Session: 19-01: Turbines and Energy recovery.

Submission Number: 179461

Feasibility Study of a Two-Stage Turbocharged Hydrogen-Fueled Internal Combustion Engine for High-Altitude Applications 

Turbocharged internal combustion engine (ICE) systems are widely employed for high-altitude, long-endurance (HALE) unmanned aerial vehicles (UAVs) due to their good altitude adaptability and fuel economy. To further extend the endurance of high-altitude flight platforms, substituting hydrogen for conventional fuels offers a promising approach because of hydrogen’s high energy-to-mass ratio. However, implementing hydrogen combustion at high altitudes presents new challenges. First, to prevent knock in hydrogen engines, the lean combustion strategy adopted increases the boost demand of the turbocharging system under rarefied atmosphere conditions. Secondly, the exhaust temperature produced by hydrogen fuel combustion is relatively lower than that of conventional fuels, resulting in insufficient available flow energy for the turbine, further limiting the attainable compressor pressure ratio. Therefore, to ensure that the turbocharging system can restore sufficient intake charge air required by the hydrogen engine at high altitude, a well-designed turbocharging system and control strategy are necessary.

This work investigates the feasibility of a two-stage wastegate turbocharging system for hydrogen-fueled ICE operating up to 15 km altitude. First, a comprehensive one-dimensional engine model is developed and validated using experimental data from the original gasoline engine. Then, the gasoline engine model is adapted for hydrogen operation by adjusting the thermophysical properties of the fuel and exhaust gas, and a combustion duration model derived from experimental data is incorporated together with a hydrogen knock prediction model. A coupled simulation model integrating the hydrogen engine and two-stage turbocharging system is established. From sea level to the cruising altitude, the operational characteristics are studied for the evaluation of altitude adaptability and matching between the turbocharger and hydrogen engine. The results show that the two-stage turbocharging configuration can achieve the required boost pressures for hydrogen ICE under targeted high-altitude conditions, and a single-wastegate control method is proposed to adjust the variable-altitude matching between the turbocharger and the hydrogen engine.

Presenting Author: Hongyu Zhou Tsinghua University

Presenting Author Biography: Hongyu Zhou is a Ph.D. student in the Department of Vehicle and Mobility at Tsinghua University. He is investigating topics such as turbocharger design and matching, system-level modeling and control strategies, turbomachinery aerodynamics.

Authors:

Hongyu Zhou Tsinghua University
Baotong Wang Tsinghua University
Mingyang Yang Shanghai Jiao Tong University
Lei Jin SinoHawk Power Technology Co., Ltd.
Xinqian Zheng Tsinghua University