Abstract: A system for controlling the flow of air entering the intake manifold of a multicylinder variable displacement internal combustion engine installed in a vehicle having a driver-operable accelerator control includes an accelerator control position sensor for determining the operating position of the accelerator control and for generating an accelerator control position signal indicating such position, as well as an engine speed sensor for determining the speed of the engine and for generating an engine speed signal indicating such speed. The present system further includes an engine cylinder operator for deactivating and reactivating at least some of the cylinders and an electronically controlled throttle valve positioned in the intake manifold of the engine so as to control the amount of air entering the engine's cylinders.

Abstract: A system for selecting the number of cylinders to be operated in a multi-cylinder variable displacement internal combustion engine installed in a vehicle having a driver operable accelerator control includes an accelerator control position sensor for determining the operating position of the accelerator control and an engine speed sensor for determining the speed of the engine, as well as a processor containing stored values for engine load as functions of engine speed and accelerator position and also engine load at wide open throttle. The processor infers engine load based on the accelerator control position and engine speed then selects the number of cylinders of the engine to be operated based at least in part of a comparison of the inferred engine load and the maximum possible load at the same engine speed.

Abstract: A system for synchronously activating cylinders of a multicylinder, fuel injected, four stroke cycle internal combustion engine, includes a valve operator for deactivating intake and exhaust valves associated with the cylinders and a controller for selecting a cylinder to be deactivated, as well as a timing mechanism for determining when the selected cylinder is operating during intake events. The controllers directs the valve operator to begin deactivating the valves of a selected cylinder during a predetermined intake event, with the valve operator completing the deactivation by a time not later than the beginning of the next exhaust event.

Abstract: A system for predicting cylinder air charge for a variable displacement internal combustion engine operating in a transition from a first number of activated cylinders to a second number of activated cylinders includes a throttle sensing system for determining the effective flow area of the air intake passage of the engine and for generating a signal corresponding to the area, an engine speed sensor for determining the speed of the engine and for generating a signal corresponding to the speed, an airflow sensor for determining the instantaneous mass airflow into the engine and for generating a signal corresponding to the airflow, and a controller for receiving the speed, flow area, and mass airflow signals and for calculating the mass of air admitted to each engine cylinder during its intake stroke, based upon the values of the signals.

Abstract: This invention tests the mechanical integrity of an evaporative purge system and fuel system by applying a vacuum to a fuel tank and measuring the extent to which this vacuum bleeds down over a time period. Included in the test method are the steps of closing the vapor management valve positioned between the engine manifold and the evaporative purge flow path of the fuel tank; waiting a predetermined period of time; and obtaining an indication of the extent to which pressure is increasing in the fuel tank due to vapor generation.