Toyota presents its innovative proposal for cold hydrogen vehicles.

Toyota is making strides in hydrogen-powered vehicle technology by presenting a system design that includes a self-pressurizer. This innovation aims to reduce the loss of escaping gas and recycle it as fuel, thereby increasing engine efficiency. In 2023, Toyota launched a liquid hydrogen system in the GR Corolla H2 concept, which maintains hydrogen at -253 degrees Celsius during filling and storage in the tank. Since hydrogen exists in a gaseous state at room temperature, the pumps must operate at low temperatures to prevent the liquid from evaporating. However, there is still evaporating gas that gets wasted.

To address this issue, Toyota introduced a “self-pressurizer” during the 2024 Super Taikyu Series race, which uses the pressure from the evaporating gas to boost pressure two to four times, generating reusable fuel without the need for additional energy. Furthermore, the company hopes to utilize any excess gas to power a small fuel cell package that drives the hydrogen pump motor, thus enhancing efficiency even further.

The implementation of liquid hydrogen vehicles presents complexities in both storage and system configuration. According to Professor Jacob Leachman from Washington State University, hydrogen pumping systems are the most likely components to fail in any hydrogen system, whether cryogenic or gaseous. Leachman noted that Toyota has developed a hydrogen pump that harnesses some of the cold energy for compression purposes, representing a significant breakthrough for those working on liquid-state hydrogen vehicles.

Leachman also mentioned an additional challenge: when sealing a liquid hydrogen container and allowing it to boil, the pressure can rise to over 140 Megapascals (20,000 psi).