Internal-combustion engines – Charge forming device – Exhaust gas used with the combustible mixture
Reexamination Certificate
1998-11-25
2001-05-15
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Charge forming device
Exhaust gas used with the combustible mixture
C123S568270, C073S001060, C073S001350, C073S001570, C073S117020
Reexamination Certificate
active
06230694
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the testing and calibration of automotive emission control valves. More specifically it relates to the testing and calibration of an exhaust gas recirculation (EGR) module that is useful in an exhaust emission control system of an automotive vehicle powered by an internal combustion engine.
BACKGROUND OF THE INVENTION
U.S. Pat. Nos. 5,241,940 (Gates, Jr.) and 5,613,479 (Gates et al.), which are hereby incorporated by reference, disclose EGR systems of the type in which a module that can be tested and calibrated according to principles of the present invention is useful. Such a module possesses a construction that provides important economic and functional advantages relating to fabrication, assembly, testing, installation, and use, and certain principles of the present invention relate to the testing and calibration of such a module.
SUMMARY OF THE INVENTION
One generic aspect of the invention relates to a method of calibrating and testing an automotive emission control that comprises an emission control valve, a fluid-operated actuator, an electric-operated fluid regulator valve, and an electric sensor, the emission control valve comprising a body containing an internal main flow passage and a valve member for controlling flow through the flow passage. The fluid-operated actuator has an operative connection for operating the valve member, the electric sensor has a sensing port for sensing a characteristic of the flow and provides an electric signal correlated with the characteristic of the flow sensed at the sensing port, and the electric-operated fluid regulator valve supplies regulated fluid for operating the actuator. The method comprises associating the emission control valve, the actuator, the regulator valve, and the sensor with a test stand that comprises a fluid pump, a fluid flowmeter, and electric circuitry; calibrating the control by operating the pump and the regulator valve, including applying a defined electric signal from the electric circuitry of the test stand as a control signal input to the electric-operated fluid regulator valve, to create fluid flow through the flow passage of the emission control valve, and by measuring fluid flow through the flow passage with the flowmeter; supplying the electric signal from the sensor as a signal input to the electric circuitry of the test stand; adjusting one of the regulator valve and the actuator to secure a desired correlation of fluid flow measured by the flowmeter to the defined signal applied to the regulator valve; and testing the sensor by creating a defined fluid flow through the flow passage, and evaluating, by the electric circuitry of the test stand, the electric signal input from the sensor that occurs at the defined fluid flow.
More specific aspects include the adjusting step comprising adjusting the regulator valve; the step of operating the pump comprising applying vacuum to a port of the emission control valve body that is downstream of the valve member in the main flow passage while a port of the emission control valve body that is upstream of the valve member in the main flow passage is communicated to atmospheric pressure; the step of testing the sensor by producing a defined fluid flow through the flow passage of the emission control valve body comprises measuring the fluid flow with the flowmeter to secure correspondence of the measured fluid flow with the desired fluid flow; the further step of calibrating the sensor to cause the signal from the sensor to correspond to the defined fluid flow measured by the flowmeter; the step of calibrating the sensor comprising electrically programming calibration data into memory of the sensor via an electric terminal of the sensor; and the associating step including the step of communicating the sensing port of the sensor to the main flow passage of the emission control valve body to sense pressure in the main flow passage.
A further generic aspect relates to a method of calibrating an automotive emission control that comprises an emission control valve, an actuator, and an electric sensor, the valve comprising a body containing an internal main flow passage and a valve member for controlling flow through the flow passage, the actuator having an operative connection for operating the valve member, and the electric sensor having a sensing port for sensing a characteristic of flow through the main flow passage. The method comprises associating the emission control valve, the actuator, and the sensor with a test stand that comprises a fluid pump, a fluid flowmeter, and electric circuitry. The pump is operated to create defined fluid flow through the main flow passage of the valve body as measured by the flowmeter of the test stand, and the sensor is calibrated to cause an electric signal from the sensor to correspond to the defined fluid flow measured by the flowmeter. A more specific aspect comprises calibrating the sensor by electrically programming calibration data into memory of the sensor via an electric terminal of the sensor.
Still another generic aspect relates to a method of re-calibrating an engine emission control that is installed in an automotive vehicle and that comprises an engine emission control valve, an actuator, and an electric sensor, the valve comprising a body containing an internal main flow passage having an inlet port, an outlet port, and a valve member for selectively restricting flow through the flow passage between the inlet and outlet ports, the actuator having an operative connection for operating the valve member, the electric sensor having a sensing port for sensing a characteristic of the flow and providing an electric signal correlated with the characteristic of the flow, the inlet port being communicated to an exhaust system of an internal combustion engine that powers the vehicle, and the outlet port being communicated to vacuum derived from an intake system of the engine so that when the engine operates and the emission control valve is open, engine exhaust gas forms fluid flow through the flow passage in a direction from the inlet port to the outlet port. The method comprises: operating the engine to apply vacuum to the outlet port and to supply exhaust gas to the inlet port; operating the actuator to allow exhaust gas flow through the flow passage; sensing a characteristic of the engine exhaust gas; and re-calibrating the sensor to secure a desired relationship between the sensed characteristic of the exhaust gas and the fluid condition sensed by the sensor.
Further specific aspects relate to: the step of re-calibrating the sensor comprising electrically programming calibration data into memory of the sensor via an electric terminal of the sensor; the step of sensing a characteristic of the exhaust gas comprising sensing a signal from a sensor in the engine exhaust system, which can be an oxygen sensor; the step of re-calibrating the sensor comprising sensing at least one additional characteristic related to operation of the engine, which can be engine intake system vacuum and/or engine operating temperature.
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paten
Busato Murray F.
Cook John E.
Siemens Canada Ltd.
Wolfe Willis R.
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