Abstract: A method and apparatus for providing a signal representative of the output torque of an internal combustion engine utilizes a correlation of average engine speed and variations in instantaneous sub-cyclic engine speed. The variations in instantaneous sub-cyclic engine speed involves a measure of the difference in those instantaneous speeds occuring at a pair of crank angles in each firing interval of an engine cycle, each crank angle of the pair being separated from the other by substantially one-half of the firing interval. The pair of crank angles in each firing interval across which the instantaneous speed difference is measured preferably are the middle of the interval and either the beginning or the end of the interval. The measured valves of instantaneous engine speed may be adjusted to remove the effects of transient changes not related to the individual cylinder firings.

Abstract: A normally-open, solenoid-controlled valve includes a stationary valve-seat spindle and a cylindrical valve sleeve encircling and slideable along part of the valve-seat spindle. The valve-seat spindle has an annular control edge and the valve sleeve includes a pressure-responsive surface which is reciprocably moved into and out of valve-closing contact with the control edge. The valve-seat spindle includes a flow passage therein extending to and discharging into a plenum region formed radially inward of the control edge between the spindle and the sleeve. The pressure-responsive surface of the valve sleeve is a substantially continuous frustrum of a cone whose apex extends in the direction of the valve opening and which extends radially outward from a sleeve inner diameter A to an outer diameter C (point C) of discontinuity in that surface.

Abstract: Methods for determining rate of fuel flow to a combustion engine is disclosed. The fuel flow rate determination is made by measuring a pertubation in air-to-fuel-flow ratio to the engine, or in the volumetric concentration of a gaseous test species in the exhaust, after adding a known amount of a test substance to the air flow intake to the engine, or to the exhaust from the engine, respectively. The desired fuel flow rate is calculated from the measured parameters.