US6018200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Load demand throttle control for portable generator and other applications
Assignee: Pramac America LLC
•
Filing: 1997-07-03
•
Granted: 2000-01-25
•
Expires: 2017-07-03
Abstract
Abstract The throttle of an engine in an engine driven generator system operating subject to a wide and rapidly variable load, as in supplying current to a welder, is operated such that control signals are sent to a throttle actuator for adjusting the engine throttle position in response to load changes. The throttle actuator may be a solenoid pulling against a spring in accordance with the average current through the solenoid coil. In this embodiment, the processor causes pulse width modulated signals to be applied across the solenoid coil with throttle position changes being reflected in changes to the width of the pulses, such changes in the pulse width being delayed for at least the predetermined time since the last preceding adjustment to the throttle. Alternatively, the throttle actuator may be a stepper motor which is stepped by throttle position change signals from a processor which monitors engine speed and generator load to determine whether the throttle should be adjusted and, if so, in which direction and to what extent for optimum response.
Inventors
- 👤 William J Anderson
- 👤 Harold C. Scott
- 👤 Chiping Sun
- 👤 Kandarp I. Pandya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:34
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/10; B23K9/1006; B23K9/1043; B23K9/1056; B23K9/1062; F; F02; F02B; F02B63/00; F02B63/04; F02B75/00; F02B75/16; H; H02; H02K; H02K1/00; H02K1/06; H02K1/22; H02K1/27; H02K1/2706; H02K1/272; H02K1/274; H02K1/2753; H02K1/278; H02K21/00; H02K21/48; H02K3/00; H02K3/04; H02K3/28; H02K7/00; H02K7/18; H02K7/1807; H02K7/1815; H02M; H02M7/00; H02P; H02P25/00; H02P25/16; H02P25/18; H02P25/188; H02P9/00; H02P9/04; H02P9/10; H02P9/107; H02P9/14; H02P9/26; H02P9/30; H02P9/48; F02B63/044; F02B2063/045; F02B2063/046; F05; F05C; F05C2201/00; F05C2201/02; F05C2201/021; H02P2101/00; H02P2101/45
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
106 words
Apparatus comprising: an engine including an output shaft and a throttle, the output shaft, in operation, rotating at a speed in accordance with the setting of the throttle; a generator including a rotor, rotationally driven by said output shaft, and a stator including at least one stator winding disposed such that rotation of the rotor induces current in the stator windings; a circuit for generating indicia of the output of the stator; an actuator, responsive to control signals applied thereto, for controlling the setting of the throttle; a control circuit, responsive to the indicia of the stator output, for generating the control signals to the actuator.
Claim 2
Dependent Claim
106 words
Apparatus comprising: an engine including an output shaft and a throttle, the output shaft, in operation, rotating at a speed in accordance with the setting of the throttle; a generator including a rotor, rotationally driven by said output shaft, and a stator including at least one stator winding disposed such that rotation of the rotor induces current in the stator windings; a circuit for generating indicia of the output of the stator; an actuator, responsive to control signals applied thereto, for controlling the setting of the throttle; a control circuit, responsive to the indicia of the stator output, for generating the control signals to the actuator.
Claim 3
Dependent Claim
29 words
The apparatus of claim 1 wherein the circuit for generating indicia of the output of the stator comprises a zero crossing detector cooperating with one of the stator windings.
Claim 4
Dependent Claim
55 words
The apparatus of claim 1 further comprising: a rectifier circuit, responsive to signals from the stator winding, for generating a DC signal; an inverter, responsive to the DC signal, for generating an AC output signal; and and wherein the control circuit generates the control signals to the actuator in accordance with the inverter output signal.
Claim 5
Dependent Claim
38 words
The apparatus of claim 3 further comprising a sensor, responsive to the inverter output signal, for generating indicia of load demand, and wherein the control circuit generates the control signals to the actuator in accordance with load demand.
