Claims
- 1. A method for controlling the camshaft timing, air/fuel ratio, and electronic throttle position in an automotive internal combustion engine, comprising:determining a camshaft timing advance value for a camshaft which operates cylinder intake and exhaust valves of the engine; determining a steady-state position for an electronic air throttle; determining a steady-state air/fuel ratio rate; determining transient values for electronic air throttle position and air/fuel ratio; and determining a rich air/fuel ratio suitable for purging a lean NOx trap based upon a quantity of fuel suitable for operating the engine at approximately a stoichiometric air/fuel ratio, but with insufficient air, so as to cause enrichment of the air and fuel mixture.
- 2. A method according to claim 1, wherein steady-state camshaft timing advance and steady-state air/fuel ratio are based upon a sensed operating position of a manually operable accelerator, as well as upon sensed engine speed.
- 3. A method according to claim 1, wherein the determination of transient electronic throttle position and transient fuel supply rate is based at least in part upon the camshaft timing advance, and upon the steady-state electronic throttle position.
- 4. A method according to claim 1, wherein transient electronic throttle position is determined as a function of at least the time rate of change of the camshaft timing.
- 5. A method according to claim 1, wherein transient electronic throttle position is determined as a function of at least the time rate of change of the camshaft timing and the instantaneous pressure within an air inlet manifold of the engine.
- 6. A method according to claim 1, wherein transient electronic throttle position comprises a steady state value and a correction value.
- 7. A method according to claim 1, wherein the transient air/fuel ratio is determined so as to track and follow the filling and emptying of the intake manifold with the result that fluctuations in output torque are minimized.
Parent Case Info
This application is a divisional of Ser. No. 09/005,571, filed Jan. 12, 1998, now U.S. Pat. No. 6,006,725.
US Referenced Citations (9)