# US 8,771,146 B2 · Method of controlling transmission of vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,146 B2 - Document ID: US8771146B2 - Status: Granted - Kind: B2 - Application number: 13/303,992 - Filed: 2011-11-23 - Published: 2012-12-13 - Granted: 2014-07-08 - Earliest claimed: 2011-06-09 - Assignees: Hyundai Motor Company - Applicants: Sung Yeol Kim; Seung Min Lee; Choung Wan Son; Seok Young Shin; Ju Hyun Nam; Sung Yop Lee; Kwang Min Won - Inventors: Sung Yeol Kim; Seung Min Lee; Choung Wan Son; Seok Young Shin; Ju Hyun Nam; Sung Yop Lee; Kwang Min Won - Web page: https://patentgrep.com/patent/US8771146B2 ## CPC - F16H 61/28: with at least one movement of the final actuating mechanism being caused by a non-mechanical force, e.g. power-assisted - F16H 61/0403: {Synchronisation before shifting} - F16H 61/0437: {by using electrical signals (F16H61/0403 and F16H61/061 take precedence)} - F16H 2059/186: {Coasting} - F16H 2059/462: {Detecting synchronisation, i.e. speed difference is approaching zero} - F16H 2061/0474: {by smoothing engagement or release of positive clutches; Methods or means for shock free engagement of dog clutches} - F16H: GEARING ## Abstract A method of controlling a transmission of a vehicle may include generating a first synchronization force between a shift gear of a target gear and an output shaft to shift gears from a current gear to a lower gear set as the target gear in response to deceleration of the vehicle, so as to form a first synchronization, removing the first synchronization force between the shift gear and the output shaft after the generating of the first synchronization force, and generating a second synchronization force between the shift gear of the target gear and the output shaft after the removing of the first synchronization force, so as to form a second synchronization. ## Claims ### Claim 1 A method of controlling a transmission of a vehicle, comprising: generating a first synchronization force between a shift gear of a target gear and an output shaft to shift gear ratio from a current gear ratio to a lower gear ratio of the target gear in response to deceleration of the vehicle, so as to form a first synchronization; removing the first synchronization force between the shift gear and the output shaft after the generating of the first synchronization force; and generating a second synchronization force between the shift gear of the target gear and the output shaft after the removing of the first synchronization force, so as to form a second synchronization. ### Claim 2 (depends on 1) The method as set forth in claim 1, wherein the removing of the first synchronization force begins when an rpm of an input shaft reaches a predetermined target rpm after the output shaft is synchronized with the input shaft through the shift gear of the target gear by the first synchronization force. ### Claim 3 (depends on 2) The method as set forth in claim 2, wherein the predetermined target rpm is set in response to an rpm of the output shaft that linearly reduces as time passes. ### Claim 4 (depends on 2) The method as set forth in claim 2, wherein the predetermined target rpm is set as a rpm of the input shaft, when the rpm of the input shaft becomes equal to the rpm of the output shaft after linearly increasing towards the rpm of the output shaft at the first synchronization. ### Claim 5 (depends on 1) The method as set forth in claim 1, wherein the generating of the first synchronization force includes controlling an actuator to linearly move a sleeve of the target gar towards a clutch gear of the target gear; the removing of the first synchronization force includes controlling the actuator to retract the sleeve of the target gear in a direction away from the clutch gear; and the generating of the second synchronization force includes controlling the actuator to linearly move the sleeve towards the clutch gear again. ### Claim 6 (depends on 5) The method as set forth in claim 5, wherein the generating of the first synchronization force includes: linearly moving the sleeve towards the clutch gear of the target gear; and maintaining a position of the sleeve within a predetermined range. ### Claim 7 (depends on 6) The method as set forth in claim 6, wherein the linearly moving of the sleeve towards the clutch gear of the target gear includes linearly increasing a displacement of the sleeve as time passes, and wherein the maintaining the position of the sleeve within the predetermined range includes maintaining the position of the sleeve within a range in which the first synchronization force is generated between the sleeve of the target gear and the clutch gear. ### Claim 8 (depends on 6) The method as set forth in claim 6, wherein the linearly moving of the sleeve towards the clutch gear of the target gear includes linearly increasing a displacement of the sleeve as time passes, and wherein the maintaining the position of the sleeve within the predetermined range includes maintaining the position of the sleeve between a predetermined upper limit and a predetermined lower limit. ### Claim 9 (depends on 5) The method as set forth in claim 5, wherein the removing of the first synchronization force is begun by retracting the sleeve out of the range within which the first synchronization force is generated between the sleeve of the target gear and the clutch gear, and wherein the removing of the first synchronization force further includes maintaining the retracted sleeve for a predetermined time period. ### Claim 10 (depends on 9) The method as set forth in claim 9, wherein the maintaining of the retracted sleeve continues for the predetermined time period until a difference in rpm between the input shaft and the output shaft increases to a degree to which backlash of elements between the input shaft and the output shaft, which have been arranged in one direction during the generating of the first synchronization force, is able to be rearranged in a reverse direction by the generating of the second synchronization force. ### Claim 11 A method of controlling a transmission of a vehicle, comprising: during a process of generating a synchronization force between a clutch gear of a target gear and an output shaft for engagement therebetween to shift gear ratio from a current gear ratio to a lower gear ratio of the target gear in response to deceleration of the vehicle, temporarily removing the synchronization force when an rpm of an input shaft reaches a predetermined target rpm. ### Claim 12 (depends on 11) The method as set forth in claim 11, wherein the temporarily removing is begun when the rpm of the input shaft reaches the predetermined target rpm after the output shaft is synchronized with the input shaft through a shift gear of the target gear by the synchronization force generated between the clutch gear of the target gear and the output shaft. ### Claim 13 (depends on 12) The method as set forth in claim 12, wherein the predetermined target rpm is set in response to an rpm of the output shaft that linearly reduces as time passes during downshifts. ### Claim 14 (depends on 12) The method as set forth in claim 12, wherein the predetermined target rpm is set as a rpm of the input shaft, when the rpm of the input shaft becomes equal to the rpm of the output shaft after linearly increasing towards the rpm of the output shaft. ### Claim 15 (depends on 11) The method as set forth in claim 11, wherein after the temporarily removing, an additional synchronization is conducted, and the temporarily removing continues until a difference in rpm between the input shaft and the output shaft increases to a degree to which backlash of elements between the input shaft and the output shaft is able to be arranged by the second synchronization.