# US 8,569,903 B2 · Methods and systems for improved engine speed control during engine starting > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,569,903 B2 - Document ID: US8569903B2 - Status: Granted - Kind: B2 - Application number: 12/913,569 - Filed: 2010-10-27 - Published: 2012-05-03 - Granted: 2013-10-29 - Earliest claimed: 2010-10-27 - Assignees: Ford Global Technologies, LLC - Applicants: Alex O'Connor Gibson; John Anthony DeMarco; Allan Roy Gale; Robert Michael Grant - Inventors: Alex O'Connor Gibson; John Anthony DeMarco; Allan Roy Gale; Robert Michael Grant - Web page: https://patentgrep.com/patent/US8569903B2 ## CPC - B60L 1/003: {to auxiliary motors, e.g. for pumps, compressors} - B60L 15/20: for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed - B60L 50/16: with provision for separate direct mechanical propulsion - B60L 50/50: using propulsion power supplied by batteries or fuel cells - B60L 58/20: having different nominal voltages - F02N 11/0814: {comprising means for controlling automatic idle-start-stop} - B60L 2210/10: DC to DC converters - B60L 2240/34: Cabin temperature - B60L 2240/421: Speed - B60L 2240/423: Torque - B60L 2240/441: Speed - B60L 2240/445: Temperature - B60L 2240/547: Voltage - B60L 2250/26: by pedal actuation - Y02T 10/40: Engine management systems - Y02T 10/64: Electric machine technologies in electromobility - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors - Y02T 10/72: Electric energy management in electromobility - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A system for improving engine starting is disclosed. In one example, an engine starting is improved by providing a variable load to the engine during engine starting. The variable load may be provided by controlling alternator field current during the engine start. ## Claims ### Claim 1 A system for controlling engine speed during an engine start, comprising: an engine; a first battery in electrical communication with an engine starter during an engine start; an alternator mechanically coupled to the engine, the alternator having a field coil excitation circuit that is electrically buffered from the first battery during the engine start, the field coil excitation circuit in electrical communication with a power source other than the first battery during the engine start; and a controller to vary a strength of a magnetic field produced by a field coil via adjusting a voltage or current supplied to the field coil excitation circuit responsive to inputs received from the engine. ### Claim 2 (depends on 1) The system of claim 1, wherein the power source is a second battery. ### Claim 3 (depends on 1) The system of claim 1, wherein the power source is a DC/DC converter and where the DC/DC converter electrically buffers the field coil from the first battery during the engine start. ### Claim 4 (depends on 1) The system of claim 1, further comprising a circuit to vary the strength of the magnetic field, the circuit including a differential amplifier, and the controller further comprising instructions for varying alternator field coil average voltage during the engine start by adjusting an output of the differential amplifier. ### Claim 5 (depends on 1) The system of claim 1, wherein the controller includes instructions for varying alternator field coil average voltage during the engine start to vary a load provided by the alternator to the engine during the engine start. ### Claim 6 (depends on 5) The system of claim 5, wherein the alternator field coil average voltage is adjusted in response to a number of combustion events since engine stop. ### Claim 7 (depends on 6) The system of claim 6, wherein the alternator field coil average voltage is further adjusted in response to a barometric pressure or engine wear. ### Claim 8 (depends on 7) The system of claim 7, wherein adjusting the alternator field coil average voltage includes decreasing the alternator field coil average voltage applied to the field coil as the barometric pressure increases. ### Claim 9 (depends on 5) The system of claim 5, wherein the controller includes further instructions for selectively shutting-down the engine during engine idle-stop conditions and selectively restarting the engine during restart conditions. ### Claim 10 (depends on 5) The system of claim 5, wherein the controller includes further instructions for adjusting the alternator field coil average voltage during an engine stop to control engine position. ### Claim 11 (depends on 4) The system of claim 4, where the differential amplifier is powered by the power source other than the first battery, and where the power source other than the first battery is a DC/DC converter. ### Claim 12 (depends on 4) The system of claim 4, further comprising a resistor electrically coupled to the differential amplifier. ### Claim 13 A method of controlling engine speed, comprising: during an engine start, electrically buffering a field coil of an alternator from a battery supplying power to an engine starter; and varying an electrical property supplied to the field coil to control engine speed during the engine start responsive to inputs received at a controller from an engine, the electrical property supplied to the field coil supplied via a substantially constant voltage source. ### Claim 14 (depends on 13) The method of claim 13, wherein the electrical property is a current or an average voltage. ### Claim 15 (depends on 14) The method of claim 14, wherein the electrical property is further varied in response to a barometric pressure, varying the electrical property including increasing the electrical property applied as the barometric pressure increases. ### Claim 16 (depends on 13) The method of claim 13, further comprising, controlling a current supplied by the alternator to a power steering system during the engine start. ### Claim 17 (depends on 13) The method of claim 13, wherein electrically buffering the field coil includes opening a switch to avoid bypassing a DC/DC converter configured to provide a regulated voltage output to the field coil. ### Claim 18 A method of operating an engine, comprising: during an engine start, adjusting an electrical property supplied to an alternator field coil in response to a selected engine start speed profile, wherein the alternator field coil is electrically coupled to an output of a DC/DC converter during the engine start, the DC/DC converter powered at least in part via a battery, the alternator field coil electrically buffered from the battery via the DC/DC converter. ### Claim 19 (depends on 18) The method of claim 18, wherein the electrical property supplied to the alternator field coil is a voltage and wherein the voltage is further adjusted in response to alternator angular velocity. ### Claim 20 (depends on 18) The method of claim 18, wherein the electrical property supplied to the alternator field coil is a current and wherein the current supplied to the alternator field coil is adjusted via a transistor, and where the transistor is controlled via a differential amplifier.