Engine and emission monitoring and control system utilizing gas sensors

For use in conjunction with an internal combustion engine which emits nitric oxides as a part of its engine emissions, an exhaust system for the engine and means in said exhaust system for reducing undesirable engine emissions, an engine monitoring system comprising:

• a plurality of sensors for detecting various engine operating conditions and for generating output signals representative thereof,
• at least one of said sensors comprising a gas sensor associated with said exhaust system which produces an output signal N1 indicative of the concentration of a preselected gas in the engine exhaust emissions,
• means responsive to the output signals from said sensors for indicating the state of selected engine operating conditions,
• wherein said engine sensors comprises an engine speed sensor, an engine knock sensor and an air/fuel sensor, and further comprising means for detecting an engine misfire comprising:
• means for reading the output signals from the gas sensor, speed sensor, knock sensor and air/fuel sensor,
• means for comparing each said sensor output signal with preselected threshold values wherein one threshold value is associated with each sensor, and
• means for generating an indicator output signal indicative of an engine misfire when each said sensor output signal exceeds its associated threshold value.

For use in conjunction with an internal combustion engine which emits nitric oxides as a pan of its engine emissions, an exhaust system for the engine, means in said exhaust system for reducing undesirable engine emissions comprising a three way converter, and further comprising a plurality of control means for varying engine operating parameters, an engine emission reduction system comprising:

• a plurality of sensors for detecting various engine operating conditions and for generating output signals representative thereof,
• at least one of said sensors comprising a gas sensor associated with said exhaust system which produces an output signal indicative of the concentration of a preselected gas in the engine exhaust emissions,
• means responsive to the output signals from said sensors for regulating said control means during preselected engine operating conditions in a fashion to reduce undesirable engine emissions during said preselected engine operation conditions,
• wherein said regulating means comprises means to recirculate a portion of the exhaust emissions from the engine to the intake for the engine,
• wherein said exhaust system includes a nitric oxide catalytic converter capable of reducing a preset concentration of nitric oxide, and wherein said system comprises means for detecting the emissions of nitric oxide from the exhaust from the exhaust system, and means for controlling said recirculation means so that the quantity of exhaust gas recirculation is sufficient to reduce the nitric oxide concentration in the exhaust gas stream to said preset concentration.

For use in conjunction with an internal combustion engine which emits nitric oxides as a part of its engine emissions, an exhaust system for the engine and means in said exhaust system for reducing undesirable engine emissions, an engine monitoring system comprising:

• a plurality of sensors for detecting various engine operating conditions and for generating output signals representative thereof,
• at least one of said sensors comprising a gas sensor associated with said exhaust system which produces an output signal N1 indicative of the concentration of a preselected gas in the engine exhaust emissions,
• means responsive to the output signals from said sensors for indicating the state of selected engine components,
• means for determining the air excess ratio of the engine combustion, and wherein said system includes means for detecting a malfunction of said gas sensor associated with said exhaust system, said means for detecting a malfunction of said gas sensor associated with said exhaust system comprising:
• means for determining if engine operation is substantially at a stoichiometric air/fuel ratio and means for then reading the output signal N1 from the gas sensor and for storing a stoichiometric value N1.sub.STOIC,
• means for determining if engine operation is substantially at a predetermined lean air/fuel ratio and means for then reading the output signal N1 from the gas sensor and for storing a lean value N1.sub.LEAN,
• means for calculating a signal ratio SR in accordance with the formula SR=N1.sub.LEAN /NI.sub.STOIC,
• means for comparing the calculated value of SR with a preset threshold for SR, and
• means for generating an output indicator signal when said calculated value for SR is less than said threshold value for SR.

For use in conjunction with an internal combustion engine which emits nitric oxides as a pan of its engine emissions, an exhaust system for the engine and means in said exhaust system for reducing undesirable engine emissions, an engine monitoring system comprising:

• a plurality of sensors for detecting various engine operating conditions and for generating output signals representative thereof,
• at least one of said sensors comprising a gas sensor associated with said exhaust system which produces an output signal N1 indicative of the concentration of a preselected gas in the engine exhaust emissions,
• means responsive to the output signals from said sensors for indicating the state of selected engine components,
• wherein said sensor comprises an air/fuel sensor which generates an output signal representative of the air/fuel ratio of the engine, and wherein said system comprises means for detecting a malfunction of the air/fuel sensor comprising:
• means for determining if engine operation is substantially at a preset rich air/fuel ratio and means for then reading the output signal NI from the gas sensor and for storing a rich air/fuel value N1.sub.RICH,
• means for determining if engine operation is substantially at a predetermined lean air/fuel ratio and means for then reading the output signal N1 from the gas sensor and for storing a lean air/fuel value N1.sub.LEAN,
• means for calculating a median value N1.sub.MEDIAN in accordance with the formula N1.sub.MEDIAN =(N1.sub.RICH +N1.sub.LEAN)/K where K is a preselected constant,
• means for reading the current output signal N1 from the gas sensor and for determining when current output signal N1 is within a preset range of N1.sub.MEDIAN for thereafter comparing the current air excess ratio with a present range of the air excess ratio, and
• means for generating an output signal indicative of a malfunction of the air/fuel sensor when the current air excess ration is outside said preset range of the air excess ratio.

For use in conjunction with an internal combustion engine which emits nitric oxides as a pan of its engine emissions, an exhaust system for the engine, means in said exhaust system for reducing undesirable engine emissions comprising a three way converter, and further comprising a plurality of control means for varying engine operating parameters, an engine emission reduction system comprising:

• a plurality of sensors for detecting various engine operating conditions and for generating output signals representative thereof,
• at least one of said sensors comprising a gas sensor associated with said exhaust system which produces an output signal indicative of the concentration of a preselected gas in the engine exhaust emissions,
• means responsive to the output signals from said sensors for regulating said control means during preselected engine operating conditions in a fashion to reduce undesirable engine emissions during said preselected engine operation conditions,
• means for introducing air into said three way converter, means for determining the air/fuel ratio, and means for activating said air introducing means when the air/fuel ratio is in a lean or stoichiometric condition and the value from the gas sensor exceeds a preset threshold.

For use in conjunction with an internal combustion engine which emits nitric oxides as a part of its engine emissions, an exhaust system for the engine, means in said exhaust system for reducing undesirable engine emissions comprising a three way converter, and further comprising a plurality of control means for varying engine operating parameters, an engine emission reduction system comprising:

• a plurality of sensors for detecting various engine operating conditions and for generating output signals representative thereof,
• at least one of said sensors comprising a gas sensor associated with said exhaust system which produces an output signal indicative of the concentration of a preselected gas in the engine exhaust emissions,
• means responsive to the output signals from said sensors for regulating said control means during preselected engine operating conditions in a fashion to reduce undesirable engine emissions during said preselected engine operation conditions,
• wherein said sensors comprise a throttle sensor which produces an output signal indicative of the position of the throttle, wherein the engine includes fuel injectors and means for selectively introducing air into the fuel injectors, means for controlling the introduction of air into the fuel injectors comprising:
• means for reading the throttle position sensor,
• means responsive to a throttle open condition less than wide open throttle for activating the fuel injector air introducing means in pulses synchronized with the injection of fuel by the fuel injectors.