Air supply concepts to improve efficiency of VCRC engines
The air supply to internal combustion engines using variable compression ratio and variable fuel supply VCRC, is improved. The improvements involve increasing thermal efficiency and/or reducing production of pollutants by this engine. The improvements can also be used with other engines that are regulated by fuel supply such as two-stroke diesel engines. These improvements are directed to engines in two basic categories; those with mechanical blowers only and those with turbo charging.
1. A two-stroke internal combustion engine in which output torque is controlled by fuel delivery and in which pollutants are minimized, while efficiency is enhanced, by starting sequential combustion of fuel and air in a cyclically varying expansion volume, including a device to initiate ignition, for a first phase of combustion with a substantially uniform mixture of the fuel and air, enough richer than stoichiometric to suppress the formation of oxides of nitrogen, with said cyclically varying expansion volume containing substantially all the fuel to be burned in one cycle together with only some of the air required in one cycle, and with the subsequent combining of the combustion products of said first phase of combustion with all the remaining air required in said one cycle to substantially complete the combustion of all the fuel in a second phase of combustion, the two-stroke internal combustion engine including:
a blower providing air flow to said engine;
a controllable coupling driving said blower from said engine, said controllable coupling being usable to control a ratio of a rotational speed of said blower with respect to a rotational speed of said engine;
a controllable throttle valve in a manifold defining an air flow passage out of said blower to an air intake of said engine;
a vent passage beyond, in a direction of the air flow out of said controllable throttle valve, to the exterior air and after the air intake of the engine;
a controllable vent valve located at an end of said vent passage remote from said controllable throttle valve, said controllable vent valve normally being closed; and
a servo control system for controlling said controllable coupling in response to a device sensing when engine braking is needed, said servo control system also controlling said controllable throttle valve and said controllable vent valve at said end of said vent passage,
said servo control system controlling said controllable throttle valve and said controllable vent valve to provide said braking of said engine.
2. The engine as set forth in claim 1 further including a blow-off valve placed in said vent passage between the air flow at the air intake of said engine and the exterior air outside said engine, said blow-off valve being capable of exhausting air flow outside of said air intake of said engine if a pressure of said air at said air intake of said engine exceeds a level which is safe for continued operation of said engine.
3. A two-stroke internal combustion engine in which output torque is controlled by fuel delivery and in which pollutants are minimized, while efficiency is enhanced by starting sequential combustion of fuel and air in a cyclically varying expansion volume, including a device to initiate ignition, for a first phase of combustion with a substantially uniform mixture of the fuel and air, enough richer than stoichiometric to suppress the formation of oxides of nitrogen, with said cyclically varying expansion volume containing substantially all the fuel to be burned in one cycle together with only some of the air required in one cycle, and with the subsequent combining of the combustion products of said first phase of combustion with all the remaining air required in said one cycle to substantially complete the combustion of all the fuel in a second phase of combustion, the two-stroke internal combustion engine including:
a turbo-compressor drawing air from the surrounding environment, said turbo-compressor being driven by a turbine which is driven by an exhaust gas flow from said engine;
a blower receiving air from an output of said turbo-compressor, said blower being adapted to function as a motor if an input pressure of said air received by said blower from the output of said turbo-compressor to said blower is higher than an output pressure of air from said blower;
a controllable coupling driving said blower from said engine, said controllable coupling being usable to control a ratio of a rotational speed of said blower with respect to a rotational speed of said engine, and
a servo control system for controlling said controllable coupling driving said blower in response to a device sensing the output pressure of air flow into said engine from said blower, said servo control system controlling said controllable coupling to maintain said output pressure of said air flow into said engine from said blower below a pressure that would be damaging to said engine.
4. The engine set forth in claim 3 further including a blow-off valve placed between an air intake of said engine and air outside said engine, said blow-off valve being capable of exhausting air flow outside said air intake of said engine if a pressure of said air at said air intake of said engine exceeds a level which is safe for continued operation of said engine.
5. The engine set forth in claim 3 further including wherein said cyclically varying expansion volume varies a compression ratio of said engine in reverse accordance with the first combustion volume.
6. A two-stroke internal combustion engine in which output torque is controlled by fuel delivery and pollutants are minimized, while efficiency is enhanced by starting sequential combustion of fuel and air in a cyclically varying expansion volume, including a device to initiate ignition, for a first phase of combustion with a substantially uniform mixture of the fuel and air, enough richer than stoichiometric to suppress the formation of oxides of nitrogen, with said cyclically varying expansion volume containing substantially all the fuel to be burned in one cycle together with only some of the air required in one cycle, and with the subsequent combining of the combustion products of said first phase of combustion with all the remaining air required in said one cycle to substantially complete the combustion of all the fuel in a second phase of combustion, the two-stroke internal combustion engine including:
a turbo-compressor drawing air from the surrounding environment, said turbo-compressor being driven by a turbine which is driven from an exhaust gas flow from said engine;
a first electric motor driven by said turbine, said first electric motor being capable of generating electrical power when driven faster than a no-load speed;
a second electric motor delivering mechanical power in parallel with said engine; and
a servo control system for controlling said first and second electric motors in response to a device sensing input air pressure to said engine, said device sensing said input air pressure to said engine having a signal which said servo control system can interpret.
7. The engine set forth in claim 6 further including a blow-off valve placed between an air intake of said engine and air outside said engine, said blow-off valve being capable of exhausting air flow outside said air intake of said engine if a pressure of said air at said air intake of said engine exceeds a level which is safe for continued operation of said engine.
8. The engine set forth in claim 6 further including wherein said cyclically varying expansion volume varies a compression ratio of said engine in reverse accordance with the first combustion volume.