Hydrogen Utilization in Vehicle Fleets: A Study on Energy Security and Greenhouse Gas Emissions

Strategic Insights -

Research at Tsinghua University in Beijing, China, has focused on the effects of hydrogen utilization in vehicle fleets, particularly on energy security and greenhouse gas emissions. The study examined the effect of various parameters on a compressed natural gas (CNG) fueled spark ignition (SI) engine under low load and low-speed conditions. The research aimed to analyze the suitability of a laboratory-based CNG SI engine for hydrogen-enriched CNG fuel.

Key Takeaways:

  • The study examined the effect of hydrogen ratios (0-50%), exhaust gas circulation (EGR) ratios (0-20.6%), and Spark timing (4-44 degrees CA bTDC) on a compressed natural gas (CNG) fueled spark ignition (SI) engine.
  • The peak torque was increased by 1.18% with the addition of hydrogen, compared to CNG fuel, and maximum brake thermal efficiency increased by 3.17% with 6% exhaust gas recirculation.
  • Thermodynamic analysis revealed that the maximum brake power during the combustion of HCNG30 fuel was 35% of total fuel energy with 14.8% EGR at 32 degrees CA bTDC, and the minimum exhaust heat rate during the combustion of HCNG10 fuel was 16% of total fuel energy with 0% EGR at 14 degrees CA bTDC.
  • The addition of hydrogen fractions reduced CO2, CO, THC, and CH4 emissions and decreased NOx by increasing EGR.
  • The research was conducted under stoichiometric conditions with a low load of 30% and low speed (900-1100 rpm).
  • The study involved the analysis of torque, brake thermal efficiency, NOX, CO2, CO, THC, CH4, in-cylinder pressure-volume curves, mass fraction burns, and thermodynamic analysis with heat transfer rate, brake power, friction power, and exhaust heat rate.

Statistics:

  • The maximum brake thermal efficiency increased by 3.17% with 6% exhaust gas recirculation.
  • The peak torque was increased by 1.18% with the count of HCNG20 in comparison to CNG fuel.
  • The maximum brake power during the combustion of HCNG30 fuel was 35% of total fuel energy with 14.8% EGR at 32 degrees CA bTDC.
  • The minimum exhaust heat rate during the combustion of HCNG10 fuel was 16% of total fuel energy with 0% EGR at 14 degrees CA bTDC.

Sources:

  • Performance, Emissions and Thermodynamic Analysis of Hydrogen-enriched Compressed Natural Gas Engine. Thermal Science and Engineering Progress, 2025;63.
  • NewsRx. New Thermal Science and Engineering Data Have Been Reported by Researchers at Tsinghua University (Performance, Emissions and Thermodynamic Analysis of Hydrogen-enriched Compressed Natural Gas Engine). Energy Weekly News. July 11, 2025; p 615.