Patent Number: 6,253,546

Title: Torque control scheme for low emission lean burn vehicle

Abstract: A method of minimizing torque disturbances in an internal combustion engine for a vehicle having a lean NOx trap that is periodically purged. The method includes the steps of generating feedforward values of first engine characteristics as a function of desired engine torque and generating feedback values of second engine characteristics as a function of intake manifold pressure. Target values are then calculated for predetermined engine variables based on the first and second engine characteristics. Engine variables are then set to the target values to compensate for torque disturbances resulting from the lean NOx trap purge cycle. According to the disclosed method, the feedforward path schedules the throttle, fuel rate and spark timing based on an engine model to produce a demanded engine torque. The feedback path then uses the values of fuel rate and spark timing to compensate for torque variations. This is accomplished by determining an error term as a function of a reference trajectory intake manifold pressure and measured intake manifold pressure.

Inventors: Sun; Jing (Bloomfield, MI), Kolmanovsky; Ilya Vladimir (Ypsilanti, MI), Buckland; Julia Helen (Dearborn, MI), Boesch; Mathew Alan (Plymouth, MI)

Assignee: Ford Global Technologies, Inc.

International Classification: F02D 37/00 (20060101); F02D 37/02 (20060101); F02D 41/30 (20060101); F02D 41/02 (20060101); F01N 3/08 (20060101); F02M 25/07 (20060101); F01N 009/00 (); F02D 043/00 ()

Expiration Date: 07/03/2018