Chrysler Corporation

Frederick W Crall

Earl E Daniels

Robert W Eshelman

Ivor W Carter

A combined starter motor and alternator for a vehicular engine system can be positioned for direct coupling to an engine power shaft between the engine and transmisson. A pair of axially offset magnetically permeable disks are bolted to the power shaft. These disks form an annular channel therebetween. A plurality of rare earth permanent magnets are mounted on the inside face of one of the disks in the channel. Positioned within the channel is a stationary, ironless stator assembly having stranded conductive wire windings embedded in an insulation matrix. These windings alternatively pass from the perimeter of the disk towards the interior of the disk as each winding forms a single pass around a longitudinal axis of the power shaft. In a starter mode of operation, a polarity sensor, such as a Hall-effect switch mounted adjacent each stator phase winding, is used to control the driver switches of a conventional H-type arrangement for providing drive current to a starter motor stator coil. The H-driver circuit features use of semiconductor switches capable of withstanding high reverse bias voltage in the H-legs extending between coil ends and the vehicle's battery or direct current energy source.

Alternator starter

A dual purpose alternator starter for an automotive vehicle designed to be positioned between the engine and transmission. In place of the ring gear in a conventional drive train assembly, a pair of off set magnetically permeable discs are bolted to the power shaft. These discs form an annular channel between them. A plurality of rare earth permanent magnets are mounted on the inside face of one of the discs in the channel. On the opposite side of this disc, a set of ring shaped switch contact members are mounted. Positioned stationary to the engine and within the channel is a stationary ironless stator assembly having flat copper windings embedded in an insulation matrix. These windings alternately pass from the perimeter of the disc towards the interior of the disc as each winding forms a single pass around the ring shaped disc. A stationary brush assembly mounted to ride against the set of switch rings on the rotating discs conducts electrical current, when operated as a starter motor, through the ironless stator windings to produce a torque in one direction on the power shaft thus starting the internal combustion engine. When operated as an alternator, the magnetic flux from the permanent magnets cutting the windings of the stationary stator produces electrical current within the stator.

A pressure transducer comprises a series-connected helical coil spring and bellows assembled into the bore of a housing by anchoring the spring and bellows at locations which place them in a state of tension. Expansion and contraction of the bellows reacts against the spring and correspondingly positions a ferrite slug within an inductance coil to cause the inductance thereof to be a function of the pressure differential acting on the bellows. One end of the coil spring is threaded onto a threaded fitting secured to one end of the bellows, and slope calibration of the transducer is accomplished by setting the amount of engagement of the spring with the threaded fitting. Offset calibration can be performed by either of two disclosed techniques, and the offset and slope calibrations can be independently made.

Pressure transducer and method

A pick-up provides a square wave signal whose period corresponds to 720.degree. /N where N is the number of engine cylinders for a four stroke, two cycle internal combustion engine. An integrator is reset by both positive-going and negative-going edges of said square wave signal to produce a sawtooth waveform having a period equal to 360.degree. /N. A blanking circuit which is coupled with the pick-up blanks the sawtooth waveform of said integrator during alternate half cycles of the square wave. The blanked sawtooth waveform is supplied to one input of a comparator and a desired timing signal to the other input of said comparator. The comparator provides an engine timing signal when a predetermined relationship between the blanked sawtooth signal and the desired timing signal is attained. In this way, the engine timing signal is given once per cycle of said blanked sawtooth waveform with the timing thereof relative to said square wave being determined by the desired timing signal. The preferred embodiment discloses a four cylinder engine configuration with electronic spark timing control.

Engine timing control circuit

A single pick-up coupled to sense engine crankshaft position can be utilized for both starting and running of the engine in an electronic spark timing advance control system. During starting, pulses from the pick-up are coupled via a zero crossing detector to the output ignition stage to cause spark plug firing at an essentially constant firing angle at or just slightly in advance of piston top dead center position. During running, the pulses from the pick-up reset, via a reset circuit, an integrator circuit so that a sawtooth waveform representative of engine crankshaft rotational position is developed. A desired timing signal derived from one or more parameters useful in controlling the time of ignition firing is compared against the sawtooth reference waveform and when a predetermined relationship between the two is attained, the ignition is fired. Should this predetermined relationship not be attained during a cycle of the sawtooth, the reset signal from the reset circuit forces ignition firing. A frequency sensitive switch circuit senses approximate engine speed to selectively control ignition firing via the zero crossing detector during starting and via the desired timing signal during running. A safety feature permits the ignition to continue to fire from the zero crossing detector in the event that firing by the desired timing signal is impaired.

Growing community of inventors

Farmington Hills, MI, United States of America

Frederick W Crall