Power plants – Combustion products used as motive fluid – External-combustion engine type
Reexamination Certificate
2001-05-01
2003-09-23
Denion, Thomas (Department: 3748)
Power plants
Combustion products used as motive fluid
External-combustion engine type
C060S039630, C123S197400, C074S055000
Reexamination Certificate
active
06622471
ABSTRACT:
The invention is directed to a method for driving a combustion motor which has a combustion chamber inside which a fuel is burned in cycles and from which the hot, pressurized combustion gas created during the combustion flows into an expansion chamber which is separate from the combustion chamber and where it moves a piston.
Furthermore, the invention is directed to a combustion motor which has a combustion chamber for the cyclical combustion of a fuel, during which a combustion gas is generated, and a separate expansion chamber which is connected with the combustion chamber via a controllable combustion chamber discharge valve and which provides a bearing for a piston that permits the movement of said piston so that the energy of the combustion gas can be converted into mechanical work or energy.
Such a method for driving a combustion motor and respectively such a combustion motor are already known from EP 0 957 250 A2. For this combustion motor, cooling water is sprayed into the expansion chamber at the end of the expansion phase when the piston is at its bottom dead center and when the combustion gas has relaxed to approximately atmospheric pressure. The low pressure caused by the sudden cooling of the hot combustion gases pulls the piston up towards its upper dead center while loading a spring. This stored energy is released to the piston during the next expansion phase when the piston is again moving from the upper to the bottom dead center. By means of spraying in a cooling liquid, the thermal energy of the hot combustion gases, which is normally discharged unused through the exhaust of customary motors without such an injection of cooling liquid, can be used to do work.
It is an important object of the invention to further improve the method of the type mentioned in the start while allowing a further increase of the efficiency of the combustion motor. According to the invention, this can be done by using a method for driving a combustion motor which has the following procedural steps:
cyclical burning of a fuel in a combustion chamber;
letting hot pressurized combustion gas created during the combustion flow into an expansion chamber separate from the combustion chamber where it moves a piston while expanding during an expansion phase; wherein at least for a partial load operation of the motor the combustion gas in the expansion chamber already reaches atmospheric pressure before the end of the expansion phase of the combustion gas; in consequence, the movement of the piston continues in the same direction of movement whilst the combustion gas in the expansion chamber expands further and pressure is generated that is below atmospheric pressure;
spraying cooling liquid into the combustion gas which is at subatmospheric pressure at the end of the expansion phase of the combustion gas; wherein the pressure of the combustion gas is reduced further and the subatmospheric pressure in the expansion chamber acts on the piston and the piston performs work under the effect of this subatmospheric pressure.
Such a thinning of the combustion gas to a value below atmospheric pressure before the implosion of the combustion gas by injection of a cooling liquid is effected has the effect of increasing efficiency; this is similar to the way in which compressing the air introduced into the combustion chamber before burning the fuel-air mix leads to higher efficiency compared to burning the fuel-air mix at atmospheric pressure. Preferably though, the pressure of the combustion gas in the expansion chamber should still be above 0.3 times atmospheric pressure immediately before the implosion phase.
In a preferred embodiment example of the invention, the compression of the air introduced into the combustion chamber is also implemented, wherein advantageously the piston is connected to the compressor piston of a compressor pump by means of a piston rod and the compression takes place during the upward movement of the piston from bottom dead center to upper dead center and is supported by the subatmospheric pressure in the expansion chamber.
The expression “expansion phase” is used for that phase during the working cycle of the motor when the volume of the expansion chamber of the motor increases and the combustion gas therefore expands (either by itself or under the effect of a force). After the injection of the cooling liquid follows the “implosion phase” during which the volume of the expansion chamber decreases while the pressure of the combustion gas increases again towards atmospheric pressure. After atmospheric pressure is exceeded, an “exhaust phase” follows during which the combustion gas is expelled from the expansion chamber. Preferably, this is to be followed by a “waiting phase” of the piston during which fuel is burned in the combustion chamber and the piston preferably to be realized as a reciprocating piston stays in its upper dead center (OT). After the combustion of the fuel in the combustion chamber which advantageously would be complete, the next expansion phase is started.
A combustion motor with an expansion chamber separate from the combustion chamber for which the combustion gas during partial load operation of the motor towards the end of the expansion phase is at a value below atmospheric pressure is already known from U.S. Pat. No. 5,311,739. This effect—here as such unwanted—occurs because the volumes of the combustion chamber and the expansion chamber are determined by the gas volume during full load operation; during partial loads, subatmospheric pressure is therefore created towards the end of the mechanically forced piston travel. By means of the measures described in U.S. Pat. No. 5,311,739, the motor can still be operated in partial load operation, in spite of this subatmospheric pressure that is being generated.
A combustion motor is advantageously suited for the embodiment of the method according to the invention which has a combustion chamber for the cyclical combustion of a fuel during which a combustion gas is generated, and a separate expansion chamber which is connected with the combustion chamber via a controllable combustion chamber discharge valve and which provides a bearing for a piston that permits the movement of said piston so that the energy of the combustion gas can be converted into mechanical work or energy, wherein at least one injection nozzle is provided that opens into the expansion chamber for the purpose of injecting a cooling liquid to decrease the volume of the expanded combustion gas suddenly; and wherein at least one roller is arranged on the piston rod of the piston as a thrust-transmitting member of a cam gear; and wherein curved surfaces of this cam gear, active in both stroke directions of the piston, are resting on both sides of this roller.
By use of this cam gear active on both sides and connected to the piston rod of the piston, the thinning of the combustion gas before the start of implosion phase can be done in an easy manner by spraying in the cooling liquid. As long as the combustion gas in the expansion chamber is under pressure above atmospheric during the movement of the piston from upper dead center to bottom dead center, a thrust-transmitting member in the shape of a roller connected to the piston rod acts on the curved surface that is further away from the piston. As soon as the pressure of the combustion gas in the expansion chamber drops below atmospheric pressure, the curved surface that is closer to the piston acts upon this thrust-transmitting member while the downward movement of the piston is being supported and the pressure of the combustion gas in the expansion chamber falls below atmospheric pressure. The energy required for thinning the combustion gas is drawn from the kinetic energy of the system. This loss of energy, though, is more than compensated for by the fact that the pressure in the expansion chamber keeps on dropping further in the subsequent implosion phase after the injection of the cooling liquid than it would have done without such a thinning and that therefore more work is performed in t
Denion Thomas
Reed Smith LLP
Trieu Thai-Ba
LandOfFree
Method for driving a combustion motor as well as a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for driving a combustion motor as well as a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for driving a combustion motor as well as a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3063407