Texas-TxLED Program


Technical Data Sheet #1114

Texas Commission on Environmental Quality
Texas Low Emission Diesel (TxLED) Program
Emissions Reductions Using Viscon In High Aromatics Diesel

The Texas TxLED goal is to lower emissions of NOx and other pollutants from diesel-powered motor vehicles and nonroad equipment. It applies to diesel fuel producers, importers, common carriers, distributors, transporters, bulk terminal operators, and retailers. The rule covers 110 counties in the eastern half of Texas, including the ozone nonattainment areas of Beaumont-Port Arthur, Dallas-Fort Worth, and Houston-Galveston-Brazoria. The rule requires that diesel fuel as defined under 30 TAC §114.6 produced for delivery and ultimate sale to the consumer –for both on and nonroad use – must contain less than 10 percent by volume of aromatic hydrocarbons and must have a cetane number of 48 or greater, or be a TxLED equivalent fuel.

The purpose of the TxLED testing was to compare exhaust emissions of an alternative ultra low sulfur candidate fuel to a Texas TxLED reference fuel under hot-start transient test cycle conditions. The primary objective was to obtain NOx emissions with the alternative candidate fuel equal to or better than the results with the TxLED reference fuel without negative effects on PM and other gaseous emissions.

Olson Ecologic testing laboratories of Fullerton, California conducted a series of exhaust emissions tests from a late model over-the-road diesel engine using a high aromatics (33%) diesel fuel with and without Viscon treatment. The test program included a 20% biodiesel blend in the high aromatics diesel treated with Viscon. The test was performed in accordance with US EPA’s Heavy Duty Transient Test Protocol. The test program was audited by an independent agent appointed by the Texas Commission on Environmental Quality. Upon review of the test results by the Texas Commission on Environmental Quality and the U.S. Environmental Protection Agency, Viscon was approved for use in the TxLED program; i.e.., authority granted by the TCEQ to Viscon California, LLC to provide Viscon for the purpose of achieving state-mandated NOx reductions.

View TxLED Approval Documents