— The new mid-size cars from Ford and Mercury are at the top of the list of low-emissions vehicles. The standard Duratec 23 I-4 with automatic transaxle on the Fusion and Milan will be rated as a Partial Zero Emissions Vehicle (PZEV) in states that have adopted California’s emissions regulations. In addition, the Duratec 30 V-6 option is the cleanest Duratec 30 ever produced, qualifying for Ultra Low Emissions Vehicle (ULEV) II tailpipe emissions.Federal Tier 1 emission standards are the basic standards in the United States, while the updated Tier 2 standards started a phase-in process in 2004 and should be fully implemented in 2007 for light-duty vehicles.The PZEV designation means that the Fusion, Zephyr, and Milan must meet the Super Ultra Low Emission Vehicle (SULEV) standards plus eliminate fuel system evaporative emissions and include a powertrain limited warranty ensuring that these stringent criteria will be met for an extended lifetime of 15 years or 150,000 miles. While the 23 I-4 meets California’s stringent standards, outside of California, the PZEV has slightly higher tailpipe emissions — even though the car’s electronics, powertrain, and emissions equipment are identical — because other states have not adopted Cali-fornia’s clean-fuels program. The Duratec 30 V-6 will meet federal Low Emissions Vehicle (LEV) II standards and ULEV II tailpipe emissions in California. To achieve the emissions control, the Ford engineers began by implementing a number of improvements to the induction, calibration, and exhaust systems of the Duratec 23 to achieve LEV II certification. From that platform, the powertrain team targeted ignition and evaporative emissions to qualify for PZEV certification.Changes to decrease emissions at startup include a Ported Electronic Thermactor Air system, which injects warmer air and additional oxygen into the intake manifold to enable more combustion and decrease the amount of unconsumed gasoline in the system. In addition, recycling cold-start exhaust back through the engine provides a second opportunity to trap emissions after the catalysts reach operating temperature. To help the catalysts reach operating temperature faster, the team installed a stainless steel, dual-walled manifold that heats up faster than the standard Duratec 23 cast-iron manifold.