Abstract: A mixing and combustion process for a compression ignition engine (10) creates an in-cylinder compressed gas charge of air and recirculated exhaust that has a temperature high enough to initiate and sustain combustion of diesel fuel that is subsequently injected. A fuel injector (26) injects diesel fuel directly into the charge using an injection pressure that is sufficiently great to cause fuel to be injected through each of multiple orifices arranged in a geometric pattern in a nozzle (42) of the fuel injector at an initial velocity that is great enough to cause the injected fuel in moving through the compressed gas charge to creates fuel/charge mixtures throughout a substantial portion of the respective combustion chamber before the kinematics of combustion can become effective to combust more than at most a relatively small amount of the injected fuel.

Abstract: A mixing and combustion process for a compression ignition engine (10) creates an in-cylinder compressed gas charge of air and recirculated exhaust that has a temperature high enough to initiate and sustain combustion of diesel fuel that is subsequently injected. A fuel injector (26) injects diesel fuel directly into the charge using an injection pressure that is sufficiently great to cause fuel to be injected through each of multiple orifices arranged in a geometric pattern in a nozzle (42) of the fuel injector at an initial velocity that is great enough to cause the injected fuel in moving through the compressed gas charge to creates fuel/charge mixtures throughout a substantial portion of the respective combustion chamber before the kinematics of combustion can become effective to combust more than at most a relatively small amount of the injected fuel.

Abstract: A liquid primary fuel is ignited by HCCI with the assistance of the early injection of a liquid pilot fuel. Pilot fuel injection and/or ignition are preferably controlled so as to permit the injected pilot fuel to become thoroughly distributed through and mixed with the primary fuel/air charge in the combustion chamber and vaporized prior to ignition. Pilot fuel having a lower autoignition temperature will be ignited by compression ignition, followed by the ignition of the homogeneous mixture of the primary fuel and air. HCCI combustion of the primary fuel is facilitated by 1) selection of the properties of the primary and pilot fuels and 2) obtaining a homogenous mixture of primary fuel and air by injecting primary fuel into the engine's intake air stream in the form of finely atomized droplets having a mean diameter in the micron range.

Abstract: A liquid primary fuel is ignited by HCCI with the assistance of the early injection of a liquid pilot fuel. Pilot fuel injection and/or ignition are preferably controlled so as to permit the injected pilot fuel to become thoroughly distributed through and mixed with the primary fuel/air charge in the combustion chamber and vaporized prior to ignition. Pilot fuel having a lower autoignition temperature will be ignited by compression ignition, followed by the ignition of the homogeneous mixture of the primary fuel and air. HCCI combustion of the primary fuel is facilitated by 1) selection of the properties of the primary and pilot fuels and 2) obtaining a homogenous mixture of primary fuel and air by injecting primary fuel into the engine's intake air stream in the form of finely atomized droplets having a mean diameter in the micron range.

Abstract: EGR mass fraction or a value indicative thereof can be calculated based on temperature measurements rather than mass flow and/or pressure measurements, hence negating the need for expensive and relatively unreliable measurement devices in an active EGR system for an internal combustion engine. The EGR system may be a low pressure EGR system configured to direct cooled, filtered EGR to the engine's air intake system using an effective, simple venturi and/or a continuously regenerated catalytic particulate trap. The resultant system can reduce NOx emissions in a diesel engine on the order of 50% and approximately 90% for CO, HC, and PM. NOx and other emissions can be reduced still further when the EGR system is combined with other pretreatment and/or after treatment devices. Many components of the low pressure EGR system are also usable in a passive EGR system.

Abstract: EGR mass fraction or a value indicative thereof can be calculated based on temperature measurements rather than mass flow and/or pressure measurements, hence negating the need for expensive and relatively unreliable measurement devices in an active EGR system for an internal combustion engine. The EGR system may be a low pressure EGR system configured to direct cooled, filtered EGR to the engine's air intake system using an effective, simple venturi and/or a continuously regenerated catalytic particulate trap. The resultant system can reduce NOx emissions in a diesel engine on the order of 50% and approximately 90% for CO, HC, and PM. NOx and other emissions can be reduced still further when the EGR system is combined with other pretreatment and/or after treatment devices. Many components of the low pressure EGR system are also usable in a passive EGR system.

Abstract: Pilot fuel injection and/or ignition are controlled in a pilot ignited, gas-fueled, compression ignition engine so as to maintain a relationship Dp/Di of <1, where Dp is the duration of the pilot injection event and Di is the ignition delay period as measured from the start of initiation of pilot fuel injection (Tp) to the start of pilot fuel autoignition (Ti). Dp/Di is less than 1 when a mixing period Dm exists between the end of pilot fuel injection and the start of autoignition. This mixing period permits the injected pilot fuel to become thoroughly distributed through and mixed with the gaseous fuel/air charge in the combustion chamber and vaporized prior to ignition, resulting in improved premixed burning of a heterogeneous mixture of the pilot fuel, the gaseous fuel, and air and dramatically reduced NOx emissions.

