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Develop Fuel-Efficient Tires
23rd October, 2007
Sumitomo Rubber Industries Ltd. plans to develop automobile tires that help improve fuel efficiency, President Tetsuji Mino said Tuesday.
The move comes in response to the European Union's planned tightening of its carbon dioxide emission rules.
In the near future, the company will be able to launch tires with rolling
resistance about half that of existing standard tires, Mino said in a speech at the
Tokyo International Automotive Conference.
The envisioned tires are expected to improve gas mileage by some 10 pct, he said.
Rolling resistance decreases when natural rubber content in tires is increased. But a lower resistance could result in a weaker grip on the road.
Sumitomo Rubber plans to develop technologies that will reduce rolling resistance while maintaining grip performance.
The tire will come in three sizes and sold at open price in Japanese replacement market.
Characteristics of ENASAVE ES801
70% of the materials used for the tire is non-petroleum.
We have succeeded to decrease the use of synthetic rubber which is a petro-related material and increase the use of natural rubber, which helps lower tire's rolling resistance. We also adopted other non-petroleum materials for filler, oil and casing. In this way, we have raised the percentage of non-petroleum materials from 44% for conventional tires to 70% for ENASAVE ES801.
Polymer synthetic rubber epoxidized natural rubber
Filler carbon black silica
Oil petroleum oil vegetable oil
Casing synthetic fiber vegetable fiber
By 30%, the rolling resistance of the tire is improved.
The increased use of natural rubber has lowered rolling resistance by 30%, compared with our own conventional tires. This means lots of improvement in fuel consumption.
Technologies Employed
New material: epoxidized natural rubber
The natural rubber loses its gripping power for braking and cornering when it is used much as it is. In order to overcome this problem, we developed epoxidized natural rubber and succeeded in decreasing the amount of use of petro-originated synthetic rubber, which used to take an important role in increasing the grip of the tire.
New development: aerodynamic technology
In order to reduce air resistance against tires in motion, we have adopted "Aerodynamic Design," an original design to eliminate letterings that usually appear in the area between tread shoulder and sidewall. With this new development, we have succeeded in reducing air resistance by degree equivalent to taking one side view mirror off and lowering tire's rolling resistance further.
New tread pattern: optimum lateral groove angle, etc.
We developed special tread pattern for the tire as follows.
Optimum lateral grooves angle lowers rolling resistance.
Aerodynamic shoulder design lowers rolling resistance.
Asymmetric lib shift reduces noise.
Straight grooves improve wet performance.
Optimum block stiffness distribution improves dry performance.
Tire sizes
185/65R15 88H
195/65R15 91H
195/55R16 86V
Release link:
http://www2.srigroup.co.jp/english/index.html
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