Hybrid cycle rotary engine
An internal combustion engine includes in one aspect a source of a pressurized working medium and an expander. The expander has a housing and a piston, movably mounted within and with respect to the housing, to perform one of rotation and reciprocation, each complete rotation or reciprocation defining at least a part of a cycle of the engine. The expander also includes a septum, mounted within the housing and movable with respect to the housing and the piston so as to define in conjunction therewith, over first and second angular ranges of the cycle, a working chamber that is isolated from an intake port and an exhaust port. Combustion occurs at least over the first angular range of the cycle to provide heat to the working medium and so as to increase its pressure. The working chamber over a second angular range of the cycle expands in volume while the piston receives, from the working medium as a result of its increased pressure, a force relative to the housing that causes motion of the piston relative to the housing.
1. A method of controlling power output of an internal combustion rotary engine having:
(i) a housing having an intake port for receiving air for provision to a combustion chamber and an exhaust port for discharging exhaust gas,
(ii) a rotor mounted to the housing and configured for rotational motion relative to the housing, wherein the combustion chamber is formed by the rotor and the housing during a combustion phase of a cycle of the engine,
(iii) a fuel injector mounted and configured to inject fuel into the combustion chamber, wherein gases formed by combustion of the injected fuel expand to produce motion of the rotor in the rotary engine during an expansion phase, and
(iv) a controller coupled to the fuel injector to control operation of the fuel injector in a duty cycle comprising a plurality of on-cycles and a plurality of off-cycles,
the method comprising:
receiving an engine signal at the controller;
in response to the engine signal,
during each on-cycle, injecting the same amount of fuel each time fuel is injected, and
during each off-cycle, withholding introduction of fuel, so that fuel is introduced only over a portion of the duty cycle equal to a ratio of on-cycles to off-cycles in order to control power output of the rotary engine; and
continuing to allow air to be delivered into the combustion chamber during each off-cycle of the rotary engine, so that the allowed air causes heat transfer from walls of the rotary engine so as to cool the rotary engine.
2. A method according to claim 1 , wherein the engine signal is an engine load signal, and wherein the ratio of on-cycles to off-cycles varies, at least in part, based on the engine load signal, the method further comprising:
reducing the ratio of on-cycles to off-cycles during light loads of the rotary engine, so that the power output of the rotary engine is reduced accordingly.
3. A method according to claim 1 , wherein the engine signal is an engine temperature signal, and wherein the ratio of on-cycles to off-cycles varies, at least in part, based on an elevation of the engine temperature signal, the method further comprising:
reducing the ratio of on-cycles to off-cycles during the elevation of the engine temperature signal, so that the power output of the rotary engine is reduced accordingly.