Five Fuels -- No Waiting
By By Tom Ripley
Are you bi-fuel curious? Volvo can go you one, er, actually three better. It's imaginatively named Volvo Multi-Fuel is a five-cylinder prototype car designed to run on, well, multiple fuels. At least one of them you have probably heard of -- Volvo charmingly calls it petrol, but you probably refer to it as gasoline. Others in the mix are natural gas (which you might burn in your stove but not in your car), hythane, biomethane, and bioethanol E85. For those of you who aren't chemistry majors, hythane is a mix of 10 percent hydrogen and 90 percent methane. Bioethanol E85 is a mix of 85 percent bioethanol and 15 percent gasoline.
The two-liter five-cylinder engine produces 200 horsepower, which gives the vehicle spritely performance. With the benefits of turbocharging that has been tuned for optimized use with all five fuels, it can accelerate from zero to 62 miles per hour (100 km/h) in just 8.7 seconds. This makes the car responsive and fun to drive. As you would expect, the Multi-Fuel is just as safe as all Volvo vehicles, with the added bonus of being exceptionally clean. One of its benefits is that combustion of pure renewable fuels like hydrogen, biomethane and bioethanol make negligible net contribution of fossil carbon dioxide to the atmosphere. Carbon dioxide has been tabbed by some as a contributor to global warming.
"The whole car is optimised for high performance, driving on any of the five different fuels," said Mats Morn, Project Leader Engine at Volvo Car Corporation. "It is a first step towards a hydrogen-powered society. Perhaps we can develop the system even further, to run on a higher blend in the future."
Why the use of multiple fuels? Volvo Car Corporation believes that the road to the future is not one but many. In its view, no renewable fuel type can alone replace the fossil fuels of today. Since local conditions vary, different markets need engines designed for different alternative fuels, together with cleaner conventional ones. With this in mind, Volvo Car Corporation has developed the Multi-Fuel to be driven on the energy source at hand -- anywhere in the world. This means that less fuel needs to be transported between continents, and you can fill up the car on the fuel that is available wherever you are.
In addition to the special engine, a key to the success of the prototype is its use of several fuel tanks. The vehicle contains one large and two smaller tanks totaling 98 liters for gaseous fuels (hythane, biomethane and compressed natural gas CNG), and one 29-liter tank for liquid fuels (bioethanol E85 and gasoline.) The small gaseous fuel tanks are made of steel, while the large tank has a durable, gas-tight aluminum liner reinforced with carbon fiber composite and an exterior layer of hardened fiberglass composite. The fuel tanks are fitted neatly under the luggage compartment floor, which means that full loading capacity is preserved. Two fuel fillers are used to fill up all five fuel types, one for gaseous and one for liquid fuels. The engine automatically adjusts itself to the right blend of gaseous or liquid fuels. To switch between fuel types, the driver simply presses a button.
When it comes to exhaust emissions, the Multi-Fuel is remarkably clean and meets the emission standards for Euro 4 and the proposed levels for Euro 5. An alternative catalyst system has also been developed to meet the tough demands on extremely low tailpipe emissions for PZEV/SULEV in the United States. The vehicle has two catalysts, one close coupled to the engine that lowers initial start emissions, and one under the floor for reduced high-speed emissions. The double catalysts and advanced engine control system lead to very low emissions. High-temperature materials in the exhaust manifold and turbo allow extremely high exhaust gas temperatures of up to 1050 øC. This enables the car to run cleaner, accelerate quicker and operate smoother at higher speeds.
Driving Today Contributing Editor Tom Ripley, who is trying to run cleaner these days, covers the automotive world and the human condition from his home in Villeperce, France.
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