Aiming at solving the difficulty of effectively analyzing the fuel consumption characteristics of conventional vehicles, this paper statistically analyzed the engine operating time and the fuel consumption rate of several typical driving cycles, and used threedimensional distribution visual analysis to identify the detailed engine fuel consumption characteristics. A transit bus was simulated under several city cycles with the statistics of the engine speed, torque and time history of fuel rate. Results have shown that the vast majority of the engine operating points fall into the low speed and lowload zone, where the engine consumes a significant amount of fuel. Furthermore, the results have also indicated that the direction of engine energysaving, i.e. high efficiency region of the engine performance MAP should be shifted to the lowspeed and lowload zone where the vehicle operates most of the time. Also, the engine should be downsized with hybrid technology. This work has great practical value in guiding enterprises in product development and energysaving designs.