Internal-combustion engines – Precombustion and main combustion chambers in series – Having combustible mixture forming means
Patent
1993-02-03
1994-10-25
Nelli, Raymond A.
Internal-combustion engines
Precombustion and main combustion chambers in series
Having combustible mixture forming means
F02F 326
Patent
active
053579240
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a direct-injection type compression-ignition internal combustion engine.
BACKGROUND ART
The present applicant has already proposed an internal combustion engine which has a collision surface formed at the center portion of a cavity formed in the top surface of the piston, has the fuel injected from the fuel injector strike the collision surface to disperse from the collision surface in the circumferential directions in the cavity, then has the dispersed fuel ignited by a spark plug or glow plug (see Japanese Unexamined Patent Publication (Kokai) No. 63-120815). In such an internal combustion engine, the spark plug or glow plug is used to ignite the fuel, but later studies showed that if the method of formation of a fuel spray using such a collision action is applied to a compression-ignition internal combustion engine, the ignition lag time becomes extremely short and therefore combustion with a gentle rise in pressure can be obtained. Therefore, the present applicant has also applied for a patent for such a compression-ignition internal combustion engine as well (PCT/JP90/00718). In this compression-ignition internal combustion engine, substantially all the injected fuel is made to burn in the cavity formed at the top surface of the piston in the same way as a general compression-ignition internal combustion engine.
A cavity formed in the top surface of a piston inherently has a volume able to accommodate an amount of air sufficient for burning all the injected fuel and therefore if all the air in the cavity can be used for the combustion, then excellent combustion can be obtained even if substantially all of the injected fuel is made to burn in the cavity of the piston as mentioned above. To use all of the air in the cavity for the combustion, however, the injected fuel must be distributed uniformly in the cavity as a whole. Nevertheless, to cause the injected fuel to uniformly distribute in the cavity as a whole is difficult for a general compression-ignition internal combustion engine, of course, and even more so for a compression-ignition internal combustion engine where the injected fuel is made to collide with a collision surface. Therefore, there is the problem that if substantially all of the injected fuel is made to burn in the cavity of the piston, the rate of utilization of the air becomes insufficient and therefore a large amount of unburned hydrocarbons and smoke is generated.
DISCLOSURE OF THE INVENTION
The object of the present invention is to provide a compression-ignition internal combustion engine which can tremendously raise the thermal efficiency while tremendously suppressing the generation of harmful components and smoke by using a novel combustion method.
According to the present invention, there is provided a direct-injection type compression-ignition internal combustion engine wherein a cavity is formed on the top surface of a piston, a fuel injector is disposed on the inner wall surface of a cylinder head above the center of the cavity, a collision portion provided with a collision surface is provided below the fuel injector, the fuel injected from the fuel injector is made to collide with the collision surface, and the collided injected fuel is made to disperse from the collision surface in the radial directions of the cavity, wherein the timing of the start of the fuel injection is set to near the top dead center of the compression stroke, the initial combustion is made to be performed in the cavity, and the remaining majority of the combustion following the initial combustion is made to be performed between the top surface of the piston around the cavity and the inner wall surface of the cylinder head.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side sectional view of a direct-injection type compression-ignition internal combustion engine,
FIG. 2 is a plan view of a piston,
FIG. 3 is a bottom view of a cylinder head,
FIG. 4 is an enlarged side sectional view of the front end portion of the fuel injector,
FIG. 5 is a
REFERENCES:
patent: 4770138 (1988-09-01), Onishi
patent: 5103776 (1992-04-01), Sato
patent: 5259348 (1993-11-01), Kobayashi et al.
Tamanouchi et al., "Effect of Fuel Composition on Exhaust Gas Emissions from DI and DI Impingement Diffusion Combustion Diesel Engines," International Congress and Exposition of the Society of Automotive Engineers, Inc., Feb. 28-Mar. 3, 1994.
Kato et al., "Development of OSKA-DH Diesel Engine Using Fuel Jet Impingement and Diffusion Investigation of Mixture Formation and Combustion," International Congress and Exposition of the Society of Automotive Engineers, Inc., Feb. 28-Mar. 3, 1994.
Nelli Raymond A.
Nippon Clean Engine Research Institute Co., Ltd.
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