Much of the world's energy consumption is dedicated to powering internal combustion based vehicles. Most gasoline and diesel car engines are only 20-30% efficient, such that a major portion of the hydrocarbon fuels is wasted, thereby depleting global resources while producing an excessive quantity of pollutants and greenhouse gasses. As illustrated in FIG. 1 (prior art), about one third of the energy used by a conventional engine manifests itself as waste heat in the cooling system (coolant load 4) while another approximately one third of the energy goes out the tailpipe (exhaust enthalpy 2) leaving one third or less to provide useful work (brake power 6). At the internal level, these inefficiencies are due to the fact that the conventional combustion process inside a spark ignition gasoline engine or compression ignition diesel engine takes far too long as compared to the rotational dynamics of the piston and crank (i.e., the power stroke of the engine).
FIG. 2 (prior art) illustrates a typical heat release profile 7 within a high efficiency direct injection Euro-diesel engine cycle, including an ignition delay period 8, a premixed combustion phase 10, a mixing-controlled combustion phase 12 and a late combustion phase 14. Combustion before about 180° of cycle rotation (top dead center) results in increased wasted heat load, while a large portion of the energy from combustion in the late combustion phase 14 (after about 200°) is wasted as exhaust heat. In other words, heat release during the time period starting when the piston is at the top of its stroke and rotating down about 20 degrees (from 180° to 200°) provides the highest percentage of useful work. The heat release before top dead center causes pushback against the rotation which manifests itself ultimately as waste heat in the cooling jacket. Ignition must be started early in gas and diesel engines because it requires a substantial amount of time to fully develop as compared to the rotational timing of the engine. In the late combustion phase 14, fuel continues to burn past the useful limit of the power stroke, thus dumping waste heat into the exhaust system.
USPTO Backgrounds
USPTO Backgrounds