and HC. Patent application Hei 2-2583
It is proposed in No. 0.

In addition, as a means to promote the activation of the activated premixture generated in the air supply chamber, it is possible to change the pressure inside the air supply chamber, the volume and shape of the air supply chamber, the thickness of the wall surrounding the air supply chamber, etc. Generally considered.

Problems to be Solved by the Invention However, since the air supply chamber has a large volume and a large surface area, there is a large cooling loss of heat within the air supply chamber, and the activated premixture cannot be activated sufficiently. In some cases, sufficient effects cannot be obtained in terms of improving output, improving startability, and reducing harmful exhaust gas components such as smoke, Co, and HC.

Means for Solving the Problem An air supply chamber, an intake passage, and an exhaust passage, which are communicated with the main combustion chamber through a communication port, are formed in the cylinder head, and a first intake stroke, a first compression stroke, and a second In a 6-stroke diesel engine that is operated in 6 strokes including an intake stroke, a second compression stroke, an expansion stroke, and an exhaust stroke, a sub-injection nozzle is provided that faces the air supply chamber and injects fuel, and the exhaust A passageway was formed close to the air supply chamber.

The heat of the combustion gas exhausted through the exhaust passage warms the wall surface of the air supply chamber, and the cooling loss of the compressed air filled in the air supply chamber is reduced. Activation of the activated premixture is promoted.

Example An embodiment of the present invention will be described based on the drawings.

A piston 2 is slidably provided within the cylinder 1, and the piston 2 is connected to a crankshaft (not shown) via a connecting rod 3. Further, a cylinder head 5 having a helad gasket 4 interposed therein is fastened to the tip of the cylinder 1 with a head bolt (not shown).

The cylinder head 5 is formed with an intake passage 7 and an exhaust passage 8 that communicate with the main combustion chamber 6 in the cylinder 1, and further includes an auxiliary combustion chamber 9, an air supply chamber 10, and a cooling water jacket 11. is formed. Note that the sub-combustion chamber 9
is formed by assembling an insert 12 to the cylinder block 5, and this insert 12 is formed with a nozzle port 13 that communicates the auxiliary combustion chamber 9 and the main combustion chamber 6. Further, the air supply chamber 10 and the main combustion chamber 6 are communicated with each other through a communication port 14 . Here, the exhaust passage 8 and the cooling water jacket 11 are formed in a position close to the air supply chamber 10.

The cylinder head 5 also includes an intake valve 15 that opens and closes a boat portion of the intake passage 7 that opens into the main combustion chamber 6.
An exhaust valve 16 that opens and closes a boat portion of the exhaust passage 8 that opens into the main combustion chamber 6 and a sub valve 17 that opens and closes a boat portion of the communication port 14 that opens into the main combustion chamber 6 slide. It can be installed freely. Furthermore, the cylinder head 5 has a main injection nozzle 18 facing the sub-combustion chamber 9.
A glow plug 19 and a sub-injection nozzle 20 facing the air supply chamber 10 are fixedly attached.

Next, a stud bolt 21 is attached to the cylinder head 5.
The rocker cover 23 is tightened by the cap nut 22 and the cap nut 22. Inside this rocker cover 23 are half-split bearings 25 and 26 that are tightened by the stud bolts 21 and nuts 24, and these bearings 2.
5 and 26, an intake rocker arm (not shown), and an exhaust rocker arm 2.
8, a sub-valve rocker arm 29, a sub-valve cam 30 fixed to the camshaft 27, an exhaust cam C (not shown), etc. are provided.

Here, the exhaust valve 16 is urged in the valve closing direction by a spring 33 via a retainer 31 and a stopper 32, and one end of the exhaust rocker arm 28 is connected to the exhaust valve 16.
The exhaust rocker arm 28 is in contact with the stem end of the exhaust rocker arm 28.
The other end is rotatably abutted on a fulcrum 34. In addition,
A shaft 35 is located approximately at the center of the exhaust rocker arm 28.
is fixed, and a roller 36 rotatably attached to the shaft 35 is in contact with the outer peripheral surface of the exhaust cam. Further, the fulcrum 34 is connected to the nut 37 after adjusting the gap between the roller 36 and the outer peripheral surface of the exhaust cam to an appropriate value.
is locked by.

Similarly, the auxiliary valve 17 has a retainer 38 and a socket 39.
One end of the auxiliary valve rocker arm 29 is brought into contact with the stem end of the auxiliary valve 17, and the other end of the auxiliary valve rocker arm 29 is pressed against the fulcrum 41. It is rotatably abutted on. A shaft 42 is fixed to a substantially central portion of the sub-valve rocker arm 29, and a roller 43 rotatably attached to the shaft 42 is attached to the sub-valve cam 30.
is in contact with the outer peripheral surface of the Further, the fulcrum 41 is locked by a nut 44 after adjusting the gap between the roller 43 and the outer peripheral surface of the sub-valve cam 30 to an appropriate value.

