Abstract: An exhaust gas recirculation system for a compression ignition engine is provided wherein the exhaust gas recirculation is shut off depending upon the sensed or calculated humidity in the intake manifold relative to the dew point of the exhaust/intake air mixture. The humidity of the exhaust/intake air mixture may be measured in the intake manifold, charge air mixer or the ambient humidity may be sensed. If humidity is measured in the air charge mixer or in the ambient air, other factors such as engine speed and load, intake manifold pressure, EGR flow and air/fuel ratio may be used to calculate the humidity in the intake manifold. When the temperature of the mixture in the intake manifold is less than the dew point of the mixture, the engine control strategy may be shut off the EGR to prevent condensation in the exhaust gas recirculation system or engine.

Abstract: A system and method for controlling an internal combustion engine to reduce or eliminate formation of EGR condensate monitor current ambient and operating conditions to determine whether conditions are favorable for condensation of EGR gases, and control the engine accordingly to avoid condensation, preferably by increasing the intake manifold temperature. The intake manifold temperature may be increased by redirecting some or all of the EGR flow to avoid the EGR cooler. Alternatively, or in combination, some or all of the charge air may be redirected to bypass the charge air cooler and/or redirected from the outlet of the turbocharger compressor to the intake, effectively increasing the intake air temperature and resulting in a corresponding increase of the intake manifold temperature. Conditions favorable for condensation may be determined based on engine speed and load, ambient temperature, manifold pressure, scheduled or actual EGR flow rate and scheduled or actual air/fuel ratio.

Abstract: A system and method for determining EGR flow in a multi-cylinder internal combustion engine include determining specific heat of the exhaust gas based on current engine operating conditions and determining EGR flow rate based on the determined specific heat and a signal provided by a sensor. In one embodiment, a species tracking model is used to determine the amount of various species within the exhaust gas which may include oxygen, nitrogen, carbon dioxide, and water, for example, to determine the current specific heat, which is compared to a reference specific heat for the sensor, the difference being used to adjust the sensor value and determine the EGR mass flow rate. The species tracking model uses a simplified combustion model to estimate the amount of each specie in the exhaust gas based on various engine operating parameters, such as fuel, air/fuel ratio, and turbo boost, for example.

Abstract: An exhaust gas recirculation system for a compression ignition engine is provided wherein the exhaust gas recirculation is shut off depending upon the sensed or calculated humidity in the intake manifold relative to the dew point of the exhaust/intake air mixture. The humidity of the exhaust/intake air mixture may be measured in the intake manifold, charge air mixer or the ambient humidity may be sensed. If humidity is measured in the air charge mixer or in the ambient air, other factors such as engine speed and load, intake manifold pressure, EGR flow and air/fuel ratio may be used to calculate the humidity in the intake manifold. When the temperature of the mixture in the intake manifold is less than the dew point of the mixture, the engine control strategy may be shut off the EGR to prevent condensation in the exhaust gas recirculation system or engine.

Abstract: A system and method for controlling an internal combustion engine to reduce or eliminate formation of EGR condensate monitor current ambient and operating conditions to determine whether conditions are favorable for condensation of EGR gases, and control the engine accordingly to avoid condensation, preferably by increasing the intake manifold temperature. The intake manifold temperature may be increased by redirecting some or all of the EGR flow to avoid the EGR cooler. Alternatively, or in combination, some or all of the charge air may be redirected to bypass the charge air cooler and/or redirected from the outlet of the turbocharger compressor to the intake, effectively increasing the intake air temperature and resulting in a corresponding increase of the intake manifold temperature. Conditions favorable for condensation may be determined based on engine speed and load, ambient temperature, manifold pressure, scheduled or actual EGR flow rate and scheduled or actual air/fuel ratio.

Abstract: A system and method for determining EGR flow in a multi-cylinder internal combustion engine include determining specific heat of the exhaust gas based on current engine operating conditions and determining EGR flow rate based on the determined specific heat and a signal provided by a sensor. In one embodiment, a species tracking model is used to determine the amount of various species within the exhaust gas which may include oxygen, nitrogen, carbon dioxide, and water, for example, to determine the current specific heat, which is compared to a reference specific heat for the sensor, the difference being used to adjust the sensor value and determine the EGR mass flow rate. The species tracking model uses a simplified combustion model to estimate the amount of each specie in the exhaust gas based on various engine operating parameters, such as fuel, air/fuel ratio, and turbo boost, for example.

Abstract: The present invention provides a method and apparatus for controlling an internal combustion engine. The engine includes a variable flow exhaust gas recirculation (EGR) system. The method includes providing a variable geometry turbocharger (VGT) in communication with the EGR system for controlling exhaust gas recirculation. The geometry of the VGT is varied by adjustably controlling a rotary electric actuator (REA) operatively connected to the VGT. A position-adjustable proportional flow EGR valve is adjusted by adjustably controlling a second rotary electric actuator (REA) operatively connected to the position-adjustable proportional flow valve.

Abstract: A system and method is provided for treating engine exhaust gases produced by an internal combustion engine. The internal combustion engine has an exhaust gas recirculation circuit which diverts engine exhaust gas from an engine exhaust gas manifold to an engine air intake manifold. An exhaust gas recirculation valve is further provided for controlling the amount of engine exhaust gas diverted toward the engine air intake manifold. Additionally, a small meter pump is provided to create a pressure differential sufficient to introduce a finely tunable and controllable amount of engine exhaust gas into the engine air intake manifold.