Liquid nitrogen system expected to last for lifetime of a vehicle and can power it at speeds below 20mph
Engineering and test consultancy Horiba MIRA is leading an Innovate UK consortium to develop the first liquid nitrogen-powered hybrid bus, Transport Engineer has reported.
The vehicle, called CE Power, will run on diesel and liquid nitrogen. The liquid nitrogen power source will be primarily used when accelerating from a stationary position when picking up and dropping off passengers – when buses typically produce the most NOx and CO2 emissions.
At speeds of 20mph or below, the liquid nitrogen – stored in a low-pressure insulated cylinder – is warmed up to the point of evaporation, creating enough pressure to drive a multi-cylinder Dearman engine. Once the vehicle reaches 20mph, the diesel engine will take over.
Horiba MIRA will manage systems integration, vehicle dynamics modelling and overall vehicle control, ensuring the liquid nitrogen system operates seamlessly and safely with the diesel engine.
Derek Charters, of Horiba MIRA, said: “Liquid nitrogen is a fascinating energy source as it can be created in any part of the world from many renewable sources, meaning its carbon footprint is minimal.
“With the UK looking to continue to reduce its reliance on carbon fuels from overseas and the search for buses with reduced emissions, this project takes the UK one step closer to achieving this goal.”
Many of the UK’s hybrid vehicles currently rely on batteries, but these need to be replaced several times. A liquid nitrogen system is expected to last for the lifetime of the bus, and enables refuelling to take place in 10-15 minutes.
Liquid nitrogen can be produced locally without the need for neodymium or lithium, both of which are used by motors and batteries and sourced from overseas.
The project will conclude in 2016. Other partners in the consortium include Dearman Engine Company, Air Products, The Manufacturing Technology Centre, Productiv, Cenex and TRL.
