Lotus: Bio-fuel research project

Maker of british sports cars Lotus developed the Lotus Exige 265E based on the Exige for research.

Powered by a modified version of the 1.8-liter engine in the standard Lotus Exige S, the Exige 265E is more powerful than its gasoline counterpart, producing 264 hp (197 kW) at 8,000 rpm, and 184 lb-ft (249 Nm) of torque (at 5,500 rpm)-increases of 21% and 16% respectively over the gasoline model.

The 265E can accelerate from 0-60 mph in 3.88 seconds, 0-100 mph in 9.2 seconds, and has a top speed of 158 mph.

Lotus considered a variety of biofuels for this project including bio-methanol, bio-ethanol and biobutanol. The group finally selected ethanol as the fuel as its characteristics allowed the engineering project team to enhance the engine performance. The pressure-charged engine provides even more opportunity to exploit the performance characteristics of a high-octane fuel. Ethanol has a high octane rating, allowing an optimum timing for engine ignition and has a fast flame speed in the cylinder, so the fuel burns faster, increasing the efficiency of the engine.

"We wanted to prove the point that green sportscars can also be very high performing sportscars. The fact that we have produced a research version of the Exige that is more powerful than the standard road car is a testament to the benefits of going green. We are also pleased that this vehicle demonstrates our engineering capabilities, our understanding of flex fuel vehicles and our knowledge of emerging fuel technologies. It also promotes bio-ethanol as a fuel of choice for the enthusiastic driver as well as the environmentally conscious driver." -Geraint Castleton-White, Head of Powertrain for Lotus Engineering

"Lotus Engineering is actively pursuing technologies that will improve the efficiency and environmentally friendliness of engines in the future. Carbon dioxide reduction is a priority, as is anything that can reduce our reliance on fossil fuels. We are one of the world leaders in powertrain engineering especially in the internal combustion sector and we are researching into all areas of alternative and conventional fuels to get greater efficiencies, power, performance and reduce net emissions and Bio Ethanol research is one area where we are expert."

"We have decided to develop a thorough understanding of the techniques and technologies of what alternative fuels can achieve, to produce vehicles that are both fun to drive and environmentally friendly. We are also working, globally, on hybrid and electric vehicles together with governments and universities and as an engineering organization we have a duty and a desire to promote these ideas to a worldwide customer base." -Mike Kimberley, Chief Executive of Group Lotus

The next phase for the vehicle is to upgrade the calibration to a flex-fuel spec to allow use with initially gasoline, followed by the possibility of a multi fuel-flex calibration to use fuels such as bio-methanol and bio-butanol in addition to the conventional gasoline and bio-ethanol. The Lotus Exige 265E is purely a research vehicle for Lotus Engineering and Lotus does not intend to put the car into production or sell aftermarket kits for Lotus Cars.

The engine. The additional power The Exige 265E features a Roots-type supercharger (with a sealed-for-life internal mechanism) and air-to-air intercooler attached to the 4-cylinder, 1.8 liter 2ZZ-GE VVTL-i engine.

A roof scoop ensures that the air-to-air intercooler works as efficiently and effectively as possible in all climates and environments. All charge-air ducting has been kept as short as possible with large diameter pipes making sure that the bends in these ducts are not too tight, to the benefit of throttle response and efficiency. The Roots-type Eaton M62 supercharger is run from the crankshaft, and has an integral bypass valve for part-load operation.

The 2ZZ VVTL-i engine has two cam profiles-a high-speed cam and a low-speed cam. The seamless switch point between these two cams is completely variable depending upon driving conditions and engine load, and the driver will not know which cam is being used at any point. This gives the Lotus Exige 265E a smooth and linear surge of power from idle speeds all the way to the maximum 8500 rpm.

Four enlarged fuel injectors increase fuel flow into the engine under normal operating conditions. Two additional fuel injectors fitted at the supercharger inlet increase the amount of fuel being injected into the engine under higher engine speeds and loads. This has also enabled the engineering project team to take advantage of ethanol's higher cooling effect to further cool the charge air prior to combustion, which in turn reduces the amount of power required to operate the supercharger.

The 265e uses a version of the Lotus T4e Engine Management system programmed to optimize the use of ethanol in the supercharged and intercooled engine.

Related news: Foursprung, P4MR, Lotus

Source: Green Car Congress, pic via RTL NL

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