# US 8,771,147 B2 · Coast stop vehicle and control method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,147 B2 - Document ID: US8771147B2 - Status: Granted - Kind: B2 - Application number: 13/306,574 - Filed: 2011-11-29 - Published: 2012-06-07 - Granted: 2014-07-08 - Earliest claimed: 2010-12-02 - Assignees: JATCO Ltd - Applicants: Naohiro Yamada; Keichi Tatewaki; Shinichiro Watanabe; Noritaka Aoyama - Inventors: Naohiro Yamada; Keichi Tatewaki; Shinichiro Watanabe; Noritaka Aoyama - Web page: https://patentgrep.com/patent/US8771147B2 ## CPC - B60W 30/18072: {Coasting} - B60W 10/026: {of lock-up clutches} - B60W 10/06: including control of combustion engines - F16H 61/143: {using electric control means} - B60W 2030/1809: {Without torque flow between driveshaft and engine, e.g. with clutch disengaged or transmission in neutral} - B60W 2510/0652: Speed change rate - B60W 2510/1045: Output speed change rate - B60W 2520/105: Longitudinal acceleration - F16H 9/18: only one flange of each pulley being adjustable - F16H 37/022: {the toothed gearing having orbital motion} - F16H 59/36: Inputs being a function of speed - F16H 59/48: Inputs being a function of acceleration - F16H 2037/023: {the combined gearing being provided with at least two forward and one reverse ratio in a serially arranged sub-transmission} - F16H 2059/186: {Coasting} - F16H 2059/363: {Rate of change of input shaft speed, e.g. of engine or motor shaft} - F16H 2059/405: {Rate of change of output shaft speed or vehicle speed} - F16H 2059/425: {Rate of change of input or turbine shaft speed} - F16H 2312/14: Going to, or coming from standby operation, e.g. for engine start-stop operation at traffic lights - Y02T 10/60: Other road transportation technologies with climate change mitigation effect - 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 - F16H: GEARING - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A coast stop vehicle which executes coast stop control for stopping an engine during the travel of a vehicle, is provided with a frictional engagement element provided between the engine and a driving wheel, a first deceleration calculating unit which calculates first deceleration, which is rotation deceleration of a rotation shaft on the driving wheel side of the frictional engagement element, and an engagement-state control unit which controls an engagement state of the frictional engagement element so that decrease of the engine rotation speed is suppressed on the basis of the first deceleration while the coast stop control is executed. ## Claims ### Claim 1 A coast stop vehicle which executes a coast stop control for stopping an engine during travel of the vehicle, comprising: a frictional engagement element provided between the engine and a driving wheel; a first deceleration calculating unit configured to calculate a first deceleration, which is rotation deceleration of a rotation shaft on a driving wheel side of the frictional engagement element; an engine rotation speed detecting unit configured to detect an engine rotation speed; a second deceleration calculating unit configured to calculate a second deceleration, which is engine rotation deceleration; and an engagement-state control unit configured to control an engagement state of the frictional engagement element such that a decrease of the engine rotation speed is suppressed based on the first deceleration and the second deceleration while the coast stop control is executed, release the frictional engagement element if the engine rotation speed is smaller than a first predetermined speed at which the engine is re-startable by re-injection of fuel, and the second deceleration is larger than the first deceleration, and engage the frictional engagement element if the engine rotation speed is smaller than the first predetermined speed, and the second deceleration is equal to or less than the first deceleration. ### Claim 2 (depends on 1) The coast stop vehicle according to claim 1, wherein the engagement-state control unit is configured to: engage the frictional engagement element if the engine rotation speed is equal to or greater than the first predetermined speed, and the second deceleration is larger than the first deceleration; and release the frictional engagement element if the engine rotation speed is equal to or greater than the first predetermined speed, and the second deceleration is equal to or less than the first deceleration. ### Claim 3 (depends on 1) The coast stop vehicle according to claim 1, wherein the engagement-state control unit is configured to release the frictional engagement element if the engine rotation speed is equal to or less than a second predetermined speed at which the engine is startable by a starter. ### Claim 4 (depends on 1) The coast stop vehicle according to claim 1, wherein the engagement-state control unit is configured to release the frictional engagement element if the engine rotation speed is equal to or less than a third predetermined speed at which car body vibration occurs. ### Claim 5 (depends on 1) The coast stop vehicle according to claim 1, wherein the frictional engagement element is a lock-up clutch of a torque converter. ### Claim 6 A control method of a coast stop vehicle, in which a coast stop control for stopping an engine during travel of a vehicle is executed, the control method comprising: calculating a first deceleration, which is rotation deceleration of a rotation shaft on a driving wheel side of a frictional engagement element provided between the engine and a driving wheel; detecting an engine rotation speed; calculating a second deceleration, which is engine rotation deceleration; and controlling an engagement state of the frictional engagement element such that a decrease of the engine rotation speed is suppressed based on the first deceleration and the second deceleration, while the coast stop control is executed, wherein the frictional engagement element is released if the engine rotation speed is smaller than a first predetermined speed at which the engine is re-startable by re-injection of fuel, and the second deceleration is larger than the first deceleration, and wherein the frictional engagement element is engaged if the engine rotation speed is smaller than the first predetermined speed, and the second deceleration is equal to or less than the first deceleration. ### Claim 7 (depends on 6) The control method according to claim 6, wherein the frictional engagement element is engaged if the engine rotation speed is equal to or greater than the first predetermined speed, and the second deceleration is larger than the first deceleration; and the frictional engagement element is released if the engine rotation speed is equal to or greater than the first predetermined speed, and the second deceleration is equal to or less than the first deceleration. ### Claim 8 (depends on 6) The control method according to claim 6, wherein the frictional engagement element is released if the engine rotation speed is equal to or less than a second predetermined speed at which the engine is startable by a starter. ### Claim 9 (depends on 6) The control method according to claim 6, wherein the frictional engagement element is released if the engine rotation speed is equal to or less than a third predetermined speed at which car body vibration occurs. ### Claim 10 (depends on 6) The control method according to claim 6, wherein the frictional engagement element is a lock-up clutch of a torque converter. ### Claim 11 A coast stop vehicle which executes a coast stop control for stopping an engine during travel of the vehicle, comprising: a frictional engagement element provided between the engine and a driving wheel; first deceleration calculating means for calculating a first deceleration, which is rotation deceleration of a rotation shaft on a driving wheel side of the frictional engagement element; an engine rotation speed detecting means for detecting an engine rotation speed; a second deceleration calculating means for calculating a second deceleration, which is engine rotation deceleration; and engagement-state control means for controlling an engagement state of the frictional engagement element such that a decrease of the engine rotation speed is suppressed based on the first deceleration and the second deceleration while the coast stop control is executed, wherein the engagement-state control means releases the frictional engagement element if the engine rotation speed is smaller than a first predetermined speed at which the engine is re-startable by re-injection of fuel, and the second deceleration is larger than the first deceleration, and wherein the engagement-state control means engages the frictional engagement element if the engine rotation speed is smaller than the first predetermined speed, and the second deceleration is equal to or less than the first deceleration.