Research of the Test for Complete-Vehicle Emission of the Bus by Chassis-Dynamometer

For the performance evaluation of heavy vehicle emissions and fuel consumption, based on heavy-duty chassis-dynamometer and constant volume sample (CVS) system, this paper analyzes the influence of different cycles on emissions. The NO_X, HC, CO, and CO₂ mileage emission factors and hundred kilometers fuel consumption of the China City Bus Cycle (CCBC) are 1.91 times, 36%, 1.42 times, 1.33 times, 1.27 times of China World Transient Vehicle Cycle(C-WTVC, respectively. Research the contribution of the different operating modes of the different cycles, including accelerate, decelerate, constant speed, and idle. Contribution rates of accelerating models to gaseous pollutants are the highest. The contribution rates of CO and NO_X is up to 67.1% and 65.4%. We collected the operating modes and conditions of the engine of test vehicle and confirmed the working range of different cycles. The test contrasts the difference of the engine's working range of the emission regulations cycles and actual travel cycles. The conclusion is that the emission regulations cycle can't reflect the complete-vehicle condition in use.