Internal-combustion engines – Precombustion and main combustion chambers in series – Having combustible mixture forming means
Reexamination Certificate
1998-12-22
2001-04-03
Kwon, John (Department: 3747)
Internal-combustion engines
Precombustion and main combustion chambers in series
Having combustible mixture forming means
C123S276000
Reexamination Certificate
active
06209512
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a two or four stroke vehicle engine, and in particular to a two or four stroke vehicle engine adapted to optimize the combustion process, especially when the engine is operating at a low load.
BACKGROUND OF THE INVENTION
In the field of vehicle engines, the need is felt to reduce fuel consumption and also possibly size and weight, leading to further reduced fuel consumption. Fuel consumption can be reduced in various ways, in particular when an engine operates at low r.p.m. and low load. One of these ways consists of especially shaping the explosion chamber by providing the piston head with concave or convex shapes which, with the top of the cylinder, define a combustion chamber of small volume (compared with the usually available combustion chamber) when the piston is at its top dead center. The fuel is injected directly into this chamber, into which there opens the induction duct which is provided with its own valve member. In this chamber there is also located an ignition means (spark plug) for the mixture which is created in it. By this means a suitable reduced-volume stratification of the air-fuel mixture can be obtained, such as to allow the engine to operate at low load. In this case, the piston moves into proximity with the top dead center to hence define the aforesaid reduced chamber into which only that fuel quantity for locally achieving mixture ignition conditions is fed. If however the engine has to operate at higher load and/or r.p.m., fuel is fed into the cylinder before the piston reaches its top dead center, so as to create a homogeneous feed.
Other methods are known comprising the provision of mixing prechambers at the top of the cylinder, combined or otherwise with a variously shaped piston head. The explosive mixture forms in these chambers and is fed, under more or less turbulent flow conditions, into the cylinder and the possible cavity present within the piston head.
Although these methods result in lower fuel consumption at low loads or allow good fuel-air mixing, they are often difficult and/or costly to implement (for example, with regard to the arrangement of the valve member and the means for its opening or closure), and usually require the use of particular metals or light metal alloys for constructing their components.
In addition to the aforegoing, the known methods result in large engine dimensions above the cylinder. In other words, the engine head assumes a considerable size.
OBJECTS AND SUMMARY OF THE INVENTION
An object of this invention is to provide an engine which is improved compared with known engines.
A particular object of the invention is to provide an engine of the aforesaid type which achieves reduced fuel consumption and lesser pollution by extremely simple means, so involving relatively low cost.
A further object is to enable an engine of the stated type, by virtue of its conformation, to use non-valuable metals (such as cast iron) for its construction, and to control its valve members in an extremely simple manner.
A further object is to provide an engine of the stated type which is of small dimensions, at least with regard to its head.
These and further objects which will be apparent to one of ordinary skill in the art are attained by an engine in accordance with the accompanying claims.
REFERENCES:
patent: 1866300 (1932-07-01), French
patent: 2587339 (1952-02-01), Rostu
patent: 2615437 (1952-10-01), Broderson
patent: 4682573 (1987-07-01), Fujikawa et al.
patent: 4716861 (1988-01-01), Fujikawa et al.
patent: 4722306 (1988-02-01), Fujikawa et al.
Kwon John
MV Agusta Motor S.p.A.
Steinberg & Raskin, P.C.
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