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An electrically controlled closed loop system for maintaining a desired air-fuel ratio within an internal combustion engine. An operator-positioned accelerator commands a given fuel flow into the engine and the flow of air is controlled by means of a servo-actuated throttle plate. The commanded fuel

An electrically controlled closed loop system for maintaining a desired air-fuel ratio within an internal combustion engine. An operator-positioned accelerator commands a given fuel flow into the engine and the flow of air is controlled by means of a servo-actuated throttle plate. The commanded fuel flow and present position of the throttle plate are used to generate a basic command signal for controlling the servo motor to adjusting the position of the throttle plate. A gas detector or roughness sensor positioned in the engine is responsive to the actual air-fuel mixture in the engine which may be greater than or less than the desired air-fuel mixture and an error signal is generated which can be used to modify or correct the basic control signal in a closed loop manner for selectively adjusting throttle plate position to more precisely maintain a desired air-fuel ratio. While the present type of system has inherent acceleration enrichment since the fuel enters before the air flow increases, an undesirable condition of excessive enrichment may occur. The rate of change of commanded fuel flow is monitored to anticipate an impending undesirable condition of excessive enrichment and a transient control signal adjustment spike is generated to momentarily increase air flow to minimize the undesirable condition even before the gas detector or roughness sensor actually detects the existence of same. A closed loop governing system for metering the fuel flow may also be provided, if desired.

대표청구항 ▼

A closed loop system for controlling the air-fuel mixture in an internal combustion engine comprising: accelerator means for supplying a quantity of fuel to said internal combustion engine; means responsive to said accelerator means for generating a first signal indicative of said quantity of suppli

A closed loop system for controlling the air-fuel mixture in an internal combustion engine comprising: accelerator means for supplying a quantity of fuel to said internal combustion engine; means responsive to said accelerator means for generating a first signal indicative of said quantity of supplied fuel; means for controlling the flow of air into said internal combustion engine; means responsive to said air flow control means for generating a second signal indicative of the actual air flow into said engine; control signal-computing means responsive to at least said first and second signals for generating a basic control signal for regulating said air flow control means, said basic control signal commanding a desired air flow as a function of the quantity of fuel supplied to the engine; means responsive to the actual air-fuel mixture existing in said engine for generating a feed-back signal indicative thereof; and means responsive to said feed-back signal for correcting said basic control signal, said air flow control means being responsive to said corrected control signal for selectively increasing and decreasing the air flow into said engine to maintain a desired optimal air-fuel ratio under substantially all engine operating conditions. An electrical system for controlling the air-fuel mixture in an internal combustion engine system having an intake system, at least one cylinder, a throttle valve disposed within said intake system for regulating the flow of air to said cylinder, means for metering a quantity of fuel into said cylinder, and manually operable accelerator means for positively controlling said fuel metering means, said electrical system comprising: means responsive to one of said accelerator means and said fuel metering means for generating a first signal indicative of the quantity of fuel to be metered into said cylinder; throttle valve positioning means responsive to a control signal for regulating the position of said throttle valve to selectively vary the flow of air into said cylinder; means responsive to one of said throttle valve and said throttle valve positioning means for generating a second signal indicative of the actual air flow into said cylinder; electronic control unit means responsive to at least said first and second signals for generating a base control signal commanding a predetermined desired air flow as a function of metered fuel and the like for controlling said throttle valve positioning means; gas sensing means disposed in said engine for generating a feedback signal indicative of the actual air-fuel mixture existing therein; loop-closing means responsive to said feed-back signal for correcting said base control signal such that said throttle valve positioning means is responsive to said corrected control signal for more accurately maintaining a desired air-fuel ratio in said internal combustion engine; and means responsive to said first signal for anticipating an undesirable condition of excessive enrichment and for generating a transient correction signal indicative thereof even before said gas sensing means detects the actual existence of same for immediately correcting said base control signal and temporarily increasing the air flow into said cylinder for minimizing said undesirable condition.