US 5,349,933 A · Fuel metering control system in internal combustion engine

Abstract

A system for controlling fuel metering in an internal combustion engine using a fluid dynamic model and the cylinder air flow past the throttle is determined therefrom. Based on the observation that the difference between a steady-state engine operating condition and a transient engine operating condition can be described as the difference in the effective throttle opening areas, the amount of fuel injection is determined from the product of the ratio between the areas and a basic fuel injection amount under the steady-state engine operating condition obtained by mapped data retrieval and by subtracting a correction amount corresponding to an air flow filling a chamber between the throttle and the cylinder from the product. Under steady-state engine operation, the correction amount becomes zero. In an embodiment, the first-order lag of a detected throttle opening is calculated and based on the value, various parameters including a pseudo manifold pressure are obtained so as to solve sensors' detection timing lag or a pressure sensor's detection lag.

Claims55

Dependent claims

A system for controlling fuel metering in an internal combustion engine on the basis of the air flowing to a cylinder of the engine determined on a fluid dynamic model describing the behavior of the air passing through a throttle provided in an air intake system of the engine, comprising;

first means for detecting operating parameters of the engine at least including engine speed, manifold pressure and throttle opening;
second means for determining a fuel injection amount (Ti) corresponding to the throttle-past air flow (Gth) under a steady-state engine operating condition at least from the engine speed and manifold pressure in accordance with a first predetermined characteristic, treating the difference between the steady-state engine operating condition and a transient engine operating condition as a difference in effective throttle opening areas;
third means for determining an effective throttle opening area (A1) under the steady-state engine operating condition in accordance with a second characteristic;
fourth means for determining a current effective throttle opening area (A2) on the basis of the throttle opening and manifold pressure to determine a ratio (A2/A1) between the effective throttle opening areas (A1, A2);
fifth means for multiplying the determined basic fuel injection amount (Ti) by the ratio (A2/A1) to determine an output injection amount (Tout);
and
sixth means for driving an injector to open for a period corresponding to the determined output fuel injection amount.

4 more elements

first means for detecting operating parameters of the engine at least including engine speed, manifold pressure and throttle opening;
second means for determining a basic fuel injection amount (Ti) corresponding to the throttle-past air flow (Gth) under a steady-state engine operating condition and an effective throttle opening area (A1) under the steady-state engine operating condition from the engine speed and manifold pressure in accordance with predetermined first and second characteristics, treating the difference between the steady-state engine operating condition and a transient engine operating condition as a difference in the effective throttle opening areas;
third means for determining a current effective throttle opening area (A2) on the basis of the throttle opening and manifold pressure;
fourth means for obtaining the change of the manifold pressure to determine an air flow (delta Gb) filling a chamber defined from downstream of the throttle to a portion immediately before the cylinder of the engine at least from the change of the manifold pressure on the basis of the ideal gas law, and then by dividing the chamber filling air flow (delta Gb) by a desired air/fuel ratio (A/F) to determine a correction amount delta Ti (=delta Gb/(A/F)) corresponding to the chamber filling air flow (delta Gb);
fifth means for obtaining a ratio (A2/A1) between the effective throttle opening areas (A1, A2) and for multiplying the determined basic fuel injection amount (Ti) by the ratio (A2/A1) and by subtracting from the product the correction amount (delta Ti) to determine an output fuel injection amount (Tout);
and
sixth means for driving a injector to open for a period corresponding to the determined output fuel injection amount (Tout).

4 more elements

first means for detecting operating parameters of the engine at least including engine speed, manifold pressure and throttle opening;
second means for determining a fuel injection amount (Timap) under a steady-state engine operating condition at least from the engine speed and manifold pressure in accordance with a predetermined first characteristic;
third means for determining a first effective throttle opening area (A) at least from a value obtained from the throttle opening;
fourth means for obtaining a second effective throttle opening area (ADELAY) in accordance with a predetermined second characteristic;
fifth means for obtaining a ratio (A/ADELAY) between the first and second effective throttle opening areas (A, ADELAY) and for multiplying the determined fuel injection amount (Timap) by the ratio (A/ADELAY) to determine an output fuel injection amount (Tout) from the product as
Tout=Timap.times.(A/ADELAY);
and
sixth means for driving an injector to open for a period corresponding to the output fuel injection amount (Tout).

5 more elements

Dependencies are inferred from the claim text.

Fuel metering control system in internal combustion engine

Life of this patent

Fuel metering control system in internal combustion engine

Life of this patent

Abstract

Claims55