Patent ID: 6363713
Filing Date: 2002-04-02
Classification: F01N,Y02A,Y02T

Abstract:
An on-board diagnostic method for a diesel emission control system including a catalyst and a fuel injection system for periodically injecting controlled amounts of diesel fuel into the exhaust stream of the diesel engine to enhance catalytic reduction of NOx, comprising a sequence of the following steps:determining a catalyst light off temperature; energizing an indicator to indicate a malfunction of said fuel injection system if the catalyst light off temperature is less than the light off temperature for a fully aged catalyst that just fails to meet the emission standards (FLT) and AR(T2) is than MR where, MR is a number between 0.5 and 1, AR(T2) is the average of R(T) @ T, R(T) is the ratio of &Dgr;T(T)/T&Dgr;T, &Dgr;T(T) is the difference between the measured post catalyst temperature, PT(T), and predicted post catalyst temperature, PPT (T), at T, and a delay time, dt, assuming no fuel injection, and T&Dgr;T is the exotherm or theoretical temperature rise.