Abstract: Pilot fuel injection and/or ignition are controlled in a pilot ignited, gas-fueled, compression ignition engine so as to maintain a relationship Dp/Di of <1, where Dp is the duration of the pilot injection event and Di is the injection delay period as measured from the start of initiation of pilot fuel injection (Tp) to the start of pilot fuel autoignition (Ti). Dp/Di is less than 1 when a mixing period Dm exists between the end of pilot fuel injection and the start of autoignition. This mixing period permits the injected pilot fuel to become thoroughly distributed through and mixed with the gaseous fuel/air charge in the combustion chamber and vaporized prior to ignition, resulting in improved premixed burning of a heterogeneous mixture of the pilot fuel, the gaseous fuel, and air and dramatically reduced NOX emissions.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing a cylinder pressure-dependent parameter on a full time, full range basis using in-cylinder pressure measurements to determine the actual value of the parameter to be optimized. The basic procedure is to determine the desired or optimum value of the parameter, determine the actual value of the parameter or a related parameter, and then adjusting an engine operating characteristic such as air/fuel ratio to maintain the controlled parameter at its optimum value. The preferred parameter is a cylinder pressure ratio (CPR) obtained by dividing first and second values of cylinder pressure, and sensed at different points in a thermodynamic cycle, by one another. The sensed values are preferably a first value P0, obtained during the compression stroke, and a second value Pa, obtained after combustion is complete.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing excess air ratio (lambda) and/or intake air charge temperature (ACT) on a full time, fall range basis. The basic procedure is to first determine the desired or optimum lambda and then to control ACT and intake manifold absolute pressure (MAP) to maintain them at the optimum values for the fuel quantity required at a particular operating point. This approach allows control of both temperature and pressure of the air entering the engine. Full range control requires that lambda and ACT be controlled both upward and downward to achieve optimal engine performance. Control of both lambda and ACT is further enhanced through the use of a supercharger with adjustable input power installed in series with a standard turbocharger compressor of the engine.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing a cylinder pressure-dependent parameter on a full time, full range basis using in-cylinder pressure measurements to determine the actual value of the parameter to be optimized. The basic procedure is to determine the desired or optimum value of the parameter, determine the actual value of the parameter or a related parameter, and then adjusting an engine operating characteristic such as air/fuel ratio to maintain the controlled parameter at its optimum value. The preferred parameter is a cylinder pressure ratio (CPR) obtained by dividing first and second values of cylinder pressure, and sensed at different points in a thermodynamic cycle, by one another. The sensed values are preferably a first value Po, obtained during the compression stroke, and a second value Pa, obtained after combustion is complete.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing excess air ratio (lambda) and/or intake air charge temperature (ACT) on a full time, full range basis. The basic procedure is to first determine the desired or optimum lambda and then to control ACT and intake manifold absolute pressure (MAP) to maintain them at the optimum values for the fuel quantity required at a particular operating point. This approach allows control of both temperature and pressure of the air entering the engine. Full range control requires that lambda and ACT be controlled both upward and downward to achieve optimal engine performance. Control of both lambda and ACT is further enhanced through the use of a supercharger with adjustable input power installed in series with a standard turbocharger compressor of the engine.

Abstract: A pintle nozzle, preferably an unthrottled pintle nozzle, is provided in which a negative interference angle is formed between the conical tip of the nozzle needle and the mating conical valve seat so that the needle seat is located at the bottom of the valve seat rather than at the top. The resulting nozzle lacks any velocity drop downstream of the needle seat, even at very low needle lifts, so that virtually all of the energy used to pressurize the fuel is converted to kinetic energy. Spray dispersion and penetration at low needle lifts therefore are significantly enhanced. Fuel flow through the converging-diameter discharge passage located between the conical needle tip and conical needle seat also self-centers the nozzle needle at low lifts, thereby helping to assure a symmetric spray and to further enhance spray characteristics.

Abstract: The performance of a gas-fueled unthrottled internal combustion engine is improved by optimizing excess air ratio (lambda) in the engine. Lambda is optimized by selecting automatically and continuously the optimum fraction of cylinders firing (OFF) as a function of engine operating parameters, eliminating the fuel charge from one or more cylinders to obtain firing in the OFF, and distributing the unused fuel to the OFF, thereby decreasing lambda in the firing cylinders to an optimum level. OFF may be calculated according to mathematically derived and empirically weighted equations, or obtained with reference to suitable look-up tables. In addition, optimum lambda and OFF may be adjusted to take into account the effects of exhaust gas recirculation (egr), engine speed, and/or engine timing. Further lambda adjustment can be performed by suitable control of egr, ignition timing, and/or turbo air bypass (TAB).