Internal-combustion engines – Transmission mechanism from piston – Crankshaft and connecting rod
Reexamination Certificate
2000-05-09
2001-08-14
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Transmission mechanism from piston
Crankshaft and connecting rod
C123S0780BA
Reexamination Certificate
active
06273052
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to reciprocating piston engines, and in particular to coupling arrangements for interconnecting a gudgeon pin and a crankshaft journal of such an engine. The invention is applicable to reciprocating piston combustion engines and compression engines and it will be convenient to hereinafter describe the invention in relation to that exemplary application, although it should be appreciated that the invention is not limited to the application.
Conventional reciprocating piston engines are generally manufactured in two and four stroke designs. A single piston is housed within each cylinder, the piston being connected from a central piston gudgeon pin to a single bearing crankshaft journal by a single solid center mounted connecting rod. After combustion has taken place in the combustion chamber of the piston, the energy derived from the expansion of the combustible material forces the piston to travel along the length of the cylinder away from the combustion chamber. This translational movement is transferred via the connecting rod to the crankshaft journal and is transformed into a rotational movement as the crankshaft is driven around its longitudinal axis. As the crankshaft completes each revolution, the connecting rod interconnecting the crankshaft journal and the gudgeon pin forces the piston back along the length of the cylinder towards the combustion chamber, where combustion once again takes place and the cycle is repeated.
Conventional engines of this type are arranged so that the maximum combustive pressure within the cylinder is generated when the piston is at top dead center and the crankshaft journal is at a corresponding top center position, that is to say, at a position closest to the cylinder combustion chamber. The resultant effect of this arrangement is that immediately following ignition at or slightly after the top center position of the crankshaft, the downward travel of the piston in the cylinder rapidly causes the enlargement of the volume of the cylinder above the upper surface of the piston. A rapid drop in combustion pressure is thus created and there is a corresponding rapid reduction in the force applied to the piston, and hence to the crankshaft journal for rotation of the crankshaft.
The applicant has observed that such an arrangement inefficiently converts energy from the combustion of gases in the combustion chamber to a motive force for turning the crankshaft. There exists a need to create a more efficient reciprocating piston engine where more power can be derived from the same amount of combustible material or, alternatively, a lesser amount of combustible material may be used to achieve the same amount of power.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a reciprocating piston engine which overcomes or ameliorates one or more of the disadvantages of known reciprocating piston engines.
With this in mind, the present invention provides a coupling arrangement for interconnecting a gudgeon pin and a crankshaft journal of a reciprocating piston engine, the arrangement comprising:
a connecting rod having a first end pivotally connected to the crankshaft journal,
a connection member pivotally connectable at a first pivot point to a second end of the connecting rod, and pivotally connectable to the gudgeon pin at a second pivot point distal from the first pivot point, and
rotation transfer means acting to transform a rotational movement of the first pivot point about the gudgeon pin into a rotational movement of the crankshaft journal about the crankshaft.
In an engine having these features, the point of attachment of the connecting rod is separated from the gudgeon pin by a connection member pivotally attached between the connecting rod and the gudgeon pin. With such an arrangement, it is possible to create a reciprocating piston engine in which the crankshaft journal need no longer be at a top center position when the piston is at its top dead center position. The crankshaft journal is able to be located at a position intermediate the top center position and a bottom center position so that, at shortly after combustion—when the combustion chamber is at its maximum pressure and the corresponding maximum force is applied to the piston—a greater torque is able to be applied to the crankshaft journal than is possible with conventional reciprocating piston engines. By maintaining or reducing the cylinder volume in the combustion chamber after the crankshaft journal turns past its top center position, the maximum available force in the engine is able to be applied to the crankshaft journal at an optimum position during its rotational cycle.
This and other advantages and features of the invention will be better appreciated from the following description which refers in more detail to the various features of the coupling arrangement of the present invention. To facilitate an understanding of the invention, reference is made in description to the accompanying drawings where the coupling arrangement is illustrated in preferred embodiments. It is to be understood, however, that the coupling arrangement of the present invention is not limited to the embodiments illustrated in the drawings.
REFERENCES:
patent: 1379115 (1921-05-01), Mallory
patent: 1420236 (1922-06-01), Bohman
patent: 5245962 (1993-09-01), Routery
patent: 0219634 (1987-04-01), None
patent: WO 88/04356 (1988-06-01), None
Kamen Noah P.
Samuels Gauthier & Stevens
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