Cold Start Calibration of Current PZEV Vehicles and the Impact of LEV-III Emission Regulations 2012-01-1245
The cold start calibration of five different four cylinder Partial Zero Emission Vehicle (PZEV) vehicles are examined. This subset of PZEV vehicles with engine displacements between 2.0 and 2.4L, include direct injection and port fuel injection applications with and without secondary air injection. Calibration parameters such as ignition timing, engine speed, and air-to-fuel ratio of each vehicle are compared. Converter light-off strategies differ drastically during Federal Test Procedure (FTP) cold start with various combinations of high engine idle speeds, aggressive ignition retard, secondary exhaust air injection, and in the case of direct injected (DI) engines, split fuel injections.
Emission studies were performed on two of the PZEV vehicles to determine the required platinum group metals (PGM) needed to achieve Super Ultra Low Emission Vehicle (SULEV) SULEV20 and SULEV30 Low Emission Vehicle (LEV) LEV-III emissions requirements. It was determined that the placement of PGM and advanced catalyst technologies are critical for low cost emission solutions. In summary, combining the non-methane organic gases (NMOG) and nitrous oxides (NOx) standards for the LEV-III proposed standards do not require new emission solutions for current PZEV calibrated vehicles. In some cases the combined standard may be easier to achieve than the current 10 wt. mg/mile NMOG PZEV standard.