Claim 6
Dependent Claim
77 words
The apparatus of claim 4 further improved wherein the actuator comprises: a cylindrical magnet, magnetized through its length; a non-magnetic push rod cooperating with the cylindrical magnet and the engine throttle; an actuator winding wound around the push rod; wherein the throttle control signal is selectively applied to the actuator winding to generate a magnetic interaction between the winding and the magnet and cause movement of the magnet and pushrod to vary the setting of the throttle.
Claim 7
Dependent Claim
31 words
The apparatus of claim 5 wherein the throttle control signal is pulse width modulated and the width of the pulse determines the power of the electrical signal supplied to the winding.
Claim 8
Dependent Claim
15 words
The apparatus of claim 5, further improved comprising a fly-back diode provided across the winding.
Claim 9
Dependent Claim
112 words
The apparatus of claim 1 wherein the actuator comprises: a throttle lever arm adapted to cooperate with the throttle such that the throttle setting varies in accordance with the position of the throttle lever arm; an elongated magnet, magnetized through the length thereof, a non-magnetic coupling between the magnet and throttle arm, such that movement of the magnet effects a corresponding movement of the throttle arm; an electrical coil, receptive of a control signal applied thereto, and disposed such that current flow therethrough effects magnetic interaction with the magnet, causing the magnet to assume a position in accordance with the power through the coil, to control the position of the throttle arm.
Claim 10
Dependent Claim
10 words
The apparatus of claim 8 wherein the magnet is cylindrical.
Claim 11
Dependent Claim
12 words
The apparatus of claim 8 wherein the magnet is formed of Alnico.
Claim 12
Dependent Claim
24 words
The apparatus of claim 8 wherein the coupling comprises an elongated non-magnetic push rod, coupled to, and in general axial alignment with the magnet.
Claim 13
Dependent Claim
42 words
The apparatus of claim 8 wherein the actuator further comprises a spring disposed to bias the throttle arm into a designated idle position such that the magnet moves against the bias of the spring to control the position of the throttle arm.
Claim 14
Dependent Claim
29 words
The apparatus of claim 8 wherein the control signals to said actuator comprise pulse width modulated (PWM) signals, the pulse width being in accordance with the desired throttle setting.
Claim 15
Dependent Claim
39 words
The apparatus of claim 1 wherein the actuator comprises a stepping motor having an output shaft mechanically coupled to the throttle, the stepping motor effecting incremental rotation of the stepping motor output shaft in response to the control signals.
Claim 16
Dependent Claim
71 words
The apparatus of claim 14 wherein the stepping motor includes: a plurality of stator coils, and a rotor having magnetic components, cooperating with the output shaft; each of said coils having a center tap and respective ends, the center tap having a first potential applied thereto; and respective switches, responsive to the control signals for selectively effecting a current path from the center tap through a portion of the associated coil.
Claim 17
Dependent Claim
43 words
The apparatus of claim 14 wherein the stepping motor includes: a plurality of stator coils, and a rotor having magnetic components, cooperating with the output shaft; respective switches, responsive to the control signals, for selectively effecting a current path through an associated coil.
Claim 18
Dependent Claim
62 words
The apparatus of claim 14 wherein: the stepping motor includes a plurality of stator coils, and a rotor having magnetic components, cooperating with the output shaft; and said control circuit effects current paths through the stator coils in predetermined sequences to generate magnetic fields which interact with the magnetic components of the rotor, and cause the rotor to move in predetermined increments.
Claim 19
Dependent Claim
31 words
The apparatus of claim 14 further including means for inhibiting adjustment of the throttle setting until at least a predetermined time has elapsed since the last preceding adjustment to the throttle.
Claim 20
Dependent Claim
45 words
The apparatus of claim 14 wherein the stator coils have stator poles associated therewith, and said control circuit generates control signals to effect current flow through single coils, in sequence, to incrementally advance the shaft by a full step, from stator pole to stator pole.
Claim 21
Dependent Claim
59 words
The apparatus of claim 14 wherein the stator coils have stator poles associated therewith, and said control circuit generates control signals to effect pairs of current paths in adjacent coils, in sequence, to incrementally advance the shaft by a full step, at full torque, from midpoint between adjacent stator poles to midpoint between next successive pair of stator poles.
