Cummins Inc.

Xiaoqiu Li

Yue Wang

Mark R Stepper

Stephanie L Goerges

Yue Yun Wang

Todd Slater

Anthony J Abbenante

A system for diagnosing operation of a cooling system for an internal combustion engine includes a coolant temperature sensor producing a temperature signal corresponding to coolant fluid temperature, means for determining either an engine load or a throttle percentage, and a control computer configured to diagnose operation of the cooling system as a function of the temperature signal, either the engine load or throttle percentage, and a fuel delivery command for controllably supplying fuel to the engine. After expiration of a diagnostic period, the control computer diagnoses the cooling system as normally operating if the diagnostic period ended by the temperature signal meeting or exceeding a predefined temperature and if a total energy used by the engine during the diagnostic period is less than an estimated energy, and diagnoses the cooling system as failing if the total energy used during the diagnostic period otherwise meets or exceeds the estimated energy.

System for diagnosing operation of a cooling system for an internal combustion engine

A system is disclosed for diagnosing operation of an EGR cooler disposed in-line with an EGR conduit fluidly coupled between an intake manifold and an exhaust manifold of the engine such that exhaust gas flowing through the EGR conduit also flows through the EGR cooler. The EGR cooler is coupled to an engine cooling system such that coolant fluid circulating through the engine also circulates through the EGR cooler. Means are provided for determining a temperature of exhaust gas produced by the engine, a temperature of exhaust gas exiting the EGR cooler, a temperature of the coolant fluid and a flow rate of exhaust gas through the EGR conduit. A control computer is configured to diagnose operation the EGR cooler as a function of the temperature of exhaust gas produced by the engine, the EGR cooler outlet temperature, the engine coolant temperature and the EGR flow rate.

System for diagnosing operation of an EGR cooler

A system is disclosed for diagnosing EGR flow rate operation in an internal combustion engine includes an intake manifold and an exhaust manifold coupled to the engine and an EGR conduit for recirculating exhaust gas from the exhaust manifold to the intake manifold. Means are provided for determining an EGR fraction corresponding to a fractional amount of recirculated exhaust gas in a total air charge supplied to the intake manifold. A control computer is configured to continually accumulate at least one EGR fraction error sum as a function of the EGR fraction and a desired EGR fraction, and to diagnose EGR flow rate operation as a function of the accumulated value of the at least one EGR fraction error sum.

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Columbus, IN, United States of America

Xiaoqiu Li