초록 ▼

An air/fuel control method for an engine including a NOx sensor in operative relationship to a catalytic converter. The method comprises the steps of providing a base fuel signal related to a quantity of air inducted into the engine and generating a bias signal for biasing the base fuel signal towar

An air/fuel control method for an engine including a NOx sensor in operative relationship to a catalytic converter. The method comprises the steps of providing a base fuel signal related to a quantity of air inducted into the engine and generating a bias signal for biasing the base fuel signal towards a leaner air/fuel ratio. The output of the NOx sensor is monitored to detect a predetermined exhaust gas NOx value representing a predefined NOx conversion efficiency. The base fuel signal is then modified as a function of the bias signal corresponding to the predetermined exhaust gas NOx value to maintain the catalytic converter within a desired efficiency range. In one aspect of the invention, the process of detecting the edge of the NOx conversion efficiency window is executed at predetermined time periods measured by the distance the vehicle traveled, or the elapsed time since last base fuel value modification.

대표청구항 ▼

1. An air/fuel control method for an engine including a NOx sensor positioned in operative relationship to a catalytic converter, the method comprising the steps of:providing a base fuel signal related to a quantity of air inducted into the engine; generating a bias signal for biasing said base fuel

1. An air/fuel control method for an engine including a NOx sensor positioned in operative relationship to a catalytic converter, the method comprising the steps of:providing a base fuel signal related to a quantity of air inducted into the engine; generating a bias signal for biasing said base fuel signal towards a leaner air/fuel ratio; monitoring an output of said NOx sensor to detect a predetermined exhaust gas NOx value representing a minimum desired NOx conversion efficiency; and modifying said base fuel signal as a function of said bias signal corresponding to said predetermined exhaust gas NOx value to maintain the air/fuel ratio at a value corresponding to a maximum desired NOx conversion efficiency.