Claim 22
Dependent Claim
68 words
The apparatus of claim 17 wherein the stator coils have stator poles associated therewith, and said control circuit generates control signals to energize a single coil, to bring the rotor into alignment with the stator pole associated with the coil, then generates signals to energize a pair of coils, to bring the rotor into alignment with the midpoint between that stator pole and the next successive stator pole.
Claim 23
Dependent Claim
126 words
The apparatus of claim 1 wherein the actuator comprises: a stepping motor having a rotary output shaft and plurality of coils, rotational movement of the shaft being effected by selective application of current through the coils; a drive circuit, responsive to control signals applied thereto for selectively effecting current flow through at least portions of the respective individual coils; and a mechanical coupling between the stepping motor shaft and the engine throttle, such that rotary movement of the stepping motor shaft effects control of the throttle setting; and said control circuit selectively generates control signals to said drive circuit to effect current paths through at least portions of the respective stepping motor coils in predetermined sequences to cause the rotary shaft to move in predetermined increments.
Claim 24
Dependent Claim
12 words
The apparatus of claim 22 wherein the control circuit comprises a microcomputer.
Claim 25
Dependent Claim
13 words
The apparatus of claim 22 wherein the drive circuit comprises an unidirectional driver.
Claim 26
Dependent Claim
50 words
The apparatus of claim 22 wherein: the respective stepping motor coils each include a center tap; and the drive circuit comprises respective switching devices, responsive to control signals applied thereto, disposed to selectively complete a current path through a portion of the coil, establishing current flow of a predetermined polarity.
Claim 27
Dependent Claim
13 words
The apparatus of claim 22 wherein the drive circuit comprises a bipolar driver.
Claim 28
Dependent Claim
81 words
The apparatus of claim 22 wherein the drive circuit comprises: a first set of switching devices disposed to selectively effect connections between the respective ends of the stepping motor coils to a first potential, and a second set of switching devices disposed to selectively effect connections between the respective ends of the stepping motor coils and a second potential; and the control circuit provides control signals to the switching devices to selectively effect current flows of selected polarity through the coils.
References Cited (Backward Citations)
US3340448A
Cited
US3694661A
Cited
US4163187A
Cited
US4045718A
Cited
US4239978A
Cited
US4293756A
Cited
US4217538A
Cited
US4379990A
Cited
US4456870A
Cited
US4542462A
Cited
US4595841A
Cited
US4608946A
Cited
JPS6082098A
Cited
US4914373A
Cited
US4782257A
Cited
US4629966A
Cited
US4654577A
Cited
US4625160A
Cited
US4647835A
Cited
US4746808A
Cited
US4882513A
Cited
US4788486A
Cited
US4827393A
Cited
US4766362A
Cited
US4780659A
Cited
US4835405A
Cited
US5168208A
Cited
US4885493A
Cited
US5057764A
Cited
US5177677A
Cited
EP0399146A1
Cited
US4950973A
Cited
US5093611A
Cited
US4947100A
Cited
US4968926A
Cited
US5150045A
Cited
US5162686A
Cited
US5369325A
Cited
US5359248A
Cited
US5239253A
Cited
US5444592A
Cited
US5444355A
Cited
US5214371A
Cited
US5504417A
Cited
US5376877A
Cited
US5327069A
Cited
US5467008A
Cited
US5254936A
Cited
US5373196A
Cited
US5510662A
Cited
US5631544A
Cited
US5656922A
Cited
US5539258A
Cited
US5712786A
Cited
US5621304A
Cited
WO1996009679A2
Cited
US5625276A
Cited
WO1996023350A1
Cited
US5703410A
Cited
US5808367A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-01-24 | 2003-07-26 | 2004-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-01-24 | 2007-07-26 | 2008-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-01-24 | 2011-07-26 | 2012-01-25 | $7700.00 | Window Closed / Lapsed |