Gm Global Technolgoy Operations, Inc.

Douglas I Fales

Robert A Roth

William H Holl

A fuel system for maintaining fuel flow when the surface of the pool of fuel in the fuel tank is below a minimum level. The fuel pump system includes a reservoir in the fuel tank and a pump in the reservoir. A motor in the pump drives a first pump which draws fuel from a secondary chamber of the pump and discharges it to the engine. The motor also drives a second pump which draws fuel from the tank through a primary chamber and discharges it to the secondary chamber. The excess of fuel discharged by the second pump over the first pump is discharged through an orifice in the pump to the reservoir. At fuel levels below the minimum, a float controlled solenoid closes an intake port to the primary chamber causing fuel to back-flow through the flow orifice to the secondary chamber to supply the first pump.

Fuel pump system

A fluid level sensor responsive to the fluid pressure at the bottom of a tank for indicating fluid level including a fluid pressure amplifier that provides an amplified fluid pressure to a gage which is calibrated to provide a measure of fluid level.

Fluid level sensor

A two-stage piston pump has serially arranged pump chambers each having an input passage and a delivery passage. The first stage has a larger displacement than the second stage such that complete filling of the second stage is attained. The piston of the first stage is reciprocated through the cooperation of a spring and a selectively energizable solenoid coil. The piston of the second stage is secured to and reciprocable with the first stage piston. The cylinder for the second stage has an overflow passage disposed to ensure that all the fluid discharged from the first stage prior to the second stage piston closing the overflow passage passes through the second stage cylinder.

Two-stage hydraulic piston pump

A switch includes a self-heating thermistor which has a certain resistance value when exposed to a medium of low thermal conductivity and a thermally conductive solid for movement into contact with the thermistor to lower its temperature and change its resistance. The solid is moved relative to the thermistor in response to any mechanical movement such as a float responding to liquid level or the closure of a door.

Solid state thermistor switch

A combustion engine with a carburetor and exhaust means is provided with an atmospheric air heater such as an exhaust stove. A metering valve supplies a variable mixture of heated air from the exhaust stove and cooler atmospheric air to the carburetor. The changing temperature and hence density of the air supplied to the carburetor produces a changing air-fuel ratio to the engine; and an oxygen sensor in the exhaust system generates a signal indicative of this ratio, which signal is applied through a feedback control system to actuation means for the metering valve to maintain the engine air-fuel ratio at a substantially constant predetermined level.

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Flint, MI, United States of America

Douglas I Fales