Internal-combustion engines – Precombustion and main combustion chambers in series – Plural precombustion chambers
Reexamination Certificate
2001-03-22
2001-11-20
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Precombustion and main combustion chambers in series
Plural precombustion chambers
C123S292000, C123S0800DA
Reexamination Certificate
active
06318335
ABSTRACT:
BACKGROUND OF THE INVENTION
This present invention involves a method of operation of an internal combustion engine. An internal combustion engine includes a piston that is moved by rapid combustion of a fuel/air mixture, wherein fresh gas is first drawn into a cylinder chamber and then compressed, vaporization of the fuel contained in or introduced into the enclosed fresh gas is carried out, then combustion thereof is commenced and with the pressure of the combustion gases generated thereby the piston is acted upon (power stroke), which after performance of the piston's power stroke expels the exhaust gases from the cylinder chamber.
With known internal combustion engines the combustion chambers (e.g. of the Ricardo, Perkins, Hercules, Deutz, ACO etc. type) are arranged stationarily in the cylinder head, engine block and/or in the engine piston. In EP-A-1-0 074 174 is disclosed a theoretical proposal which provides a rotating preliminary combustion chamber in which a portion of a rich mixture is to be burnt, which is then intended to serve as an igniter of a leaner mixture in the ordinary combustion chamber.
A common feature of all embodiments is the design-related and process-related brief time for vaporization of the fuel and for combustion thereof It is also a drawback that combustion cannot be carried out under a volume which is kept constant, but takes place in a stroke volume between approx. −15° before to +35° after top dead center. This results in incomplete fuel combustion and noxious exhaust gases. In the case of fuels, which require more time for their mixture preparation (diesel), or for their combustion (alcohol), there is in addition a restriction on the maximum possible speed. The available combustion time is within an order of magnitude of about 0.001 s. Forced compromises such as, e.g., an increase in the excess air or tolerance of incomplete combustion lead to a drop in efficiency as well as an increase in emission of pollutants. With the known methods of operation a decrease in the excess air would lead to incomplete combustion, to further energy losses as well as to increased discharge of pollutants. Increasing the theoretical efficiency by lowering the exhaust temperature is possible only with increased expenditure on apparatus.
To lengthen the mixture preparation and combustion time, the fuel is already mixed with air in the carburetor or, in the case of indirect fuel injection, in the inlet port, with the result however that the problems can be reduced only to a limited extent.
The present invention is directed to overcoming one or more of the problems set forth above.
SUMMARY OF THE INVENTION
It is an aspect of the present invention for an internal combustion engine with at least one piston that is driven by a crankshaft and guided in a cylinder whose cylinder chamber located above the piston can be alternately connected by a valve control system to an inlet pipe for fresh gas and to an exhaust pipe for the exhaust gases and is connected to a combustion chamber in which vaporization of the fuel contained in or introduced into the compressed fresh gas and then combustion thereof are effected.
Another aspect of the invention to improve the method of operation described hereinbefore particularly with respect to its efficiency and to develop a suitable internal combustion engine for carrying out this method of operation.
Starting from the method described hereinbefore, this aspect is achieved according to the invention by the fact that in a compression stroke the fresh gas which is compressed in the process is forced into a first combustion chamber in which, after it is closed off from the cylinder chamber, the vaporization is carried out and the combustion is commenced, while at the same time a second combustion chamber previously closed on all sides is opened to the cylinder chamber and the piston for carrying out a power stroke is subjected to combustion gases expanding from this second combustion chamber and previously generated in the same way, so that at each compression stroke alternately one of the two combustion chambers is filled and for each subsequent power stroke the piston is displaced from the other of the two combustion chambers.
In this case it is appropriate if both combustion chambers are kept closed during the induction stroke, the vaporization taking place in one combustion chamber while exhaust residues are located in the other combustion chamber, that during the compression stroke only the second combustion chamber is open to the cylinder chamber and in the first combustion chamber the combustion is commenced, that after top dead center, the second combustion chamber is closed off from the cylinder chamber, while the first combustion chamber is open, that in the power stroke during at least the majority of the stroke the first combustion chamber remains open, while in the second combustion chamber the vaporization is commenced, and that shortly before or shortly after bottom dead center for commencement of the exhaust stroke the first combustion chamber is closed and during the exhaust stroke remains closed, while in the second combustion chamber the vaporization is continued during the exhaust stroke.
Starting from the internal combustion engine described hereinbefore, the above-mentioned aspect is achieved according to the invention by the fact that the combustion chamber is formed by two separate combustion chambers of preferably and substantially equal size, which each have an inlet and/or outlet opening, which can be connected to the cylinder chamber by appropriate control means in adaptation to the strokes of the associated piston alternately one after the other for receiving the compressed fresh gas or for expanding the combustion gases.
According to the invention the whole of the mixture preparation and the combustion process are separated in time and space from the previously known four-stroke or two-stroke process. In parallel with these known stroke processes runs, according to the invention, a fifth or third “combustion stroke”. By this means sufficient time is gained for mixture preparation and the combustion process and hence better energy exploitation and a reduction in pollutant discharge are obtained. Optimization of the process is effected by an optimum choice of the position and moment for fuel injection and the ignition, by the use of any desired, if necessary slow-burning fuels and fuel mixtures (e.g. naphtha with water), by the combustion of combustion moderators or catalysts (e.g. water, nickel charge for mixture of naphtha with water, ceramic charges for flameless combustion, etc.), by optimization of the degree of compression, or by additional water injection in order to be able to lower the exhaust temperatures without considerable pressure loss.
In an appropriate embodiment the two combustion chambers can be arranged in a drivable body of revolution which is mounted rotatably in the cylinder head and which is preferably a rotary slide arranged with axis parallel to the crankshaft and sealingly encompassed by a stationary rotary slide housing which comprises a connecting opening to the cylinder chamber.
Further it is appropriate if the two combustion chambers are located on two parallel chords arranged in inverse symmetry to the axis of rotation of the circular rotary slide and each comprise mutually opposed inlet and/or outlet openings which on rotation of the rotary slide are temporarily brought into register with the connecting opening of the rotary slide housing.
A modified embodiment is according to the invention characterized in that the rotary slide comprises, axially offset from the two combustion chambers, two through-channels which in a given rotational position of the rotary slide connect an inlet and/or exhaust opening provided in the rotary slide housing opposite the cylinder chamber, to the inlet and/or exhaust pipe.
In this case it is advantageous if the two through-channels are located on two parallel chords arranged in inverse symmetry to the axis of rotation of the rotary sl
diro GmbH & Co. KG
Husch & Eppenberger LLC
Kercher Kevin M.
Muir Robert E.
Wolfe Willis R.
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