# US 2013/0157809 A1 · Transmission with range engagement assurance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0157809 A1 - Document ID: US20130157809A1 - Status: Published application - Kind: A1 - Application number: 13/613,898 - Filed: 2012-09-13 - Published: 2013-06-20 - Earliest claimed: 2011-12-19 - Assignees: Eaton Corporation - Inventors: Jon Allen Steeby; Marcel Amsallen - Web page: https://patentgrep.com/patent/US20130157809A1 ## CPC - F16H 61/70: specially adapted for change-speed gearing in group arrangement, i.e. with separate change-speed gear trains arranged in series, e.g. range or overdrive-type gearing arrangements - F16H 61/0025: {Supply of control fluid; Pumps therefor} - F16H 61/0403: {Synchronisation before shifting} - F16H: GEARING ## Abstract An auxiliary transmission module has an auxiliary transmission having an input shaft, an output shaft, and a mechanical synchronizer, and a controller. The controller is configured to command a downshift for the auxiliary transmission, control the input shaft to a generally synchronous speed with the output shaft for engagement, and increment the speed of the input shaft by a predetermined speed differential above the speed of the output shaft or engagement if the auxiliary transmission is unengaged after controlling to the generally synchronous speed. A method of downshifting includes commanding a downshift for the auxiliary transmission, controlling an input shaft to a generally synchronous speed with an output shaft for engagement, comparing a rotational speed upstream with a rotational speed downstream to verify engagement, and controlling the input shaft to an asynchronous speed with the output shaft for engagement during a recycle event when it is unverified. ## Claims ### Claim 1 A method of downshifting an auxiliary transmission having a mechanical synchronizer, the method comprising: commanding a downshift for the auxiliary transmission; controlling an input shaft of the auxiliary transmission to a generally synchronous speed with an output shaft of the auxiliary transmission to engage the auxiliary transmission; comparing a rotational speed upstream of the auxiliary transmission with a rotational speed downstream of the transmission to verify engagement; and controlling the input shaft of the auxiliary transmission to an asynchronous speed with the output shaft of the auxiliary transmission to engage the auxiliary transmission during a recycle event when engagement is unverified. ### Claim 2 (depends on 1) The method of claim 1 wherein the asynchronous speed is provided by rotating the input shaft at a predetermined speed differential faster than the output shaft. ### Claim 3 (depends on 2) The method of claim 2 further comprising incrementing the asynchronous speed with the speed differential during another recycle event to engage the auxiliary transmission. ### Claim 4 (depends on 2) The method of claim 2 wherein the predetermined speed differential is fifteen revolutions per minute. ### Claim 5 (depends on 1) The method of claim 1 further comprising controlling an engine speed to control the speed of the input shaft to the auxiliary transmission. ### Claim 6 (depends on 1) The method of claim 1 further comprising downshifting a main transmission upstream of the auxiliary transmission. ### Claim 7 (depends on 1) The method of claim 1 further comprising shifting the auxiliary transmission while a main transmission upstream of the auxiliary transmission is in neutral. ### Claim 8 (depends on 1) The method of claim 1 further comprising receiving an entry condition of near zero throttle. ### Claim 9 (depends on 1) The method of claim 1 further comprising receiving an entry condition of an engine torque demand being zero or less. ### Claim 10 An auxiliary transmission module comprising: an auxiliary transmission having an input shaft, an output shaft, and a mechanical synchronizer; and a controller in communication with the auxiliary transmission and configured to (i) command a downshift for the auxiliary transmission, (ii) control the input shaft to a generally synchronous speed with the output shaft to engage the auxiliary transmission, and (iii) increment the speed of the input shaft by a predetermined speed differential above the speed of the output shaft to engage the auxiliary transmission if the auxiliary transmission is unengaged after controlling the input shaft to the generally synchronous speed. ### Claim 11 (depends on 10) The auxiliary transmission module of claim 10 further comprising: a first speed sensor upstream of the auxiliary transmission; and a second speed sensor downstream of the auxiliary transmission; wherein the controller is configured is configured to determine engagement of the auxiliary transmission by comparing data from the first and second speed sensors. ### Claim 12 (depends on 11) The auxiliary transmission module of claim 11 wherein the first speed sensor is configured to measure the rotational speed of the input shaft. ### Claim 13 (depends on 11) The auxiliary transmission module of claim 11 wherein the second speed sensor is configured to measure the rotational speed of the output shaft. ### Claim 14 (depends on 10) The auxiliary transmission module of claim 10 wherein the auxiliary transmission is a two speed transmission. ### Claim 15 (depends on 10) The auxiliary transmission of claim 10 wherein the mechanical synchronizer comprises a range jaw clutch assembly. ### Claim 16 A transmission comprising: a main transmission section; an auxiliary range transmission section downstream of the main transmission and connected to the main transmission section by a mainshaft; and a controller configured to (i) command a downshift for the auxiliary transmission, (ii) control the mainshaft to a generally synchronous speed with the output shaft of the auxiliary transmission section to engage the auxiliary transmission, (iii) verify engagement of the auxiliary transmission, and (iv) increase the speed of the mainshaft by a predetermined speed differential above the speed of the output shaft to engage the auxiliary transmission if engagement is unverified. ### Claim 17 (depends on 16) The transmission of claim 16 wherein the auxiliary range section comprises a mechanical synchronizer. ### Claim 18 (depends on 16) The transmission of claim 16 wherein the auxiliary range section comprises an automatic range section actuator. ### Claim 19 (depends on 16) The method of claim 16 wherein the controller is configured to increase an engine speed to increase the speed of the mainshaft during downshifting. ### Claim 20 (depends on 16) The method of claim 16 wherein the controller is configured to command the downshift for the auxiliary transmission in response to receiving an engine torque demand of zero or less.