Abstract: An engine control system and method maintains an optimum exhaust fuel to air ratio in an internal combustion engine. A secondary air injection (SAI) pressure is measured in an SAI system. The SAI pressure measurement is converted into an SAI flow value. A fuel compensation value is obtained based on the SAI flow value. Fuel delivery is compensated to the engine based on the fuel compensation value. In a second embodiment, the fuel compensation value is obtained based on the SAI pressure measurement. Fuel delivery is compensated to the engine based on the fuel compensation value. In a third embodiment, a primary flow value is calculated at an air intake of the engine. A fuel compensation value is calculated based on the SAI flow and primary flow values. Fuel delivery to the engine is compensated based on the fuel compensation value.

Abstract: A magnetic data recording system and apparatus providing the flexibility of using a magnetoresistive read/write head in other than its standard orientation. The invention includes a plurality of magnetic recording disks supported on a spindle rotated by a motor. A plurality of arms, each mounted to a common actuator for arcuate motion, support at their distal ends the magnetoresistive read/write heads. The arms suspend the heads in close proximity to upper and lower surfaces of the disks so that the heads may record signals thereto and read signals therefrom. Generally such systems comprise two sets of such heads, a set of up-heads designed for facing upward to read the bottom surface of a disk and another set of down-heads designed to face downward to read an upper surface of a disk.