Dual fuel engines on the way

The Earth’s long overlooked abundance of natural gas is finally being tapped as an economical replacement for diesel.

As awareness of the availability and everyday potential for the fuel grows, more companies are exploring ways to insert it into the world’s energy mainstream.

One of the innovators is Cummins, which just announced that its high-horsepower, big-block V configuration engines will soon be able to run on a dual fuel ratio of 70:30, with up to 70 percent natural gas blended with diesel in some situations.

The lineup includes engines from 800 to 3,500 h.p.

The QSK50 series are the first Cummins engines to get the dual fuel makeover. Production of these dual fuel engines will begin next year and will be Tier 2 aimed at the oil and gas industry. Other dual fuel QSK50 engines will meet the Tier 4 Final standards as they go into production.

Dual fuel engines function with a single integrated control system that makes a seamless transition between two fuels. The default fuel will always be straight diesel. The alternate fuel is liquid, low pressure natural gas.

The control system automatically selects the best fuel ratio when the operator decides to go into the dual fuel mode. Cummins said dual fuel engines will run a ratio of about 50:50 in most situations.

The dual fuel system will also be made available as a retrofit on existing QSK engines.

Cummins said dual fuel engines will go into the gas and oil patches first because of the immediate proximity of natural gas, which can go from the well head directly into on-site diesel engines that power the operations.

“In the oil and gas industry, variable-speed pressure pumping applications traditionally consume a lot of fuel due to the rugged duty cycle,” a Cummins news release said.

“These customers can expect to see significant fuel savings from the Cummins dual fuel solution.”

Nick Ciavarro, industrial application engineer at Cummins, said in an e-mail the company’s first focus is on large commercial engines with displacements greater than 20 litres.

“As far as power and emissions, there are no published data sheets or horsepower ratings yet,” he said.

“And while dual fuel is interesting and exciting, there’s just not a lot of applicability for most ag machines in the near future.”

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