Abstract
To clarify the characteristics of nitrogen dioxide (NO2) emission from diesel vehicles which are the main source of air pollution in the Tokyo metropolitan area, we tested a diesel truck (engine type: direct injection, carrying weight: 4, 000 kg, equivalent inertia weight: 5, 855 kg) on a chassis dynamometer.
We measured NOx and NO concentrations in the exhaust gas from the truck using a Constant Volume Sampling (CVS) system and calculated the emission rates of NOx and NO by the Modal Mass Dilute Method, and obtained the emission rate of NO2. The NO2/NOx (v/v) fractions at idling and at four constant speeds were 31%(idling), 26%(20 km/h), 22%(40 km/h), 25%(60 km/h) and 17%(80 km/h).
Under the driving conditions of the M-15 test pattern, the fractions at acceleration and deceleration ranged between 11-21% and 50-60%, respectively. The integration of NO2/NOx fractions and NO2 emission rates under the driving conditions of the Tokyo Metropolitan Test Driving Pattern No.2, No.5 and No.8 were (24% and 1.23g/km at 8.1km/h (average speed)), (20% and 0.69g/km at 18.2km/h) and (18% and 0.52g/km at 28.8km/h), respectively. In these three test patterns, NO2 emissions in the acceleration mode were greater than in the other three modes.
