Acurex Environmental Corporation, a nationally recognized firm in heavy-duty alternative fuel technologies, including methanol, CNG, LNG, and propane, was contracted to provide engineering support. Two of the test sites have particular relevance to regional freight hauling and excellent conversion potential for traditional tractor-trailer freight haul services. Golden State Foods supplies food products to McDonald's restaurants. This site is demonstrating the DDC 6V92TA, a classic workhorse engine now performing on methanol in hundreds of city transit buses. Both engines are rated at 300 horsepower, and both are installed in new Freightliner chassis.
Methanol has a low cetane number, meaning it resists ignition more than conventional diesel fuel.
Heavy-duty engines can compression ignite methanol when they are at operating temperature, but otherwise need help getting started. The DDC dedicated methanol engines are designed with glowplugs to provide ignition assistance during starting. Other modifications to the traditional engine configuration include special cylinder heads, redesigned fuel injectors, and a modified blower bypass to reduce the amount of air entering the cylinders. This reduced scavenging increases the temperature of the residual gases in the cylinder, partially compensating for the poorer ignition quality of methanol. This increase also assists methanol ignition by increasing the inlet air temperature into the cylinders.