Abstract: The present invention provides an intake port design that provides a low thermal inertia characteristic, thereby decoupling the surface temperature of the intake port walls from that of the coolant through use of an air gap formed between the intake port and the cylinder head. At idle and part-throttle, the intake port is at a higher surface temperature yielding better cold-start emissions, better mixture preparation, and less dense intake charge (“thermal throttling”) for better fuel economy. At wide-open-throttle, the intake port is at a lower surface temperature yielding better volumetric efficiency for improved torque and reduction in knocking tendency enabling higher compression ratio for improved fuel economy and performance. The intake port design of the present invention can be manufactured with a hydroform manufacturing process resulting in improved dimensional consistency and smooth surface finish. Additionally, the process eliminates some cylinder head machining processes.

Abstract: An EGR valve position control method controls a position of an EGR valve according to a pressure change across the valve and a desired EGR valve position. The method calculates a desired EGR valve position and generates one or more duty cycle control terms based on a difference between the desired EGR valve position and an actual EGR valve position. Additionally, the method provides feedforward control based on the pressure change and the desired EGR valve position in order to generate feedforward duty cycle control terms. The method controls the position of the EGR valve based on the duty cycle control terms.

Abstract: An EGR valve position control method controls a position of an EGR valve according to a pressure change across the valve and a desired EGR valve position. The method calculates a desired EGR valve position and generates one or more duty cycle control terms based on a difference between the desired EGR valve position and an actual EGR valve position. Additionally, the method provides feedforward control based on the pressure change and the desired EGR valve position in order to generate feedforward duty cycle control terms. The method controls the position of the EGR valve based on the duty cycle control terms.

Abstract: Prior to transitioning a multiple-displacement engine from a full-displacement engine operating mode to a partial-displacement engine operating mode, a base slip rate of a torque converter coupled to the engine engine is increased by a predetermined slip rate offset. The engine is then transitioned to partial-displacement mode upon the earlier of either achieving the desired offset slip rate, or once a maximum time delay has occurred since the slip rate offset was enabled. An offset slip rate is maintained throughout partial-displacement engine operation, and through a transition back to a full-displacement mode. The slip rate offset is removed or disenabled once the engine is again operating in the full-displacement mode. The slip rate offset is either a calibratable constant or is determined as a function of one or more suitable engine or vehicle operating parameters affecting vehicle NVH levels, such as engine speed and vehicle speed.

Abstract: A method and code for controlling the operation of a deactivatable valve lifter of an internal combustion engine includes determining an oil viscosity measure based upon an engine oil pressure achieved when the engine is operating at a warm engine idle operating condition; determining a minimum oil temperature for actuator operation based on a comparison of the oil viscosity measure with a stored value representing the oil's nominal viscosity; and enabling actuator operation when an instantaneous oil temperature is not less than the minimum oil temperature.

Abstract: A method and code for controlling the operation of a deactivatable valve lifter of an internal combustion engine includes determining an oil viscosity measure based upon an engine oil pressure achieved when the engine is operating at a warm engine idle operating condition; determining a minimum oil temperature for actuator operation based on a comparison of the oil viscosity measure with a stored value representing the oil's nominal viscosity; and enabling actuator operation when an instantaneous oil temperature is not less than the minimum oil temperature.

Abstract: A method for estimating an output torque generated by a multi-displacement engine operating in a partial-displacement mode includes multiplying a measure representing a mass air flow through the engine's intake manifold by a engine-speed-based mass-air-flow-to-torque conversion factor, and thereafter summing the product with a torque offset value likewise based on engine speed data, to obtain a base indicated potential output torque. The base indicated potential output torque is then multiplied with a torque-based efficiency conversion factor representing at least one of a partial-displacement mode spark efficiency, fuel-air-ratio efficiency, and exhaust gas recirculation efficiency, and the resulting product is summed with a torque-based frictional loss measure to obtain the desired estimated engine output torque.

