Abstract: A throttle body fuel injection system and method that is arranged to easily replace four-barrel carburetors includes a throttle body assembly with four main bores, each with a throttle plate and an associated fuel injector. Each injector feeds fuel into a circular fuel distribution ring via a fuel injection conduit, which introduces pressurized fuel into the air stream. The fuel distribution rings and bores have profiles that avoid constrictions for to prevent low pressure zones according to the Venturi effect. The throttle body includes an idle air control circuit having a port opening into main intake bores downstream of the point of fuel distribution into the air stream, thereby reducing the tendency for a lean fuel mixture at idle. An ECU “feed forward” algorithm controls fuel injection as a function of the position of the idle air control valve.

Abstract: A self-tuning fuel injection system and method having a first long-term fuel trim correction algorithm to selectively replace an operating zone within a volumetric efficiency look-up table based with a proposed correction only if mathematical comparisons with a surrounding determinative zone reveal that the correction will not result in an abrupt discontinuity. Mathematical comparison models may include absolute values of the differences or percent differences of each proposed cell and its neighbors, the difference of each proposed cell and the mean of its eight neighbors, and standard deviation of each proposed cell and its neighbors. A second repair algorithm repairs values surrounding an operating zone that have such a dissimilar magnitude as to cause poor engine performance using linear interpolation, for example. According to the invention, either the correction or the repair algorithm, or both, are executed in series or in parallel.

Abstract: A throttle body fuel injection system and method that is arranged to easily replace four-barrel carburetors includes a throttle body assembly with four main bores, each with a throttle plate and an associated fuel injector. Each injector feeds fuel into a circular fuel distribution ring via a fuel injection conduit, which introduces pressurized fuel into the air stream. The fuel distribution rings and bores have profiles that avoid constrictions for to prevent low pressure zones according to the Venturi effect. The throttle body includes an idle air control circuit having a port opening into main intake bores downstream of the point of fuel distribution into the air stream, thereby reducing the tendency for a lean fuel mixture at idle. An ECU “feed forward” algorithm controls fuel injection as a function of the position of the idle air control valve.

Abstract: A single point fuel injection throttle body assembly including an idle air control circuit having an port opening into main intake bores downstream of the point of fuel distribution into the air stream. When the idle air control circuit is open, an air/fuel mixture, rather than simply air, is drawn into the into the intake manifold, thereby reducing the tendency for a lean fuel mixture at idle. A unique engine control unit “feed forward” algorithm controls the fuel injection as a function of the position of the idle air control motor so that as the idle air control circuit is opened, the pulse widths of the fuel injector signals are increased. This feature allows the initial open-loop-based fuel mixture supplied by system to be more accurate and eliminates rough unstable idle associated with closed-loop control lag times.

Abstract: A self-tuning fuel injection system and method having a first long-term fuel trim correction algorithm to selectively replace an operating zone within a volumetric efficiency look-up table based with a proposed correction only if mathematical comparisons with a surrounding determinative zone reveal that the correction will not result in an abrupt discontinuity. Mathematical comparison models may include absolute values of the differences or percent differences of each proposed cell and its neighbors, the difference of each proposed cell and the mean of its eight neighbors, and standard deviation of each proposed cell and its neighbors. A second repair algorithm repairs values surrounding an operating zone that have such a dissimilar magnitude as to cause poor engine performance using linear interpolation, for example. According to the invention, either the correction or the repair algorithm, or both, are executed in series or in parallel.

Abstract: A single point fuel injection throttle body assembly including an idle air control circuit having an port opening into main intake bores downstream of the point of fuel distribution into the air stream. When the idle air control circuit is open, an air/fuel mixture, rather than simply air, is drawn into the into the intake manifold, thereby reducing the tendency for a lean fuel mixture at idle. A unique engine control unit “feed forward” algorithm controls the fuel injection as a function of the position of the idle air control motor so that as the idle air control circuit is opened, the pulse widths of the fuel injector signals are increased. This feature allows the initial open-loop-based fuel mixture supplied by system to be more accurate and eliminates rough unstable idle associated with closed-loop control lag times.