In such a configuration, the operation of the six-cycle diesel engine will first be described with reference to FIGS. 3 and 4. FIG. 3(a) shows the first intake stroke. Intake valve 1
5 is open, and as the piston 2 slides downward, air is drawn into the main combustion chamber 6 through the intake passage 7.

FIG. 3(b) shows the first compression stroke. The air sucked into the main combustion chamber 6 during the first intake stroke is transferred to the piston 2.
is compressed as the value increases. Note that the auxiliary valve 17 is open, and the compressed air is filled into the auxiliary combustion chamber 9 and also into the air supply chamber 10.

FIG. 3(c) shows the final stage of the first compression stroke. At the timing when the piston 2 reaches the road dead center, the auxiliary valve 17
is closed and the air supply chamber 10 is discharged from the sub-injection nozzle 20.
Fuel is injected inside. This fuel is mixed with the swirling air in the air supply chamber 10 to generate an activated premixture. In addition, in the fuel injection at this time, the compression ratio and temperature in the air supply chamber 10 are low, so that the fuel does not ignite.

FIG. 3(d) shows the second intake stroke. When the piston 2 descends by about 90" at the crank angle, the pressure inside the main combustion chamber 6 becomes negative relative to the outside. When the intake valve 15 is opened at this timing, air passes through the intake passage 7 and enters the main combustion chamber. Inhaled within 6 days.

Note that when the piston 2 reaches the bottom dead center, the same amount of air is sucked into the main combustion chamber 6 as in the first intake stroke.

FIG. 3(e) shows the state immediately before the end of the second intake stroke. The intake valve 15 is closed and the auxiliary valve 17 is opened, and the activated premixture in the air supply chamber lo is injected into the main combustion chamber 6, and the amount of air in the main combustion chamber 6 is reduced to the first level. This is approximately 1.5 times the amount of air in the main combustion chamber 6 at the end of the intake stroke.

FIG. 3(f) shows the second compression stroke.

FIG. 3(g) shows the final stage of the second compression stroke. The compressed air mixed with the activated premixture rises to a temperature that can be ignited, and when the piston 2 reaches its dead center, fuel is injected from the main injection nozzle 18 into the sub-combustion chamber 9, causing ignition. happen.

FIG. 3(h) shows the expansion stroke. Combustion gas is ejected from the sub-combustion chamber 9 into the main combustion chamber 6, combustion occurs within the main combustion chamber 6, and the piston 2 is pushed downward, thereby transmitting power to the crankshaft.

FIG. 3(i) shows the exhaust stroke. When the exhaust valve 16 is opened, the piston 2 rises, and the combustion gas in the main combustion chamber 6 is discharged through the exhaust passage 8.

Here, the activated premixture in the air supply chamber 10 is shown in FIG. 3(C).
However, since the exhaust passage 8 is formed close to the air supply chamber 10, the heat of the combustion gas exhausted through the exhaust passage 8 The wall surface of the air supply chamber 10 is heated. Therefore, cooling loss of heat when compressed air is filled into the air supply chamber IO is reduced, and activation of the activated premixture generated in the air supply chamber 10 is promoted. On the other hand, since the cooling water jacket 11 is formed close to the air supply chamber 10, the cooling water flowing inside the cooling water jacket 1
The wall surface of the air supply chamber 10 is cooled, and ignition is prevented from occurring at a stage when the temperature inside the air supply chamber 10 becomes too high and an activated premixture is generated. Note that by changing the formation positions of the exhaust passage 8 and the cooling water jacket 11 with respect to the air supply chamber 10, the temperature of the wall surface of the air supply chamber 1o can be adjusted.

Effects of the Invention The present invention has an exhaust passage and an air supply chamber formed in the cylinder head as described above, and the exhaust passage is formed close to the air supply chamber, so that the combustion gas exhausted through the exhaust passage is reduced. The heat can warm the walls of the air supply room,
Therefore, the cooling loss of heat in the compressed air filled in the air supply chamber is reduced, and the activation of the activated premixture generated by injecting fuel from the sub-injection nozzle into the compressed air in the air supply chamber is promoted. Therefore, it is possible to improve the output and startability of a 6-stroke diesel engine, and
It has the effect of more reliably achieving a reduction in harmful exhaust gas components such as smoke, CO, and HC.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a longitudinal sectional front view, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is an explanation explaining the operation of a 6-cycle diesel engine. 4 are timing charts illustrating the timing of opening and closing of the valve and the timing of fuel injection. 5... Cylinder head, 7... Intake passage, 8...
Exhaust passage, 9... Sub-combustion chamber, 10... Air supply chamber lZ diagram

Claims (1)

[Claims] An air supply chamber, an intake passage, and an exhaust passage, which are communicated with the main combustion chamber through a communication port, are formed in the cylinder head, and a first intake stroke, a first compression stroke, a second intake stroke, and a second In a 6-cycle diesel engine that is operated in six strokes including a compression stroke, an expansion stroke, and an exhaust stroke, a sub-injection nozzle is provided that faces the air supply chamber and injects fuel, and the exhaust passage is connected to the air supply chamber. A 6-stroke diesel engine characterized by being formed close to each other.