Abstract: A valve control and diagnostic system uses physical stops to determine whether a connection between the valve motor and the valves has become degraded. The method can detect degradation in both the opening and closing direction, as well as in multi-valve systems, such as used on internal combustion engines.

Abstract: A method for detecting a malfunction in a manifold absolute pressure sensor used in an internal combustion engine. The method includes obtaining a plurality of samples from the manifold absolute pressure sensor. A plurality of samples is obtained from a mass airflow sensor for measuring air flow to the engine. A plurality of inferred manifold absolute pressures is estimated from the plurality of samples obtained from the mass airflow sensor. A linear functional relationship is determined between manifold absolute pressure and inferred absolute pressure from the obtained samples of the manifold pressure sensor and the estimated inferred manifold absolute pressures, such functional relationship having an offset term and a slope. A comparison is made between the determined offset term and the determined slope with a predetermined offset threshold and a predetermined slope threshold level, respectively.

Abstract: A method for determining EGR flow in an internal combustion engine, such flow being from an exhaust manifold of the engine to an intake manifold of the engine through an EGR valve. The method includes using information provided by a mass air flow sensor disposed upstream of an exhaust gas inlet to the intake manifold and information provided by an manifold absolute pressure sensor disposed downstream of such exhaust gas inlet to provide an indication of the flow of exhaust gas into the intake manifold through such inlet. The method compares such estimated exhaust gas flow into the intake manifold with a commanded exhaust gas flow to the EGR valve. With such method, a determination may be made as to whether the EGR valve is operating properly.

Abstract: A valve control and diagnostic system uses physical stops to determine whether a connection between the valve motor and the valves has become degraded. The method can detect degradation in both the opening and closing direction, as well as in multi-valve systems, such as used on internal combustion engines.