Patent Number: 6,167,697

Title: Device for controlling the air/fuel ratio of the mixture supplied to an endothermal engine

Abstract: A device for controlling the air/fuel ratio of the mixture supplied to an endothermal engine, in which a first and a second oxygen sensor disposed along an exhaust duct of the engine upstream and, respectively, downstream of a catalytic converter generate a first and respectively a second signal representative of the stoichiometric compositions of the combusted gases, the device having a first control circuit receiving as input the first signal and generating a correction parameter adapted to be applied to a quantity of fuel calculated in an open loop in order to obtain a corrected quantity of fuel for an injection unit of the engine, the device having a second control circuit which receives the second signal, supplies a correction signal to the first circuit in order to modify the correction parameter and has a control branch adapted to sample the second signal at a predetermined time frequency and to vary the correction signal when the difference between two successively sampled values is greater than a predetermined threshold so as to modify the air/fuel ratio and to minimise the time in which the catalytic converter operates at low efficiency.

Inventors: Poggio; Luca (Spinetta Marengo, IT), Violani; Marco (Florence, IT), Secco; Marco (Nizza Monferrato, IT), Gaviani; Giovanni (Rimini, IT)

Assignee: Magneti Marelli S.p.A.

International Classification: F02D 41/14 (20060101); F01N 003/00 ()

Expiration Date: 01/02/2018