Abstract: A motor driven air moving apparatus adapted to high speed, constant duty operation has a DC permanent magnet motor with a stator and rotor, one having a wound core with an even number of identically sized, evenly spaced teeth and the other having an even number of identically sized, permanent magnet poles. One of the rotor and stator has a skew at an angle from the axial, the maximum achievable skew being less than one tooth pitch due to short axial core width. A groove is provided along the midline of each of the teeth of the core which is parallel to and shallower than the tooth separating slots and contains no winding. The groove is effective to divide the tooth magnetically in half and thus decrease the effective tooth pitch, whereby, simultaneously, the magnetically induced pulsating angular velocity of the rotor and resultant audible noise are reduced and the system efficiency of the motor and air moving apparatus combination at high speeds in constant duty operation is increased.

Abstract: A binary threshold comparator is disclosed for first and second binary numbers, wherein the first is variable and the second is a threshold or reference, with the complement of the second number available. The comparator may be a high threshold (greater/equal) comparator or a low threshold (less/equal) comparator. It comprises 5 MOSFETs per bit stage, with two additional MOSFETs per comparator for high/low determination and carry in precharge. A particular multi-bit embodiment of the comparator has a modified most significant bit stage which provides a complement of the normal output when the most significant bits of the numbers to be compared are different to prevent an immediate reversal of comparator output when a counter containing the variable number rolls over from all ones to all zeros or vice versa.

Abstract: A switching circuit for and inductive load with a parallel freewheeling diode comprises a semiconductor switch in series therewith across a power supply and a switch control effective to change the semiconductor switch from a nonconducting to a conducting state by sourcing current to the control electrode to charge the internal capacitance. The switch control means is responsive to the load voltage to produce a lower current rate to the control electrode while the load voltage indicates a condition other than reverse bias for the freewheeling diode in order to reduce RFI by slowing the switching of the semiconductor switch while the freewheeling diode is recovering and a higher current rate as soon as the load voltage indicates reverse bias for the freewheeling diode in order to minimize time spent in the active conduction region of the semiconductor switch and thus minimize resultant heat generation during switching.

Abstract: An induction motor comprises a stator and rotor totally enclosed in a case with no air communication through the case, an internal shaft mounted fan at each end of the rotor and an external fan and fan shield at one end to direct cooling air along the outer surface of the case. The motor is further provided with hollow, toroidal baffles internally at each end which force the air within the case at each end of the motor to be circulated across the bearing and ends of the windings to pick up heat and along the internal surface of the case to exchange the heat through the case with the fan driven outside air. A further improvement is the provision of an air channel from the fan shield along the outer surface of the case to the other end of the motor and radial ducts from the channel to the interior of the baffle and from the opposite side of the baffle to the case, whereby a portion of the fan driven external cooling air is forced through the interior of the driving end baffle.

Abstract: An audio amplifier of the type including circuitry to detect clipping and adjust the gain of an amplifier input element to control the clipping in closed loop operation further includes circuitry effective to sense the temperature of an amplifier component and change the amplifier bias voltage that determines the maximum non-clipping voltage so as to induce clipping in the amplifier when the temperature exceeds a predetermined temperature. The clipping control circuitry then reduces the input gain to the amplifier to control the clipping and, in so doing, reduces power dissipation to a level allowing the temperature to decrease to the predetermined temperature. The circuit provides for closed loop control of amplifier temperature in marginal temperature situations with minimal intrusion on the music reproduction process.

Abstract: Slot antenna apparatus for the roof of a motor vehicle having a central electrically non-conducting portion comprises a horizontal sheet of electrically conducting material under the central portion of the roof. The sheet includes a looped slot having a total loop length of substantially one wavelength in the commercial FM broadcasting band and dividing the sheet into inner and outer portions. A coaxial feed cable adapted for connection at its lower end to AM-FM radio receiver apparatus is routed up one of the vertical pillers to the roof portion of the body and across the roof portion to the center front of the slot to feed the antenna at its front center relative to the vehicle body. A ground conductor connects the outer portion of the horizontal sheet to a point on the vehicle body comprising a voltage null in the vehicle body standing voltage pattern to provide a DC ground and an RF ground at commercial AM broadcast frequencies.

Abstract: Power antenna control apparatus is disclosed for a vehicle having an ignition switch with off, run and start positions, engine start means responsive to the ignition switch in its start position, a radio receiver effective to generate an extend signal when activated and a retract signal when deactivated and means effective to deactivate the radio receiver with the ignition switch in its off and start positions. The control comprises control means responsive to the extend and retract signals to activate the drive means toward, respectively, fully extended and retracted antenna positions and further comprises control means responsive to the ignition switch in its start position to deactivate the drive means at least in the extend direction and for at least a predetermined period of time deemed sufficient for engine starting, whereby reversal of antenna extension during engine starting is prevented.

