This Friday, three trucks employed by West Marin Compost and Lunny Grading and Paving will become the first in the state to be outfitted with devices that filter and clean engine oil while the truck is running. Kevin Lunny said he stumbled upon the technology, developed by the company OnBoard Oil Tech, while searching on the Internet for ways to make his trucks greener and said it was a “huge savings” both financially and environmentally. The device, which has been in production for a year, reduces the need for oil changes—which for diesel engines needing about 10 gallons of oil can cost up to $400 eight to 12 times a year, according to Anthony Evans, vice president of sales for the company. The benefits are broad, he said, citing reduced oil consumption and waste, which can end up in landfills or pollute watersheds. The system is being installed on two trucks and one wheel loader used for the compost project—a public-private partnership—and grading company. Engines with the system can go up to 250,000 miles without an oil change, whereas diesel trucks traditionally go 15,000 to 25,000 between oil changes, according to Mr. Evans. If all goes well in the next year, Mr. Lunny said he would like to install the system on his company’s remaining eight or so trucks. While the technology is currently just for diesel engines, OnBoard has plans to roll out a similar product for heavy-duty pickup trucks by the end of 2013. Friday’s ribbon cutting will take place at 10:30 a.m.at the Lafranchi Dairy in Nicasio.