# US 8,770,173 B2 · Multi-phase engine stop position control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,173 B2 - Document ID: US8770173B2 - Status: Granted - Kind: B2 - Application number: 12/759,898 - Filed: 2010-04-14 - Published: 2011-10-20 - Granted: 2014-07-08 - Earliest claimed: 2010-04-14 - Assignees: GM Global Technology Operations LLC - Applicants: Jun Han; Lan Wang; Goro Tamai - Inventors: Jun Han; Lan Wang; Goro Tamai - Web page: https://patentgrep.com/patent/US8770173B2 ## CPC - F02N 11/0818: {Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode} - F02D 41/0097: {using means for generating speed signals} - F02D 41/042: {for stopping the engine} - F02N 19/005: {Aiding engine start by starting from a predetermined position, e.g. pre-positioning or reverse rotation} - F02D 41/065: {at hot start or restart (F02D41/067 takes precedence)} - F02D 2041/0095: {Synchronisation of the cylinders during engine shutdown} - F02D 2200/101: Engine speed - F02N 11/0814: {comprising means for controlling automatic idle-start-stop} - F02N 2019/008: {the engine being stopped in a particular position} - F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) ## Abstract A method is provided for controlling engine stop position in a vehicle having an engine with auto stop/auto start functionality. The method includes automatically ramping down engine speed upon initiation of an auto stop event, executing closed-loop speed control of the engine when the engine speed begins to ramp down, and for as long as the engine speed remains above a threshold engine speed while ramping down the engine speed; executing closed-loop position control of the engine while ramping down the engine speed once the engine speed is less than the threshold engine speed and greater than zero; and stopping the crankshaft to within a calibrated range of a targeted engine stop position. A controller is also provided that includes a hardware module and an algorithm adapted for executing the foregoing method, and a vehicle is provided having an engine with auto stop/start functionality and the controller noted above. ## Claims ### Claim 1 A vehicle comprising: an engine with a crankshaft and auto start/auto stop functionality; a transmission having a transmission state; and a proportional-integral (PI) controller adapted for controlling a cranking position of the engine during an auto stop event, wherein the PI controller is in communication with the engine, and is configured for: automatically ramping down engine speed upon initiation of an auto stop event; executing closed-loop speed control of the engine when the engine speed begins to ramp down, and for as long as the engine speed remains above a threshold engine speed while ramping down the engine speed; setting an I-term of the PI controller as a function of at least the transmission state and a speed of the vehicle; after setting the I-term, executing closed-loop position control of the engine while ramping down the engine speed when a predetermined condition is detected; and stopping the crankshaft to within a calibrated range of a targeted engine stop position. ### Claim 2 (depends on 1) The vehicle of claim 1, wherein the algorithm is further adapted for switching back to closed-loop speed control of the engine once the engine speed equals zero. ### Claim 3 (depends on 2) The vehicle of claim 2, wherein the predetermined condition includes one of: the engine speed being less than the threshold engine speed and greater than zero, and an engine profile position passing a calibrated trigger position. ### Claim 4 (depends on 2) The vehicle of claim 2, wherein the algorithm is further adapted for: calculating a changing angular value of the crankshaft; and using the changing angular value of the engine as a closed-loop feedback variable during the closed-loop position control. ### Claim 5 (depends on 2) The vehicle of claim 2, wherein the algorithm is further adapted for: determining if a set of exit conditions is present when the engine is stopped; and transitioning from closed-loop position control to closed-loop speed control only if the set of exit conditions is present. ### Claim 6 A proportional-integral (PI) controller for use aboard a vehicle having a transmission and an engine with a crankshaft and auto stop/auto start functionality, the controller comprising a hardware module and an algorithm adapted for controlling a cranking position of the engine during an auto stop event, wherein the algorithm is adapted for: automatically ramping down engine speed upon initiation of an auto stop event; executing closed-loop speed control of the engine when the engine speed begins to ramp down, and for as long as the engine speed remains above a threshold engine speed while ramping down the engine speed; setting an I-term of the PI controller as a function of at least a state of the transmission and a speed of the vehicle; after setting the I-term, executing closed-loop position control of the engine while ramping down the engine speed when a predetermined condition is detected; and stopping the crankshaft to within a calibrated range of a targeted engine stop position. ### Claim 7 (depends on 6) The controller of claim 6, wherein the algorithm is further adapted for switching back to closed-loop speed control of the engine once the engine speed equals zero. ### Claim 8 (depends on 6) The controller of claim 6, wherein the predetermined condition includes one of: the engine speed being less than the threshold engine speed and greater than zero, and an engine profile position passing a calibrated trigger position. ### Claim 9 (depends on 6) The controller of claim 6, wherein the algorithm is further adapted for: calculating a changing angular value of the crankshaft; and using the changing angular value of the engine as a closed-loop feedback variable during the closed-loop position control. ### Claim 10 (depends on 6) The controller of claim 6, wherein the algorithm is further adapted for: determining if a set of exit conditions is present when the engine is stopped; and transitioning from closed-loop position control to closed-loop speed control only if the set of exit conditions is present. ### Claim 11 A method for controlling an engine stop position in a vehicle having a proportional-integral (PI) controller, a transmission having a transmission state, and an engine with auto stop/auto start functionality and a crankshaft, the method comprising: automatically ramping down engine speed upon initiation of an auto stop event; executing closed-loop speed control of the engine when the engine speed ramps down, and for as long as the engine speed remains above a threshold engine speed; setting an I-term of the PI controller as a function of at least the transmission state and a speed of the vehicle; after setting the I-term, executing closed-loop position control of the engine while ramping down the engine speed when a predetermined condition is detected; and stopping the crankshaft of the engine to within a calibrated range of a targeted engine stop position. ### Claim 12 (depends on 11) The method of claim 11, further comprising: switching back to closed-loop speed control of the engine once the engine speed equals zero. ### Claim 13 (depends on 11) The method of claim 11, wherein the predetermined condition includes one of: the engine speed being less than the threshold engine speed and greater than zero, and an engine profile position passing a calibrated trigger position. ### Claim 14 (depends on 11) The method of claim 11, further comprising: calculating a changing angular value of the crankshaft; and using the changing angular value of the engine as a closed-loop feedback variable during the closed-loop position control. ### Claim 15 (depends on 11) The method of claim 11, further comprising: determining if a set of exit conditions is present when the engine is stopped; and transitioning from closed-loop position control to closed-loop speed control only if the set of exit conditions is present.