Isochoric heat addition engines and methods

A method of adjustably reducing by a percentage in power output of an internal combustion rotary engine, the internal combustion rotary engine comprising:

• a housing having an intake port, a recess that forms a part of a combustion chamber, and an exhaust port, wherein the intake port and the exhaust port are adjacent to one another within the housing and located so that both the intake and exhaust ports are closer to the combustion chamber on one side of the housing than another side;
• a fuel injector configured to inject fuel into the recess, the fuel injector mounted in the housing;
• a rotor having a lobe, the rotor being rotatably mounted in the housing and coupled to a shaft;
• two gates, each gate movably mounted with respect to the housing on opposing sides of the recess, so that each gate is engaged at least periodically with the rotor, wherein during engagement of at least one of the two gates with the rotor a volume is maintained between a surface of the at least one gate, the rotor, and the housing, the volume undergoing changes in accordance with the cycle during rotation of the rotor;
• and
• a controller configured to control the fuel injector,
• the method comprising:
• reducing the volume from a first quantity to a second quantity in a compression phase of the cycle so as to compress air disposed therein;
• holding the volume constant at the second quantity after the compression phase and during a combustion phase of the cycle by engaging the two gates against the rotor so as to form the combustion chamber;
• injecting fuel into the combustion chamber by the fuel injector, wherein reduction in volume of air during the compression phase of the cycle in combination with the introduction of fuel are sufficient to cause spontaneous combustion of the fuel;
• controlling the fuel injector to inject the same amount of fuel each time fuel is injected or to withhold introduction of fuel during a percentage of cycles, so that fuel is introduced only over a sufficient number of cycles per unit of time in order to produce a reduction by the percentage, in the power output of the engine;
• and
• increasing the volume of gases in an expansion phase of the cycle to a third quantity that is larger than the first quantity, by disengaging one of the two gates from contact with the rotor and the other one of the two gates remains engaged with the rotor until a completion of the expansion phase, while expanding gases from combustion apply a torque to the rotor relative to the housing so as to cause the rotor, and therefore the shaft, to rotate,
• wherein the intake port and the exhaust port are located within the housing so that angular displacement, of the rotor lobe in operation of the engine in the compression phase of the cycle, between a first position when the rotor lobe is close to the intake port and a second position when the rotor lobe is close to the recess so as to form the combustion chamber is substantially less than angular displacement of the rotor lobe in operation of the engine in the expansion phase of the cycle, between the second position and a third position when the rotor lobe is close to the exhaust port, and
• for each cycle that withholds the introduction of fuel, supplying heat by heat transfer from (i) walls of the engine directly, (ii) a heat exchanger, or both, during a phase of such cycle when combustion would occur if introduction of fuel had not been withheld and during the expansion phase of such cycle.