2013 Lightweighting Special:TI Auto makes plastic fuel tanks even lighter

While it is common knowledge that plastic fuel tanks are around 40 percent lighter than metal alternatives, fuel tank manufacturer TI Automotive has gone one step further to reduce weight by 10-15 percent, depending on the specific drawings. This is achieved by TI’s patented and award- winning ‘Ship-in-the-bottle’ method combined with a few modifications to the blow-moulding machine. The ‘Ship-in-the- bottle’ method also allows TI to stick to ever-evolving and stringent emission norms across the world.

Speaking exclusively to Autocar Professional, Olivier Van Boxlaer, plant head – Chennai, confirms that certain production techniques have helped the company reduce weight in its fuel tanks.

“We have special techniques that we use in our machines to maintain a standard wall thickness of around 3mm. I don’t have the precise figures as it varies with each design, but the reduction is roughly between 10 and 15 percent,” he says. With uniform wall thickness and strategically placed baffles inside the tank, TI Automotive is able to both reduce weight and prevent fuel from sloshing around during a car’s operations, thereby doing its bit to aid the handling of the car.

Expanding in India

On April 24, TI Automotive, operating under the name Bundy India here, inaugurated its plastic fuel tank manufacturing facility in Sriperumbudur, near Chennai. This is the company’s first tank manufacturing facility in the country. Initial supplies will go for the Nissan Evalia MPV and both export and domestic models of the Micra hatchback and Sunny midsizer models. With an installed capacity of 300,000 fuel tanks per year, the facility might soon go in for additional lines on the back of orders from Toyota Kirloskar Motor, Tata Motors and Hyundai Motor India.

Production for Nissan is mainly of two types. The 55-litre Evalia fuel tank weighs a mere 7.8kg in both its petrol and diesel avatars. While all petrol tanks get a six-layer coating, diesel tanks require just one layer – given the lighter emission norms. However, TI Automotive’s diesel tanks for all the three cars are made out of six layers in order to “maintain quality standards.” While both the Sunny and the Micra carry similar 41-litre fuel tanks, there are variants, given the different engine options that the cars come in. The variants are for the higher- and lower-powered petrol engines and for the export models of these two cars. A fuel tank with a high pressure fuel module is fitted for the 1.5-litre petrol engine on the Sunny, while a low pressure module suffices for the 1.2-litre motor in the Micra. The 41-litre tank weighs between 4.7kg and 4.9kg, depending on the variant. Both tanks are a good 40 percent lighter than metal fuel tanks and a further 10-15 percent lighter in TI’s hands.

TAPT-ing the future

Plastic fuel tanks aid in both weight reduction and strength, says Boxlaer. “From the strength point of view, plastic tanks meet crash, drop, rollover and fire tests better than metal tanks,” he adds. While the designs for these tanks are more often than not provided by the OEMs, TI Automotive’s R&D centres in Germany and South Korea work their own magic now and then.

A recent development by these centres was the Tank Advanced Process Technology (TAPT) for fuel tanks to be used in hybrid cars. “Given how quiet hybrid vehicles are, fuel sloshing noises are easily picked up by the passengers,” Boxlaer says. “In addition, the heat emanated by the batteries under the seat affects how the vapour from the tanks is dealt with,” he adds.

The TAPT tanks, with their carefully placed structural additions and baffles to prevent fuel vapour from going haywire, went into production at TI’s facilities worldwide in 2012. The ‘Ship-in- the-bottle’ method was patented by TI in 2009. With this method, the Detroit-based manufacturer is able to place O-rings and inlet check valves inside the parison – the tube-like structure before it is moulded into a tank – during the blow-moulding process by itself. This prevents quality errors like gaps that might lead to fuel loss and vapour escape. As far as raw materials are concerned, the Chennai plant imports all of its raw materials. One of TI’s most important raw materials is EVOH – ethylene vinyl alcohol – which is used as a barrier material. It reduces the permeation of fuel in petrol tanks. While this by itself doesn’t necessarily translate to weight reduction, it helps TI meet stringent emission norms across the globe.

Banking on India

Given the presence of many global and domestic OEMs in and around Chennai, Ramandeep Singh, assistant general manager for operations, at the newly inaugurated plant, expresses confidence in bagging more orders. The company already plans to increase production but is torn between adding a parallel clamp to the existing blow-moulding machine. This might mean shutting down production for a while, or installing a new machine altogether. TI Automotive will also shift its assembly lines that manufacture fuel carrying systems like pipes and hoses from its Vadodara plant to Chennai soon. Its small sub-assembly plant in Chennai catering to Nissan will also be shifted here. The company’s current verticals include powertrain systems, HVAC fluid systems, pump and module systems, tank systems and fluid carrying systems, of which the last two are produced in India. With over 80 percent of all cars globally using plastic fuel tanks and 70 percent of those containing at least one of TI’s products, the business opportunity is huge. “And now that we are in India, we can only see ourselves growing,” signs off Frank Buscemi, global communications director.