Hybrid electric vehicles (HEVs) are considered the most practical option for reducing emissions and fuel consumption of conventionally powered vehicles. Energy management strategies (EMSs) are the core technology of HEVs because of decreasing the cost of the system and limiting its negative effects. Equivalent consumption minimization strategy (ECMS) can achieve instantaneous optimal control and has attracted attention in recent years. In this study, an adaptive equivalent consumption minimization strategy (A-ECMS) based on driving cycle recognition is constructed for a parallel HEV. First, select the standard driving cycle and analyze its characteristic parameters. And then training learning vector quantization (LVQ) neural network-based driving cycle recognizer to achieve an average of 98% accuracy. At last, the optimal equivalent factor (EF) is selected for ECMS by recognizing the current driving cycle. It is jointly simulated and analyzed by AVL CRUISE and MATLAB/Simulink software under NEDC and CHTC-LT driving cycle. The results show that compared with the logic-based EMS, in the NEDC driving cycle the 100 km fuel consumption of A-ECMS decreases by 3.8%, and the battery state of charge (SOC) increases by 1.1%. In the CHTC-LT driving cycle, fuel economy improves by 3.6%, proving the superiority of the A-ECMS.

Driving condition is a key factor that affects the power demand of vehicles, and its accurate recognition helps to improve the adaptability of energy management strategy for fuel cell vehicles and thus achieve a reasonable distribution of power demand in hybrid powertrains. However, the current driving condition recognition methods suffer from severe time delay, which is not conducive to real-time control. In this study, a fusion algorithm-based driving condition recognition method is proposed to solve this problem, and efforts are made in two aspects. Firstly, a driving condition recognition model combining Markov chain prediction model and learning vector quantization neural network recognition model is established. Secondly, the key parameters affecting recognition accuracy and real-time performance are analyzed and optimized to further improve the recognition performance. Simulation and experimental results show that the real-time performance of the proposed method is significantly improved compared with the method based on historical condition data under the premise of ensuring recognition accuracy and stability. Moreover, the proposed method is applied to the energy management of a medium fuel cell truck, and simulation results highlight that the proposed method can effectively improve the adaptability of the energy management strategy. Compared with the energy management strategy without condition recognition, the fluctuation of fuel cell output power is reduced by 30.4%, and the equivalent hydrogen consumption is reduced by 1.2%, which contributes to the improvement of fuel cell lifetime and economy.

To reduce emissions and save energy, alternative fuel and dual-fuel mode have been widely applied in the field of diesel engines. The pilot injection has potential to reduce engine vibration noise and pollutant emissions. The effects of a diesel fuel pilot injection strategy on the performance of an ethanol/F-T diesel dual-fuel engine were experimentally investigated on a four-cylinder four-stroke common rail diesel engine modified with an ethanol injection system. The results indicate that the variation in the combustion characteristic parameters with pilot injection timing is nonlinear and the difference is small, while soot, NO_x, and CO tend to decrease, with an increase in pilot injection timing. With the increase in pilot injection amount, p_max, combustion duration, CO and soot increased; p_max phase and CA50 were closer to TDC; HRR_max and the ignition delay period decreased. The BSFC tends to increase with the increase in pilot injection timing and the increase in pilot injection amount, while the BTE shows the opposite trend. The value and the variation range of COV_pmax are small. The effect of the pilot injection amount on ethanol/F-T diesel dual-fuel engine is more significant. The research presented in this paper can provide reference directions for the formulation of a fuel injection strategy of ethanol/F-T diesel dual-fuel combustion mode to reduce NO_x without worsening the combustion process and presenting an insufficient fuel economy.