Abstract: A power antenna control for a motor vehicle comprises a Hall effect device responsive to motor armature rotation to generate pulses for equal predetermined increments of antenna travel. These pulses are applied to both position and stall counters. In extension, the antenna drive is stopped when the position counter reaches a number corresponding to a predetermined extended position, which may be full extension or some lesser extension. In retraction, the stall counter is used with a clock to indicate stall which, when detected, causes the antenna drive to be stopped. Automatic current limiting for drive torque limitation during stall is activated only when the position counter indicates a limited position range near full retraction. Further during retraction, if the antenna is stopped within a small position range of full rectraction, it is reset to a count indicating full retraction. The system eliminates the need for hard stall sensing reaction switches and thus reduces antenna drive cable fatigue.

Abstract: An electropneumatic door lock control in which a pump activatable to generate a first or second pressure is controlled by a bistable pressure latch and communicated through passenger lock and auxiliary solenoids to pneumatic passenger lock and auxiliary actuators. Initiation means for first and second locking operations of a passenger door lock and a third locking operation of an auxiliary lock are interconnected with the bistable pressure latch, a bistable passenger latch and a bistable auxiliary latch and first and second timers to control the locking operations so that the first and second locking operations generate different pressures but activate the same timer for a duration of activation while the third locking operation generates one of the pressures but activates the other timer for a different duration of activation. With each activation of one of the initiation means the non-chosen latches and timer are deactivated.

Abstract: A knock sensor includes a circular mounting surface with a flat, self-resonant vibration element and piezoelectric disk coaxially mounted thereon. The vibration element comprises a central circular portion and a pair of outer semicircular portions of larger radius, the outer semicircular portions being shifted in opposite direction along their common border from the axis by an equal distances and each being divided into an equal number of sectors by radial slots centered on the axis and extending outward from the first radius with equal angles therebetween to from diametrically opposed pairs of similarly shaped and sized vibrating sectors. The pairs of sectors have resonant frequencies together forming a sensor passband wider than the individual passbands of the pairs taken separately. In addition, differences in resonant frequency between members of a pair due to misalignment of the axes of the vibration element and mounting surface do not significantly affect the sensor passband.

Abstract: A power MOSFET switching control for multiple loads requiring current limiting at initial energization comprises at least two MOSFETs connected in series between one of the multiple loads and a power supply. Each MOSFET has a control electrode with a control electrode capacitance. Each control electrode is connected to a single charge pump, powered by the power supply, repeatedly in a pulsed manner to limit average current through its MOSFET. The individual control electrodes are connected to the charge pump alternately in a predetermined order such that no two control electrodes are connected to the charge pump simultaneously. In one mode of operation, the control electrodes and charge pump are connected and disconnected by clocked, multiplexing switch control means at predetermined times. In another mode of operation, only the connections are accomplished at the predetermined times; and the disconnections are in response to control electrode voltage sensing means.

Abstract: An automatic vehicle headlamp dimming control is the type having an operator controlled first voltage divider across a power supply, a light sensitive resistance connected in electrical series with an electrically controlled variable resistance in a second voltage divider across the output of the first voltage divider, an energizing circuit adapted to energize the headlamp system from the power supply at high or low intensity in response to the output of the second voltage divider compared to a fixed reference voltage and first electric feedback means from the energizing circuit to the electrically controlled variable resistance for producing hysteresis feedback.

Abstract: A low impedance interface circuit for use with an internal combustion engine between a capacitive piezoelectric combustion pressure sensor and LPP signal processing circuitry comprises an operational amplifier with a negative feedback capacitor and an input DC blocking capacitor, a voltage follower amplifier with a first resistor at its input and a second resistor at its output connecting it in parallel with the feedback capacitor, a DC filter capacitor connected to the input of the voltage follower amplifier and forming a low pass filter with the first resistor to maintain a substantially constant DC voltage equal to the DC operating voltage for DC feedback, a current source controlled by the output of the operational amplifier and connected in series with the first resistor to provide increased current for the charging of the DC filter capacitor and a diode bypassing the first resistor to allow fast charging of the DC filter capacitor and DC blocking capacitor during startup.

