23 December 1997

The US Environmental Protection Agency (EPA) issued a Notice of Proposed Rulemaking for the Phase 2 Nonroad Spark-ignition Engines at or below 19 kilowatts. The Phase 2 standards will reduce hydrocarbons plus oxides of nitrogen (HC+NOx) by an additional 30% beyond the current Phase 1 standards. The proposed rule includes provisions that give industry flexibility and ease the transition to the more stringent Phase 2 program, especially for small volume engine and equipment manufacturers. The new standards would be phased in between 2001 and 2005.

The "Phase 2" proposed rule follows several years of negotiations between EPA, engine manufacturers and environmental groups. The proposal is based closely on two Statements of Principles (SOPs) signed by EPA and industry groups. EPA published an Advance Notice of Proposed Rulemaking in March 1997 which announced the signing of the two SOPs and requested comments on all aspects of the SOPs for purposes of developing the proposed rule. As a result of a suit by the Sierra Club, EPA is under a court-ordered deadline to complete a final Phase 2 rule for these engines by 23 December 1998.

The proposed Phase 2 program is expected to result in a shift to cleaner, more durable engine technology. Notably, the Phase 2 program will lead to increased use of automotive-style overhead valve (OHV) technology in nonhandheld engines. In addition, the proposal includes new programmatic requirements to ensure that engines meet the tighter standards throughout the useful life of the equipment. When compared to Phase 1 standards, Phase 2 standards may not appear more stringent in all cases. This is because Phase 1 standards are "new engine" standards and Phase 2 standards are in-use standards. Highlights of the proposed rule include:

  • Tighter emission standards for HC+NOx (in grams per kilowatt-hour (g/kW-hr)) to be phased-in during model years 2001 through 2005.
  • Three useful life categories for nonhandheld engines and two useful life categories for handheld engines to account for widely varying product lives.
  • A compliance program to ensure engines continue meeting the standards for the useful life of the engine, including certification, production line testing, and in-use testing.

Contact: Robert Larson, EPA, 734-668-4277

Source: US EPA