OCTOBER 10, 2013 — Wärtsilä has now released its Wärtsilä 20DF dual-fuel engine for sale in the U.S. market. The engine meets U.S. Environmental Protection Agency (EPA) Tier 4 emissions compliance criteria.

Wärtsilä's 34DF received EPA certification earlier this year (see earlier story)

Wärtsilä says the 20DF is a proven and successful engine, and its release to the U.S. market is in response to the growing demand for natural gas fueled engines.

"The Wärtsilä 20DF will further accelerate the adoption of LNG as a marine fuel in the U.S.," says Lars Anderson, Vice President, four-stroke at Wärtsilä Ship Power. "The ability to meet EPA Tier 4 emissions requirements without the need for exhaust after-treatment, while at the same time increasing the safety and operational flexibility for LNG vessels, provides significant value to our customers."

The Wärtsilä 20DF is a commercial duty, medium-speed, dual-fuel engine. Engines supplied to the U.S. market will operate primarily on natural gas, with marine diesel oil (MDO) as a pilot fuel or as an emergency backup fuel.

The Wärtsilä 20DF covers the power range from 1,056 kW (1,415 HP) to 1,584 kW (2,122 HP) per engine.

Wärtsilä's four-stroke dual-fuel engine portfolio has the widest power range in the market. The Wärtsilä 20DF, Wärtsilä 34DF and Wärtsilä 50DF output ranges from 1,056 kW (1,415 HP) to 17,550 kW (23,515 HP) per engine.

Wärtsilä has delivered over 1,000 dual-fuel engines. This portfolio of engines currently has over 7 million operating hours.

Wärtsilä's lean burn, low pressure dual-fuel engine technology utilizes a very low percentage diesel fuel as a pilot ignition source, amounting to about 1 per cent of total energy. This contrasts with other gas engine technologies that employ a significantly higher percentage of diesel pilot fuel. The Wärtsilä lean burn advantage results in lower operational costs and reduced emissions.