Mercedes-Benz says its new BLUETEC diesel engine is intended to go on sale in 2008. The engine, which uses a spray of urea to control nitrogen oxide emissions from the diesel process, will make Mercedes the builder of the first vehicles to meet the new diesel emissions rules taking effect this year. The BLUETEC system will be offered in M-, R- and GL-Class sport-utes. The Environmental Protection Agency must first approve Mercedes' plan to monitor the regular refilling of the urea tanks on BLUETEC vehicles, something the agency has not yet ruled on. Honda on Monday announced its own clean-diesel system that will use a two-layer catalyst to clean diesel emissions without the use of a urea spray system.