Content provided in partnership with

Manufacturing Industry

Air/fuel control key to engine performance: Continental Controls' products combine to increase output, fuel efficiency while holding the line on exhaust emissions

Diesel Progress North American Edition, May, 2005 by Mike Mercer

The increased demand and cost of natural gas coupled with ever-tightening exhaust emission standards present a challenge to operators of gaseous-fueled engines. Continental Controls Corp. (CCC), San Diego, Calif., has developed its ECV5 emissions control valve and VM-350 mixing venturi to help meet those challenges.

The ECV5 is a computerized valve designed to precisely control the pressure of the fuel delivered to the mixing venturi or carburetor mixing bowl. The standard ECV5 installation kit typically includes a zirconium oxide [O.sub.2] sensor, two type-K thermocouples and a computerized monitoring and display unit. When the ECV5 and VM-350 mixing venturi are used in conjunction with a three-way catalytic converter, engine emissions are reduced to a minimum, the company said.

Most Popular Articles in Business: Research and Markets : Tesco Plc - SWOT Framework Analysis; Do Us a Flavor - Ben & Jerry's Issues a Call for Euphoric New Flavors; eBay made easy: ready to start an eBay business? These 5 simple steps will ...; Katrina's lawsuit surge: a legal battle to force insurers to pay for flood ...; Wal-Mart's newest distribution center opened last month near the southwest ...; More »

The VM-350 mixing venturi is designed to replace carburetors or mixing bowls and precisely mix the air and fuel admitted to the engine. This venturi also has an option to measure air flow to the engine. When used as a package with the ECV5, the VM-350 or VM-350 XL replaces the carburetor and pressure regulator on both rich-burn and leanburn turbocharged or naturally aspirated, gaseous-fueled reciprocating engines with outputs of up to about 4000 hp, depending on the fuel supply pressure.

"The ECV5 and VM-350 system bases its control on fuel pressure and then we take feedback from the [O.sub.2] sensor to readjust the pressure set-point," said Rick Fisher of CCC. "This is a more efficient approach than the typical bypass or restrictor-type valve systems."

According to Fisher, with a bypass control system, the engine is set up to run lean initially with fuel added as needed based on engine load. A restrictor valve system is set up just the opposite and relies on a pressure regulator to control fuel pressure to the engine, then a butterfly or stepper motor is used to restrict fuel to the engine based on its load requirements. Both of these systems, Fisher said, offer limited performance capability because they can only add or restrict fuel over a narrow range.

"The beauty of our system is that it is a full-authority fuel valve that can control all of the fuel to the engine all of the time," said Fisher. "The ECV5 can be used in conjunction with a carburetor, but to control the fuel in that setup, the ECV5 has to chase the profile up and down a wider scale. It can do it, but it is more difficult. In addition, a carburetor is not the most efficient method to mix air and fuel."

These obstacles are eliminated when the VM-350 mixing venturi is used with the ECV5. "The venturi is the ultimate in air-fuel control when used with the ECV5 because it keeps the fuel pressure profile the same throughout the whole engine operation range," said Fisher. "The fuel pressure to the engine is the same regardless of engine load so we are able to set up the pressure of the unit to be right around zero. There is nothing to change; the pressure is altered within the venturi based on its design to counteract the pressure.

"The only time the fuel pressure to the venturi has to change--this is handled by the ECV5--is if the btu value of the fuel or the ambient air temperature changes. However, these are subtle changes by comparison to a load change on a carbureted application.

"Using the venturi and the ECV5 together really allows us to take care of almost any application. The venturi could be used with other air-fuel ratio controllers in applications where just the carburetor is replaced by the venturi. However, the ultimate package is the ECV5 and the VM-350 venturi used together."

One company to successfully adapt the ECV5 and VM-350 as a package is ConocoPhillips Pipe Line Co. with five crude oil pipeline stations that have been or are in the process of being upgraded, to solve serious engine performance issues. One station, located in Coalinga, Calif., was a special case. It incudes three naturally aspirated, spark-ignited Enterprise GSG-8 engines rated 800 hp at 525 rpm.

Each inline, eight-cylinder engine drives a Sulzer Bingham two-stage pump through a Lufkin gearbox. The pumps now have a maximum flow capability of 120,000 barrels of oil per day and currently average about 96,000 barrels per day. Two of these engines have been converted to include an ECV5 with an [O.sub.2] sensor in the exhaust stream and ECVI display along with two CCC's VM-350 venturi.

"The reason we switched to the Continental Controls fuel control setup was to get the engines to run correctly and to get the most horsepower out of them possible" said Keith Blumert of ConocoPhilips Pipe Line. "In the past we ran the engines and pumps at a lower pipeline throughput. However, with the increased demand for refining capacity, we needed to increase the flow on that pipeline. When we tried to step it up, the Enterprise engines detonated, especially in the hot summer months, and we were unable to get full power out of them. That was when we went looking for a solution."

Manufacturing Industry

Air/fuel control key to engine performance: Continental Controls' products combine to increase output, fuel efficiency while holding the line on exhaust emissions

Diesel Progress North American Edition, May, 2005 by Mike Mercer

Find Research Guides for:

Find Featured Titles for: Health

Most Popular Articles in Business

Most Popular Publications in Business