Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2001-12-07
2003-09-30
Tyler, Cheryl J. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S418000, C417S546000, C123S0460SC
Reexamination Certificate
active
06626650
ABSTRACT:
The present invention relates to a cyclically operated fluid displacement machine.
The present invention can provide a cyclically operated fluid displacement machine either in the form of an engine or a compressor.
The present invention aims to provide a machine which is very simple and in particular which does not require a valve train system, separate alternator and starter motor or cam shaft. The machine of the present invention could be used as an engine in a hybrid vehicle, the engine producing electrical power which would then be used by electrical motors to power the vehicle.
U.S. Pat. No. 5,172,784 describes an arrangement for powering a hybrid vehicle which comprises external combustion Stirling engines coupled to linear generators and used in conjunction with a battery pack to power electric motors for a vehicle.
U.S. Pat. No. 4,924,956 describes a tandem double-acting free piston engine comprising a housing including a cylinder having first and second combustion chambers at opposite ends thereof and a third combustion chamber between the ends. One double acting piston is displaceable between the first and third combustion chamber. A second double acting piston is displaceable between the second and third combustion chambers. The two double acting pistons are linked so that they move in timed relationship with each other. A linear alternator is combined in the engine by attaching one coil to each of the double acting pistons and by surrounding the cylinder with other electrical coils, the fields of which are intersected by the coils on the two pistons.
The present invention provides a cyclically operated fluid displacement machine which comprises:
a housing;
a reciprocating member reciprocal linearly along an axis of reciprocation in the housing and defining with the housing first and second variable volume chambers;
a fluid inlet connected to the first variable volume chamber;
a fluid outlet connected to the second variable volume chamber;
inlet valve means which allows flow of fluid through the fluid inlet into the first variable volume chamber and which prevents flow of fluid from the first variable volume chamber out of the fluid inlet;
transfer valve means which allows flow of fluid from the first variable volume chamber to the second variable volume chamber and which prevents flow of fluid from the second variable volume chamber to the first variable volume chamber;
outlet valve means which allows flow of fluid from the second variable volume chamber out of the fluid outlet and which prevents flow of fluid from the fluid outlet into the second variable volume chamber; wherein:
during movement of the reciprocating member in the housing in a first direction fluid is drawn into the first variable volume chamber and the fluid in the second variable volume chamber expelled from the second variable volume chamber via the fluid outlet; and
during movement of the reciprocating member in the housing in a second direction, opposite to the first direction, fluid is compressed in the first variable volume chamber and fluid is transferred from the first variable volume chamber via the transfer valve means to the second variable volume chamber;
characterised in that:
the reciprocating member comprises a middle section which extends perpendicularly of the axis of reciprocation and two end sections on opposite sides of the middle section, each of the end sections comprising a wall extending generally parallel to the axis of reciprocation and each of the end sections defining with the middle section an open-ended cylinder open at one end;
the housing has a first piston portion which extends into a first of the open-ended cylinders of the reciprocating member and which acts as a piston in the first open-ended cylinder with the first piston portion and the first open-ended cylinder together defining the first variable volume chamber; and
the housing has a second piston portion which extends into a second of the open-ended cylinders of the reciprocating member which acts as a piston in the second open-ended cylinder with the second piston portion and the second open-ended cylinder together defining the second variable volume chamber.
The construction of the machine given above provides an engine or a compressor which has a reduced weight at reduced cost and is simple. In effect, the machine has a single moving member. The machine would be ideal, for instance, for use as an engine in a hybrid vehicle.
Preferably, the reciprocating member has a generally circular radial cross-section and the end sections each comprise an annular wall spaced from a central axis of the reciprocating member.
Making the reciprocating member circular in cross-section eases the manufacture of the machine as a whole.
Preferably, an electrical winding is provided in the housing surrounding the reciprocating member, the electrical winding extending parallel to and adjacent to the end-section walls of the reciprocating member.
The present invention can provide a very compact and simple combined machine and electrical power generator. By locating the winding next to the reciprocating member more power and/or greater electrical control is provided. The construction of the engine can allow the greater percentage of the work of the piston in an engine to be extracted and also the construction of machine allows electrical force to be used efficiently to compress gas in a compressor or to compress fuel/air mixture in an engine. Electrical control can also be used to control the position of the reciprocating member accurately.
Preferably, the electrical winding extends parallel to the axis of reciprocation on the reciprocating member and has a length equivalent to at least the sum of the axial length of the reciprocating member and the distance travelled by the reciprocating member in each reciprocation. This ensures good efficiency.
Preferably the end section walls of the reciprocating member are slidable in slots defined in the housing and the electrical winding in the housing extends adjacent to, and parallel with, surfaces defining the slots. Preferably a seal is formed between the end sections of the reciprocating member and the slots in which the end section slides.
In some embodiments resilient means acts between the housing and the reciprocating member to bias the reciprocating member to move in one direction. Preferably the resilient means act to bias the reciprocating member to reduce the second variable volume chamber to a minimum volume.
The reciprocating member in the present machine is essentially a free motion member. In the prior art, free motion pistons have tended to be used in diesel engines or in Stirling engines. In diesel engines combustion could be ensured by the functioning of the diesel cycle. However, the engines tend to be fairly large and bulky. Stirling engines lack the benefit of internal combustion. The resilient means biassing the reciprocal member could comprise a standard coiled spring or a gas spring. The machine could be configured to work at a frequency equivalent to its resonant frequency, e.g. 3000 rpm. The machine could also be operated by pausing the reciprocating member at a convenient point, with the duration of the pause being variable to vary power output.
Preferably, each of the inlet valve means, the outlet valve means and the transfer valve means comprises either a one-way valve which opens and closes under the action of a pressure differential thereacross or a ported valve comprising a port opening onto one of the variable volume chambers which is cyclically opened and closed by the reciprocating member during reciprocation.
The present invention can remove the need for a complicated valve train system. The present invention when used as an engine can combine an alternator and a starter motor by using electrical winding.
The present invention does away with the need for a cam shaft to control movement of valves. The present invention works essentially on a two-stroke cycle when the invention is used as an engine.
Preferably the inlet valve means comprises a spring-bi
Allen Jeffrey
Kenchington Steven
Liu Han L
Lotus Cars Limited
Luedeka Neely & Graham P.C.
Tyler Cheryl J.
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