SwRI Develops Hydrogen Internal Combustion Engine for Heavy-Duty Long-Haul Trucking

The Southwest Research Institute (SwRI) has developed a hydrogen internal combustion engine (H2-ICE) aimed at reducing emissions in heavy-duty, long-haul trucks. This engine is designed to produce very low levels of NOx and CO2 while providing enough power and torque for trucking needs.

Created through a consortium of engine and truck manufacturers, fuel and lubricant suppliers, and Tier-I suppliers, the H2-ICE seeks to prove that hydrogen-powered vehicles can complement other zero-emission options. The goal is to meet the California Air Resource Board’s (CARB) Ultra-Low NOx standard of 0.02 g/hp-hr.

The hydrogen engine powers a Class-8 demonstration vehicle, showing its real-world potential. It delivers 370 horsepower and 2,025 Newton-meters of torque with an efficiency above 40%, peaking at 43%. These figures are impressive but should be compared with existing heavy-duty truck standards.

Emissions from the H2-ICE are about 1.5 grams of CO2 per horsepower-hour, significantly lower than traditional diesel engines. However, it still emits CO2, unlike battery-electric and hydrogen fuel cell technologies, which have zero tailpipe emissions.

The efficiency of 43% is good but less than the 50-60% typically seen in hydrogen fuel cells. This difference raises questions about the long-term viability of hydrogen internal combustion engines in a market focused on high efficiency and low emissions.

H2-ICE can use existing engine manufacturing infrastructure, potentially lowering initial costs. However, the hydrogen refueling infrastructure is still underdeveloped, especially for heavy-duty applications, posing a barrier to widespread adoption.

In the short term, H2-ICE offers a practical way to reduce emissions in heavy-duty trucks without needing completely new manufacturing processes. Its compatibility with current engine designs may enable quicker deployment compared to hydrogen fuel cell vehicles. However, for long-term decarbonization, hydrogen fuel cells and battery-electric vehicles might be more sustainable due to their higher efficiencies and zero emissions. The success of H2-ICE will depend on improvements in hydrogen production, refueling infrastructure, and engine efficiency.