Internal-combustion engines – Multiple cylinder – Cylinders radiating
Patent
1997-06-25
1999-01-26
McMahon, Marguerite
Internal-combustion engines
Multiple cylinder
Cylinders radiating
123 70R, 123 74D, F02B 3312, F02B 3344, F02B 7532
Patent
active
058627812
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention concerns a two-stroke internal combustion engine comprising a number of working cylinders having bases and subdivided via their pistons into a lower and an upper cylinder chamber, wherein the lower cylinder chamber functions substantially for compression and the upper cylinder chamber substantially for compression and combustion.
A two-stroke motor of this type has been proposed by the inventor Gottfried Hillekum and has become known in the art from German Patent No. 409919 of Feb. 16, 1925 entitled "Two-stroke Internal Combustion Engine with Two Oppositely Lying Cylinders".
Disadvantageously, this crank slide two-stroke internal combustion engine circulates the exhaust out of the working cylinder using a fresh fuel-air mixture (fresh gas) when the piston moves through its bottom dead center position. Since, at this point of time, operation of the engine requires inlet and outlet openings to be simultaneously opened, a portion of the fresh gas unavoidably is circulated along with the exhaust. These circulation losses lead to increased fuel consumption, to high carbon monoxide and hydrocarbon concentrations in the exhaust gas, to increased particle formation, to charring and to wear.
It is therefore the underlying purpose of the present invention to further improve the conventional motor in such a fashion that its disadvantages are avoided.
SUMMARY OF THE INVENTION
In a first solution in accordance with the invention, the circulation losses are avoided in that no circulation is performed. At the point in time at which the piston moves approximately in its bottom dead center position, the exhaust gas flows out through the outlet opening. At high temperatures, the mass of exhaust gas which remains after closing the outlet opening is small. Fresh gas subsequently brought in during the compression stroke mixes with the remaining exhaust gas. Elimination of the circulation step leads to a well-dosed mixture of exhaust gas which lowers nitrogen oxide emissions.
In a second solution in accordance with the invention, the circulation losses are avoided in that circulation uses pure fresh air from an auxiliary compressor (e.g. an exhaust turbo compressor). At the point in time at which the piston moves at approximately its bottom dead center position, the exhaust gas is forced through the outlet opening. The remaining circulation air, together with the fresh gas subsequently introduced during the compression stroke, lead to a doubled reactive gas mass so that approximately twice the power can be expected. Even higher power levels can be achieved if the auxiliary machine can be used as a charger. Utilization of the auxiliary machine as a circulator and charger leads to better distribution of the auxiliary machine load so that even engines having a low number of cylinders can profit from the advantages of an auxiliary compressor.
The purpose in accordance with the invention is achieved with a plurality of novel construction and method features.
During the circulation process, conventional two-stroke engines must bring the fresh gas into the working cylinder at the bottom dead center position of the piston within an amount of time which is in general much too short. In contrast thereto, the motor in accordance with the invention has the entire compression stroke. In this manner, circulation losses are reduced to a minimum.
Charging during compression can, however, not be carried out by the lower cylinder chamber of the working cylinder, since the lower cylinder chamber is in a state of expansion. A prominent feature of the invention consists in having the lower cylinder chambers of other working cylinders contribute to each charging of an upper cylinder chamber. In principle, a working cylinder contributing to charging can be disposed at an opposite or adjacent position.
The engine in accordance with the invention is principally distinguished in that at least one storage cylinder is provided for to which at least two working cylinders are attached in such a fashion that at l
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McMahon Marguerite
Vincent Paul
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