Air density computer for an internal combustion engine fuel control system

Claim 2

A fuel control system for an internal combustion engine having a controlled operating temperature, a throttle controlled air intake manifold, and at least one electrically controlled fuel injector mounted in the air intake manifold proximate the engine's intake valve port for spraying fuel into the engine in response to electrical signals comprising: sensor means including an intake manifold pressure sensor adapted for communication with an internal combustion engine for generating signals indicative of the engine's operating parameters; a temperature sensor means mounted in the air intake manifold proximate said fuel injector and outside the fuel spray emanating from said fuel injector for sensing the temperature of just the air in the immediate vicinity of the engine's intake valve port even after the engine has reached the controlled operating temperature and for generating a temperature signal indicative of the temperature of the air just prior to being inhaled by the engine; constant current means, operative to communicate a constant current to said temperature sensor means; inverter means for amplifying and inverting said temperature signal to generate an air density signal indicative of the relative density of the air being inhaled by the engine; and a fuel control computer responsive to said sensor means signals including the signals from said pressure sensor for generating electrical signals indicative of the engine fuel requirements, said fuel control computer further responsive to said air density signal for compensating said electrical signals for changes in the density of the air being inhaled by the engine; whereby said air density compensated electrical signals communicated to said at least one fuel injector controls the fuel delivery to the engine and maintains the desired fuel to air ratio during the warm-up period after the engine has reached the controlled operating temperature but the temperature of air being inhaled by the engine is still changing.

Claim 3

The system as claimed in claim 1 wherein said inverter means further includes means for establishing a DC bias on the air density signal generated by said inverter means.

Claim 4

In combination with an internal combustion engine fuel control system having sensor means including an intake manifold pressure sensor operative to generate signals indicative of the engine's operating conditions, a fuel control computer responsive to signals from said sensor means operative to generate pressure compensated injector signals indicative of the engine's fuel requirements, and at least one fuel injector mounted in the engine's air intake manifold proximate the engine's intake valve ports for spraying fuel into said engine in response to said injector signals operative to control fuel delivery to the engine, an air density computer for compensating fuel delivery to the engine during the transient warm-up period between the time the engine starts and the engine including its accessories reach a stable operating temperature comprising: a temperature sensor mounted in the air intake manifold of said engine proximate the fuel injector and outside the fuel spray emanating from the fuel injector for sensing changes in the temperature of just the air in the immediate vicinity of the engine's intake valve port even after the engine reaches a stable operating temperature and for generating a temperature signal indicative of the temperature of the air just prior to being inhaled by the engine; a constant current generator, operative to provide said temperature sensor with an electrical current of a predetermined magnitude; an amplifier, responsive to the temperature signal generated by said temperature signal for generating an amplified signal which is an inverted function of said temperature signal; Dc bias means operative to superimpose a predeterminable electrical DC bias signal on said amplified and inverted signal to produce an air density signal indicative of the relative density of the air being inhaled by the engine; and means for communicating said air density signal to the fuel control computer, wherein the fuel control computer signal indicative of the engine's fuel requirements is modulated as a function of the relative air density signal, whereby the desired fuel to air ratio delivered to the engine is maintained during the transient warm-up period.

Claim 5

In combination with an internal combustion engine fuel control system having sensor means including an intake manifold pressure sensor operative to generate signals indicative of the engine's operating conditions, a fuel control computer responsive to signals from said sensor means operative to generate pressure compensated injector signals indicative of the engine's fuel requirements, and at least one fuel injector mounted in the engine's air intake manifold proximate the engine's intake valve ports for spraying fuel into said engine in response to said injector signals operative to control fuel delivery to the engine, an air density computer for compensating fuel delivery to the engine during the transient warm-up period between the time the engine starts and the engine including its accessories reach a stable operating temperature comprising: a temperature sensor mounted in the air intake manifold of said engine proximate the fuel injector and outside the fuel spray emanating from the fuel injector for sensing changes in the temperature of just the air in the immediate vicinity of the engine's intake valve port even after the engine reaches a stable operating temperature and for generating a temperature signal indicative of the temperature of the air just prior to being inhaled by the engine; a constant current generator, operative to provide said temperature sensor with an electrical current of a predetermined magnitude; an amplifier, responsive to the temperature signal generated by said temperature signal for generating an amplified signal which is an inverted function of said temperature signal; Dc bias means operative to superimpose a predeterminable electrical DC bias signal on said amplified and inverted signal to produce an air density signal indicative of the relative density of the air being inhaled by the engine; and means for communicating said air density signal to the fuel control computer, wherein the fuel control computer signal indicative of the engine's fuel requirements is modulated as a function of the relative air density signal, whereby the desired fuel to air ratio delivered to the engine is maintained during the transient warm-up period.