Catalyst heating control method of parallel type hybrid vehicle

Abstract

Disclosed herein is a catalyst heating control method for a parallel hybrid vehicle that can generate a predetermined torque required to maintain a stable no-load operation state of an engine when a catalyst is warmed in a cold-start state of the engine while sufficiently reducing the ignition efficiency.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority of Korean Patent Application Serial Number 10-2006-0090067 filed on Sep. 18, 2006 with Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference herein in its entirety.FIELD OF THE INVENTION[0002]The present invention relates to control strategies for engines, and more particularly, to control strategies for rapidly heating a catalytic converter in a parallel type hybrid vehicle.BACKGROUND OF THE INVENTION[0003]A large amount of harmful substances is present in emissions at an initial startup stage of a vehicle engine. Emission control devices, such as catalytic converters, can reduce emissions generated by engine combustion. However, the effectiveness of such emission control devices varies with operating temperature. For example, the efficiency of an emission control device may be much greater at higher temperatures than it is at lower temperature. Thus, to e...

AI Technical Summary

Benefits of technology

The present invention provides a catalyst heating control method for a parallel hybrid vehicle that can efficiently purify harmful substances from discharge gas at an initial startup stage of the engine. The method compensates for reduced ignition efficiency of the engine with a motor torque to maintain a stable no-load operation state of the engine. The method uses a control map that takes into account engine rpm and charging efficiency to determine the target catalyst heating ignition efficiency and the motor compensation requirement torque. The method also includes determining whether the catalyst heating control is necessary based on the temperature of the cooling water of the engine. The method can be used with a wide variety of motor vehicles and is particularly useful with parallel hybrid vehicles.

Problems solved by technology

A large amount of harmful substances is present in emissions at an initial startup stage of a vehicle engine.

However, the effectiveness of such emission control devices varies with operating temperature.

That is, the retardation of ignition timing, while reducing the ignition efficiency of an engine, provides additional heat to increase the temperature of discharge gas when a discharge port is opened instead of reducing the engine torque.

However, conventional systems utilizing the lean burn control method is difficult to rapidly heat catalytic converters when the ignition efficiency is required to be reduced to a range where the torque must maintain a stable no-load operation state of the engine.

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