Patent application EP18177158A (EP), filed 2018-06-12
Publication number: EP3415391A1
Title: SYSTEM AND METHOD FOR CONTROLLING THE SPEED OF A WORK VEHICLE DURING DOWNHILL OPERATION
Abstract: A method for controlling the speed of a work vehicle (10) during downhill operation may include controlling (302) an operation of at least one of an engine (104) or a transmission (106) of a work vehicle (10) so as to maintain the work vehicle operating at a requested speed and identifying (204, 304) an operating condition of the work vehicle that provides an indication that the work vehicle is traveling downhill. In addition, the method includes determining (214, 314) whether at least one pre-condition (216, 218) for downshifting the transmission from a current gear ratio to a downshift gear ratio is satisfied when the operating condition indicates that the work vehicle is currently traveling downhill. Moreover, when it is determined that the pre-condition(s) is/are satisfied, the method may include controlling (220, 308) the operation of the transmission such that the transmission is downshifted from the current gear ratio to the downshift gear ratio.
IPC codes: B60W  10/    06            A I
B60W  10/    11            A I
B60W  30/    14            A I
B60W  30/    18            A I
Claims: number: 1
text: A method for controlling the speed of a work vehicle (10) during downhill operation, the method comprising:
number: 2
text: The method of claim 1, wherein the requested speed corresponds to a requested axle speed for the work vehicle (10).
number: 3
text: The method of claim 2, wherein determining whether the first pre-condition is satisfied comprises determining whether the following relationship is satisfied: ω Req_Axle ≤ ω eng * η downshift;<img class="EMIRef" id="538248609-ib0003" />
wherein,ωReq_Axle corresponds to the requested axle speed for the work vehicle,ωeng corresponds to a current engine speed for the engine, andωdownshift corresponds to the downshift gear ratio.;4. The method of claim 1, wherein the at least one pre-condition further comprises a second pre-condition requiring that a maximum allowable engine speed for the engine (104) be greater than or equal to an estimated engine speed for the engine (104) following the downshift.;5. The method of claim 4, wherein determining whether the second pre-condition is satisfied comprises determining whether the following relationship is satisfied: ω max − _eng ≥ ω eng η current η downshift;<img class="EMIRef" id="538248609-ib0004" />
wherein,ωmax_eng corresponds to the maximum allowable engine speed for the engine (104),ωeng corresponds to a current engine speed for the engine (104),ηcurrent corresponds to the current gear ratio, andηdownshift corresponds to the downshift gear ratio.;6. The method of claim 1, further comprising monitoring a current engine speed of the engine (104) relative to a requested engine speed for the engine (104).;7. The method of claim 6, wherein identifying the operating condition of the work vehicle (10) comprises identifying that the engine speed is greater than the requested engine speed.;8. The method of claim 7, wherein identifying the operating condition of the work vehicle (10) further comprises identifying that an engine torque for the engine (104) is negative and that the engine speed is increasing over time.;9. A system for controlling the speed of a work vehicle (10) during downhill operation, the system comprising:;an engine (104);
a transmission (106) coupled to the engine (104);
a controller (118) communicatively coupled to at least one of the engine (104) or the transmission (106), the controller (118) including a processor (124) and related memory (126), the memory (126) storing instructions that, when implemented by the processor (124), configure the controller (118) to:;control an operation of at least one of the engine (104) or the transmission (106) so as to maintain the work vehicle (10) operating at a requested speed;
identify an operating condition of the work vehicle (10) that provides an indication that the work vehicle (10) is traveling downhill;
determine whether at least one pre-condition for downshifting the transmission (106) from a current gear ratio to a downshift gear ratio is satisfied when the operating condition indicates that the work vehicle (10) is currently traveling downhill, the at least one pre-condition including a first pre-condition requiring that the requested speed be less than or equal to an estimated speed for the work vehicle (10) following the downshift; and
when it is determined that the at least one pre-condition is satisfied, control the operation of the transmission such that the transmission is downshifted from the current gear ratio to the downshift gear ratio.;10. The system of claim 9, wherein the requested speed corresponds to a requested axle speed for the work vehicle (10).;11. The system of claim 10, wherein the controller (118) is configured to determine whether the first pre-condition is satisfied by determining whether the following relationship is satisfied: ω Req_Axle ≤ ω eng * η downshift
number: 12
text: The system of claim 9, wherein the at least one pre-condition further comprises a second pre-condition requiring that a maximum allowable engine speed for the engine (104) be greater than or equal to an estimated engine speed for the engine (104) following the downshift.
number: 13
text: The system of claim 12, wherein the controller (118) is configured to determine whether the second pre-condition is satisfied by determining whether the following relationship is satisfied: ω max − _eng ≥ ω eng η current η downshift
number: 14
text: The system of claim 9, wherein the controller (118) is further configured to monitor a current engine speed of the engine (104) relative to a requested engine speed for the engine (104).
number: 15
text: The system of claim 14, wherein the controller (118) is configured to identify the operating condition of the work vehicle (10) by identifying that the engine speed is greater than the requested engine speed.
Office action: search_report, dated 2018-12-19
Rejection reasons: novelty_epc_54
Prior art cited: ref_id: US2001016795A1
ref_type: patent
severity: background
ref_id: US2013066493A1
ref_type: patent
severity: background
ref_id: US2016264122A1
ref_type: patent
severity: background
ref_id: US2002115531A1
ref_type: patent
severity: background
ref_id: US2001016795
ref_type: patent
severity: novelty_destroying
ref_id: US2013066493
ref_type: patent
severity: background
ref_id: US2016264122
ref_type: patent
severity: background
Final disposition: pending (2018-12-19)