Patent ID: 6308671
Filing Date: 2001-10-30
Classification: F01L,F02D,Y02T

Abstract:
A method of improving the operating characteristics of an internal combustion engine equipped with an electronically controlled throttle, a fuel injector and a variable valve timing mechanism, said variable valve timing mechanism being used to control the timing of at least one of intake valves and exhaust valves of said engine, said method comprising the repeated performance of at least the following steps:(a) ascertaining a desired torque requested of said engine;(b) calculating a desired fuel flow based on an amount necessary for said engine to provide said desired torque and on dilution occurring within cylinders of said engine;(c) determining a per-cylinder fuel amount based on said desired fuel flow and the number of said cylinders in said engine;(d) calculating an injector pulse width with which to activate said fuel injector based on said per-cylinder fuel amount;(e) calculating a desired air flow based on said desired fuel flow according to a desired air-fuel ratio;(f) monitoring an actual position of said throttle;(g) determining a desired position of said throttle as a function of at least two of said desired air flow, an absolute pressure in an intake manifold of said engine, a speed of said engine and a volumetric efficiency of said engine;(h) adjusting said throttle to said desired position with regard to said actual position of said throttle;(i) determining a desired position for said variable valve timing mechanism as a function of at least said speed of said engine and a load of said engine;(j) directing said variable valve timing mechanism to move to said desired position thus causing said timing at which said at least one of said intake valves and said exhaust valves open and close to operate according to a schedule that improves said operating characteristics of said engine;(k) monitoring an actual position of said variable valve timing mechanism;(l) determining said volumetric efficiency of said engine as a function of said speed of said engine, said load of said engine and one of said desired and actual positions of said variable valve timing mechanism; and(m) calculating said dilution occurring within said cylinders of said engine based on said speed of said engine, said load of said engine and one of said desired and actual positions of said variable valve timing mechanism.