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In order to narrow the gap between real-road and certification test fuel consumption rate of heavy-duty commercial vehicles. CHTC (China Heavy-duty vehicle Test Cycle) series test cycles have been developed, and will replace C-WTVC (China-World Transient Vehicle Cycle) test cycle in the latest standard for fuel consumption rate measurement of heavy-duty commercial vehicle. Due to the change of test cycle, the fuel consumption limits standard should also be revised. In this paper, all kinds of the heavy-duty commercial vehicles have been chosen, and the fuel consumption rates under CHTC and C-WTVC have been measured. The fuel consumption values under idling, acceleration, deceleration and constant speed conditions were calculated after the treatment of same mileage. Also the fuel consumption rate under different conditions were compared in order to realize the reasons causing the fuel consumption rate variation. Results showed that the fuel consumption rate of CHTC were slightly lower than C-WTVC except for bus and coach. And the main reasons for the fuel consumption rate variation were attributed to the fuel consumption rate under constant speed condition and the accelerated condition. In addition, the driving efficiency of the two test cycles was another reason, that is, the difference of the duration of each condition under the same mileage. The longer the duration, the higher the fuel consumption.

The emission characteristics under different operating modes (engine mode and hybrid mode) and different test cycles (C-WTVC and CHTC) of a heavy-duty hybrid electric dump truck was investigated on the chassis dynamometer. The emission performance was recorded using Portable Emissions Measurement System (PEMS) and analyzed combined with the characteristic parameters of the test conditions. It is found that the NOx emission under hybrid mode is higher than that under engine mode, while the CO emission under hybrid mode is lower than engine mode. Under engine mode, the NOx emission of CHTC is higher than that of C-WTVC. However, under hybrid mode, the NOx emission of CHTC is lower than C-WTVC. Analysis of CO emission characteristics shows that under engine mode, CO emission is concentrated at low speed and small load condition, while under hybrid mode, CO emission is concentrated at high speed and large load condition.

In this paper, the simulation method of calculating the fuel consumption of heavy-duty commercial vehicles based on VECTO (Vehicle Energy Consumption Calculation Tool) was introduced, and the fuel consumption of four vehicles under C-WTVC and CHTC cycles was calculated with VECTO. The differences between C-WTVC and CHTC cycles were analyzed by comparing the characteristic parameters, and the fuel consumption map and driving acceleration of two cycles were compared, so as to explore the influence of different test cycles on fuel consumption. The results show that compared with the C-WTVC cycle, the fuel consumption of CHTC cycle increases by 17.08g/km~28.12g/km, with an increase of 6.42%~17.26%. Most of the engine working points in the CHTC cycle work in the middle and low speed and torque regions and the acceleration range of CHTC cycle is wider are important reasons for the increase of fuel consumption.