Pierre Menendez, Michelin Group’s Director of Technical Communications
Michelin Group’s director of technical communications tells Shapur Kotwal about the advances in the Energy Saver ‘green’ tyre that can help deliver substantial fuel savings.
The Energy Saver tyre's main benefit is that it has less rolling resistance compared to rivals. How did you manage to achieve this?
We launched a massive research programme in the late 1980s, and in the early 1990s we introduced silica for the first time in the industry. We mixed silica with rubber and thanks to silica’s inter-twining molecular structure there is less heat build up when a tyre is deformed.   The biggest advantage of silica is that not only is heat build up controlled better but it also provides very good wear resistance, which makes the tyre last very long, and traction in wet conditions is also excellent. It has less rolling resistance which means it has the ability to heat less as it rolls. Tyres deform when they roll on the road and each time this happens, they generate heat. The more you can reduce heat build up, the more efficient your tyre will be and the car will consume less fuel.    Michelin has worked for the past 15 years to reduce heat build up in tyres following deformation. Standard technology cannot allow advances on rolling resistance, which are fuel economy, mileage and traction. That is why our competitors, who do not have this tech, have to compromise on mileage and/or traction if they want to increase fuel economy.
Does the tread pattern play a large role in lowering rolling resistance?
The tyre with the best rolling resistance is a slick tyre (which does not have tread design). But it is not appropriate for daily driving as in the event of rain you need to have grooves in the tread design to be able to absorb the water and humidity on the road. So now we have tools to determine the positioning and number of the grooves, and the mass of the tyre. Both these factors have an impact on the noise generated from the tyre as well as the rolling resistance.
This tyre is supposed to have very low carbon black percentage. Why?
The third-generation Energy tyres used in the early 1990s had about 20 percent silica to replace carbon black. With the fourth-generation tyre, we used about 99 percent silica to replace carbon black, which is basically all of it. Why not 100 percent? That’s because the tyres would otherwise not be black and the carbon black protects the tyre from ageing. That is why we keep a minimum of one percent.
Having too much silica in the tyre also has its drawbacks, doesn’t it?
No. We just need a minimum of carbon black to protect the rubber from cracking, from being affected by ultraviolet light.
Your silica tyre is best for wet weather braking but how is it in the dry?
We have no gain but we have no loss either. For example, in Formula 1 we have used the same kind of tyre with silica and have had extremely high levels of traction.
Has any Formula 1 tech come into this tyre?
We can say that there is a transfer of technology in as much that in Formula 1 racing you use the tyres in extreme conditions that you would not otherwise use on a normal basis. Therefore, it pushes you in corners where you would never go and in doing so you understand chemical and physical situations you would not be faced with otherwise. And you can use this knowledge in the development of everyday tyres.
Manufacturing this tyre is an expensive process but can you make it in India?
There is no reason why we cannot produce this tyre in India. Obviously, you need to have the proper raw material and manufacturing tools, which at present we probably do not have in India. We do not have any plans to do so but there is no reason why it cannot be done.
Is the Energy Saver more sensitive to poor road conditions as prevalent in India?
This tyre is for normal use in Europe but we do have a truck tyre too that has re-enforcements like sidewall protection. So if we need to do this for India, it could be done. You could lose a little performance because of the extra mass; however, it would still be a very efficient product.
Looking at the tyre’s lifecycle, how much fuel could a motorist save on a car, say like the Maruti Swift?
With normal average driving, you could save between 0.2 to 0.4 litres per 100 kilometres. That would be for a normal cycle where you drive from 80 to 110kph and downtown driving. But keep in mind that over 45,000km that saving can add up to the equivalent of 100 euros (Rs 6,500). And that is only from an individual standpoint; from a societal point of view, it adds up to a lot.
The importance of India as a strong export base for auto parts suppliers is increasing, says Anil Kumar M R, President a...
In an exclusive interview, Radha Krishnan, President and Founder, Detroit Engineered Products (DEP) talks about how the ...
Paul Farrell, the Executive Vice President and Chief Strategy Officer of component supplier BorgWarner tells Autocar Pro...