EPA TO REQUIRE LARGER CANISTERS ON VEHICLES

The Environmental Protection Agency has proposed a rule to require U.S. auto manufacturers to install larger canisters on new automobiles to reduce hydrocarbon emissions. The oil industry had recommended such action instead of tighter restrictions on the volatility of gasoline, but EPA proceeded with that rulemaking last year (OGJ, Mar. 27, 1989, p. 79). EPA said the latest rule will reduce emissions of volatile organic compounds (VOCS) from motor vehicles by about 5% nationwide. VOCs react in

Jan. 15, 1990

2 min read

The Environmental Protection Agency has proposed a rule to require U.S. auto manufacturers to install larger canisters on new automobiles to reduce hydrocarbon emissions.

The oil industry had recommended such action instead of tighter restrictions on the volatility of gasoline, but EPA proceeded with that rulemaking last year (OGJ, Mar. 27, 1989, p. 79).

VOCS REDUCTION

EPA said the latest rule will reduce emissions of volatile organic compounds (VOCS) from motor vehicles by about 5% nationwide. VOCs react in the atmosphere in the presence of sunlight to form smog.

The rule will require vehicle manufacturers to use larger charcoal canisters to capture more vapors, as well as to improve the systems for channeling the vapors to the engine.

EPA said the changes will add about $10 to the price of a vehicle. The rule is to apply to all gasoline fueled passenger cars and trucks.

William K. Reilly, EPA administrator, said "This proposed rule is the most important modification to motor vehicles this agency can require under the current Clean Air Act to achieve a genuine air quality improvement.

"This action, along with other key parts of President Bush's program, such as reductions in gasoline volatility and tougher tailpipe standards, will result in dramatic reductions in ozone nationwide."

HOW IT WORKS

The evaporative control system functions by storing vapors in a charcoal canister. Later, when the vehicle is driven, vapors are purged from the canister and routed to the engine where they are burned as fuel.

If the canister is not large enough to store the vapors or if they are not purged sufficiently, the canister can become overloaded and vapors can escape into the atmosphere.