Abstract: A control decreases dilution (EGR) in an internal combustion engine from a schedule if surge is detected and allows it to return to the schedule in the absence of surge. Surge is detected by timing a predetermined crank angle of 70-10 degrees BTDC, an angle including only crank deceleration, for consecutive engine firings, updating an average time therewith and computing the difference between the new time and the average. The successive differences are examined for zero crossings and compared to a stored maximum difference. If difference exceeds the maximum it becomes the new maximum difference. If a zero crossing is detected, the time since the last zero crossing is calculated to determine if the difference variations have a frequency of 2-10 Hz. If so, and the maximum difference exceeds a reference, a surge signal is generated.

Abstract: A signal seeking radio receiver is disclosed in which the AGC voltage applied to the RF amplifier is automatically reduced only when a sweep tune signal is present with a signal generated by the detection of a parameter associated with low ambient light typical of nighttime operating. The night signal may be produced by an ambient light sensor or in response to the activation of a vehicle running light. Thus the stop sensitivity of the tuner in signal seeking mode is reduced at night to prevent stopping on undersirable skywave signals but is normal during daytime operation when the running light is not activated. The sweep tune signal may be the fast/slow AGC control signal or mute signal generated during signal seeking; and its removal when the sweep stops on a station provides normal AGC operation for listening, even at night.

Abstract: A dilution control adjusts an EGR valve, variable valve lift mechanism or similar dilution control device in an internal combustion engine in response to the relationship between ignition timing and the timing of peak combustion pressure (LPP) in the vicinity of a desired timing of peak combustion pressure (DLPP). The relationship is derived in the process of controlling ignition timing in response to LPP, wherein LPP is controlled to DLPP or as close to it as possible. In this process, LPP varies slightly back and forth through DLPP or through a maximum retard value, if LPP is not attainable. The apparatus detects whether LPP is retarded with respect to DLPP as it reverses from retard to advance, increases dilution if it is so retarded and decreases dilution if it is not. The engine thus operates with maximum EGR consistent with LPP being equal to the desired value DLPP.

Abstract: A control for a wound rotor induction motor including shorting switches in a secondary resistance network comprises an input comparator with voltage limiting switched by the rotor voltage, a pulse generator responsive to the input comparator to generate voltage pulses of predetermined constant duration at a frequency proportional to the frequency of the rectangular voltage wave, a low pass filter effective to filter the output of the pulse generator to a DC voltage inversely related to rotor speed, a DC power supply effective to generate a plurality of DC reference voltages, a plurality of switch control comparators, each receiving the output of the low pass filter on one input and one of the DC reference voltages on the other input and a plurality of switch actuators, each switch actuator being responsive to the output of one of the switch control comparators to activate a group of shorting switches at a predetermined rotor speed during motor acceleration and deceleration.

Abstract: An AM-FM-cellular telephone multiband antenna adapted for mounting on a motor vehicle fender includes a first mast section having a length of one quarter wavelength at a first frequency near 835 MHz in the cellular telephone band, a phasing coil connected collinearly above the first mast section and having an effective electrical length of three halves wavelength at the first frequency and a second mast section connected collinearly above the phasing coil and having a length of one half the wavelength at the first frequency, whereby the phasing coil and second mast section increase the gain of the total assembly compared to a quarter wavelength antenna for cellular telephone operation at frequencies near the first frequency and further tune the antenna to resonance at a second frequency in the FM radio while providing reception at frequencies in the AM radio band. The antenna is especially suited for power telescoping operation.

Abstract: Conventional bridged amplifiers obtain output voltage range and DC operating voltage from full and half voltage outputs of a voltage divider. A low voltage unipolar supply powers the voltage divider for small signals. A peak detector selects the higher peak amplifier output; and a voltage follower with an output voltage range from a high voltage unipolar supply maintains an output voltage a predetermined level above the peak. The output of the follower controls a transistor connecting the high voltage supply to the full voltage output of the voltage divider to allow the bridged amplifier outputs to increase above the low voltage supply as necessary in class G operation.

Abstract: Slot antenna apparatus for a motor vehicle roof having a central portion made of electrically non-conducting material comprises a horizontal sheet of electrically conducting material attached to the roof with a looped slot adjacent the central portion of the roof dividing the sheet into inner and outer portions and having a total loop length of substantially one wavelength in the commercial FM broadcasting band. Antenna feed means are provided at the front center of the slot for FM receiver apparatus and at the side center of the slot essentially 90 degrees rotated from the front center of the slot for AM receiver apparatus. The AM and FM feeds may be connected by coaxial cable to AM and FM tuners in a common radio receiver in the vehicle dashboard; or separate AM and FM portions of the receiver may be installed adjacent the appropriate antenna feeds. The antenna is grounded at DC and in both the AM and FM commercial frequency bands.