# US 2013/0158765 A1 · Modular auxiliary power unit assembly for an electric vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0158765 A1 - Document ID: US20130158765A1 - Status: Published application - Kind: A1 - Application number: 13/767,962 - Filed: 2013-02-15 - Published: 2013-06-20 - Earliest claimed: 2009-01-29 - Assignees: General Electric Company - Inventors: Michal-Wolfgang Waszak; Parag Vyas; Jan Hemmelmann; Robert Dean King - Web page: https://patentgrep.com/patent/US20130158765A1 ## CPC - B60W 20/12: using control strategies taking into account route information {(estimation or calculation of non-directly measurable driving parameters B60W40/00)} - B60K 6/46: Series type - B60L 50/10: using propulsion power supplied by engine-driven generators, e.g. generators driven by combustion engines - H02P 9/04: Control effected upon non-electric prime mover and dependent upon electric output value of the generator - B60L 2220/18: Reluctance machines - B60L 2270/142: acoustic - B60L 2270/145: Structure borne vibrations - Y02T 10/62: Hybrid vehicles - 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 - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES - 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 - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A system and method for a propulsion system includes an electric motor and an energy storage unit configured to supply a primary power to the electric motor. The propulsion system also includes a plurality of auxiliary power units (APUs) configured to supply a secondary power to at least one of the electric motor and the energy storage unit. Each of the plurality of APUs includes a free-piston engine configured to generate a mechanical output, a linear generator configured to transform the mechanical output to an electrical power, and a controller. The controller receives a power command from the electric motor and/or the energy storage unit, determines an amount of secondary power needed to meet the power command, and selectively activates a number of the plurality of APUs to generate the needed amount of secondary power. ## Claims ### Claim 1 An auxiliary power assembly comprising: a plurality of auxiliary power units (APUs) configured to generate a secondary power, each of the plurality of APUs comprising a free-piston combustion engine (FPE) and a linear generator; and a controller configured to: sense a power requirement of at least one of an electric motor and an energy storage device; determine an optimal operation strategy of the plurality of APUs based on the sensed power requirement; and operate the plurality of APUs according to the optimal operation strategy to provide the secondary power to at least one of the electric motor and the energy storage device. ### Claim 2 (depends on 1) The auxiliary power assembly of claim 1 wherein the controller is configured to operate each of the plurality of APUs in one of an active and a non-active state. ### Claim 3 (depends on 2) The auxiliary power assembly of claim 2 wherein the controller is configured to operate less than all of the plurality of APUs in the active state to provide the secondary power according to the optimal operation strategy. ### Claim 4 (depends on 2) The auxiliary power assembly of claim 2 wherein the controller is configured to operate each of the APUs in the active state above a minimum efficiency threshold according to the optimal operation strategy. ### Claim 5 (depends on 1) The auxiliary power assembly of claim 1 wherein the controller is configured to operate the plurality of APUs according to the optimal operation strategy to provide at least one of a supplemental power to the electric motor, a supplemental power to an auxiliary load, and a recharging power to the energy storage device. ### Claim 6 (depends on 1) The auxiliary power assembly of claim 1 wherein the controller is configured to individually regulate a firing sequence of fuel injectors associated with each of the plurality of APUs to selectively transition the plurality of APUs between the active state and the non-active state. ### Claim 7 (depends on 6) The auxiliary power assembly of claim 6 wherein the firing sequence of fuel injectors optimizes an operating efficiency of the auxiliary power assembly. ### Claim 8 A method for supplying auxiliary power to a vehicle comprising: providing a vehicle propulsion system comprising an electric motor, an energy storage device, and a DC link electrically connecting the electric motor and the energy storage device; electrically connecting each of a plurality of crankshaft-less engine and linear generator combinations to the DC link; determining a band-limited power requirement of the vehicle propulsion system; and selectively activating a number of the plurality of crankshaft-less engine and linear generator combinations to provide power to the DC link based on the vehicle propulsion system band-limited power requirement. ### Claim 9 (depends on 8) The method of claim 8 further comprising: determining a charge requirement of the energy storage device; and if the charge requirement is below a charge threshold, controlling the plurality of crankshaft-less engine and linear generator combinations to recharge the energy storage device. ### Claim 10 (depends on 8) The method of claim 8 further comprising individually operating each of the activated crankshaft-less engine and linear generator combinations above an efficiency threshold. ### Claim 11 (depends on 8) The method of claim 8 further comprising selectively operating a fuel-injection timing sequence for each of the activated crankshaft-less engine and linear generator combinations to minimize noise and vibration of each of the activated crankshaft-less engine and linear generator combinations. ### Claim 12 (depends on 8) The method of claim 8 further comprising selectively operating a fuel-injection timing sequence for each of the activated crankshaft-less engine and linear generator combinations to operate at a frequency other than a natural frequency of each of the activated crankshaft-less engine and linear generator combinations. ### Claim 13 (depends on 8) The method of claim 8 wherein determining the band-limited power requirement of the vehicle propulsion system comprises determining a band-limited, real-time power requirement of the electric motor. ### Claim 14 (depends on 8) The method of claim 8 wherein selectively activating a number of the plurality of crankshaft-less engine and linear generator combinations comprises individually controlling each of the activated crankshaftless engine and linear generator combinations to deliver an equal fraction of the band-limited power requirement.