US 11,773,967 B2
Method and transmission control apparatus for operating a multiple-speed vehicle transmission
Ralf Beck, Oberteuringen (DE)
Assigned to ZF Friedrichshafen AG, Friedrichshafen (DE)
Filed by ZF Friedrichshafen AG, Friedrichshafen (DE)
Filed on Sep. 8, 2022, as Appl. No. 17/930,516.
Claims priority of application No. 10 2021 214 373.3 (DE), filed on Dec. 15, 2021.
Prior Publication US 2023/0184329 A1, Jun. 15, 2023
Int. Cl. F16H 59/72 (2006.01); F16H 61/20 (2006.01); F16H 59/52 (2006.01); F16H 59/66 (2006.01); F16H 61/16 (2006.01); F16H 59/68 (2006.01)
CPC F16H 61/20 (2013.01) [F16H 59/52 (2013.01); F16H 59/66 (2013.01); F16H 59/72 (2013.01); F16H 61/16 (2013.01); F16H 2059/6823 (2013.01); F16H 2200/006 (2013.01); F16H 2200/0052 (2013.01); F16H 2200/0082 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for operating a multi-gear vehicle transmission in a motor vehicle during a coasting phase of the motor vehicle, the method comprising:
engaging a driving gear during an overrun phase of a coasting phase;
closing shifting elements of the driving gear during the overrun phase;
engaging a neutral gear during a freewheeling phase of the coasting phase;
determining whether the motor vehicle is in the overrun phase of the coasting phase;
determining whether a condition for a transition to the freewheeling phase of the coasting phase is fulfilled;
determining whether a transmission condition with elevated drag losses exists; and
at least partially closing at least one further shifting element if the motor vehicle is in the overrun phase of the coasting phase, the condition for the transition to the freewheeling phase is fulfilled, and a transmission condition with elevated drag losses exists.