Abstract: A method and a system are provided for purging a hydrocarbon trap coupled to an internal combustion engine. An air supply device supplies oxygen to the hydrocarbon trap to facilitate the oxidation of stored hydrocarbons. A controller causes the air supply device to provide the oxygen in pulses instead of in a constant stream. By providing the oxygen in pulses, a sufficient amount of oxygen can be supplied to effectively purge the hydrocarbon trap, while, at the same time, preventing the unheated air from the air supply device from cooling the hydrocarbon trap below its purge threshold temperature.

Abstract: A crankshaft, for use with a variable compression ratio engine having a connecting rod and a rod bearing, includes a crankpin adapted to be coupled to the connecting rod with the rod bearing disposed between the crankpin and the connecting rod. The crankpin includes a circumferential surface having first and second side surface portions and a main surface portion disposed between the side surface portions. The main surface portion is configured to receive the rod bearing. The first side surface portion has a first aperture disposed at least partially outwardly of the rod bearing when the rod bearing is received on the main surface portion of the crankpin and the crankpin is coupled to the connecting rod. The crankpin further defines, at least partially, a first fluid passage for supplying pressurized fluid to the first aperture, such that the fluid is useable to vary compression ratio of the engine.

Abstract: A control system 14 for a bi-fuel engine 12 is provided. The control system 14 includes a powertrain controller 52 and a bi-fuel controller 54. The controller 52 has a set of fuel injector drivers 92. The controller 50 has a set of gasoline fuel injector drivers 104 and a set of alternate fuel (AF) fuel injector drivers 106. Each of drivers 92 in controller 52 is electrically connected to a driver 104 and a driver 106 in controller 50. Thus, a control signal generated by a single driver 92 can be utilized by either of drivers 104, 106 to generate a corresponding control signal for controlling a gasoline fuel injector 38 or a AF fuel injector 40, respectively.

Abstract: A system and method for selecting one of first and second camshafts in an engine is provided. The first and second camshafts control air flow communicating with the first and second cylinders, respectively, of the engine. The engine includes a crankshaft being driven by first and second pistons with the first and second cylinders. The method includes determining which of the first and second camshafts is moving at a faster rate of movement toward a first scheduled phase angle with respect to the crankshaft. Finally, the method includes selecting one of the first and second camshafts having the faster rate of movement for reducing engine torque fluctuations.

Abstract: A system and method for controlling first and second phase shiftable camshafts in a variable cam timing engine is provided. The method includes determining when the first camshaft is moving toward a first scheduled phase angle with respect to the crankshaft at a faster rate than the second camshaft is moving toward the first scheduled phase angle. Finally, the method includes slowing down the first camshaft so that the rate of movement of the first camshaft approaches a rate or movement of the second camshaft toward the first scheduled phase angle.

Abstract: An engine control method for improving air-fuel ratio control controls airflow when fuel injector limits are reached. The method includes a transient fuel model to calculate a required fuel injection amount based on actual cylinder air charge and feedback from an exhaust sensor. When the required fuel injection amount is outside an operable range, for example, less than zero, airflow is controlled to prevent deviations of exhaust air-fuel ratio. Otherwise, airflow is controlled to provide a desired engine torque. Alternatively, a minimum allowable airflow is determined based on a minimum achievable fuel flow. Then, airflow is prevented from falling below this minimum allowable airflow. The method is particularly useful in preventing rich excursions during rapid decreases in desired engine torque, such as during a driver tip-out.