Mazda’s award-winning Renesis petrol rotary engine will run on hydrogen as a zero-emission engine and the development could be in production within two years.
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While petrol/electric hybrids, alternative fuel engines and fuel cell technology were evident throughout the Tokyo motor show, Mazda’s announcement stood out because its rotary engine can be developed with very few changes to become a dual-fuel power unit or a hydrogen-only engine.
Mazda is unique in using rotary technology and it says using hydrogen as a fuel source is part of its programme to explore all the potential of this internal combustion engine.
Hydrogen power is becoming the preferred choice of the motor industry searching for zero and ultra-low emission fuels and as a potential source of power for fuel cell motoring.
Stephen Odell, director and senior managing executive officer in charge of marketing, sales and customer service for Mazda Motor Corporation said at the Tokyo show: “Our latest Renesis rotary unit requires minimal change to allow it to be used as a dual fuel engine.
“This is ideal in the short-term until hydrogen becomes a mainstream fuel option for the industry. I am convinced hydrogen will become the best alternative fuel for us all”.
Although Mazda says it has no on-sale date for this technology, it is expected that the ‘short-term’ referred to by Odell means within two years.
The Mazda rotary engine has hydrogen injected in a dense gaseous state into the rotor engine chambers via an electronically controlled hydrogen injector system that uses dual injectors in each of the rotor housings.
Because of its rotary design, this engine has separate chambers for induction and combustion. Mazda say this is an ideal layout for the use of hydrogen as a fuel. Separating the two chambers provides for a clean burn and stops backfiring, a characteristic of a conventional piston/bore combustion petrol engine when hydrogen is used.
The rotary engine design allows ample space for twin injectors in each induction chamber to be used. Because hydrogen has an extremely low density, a much greater volume is required compared to petrol.
The twin spark plugs per rotor chamber ensure the low combustion hydrogen gas is fully ignited quickly providing maximum power and no pollution.
The Mazda rotary system will allow future generations of customers to use petrol or hydrogen to fuel their car at the flick of a switch.
Currently the project is undergoing running tests in an RX-8. Early indications are that the car runs as reliably and is as easy to operate on either hydrogen or petrol.
Power output of a new Renesis petrol engine is 210 PS in standard specification with 222 Nm of torque. Using hydrogen, the target is to achieve 110PS of power and 120 Nm of torque.
This may not give the power output normally associated with petrol-only RX-8s, but where required, such as low emission city driving areas of the future, the hydrogen and petrol option offered by the rotary engine technology is viable.
