US 12,442,344 B2
Method and device for controlling stopping of engine
Tomohiro Sakata, Kanagawa (JP); and Seiji Hashimoto, Kanagawa (JP)
Assigned to NISSAN MOTOR CO., LTD., Yokohama (JP)
Appl. No. 18/849,752
Filed by NISSAN MOTOR CO., LTD., Yokohama (JP)
PCT Filed Mar. 24, 2022, PCT No. PCT/JP2022/013770
§ 371(c)(1), (2) Date Sep. 23, 2024,
PCT Pub. No. WO2023/181224, PCT Pub. Date Sep. 28, 2023.
Prior Publication US 2025/0198359 A1, Jun. 19, 2025
Int. Cl. F02D 41/24 (2006.01); F01N 3/20 (2006.01)
CPC F02D 41/24 (2013.01) [F01N 3/20 (2013.01)] 5 Claims
OG exemplary drawing
 
1. An engine stop control method comprising:
stopping an engine temporarily in response to a stop request for stopping the engine temporarily;
reducing a quantity of oxygen stored in a catalytic converter by an air fuel ratio enrichment operation of controlling an in-cylinder air fuel ratio to be richer than stoichiometric, in response to the stop request;
calculating the quantity of stored oxygen while the engine is operating;
setting an amount of air fuel ratio enrichment for the air fuel ratio enrichment operation, in accordance with a value of the quantity of stored oxygen calculated when the stop request occurs, such that the amount of air fuel ratio enrichment decreases as the value of the quantity of stored oxygen decreases;
reducing an opening of a throttle valve disposed in an intake passage, in response to the stop request; and
permitting the engine to be stopped, in response to a condition that the reduction of the opening of the throttle valve causes an internal pressure of a section of the intake passage downstream of the throttle valve to reach a predetermined negative pressure, and the air fuel ratio enrichment operation causes the quantity of oxygen stored in the catalytic converter to reach a predetermined target value.