# US 8,739,950 B2 · Auxiliary pump system for hybrid powertrains > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,739,950 B2 - Document ID: US8739950B2 - Status: Granted - Kind: B2 - Application number: 12/549,535 - Filed: 2009-08-28 - Published: 2010-03-25 - Granted: 2014-06-03 - Earliest claimed: 2008-09-25 - Assignees: GM Global Technology Operations LLC - Applicants: Philip C. Lundberg; John C. Schultz; Vijay A. Neelakantan - Inventors: Philip C. Lundberg; John C. Schultz; Vijay A. Neelakantan - Web page: https://patentgrep.com/patent/US8739950B2 ## CPC - F15B 21/14: Energy-recuperation means - F15B 2211/212: the pressure sources being accumulators - F15B 2211/214: the pressure sources being hydrotransformers - F15B 2211/625: Accumulators - F15B 2211/88: Control measures for saving energy - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract An auxiliary pump system for a hybrid powertrain includes a hydraulic accumulator, a hydraulic transformer, a plurality of control devices, a sump, and a plurality of fluid flow paths. The accumulator is charged by a high flow, high pressure hydraulic fluid by opening a first of the control devices and closing a second of the control devices. The accumulator is discharged by closing the first of the control devices and opening the second of the control devices. A high pressure, low flow hydraulic fluid is communicated from the accumulator to the hydraulic transformer. The hydraulic transformer converts the high pressure, low flow hydraulic fluid into a high flow, low pressure hydraulic fluid that is employed by systems within the hybrid powertrain. ## Claims ### Claim 1 A system in a motor vehicle, the system comprising: an automatic transmission configured to control an output speed ratio of the motor vehicle; a hydraulic control system having an engine driven pump and a plurality of clutches configured to control the automatic transmission; a first control device having an open state and a closed state, the first control device in fluid communication with the hydraulic control system; a hydraulic transformer having a first pump/motor unit connected with a second pump/motor unit, wherein the second pump/motor unit is in fluid communication with the first control device; a second control device having an open state and a closed state, the second control device in fluid communication with the first pump/motor unit; and an accumulator for storing and releasing the hydraulic fluid, the accumulator in fluid communication with the second control device, wherein the accumulator is charged with pressurized hydraulic fluid when the first control device and the second control device are in the open state and the engine driven pump is operational and wherein the pressurized hydraulic fluid from the engine driven pump drives the second pump/motor unit, the second pump/motor unit drives the first pump/motor unit, and the first pump/motor unit delivers a flow of pressurized hydraulic fluid having a higher pressure and a lower flow than the pressurized hydraulic fluid from the engine driven pump to the accumulator, wherein the accumulator stores the pressurized hydraulic fluid when the second control device is in the closed state, and wherein the accumulator discharges the pressurized hydraulic fluid to the hydraulic transformer when the second control device is in the open state and when the engine driven pump is non-operational and wherein the pressurized hydraulic fluid from the accumulator drives the first pump/motor unit, the first pump/motor unit drives the second pump/motor unit, and the second pump/motor unit delivers a flow of pressurized hydraulic fluid having a lower pressure and a higher flow than the pressurized hydraulic fluid from the accumulator to the plurality of clutches in the hydraulic control system. ### Claim 2 (depends on 1) The system of claim 1 wherein the first control device includes an on/off solenoid or a variable force solenoid. ### Claim 3 (depends on 1) The system of claim 1 wherein the pressurized hydraulic fluid from the accumulator exhausts from the first pump/motor unit to a sump, and wherein the second pump/motor unit receives hydraulic fluid from the sump. ### Claim 4 (depends on 1) The system of claim 1 wherein the second control includes an on/off solenoid or a variable force solenoid. ### Claim 5 (depends on 1) The system of claim 1 wherein the accumulator is connected directly to the second control device by a first fluid passage. ### Claim 6 (depends on 5) The system of claim 5 wherein the second pump/motor unit is connected directly to the hydraulic control system by a second fluid passage. ### Claim 7 (depends on 6) The system of claim 6 wherein the first pump/motor unit is connected directly to the second control device by a third fluid passage. ### Claim 8 (depends on 1) The system of claim 1 wherein the flow of pressurized hydraulic fluid having a lower pressure and a higher flow than the pressurized hydraulic fluid from the accumulator has a flow rate from approximately 5 to approximately 10 liters per minute and a pressure approximately 350 kPa. ### Claim 9 (depends on 1) The system of claim 1 wherein the flow of pressurized hydraulic fluid having a higher pressure and a lower flow than the pressurized hydraulic fluid from the engine driven pump has a flow rate of approximately 1 liter per minute and a pressure of approximately 2000 kPa. ### Claim 10 A system in a motor vehicle, the system comprising: an automatic transmission configured to control an output speed ratio of the motor vehicle; a hydraulic control system having an engine driven pump and a plurality of clutches configured to control the automatic transmission; a first control device having an open state and a closed state, the first control device in fluid communication with hydraulic control system; a hydraulic transformer having a first pump/motor unit connected with a second pump/motor unit, wherein the second pump/motor unit is in fluid communication with the first control device; a second control device having an open state and a closed state, the second control device in fluid communication with the first pump/motor unit; and an accumulator for storing and releasing the hydraulic fluid, the accumulator in fluid communication only with the second control device, wherein the accumulator is charged with pressurized hydraulic fluid when the first control device and the second control device are in the open state and the engine driven pump is operational and wherein the pressurized hydraulic fluid from the engine driven pump drives the second pump/motor unit, the second pump/motor unit drives the first pump/motor unit, and the first pump/motor unit delivers a flow of pressurized hydraulic fluid having a flow rate of approximately 1 liter per minute and a pressure of approximately 2000 kPa, wherein the accumulator stores the pressurized hydraulic fluid when the second control device is in the closed state, and wherein the accumulator discharges the pressurized hydraulic fluid to the hydraulic transformer when the second control device is in the open state and when the engine driven pump is non-operational and wherein the pressurized hydraulic fluid from the accumulator drives the first pump/motor unit, the first pump/motor unit drives the second pump/motor unit, and the second pump/motor unit delivers a flow of pressurized hydraulic fluid having a flow rate from approximately 5 to approximately 10 liters per minute and a pressure approximately 350 kPa. ### Claim 11 (depends on 10) The system of claim 10 wherein the first control device includes an on/off solenoid or a variable force solenoid. ### Claim 12 (depends on 10) The system of claim 10 wherein the pressurized hydraulic fluid from the accumulator exhausts from the first pump/motor unit to a sump, and wherein the second pump/motor unit receives hydraulic fluid from the sump. ### Claim 13 (depends on 10) The system of claim 10 wherein the second control includes an on/off solenoid or a variable force solenoid. ### Claim 14 (depends on 10) The system of claim 10 wherein the accumulator is connected directly to the second control device by a first fluid passage. ### Claim 15 (depends on 14) The system of claim 14 wherein the second pump/motor unit is connected directly to the hydraulic control system by a second fluid passage. ### Claim 16 (depends on 15) The system of claim 15 wherein the first pump/motor unit is connected directly to the second control device by a third fluid passage.