Abstract: In an internal combustion engine adapted to operate in a cylinder-deactivation mode, a method for controlling the reactivation of a deactivated cylinder includes determining a difference between a torque request from a vehicle operator, and an estimate of a maximum engine torque achievable in cylinder-deactivation mode based at least in part on a current engine speed. The difference is integrated over time to obtain a torque request “error.” A reactivation of the deactivated cylinder is triggered when the torque request error exceeds a first threshold value, which can be a calibrated value, a calibrated value adapted, for example, for driving style, or a value determined from a vehicle operating parameter such as vehicle speed. The use of the torque request error advantageously avoids reactivation of the deactivated cylinders in response to brief transients in the torque request signal that otherwise temporarily exceed the maximum achievable engine output torque.

Abstract: A method for enabling a transition of a multiple-displacement engine to a different engine operating displacement includes determining a temperature measure correlated with an instantaneous engine oil temperature at an engine start-up, for example, a detected engine coolant temperature at engine start-up; determining a start-up delay period based on the temperature measure, as with a lookup table of calibratable values; and enabling a displacement mode transition no earlier than when the engine run time since start-up exceeds the start-up delay period.

Abstract: A method for controlling the operation of a deactivatable valve lifter of an internal combustion engine includes determining a first measure of heat loss from one or more components associated with a given deactivated cylinder based, for example, on the number of engine cycles that have occurred since cylinder deactivation. The given cylinder is reactivated when the component heat loss measure reaches a threshold level, as by comparing the first measure to a first predetermined threshold value. After cylinder reactivation, the given cylinder can thereafter be deactivated only after the temperature of the components has been restored to a nominal operating temperature, for example, as inferred from a second measure, representing the heat generated within the given cylinder subsequent to cylinder reactivation, determined based upon engine mass air flow or fuel flow. In this manner, the respective temperatures of such engine components are maintained above a desired minimum temperature.

Abstract: A method for determining an event-based hydraulic control delay in a multi-displacement system for an internal combustion engine, with which to adjust the triggering a solenoid in hydraulic communication with a hydraulically-deactivatable valve train component, includes retrieving either a first mapped value representative of a time-based hydraulic deactivation delay, or a second mapped value representative of a time-based hydraulic reactivation delay, based on a current engine speed and a current oil temperature, preferably using different lookup tables for each of the first and second mapped values. The method further includes determining a current time period between generated crankshaft position pulses, and dividing either the first value or the second by the first time period to obtain either an event-based hydraulic deactivation delay or an event-based hydraulic reactivation delay.

Abstract: A process for enabling cylinder deactivation in a multiple displacement engine involving oil aeration includes detecting engine speed. Once the engine speed has been determined, a delay period is established prior to enabling cylinder deactivation. The delay period is a function of whether engine speed exceeds a preselected threshold and an amount by which the threshold is exceeded. When the delay period expires, a request is generated for cylinder deactivation.

Abstract: A method for controlling airflow in an intake manifold of a multiple-displacement engine during an engine displacement mode transition includes determining, before a displacement mode transition, a post-transition mass air flow rate necessary to maintain a pre-transition engine torque output, as well as an airflow transient multiplier based on engine speed and an estimated post-transition manifold air pressure. After multiplying the requested mass air flow rate with the transient multiplier, the resulting compensated requested mass air flow rate is divided by a maximum mass air flow rate to obtain a requested percent airflow.

Abstract: The present invention provides a control system for the active adaptive control of exhaust gas recirculation and spark advance for an internal combustion engine automobile. While the automobile is operating, a control algorithm continuously receives data input from various sources such as the driving mode monitor, fuel consumption monitor, engine roughness monitor, and the engine knock monitor. Based on the data, the control algorithm then causes either an EGR command, a spark advance command, both an EGR and spark advance command, or no command at all to be generated so as to optimize the fuel economy of the automobile. This process is repeated until there is no further beneficial effect on fuel economy or engine roughness and/or engine knock is detected.

Abstract: A method of adapting a linear EGR system is provided to adjust flow rates based on engine roughness. Initially, the level of engine combustion roughness is measured and quantified by a known dynamic crankshaft fuel control methodology. In response, the method adjusts the EGR valve desired position higher or lower based on the measured combustion roughness. For example, if the engine is running "smooth", then more EGR is used. If the engine is running "rough", less EGR is used. As the engine approaches a roughness target, the EGR is stabilized.