Gm Global Technolgoy Operations, Inc.

Stephen J Sutton

John E Creager

Robert B Gelenius

Richard F Kostelic

J Robert Holen

An improvement in automotive fuel pump assemblies of the type including a tubular cylindrical housing, an electric motor in the housing and a pump in the housing driven by the armature of the motor. The pump includes a first pump body adjacent a flux ring of the motor, a second pump body between the first pump body and the end of the tubular housing, and an impeller in a cavity between the pump bodies. The improvement resides in the provision of axially extending grooves in outer cylindrical surfaces of the pump bodies which register in only a single predetermined angular positional relationship of the pump bodies and in the provision of spring clips which fit in the registered grooves to maintain the predetermined positional relationship and to unitize the pump bodies for efficient handling prior to insertion in the tubular housing.

Fuel pump

Diesel fuel tends to deposit an insulating coating on surfaces it contacts. A probe, preferably in the form of a siphon tube, is coupled to a detection circuit which is responsive to either low resistance or high capacitance between the probe and ground. The probe is initially uncoated to make a resistive coupling to a fuel container when accumulated water touches the probe. When insulating deposits from the diesel fuel or other fuel oil coat the probe, capacitive coupling will occur between the probe and the accumulated water. In either case the presence of water triggers an output signal by the detection circuit.

Apparatus for detecting water in fuel

A capacitive probe for sensing the presence of water in a fuel tank increases in capacitance when water is present. A threshold detector circuit includes the capacitive probe and a reference capacitor and an oscillator for periodically charging them to the same voltage and a comparator for comparing the capacitor voltages during discharge to determine when the probe capacitance exceeds the reference capacitance. The comparator controls a lamp driver which is connected to ground and which is also connected by a single conductor to a remote indicating lamp in series with a power supply. The single conductor carries the lamp energizing current as controlled by the lamp driver and also supplies the operating voltage to the detection circuit. The resistance of the incandescent lamp varies with applied voltage so that the voltage presented to the detector circuit is partially regulated by the lamp resistance so that large changes in the power supply voltage are only partially reflected in the threshold circuit operating voltage.

Threshold detector for a condition indication

A float operated fuel level sender for an automotive vehicle fuel tank includes a molded plastic case secured to a conductive plate. A potentiometer assembly (electrically connected to a fuel gauge) includes a resistor secured within the plastic case and a wiper element movable with the float arm along the length of the resistor. The wiper element is electrically and mechanically connected to the float arm which in turn is connected through a contact element to the conductive plate to provide an electrical ground return. The plastic case has an integral resilient finger formed therein which is biased against the end of the float arm to urge the contact member against the conductive plate thereby assuring a good ground connection.

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Fenton, MI, United States of America

Stephen J Sutton