Abstract: A fuel system and powertrain for a flexible fuel system vehicle utilizes a controller system to control variables in an engine and the final drive optimize operating efficiency of the vehicle while using an alcohol-gasoline blend. The controller system regulates engine operating variables such as fuel pressure, fuel flow, air-fuel flow, air-fuel temperature, and valve timing. The controller system regulates engine operating variables such as transmission gear selection and gear changing as well as differential ratio changes.

Abstract: A simplified variable intake manifold is disclosed for use with an internal combustion engine. The manifold utilizes a single valve actuator to vary the resonant frequency of a pair of plenums. The two plenums are joined by first and second communication passages of differing lengths connected to provide cross flow between two plenums. Each plenum has an inlet for receiving intake air from a throttle body and a group of runners adapted for connection with a like group of engine cylinders to direct inlet air from the plenums to combustion chambers of the cylinders. A control valve having an elongated shaft extends through the first and second communication passages and includes separate blades rotatable with the shaft to open or close the passages to provide at least three modes of tuning of the plenums. A stepper motor or other suitable device acts upon the shaft to rotate the blades within the communication passages.