Sensing & Controls News

Air/Fuel Ratio Control For Natural Gas Engines

Altronic, Inc. has announced the newest addition to its EPC air-fuel ratio controllers for natural gas engines. The new EPC 50 is targeted toward low horsepower, carbureted natural gas fueled engines operating at or near a stoichiometric air/fuel ratio and is ideally suited for applications with three-way catalytic converters, the company said.

The EPC 50 employs microprocessor technology, allowing for a high level of sophistication in control strategy, ease of configuration and diagnostic capability, Altronic said. While it is designed to be mounted in the engine/compressor control panel, a NEMA 3R housing is also available as an alternative mounting option.

The single control output of the EPC 50 allows for its use on any engine application incorporating a single fuel gas regulator. An oxygen sensor is used in the exhaust stream to sense O2 content, and a thermocouple input signals when proper exhaust temperature has been reached to allow for accurate sensor operation. A system fuel control valve installed in the fuel line to the carburetor is precisely adjusted by a stepper motor under microprocessor control to maintain the correct O2 content in the exhaust. The desired air/fuel ratio can be easily adjusted by changing the control target voltages through the sealed membrane keypad or through the use of a PC.

The EPC 50 also incorporates a thermocouple input and a dedicated output for implementation of catalyst overtemperature protection. A second digital output is available for use as an alarm for diagnostics or uncontrolled operation. The EPC 50 has an alphanumeric LCD display showing the target voltage, sensor voltage, operating temperature, stepper motor position and diagnostic information.

Power requirement is 24 (12 to 30) V dc, 1 amp. In remote areas, power can be provided by an Altronic 24 VDC Alternator Power Package.