Cars become fatter, and fuel guzzlers too

Written by Shweta Bhanot | Mumbai, May 30 | Updated: May 31 2008, 06:07am hrs
This could add fuel to the current debate on rising oil prices and the need to curtail fuel consumption. Passenger cars have become 30% heavier on an average over the past 30 years, which could potentially lead to high fuel consumption and emissions. This is happening despite all measures taken by manufacturers to reduce weight to the extent possible. Car makers are in a fix since they cannot compromise on safety and comfort requirements, which, ironically, are the reasons behind increasing weight of the cars over the last few years.

Explains Hermann Althoff, group vice president, engineering plastics Asia Pacific, BASF South East Asia Pte Ltd, "Even though ever-lighter materials are employed, this is more than offset by the installation of more and more new components such as automatic windows, seatbelt tensioners and airbags, among others."

Way back in 1985, a typical car had a catalyst, power steering and driver air bag. However, today, the list is almost unending. "Anti-lock braking systems, more airbags, air conditioners, power steering, belt tensioners and increasing requirements for stiffer chassis, among others, have been added," says Althoff.

According to Wilfried Aulbur, MD & CEO, Mercedes-Benz India, said, "The vision of accident free driving at Mercedes-Benz is the central concept for vehicular safety in passenger cars at present and also in the times to come." The company justifies that cars today have to be intelligent machines loaded with advanced technology to rule out irrational human behaviour while driving and works for safety of the car occupants first. Hence, the quest for refining and coming up with even more advanced technologies in cars is an attempt to make them safer and more ecologically friendly, drives the core of research at Daimler, globally, according to the company. Mercedes-Benz cars weigh in the range of 1,415 kgs (SLK Class) to 2,285 Kgs (M Class).

Benoit Tiers, managing director, Audi India, however, begs to differ. "Audi cars are becoming lighter by the day." He said that Audi AG is the biggest user of aluminum which not only brings down the weight of the car but also makes it more fuel efficient. Also, it increases the scope to recycle the car.

Asked what the weight of the new Honda Accord is, Jnaneswar Sen, senior general manager, marketing, Honda Siel Cars India Limited, said, "Generally, a car weighs around 700 kgs. This is nearly double that.." The new Honda Accord has a recyclability of 95%.

"This (weight reduction) is important as fuel consumption is predominantly determined by weight," said Althoff, adding that future weight and fuel savings can be achieved by increasing the share of plastics in cars up to 20% from the present 14%.

Increasing use of manufacturing plastics in replacement of metal in the car, especially in metal heavy parts like in chassis, engine components and bodywork, among others, is believed to not only bring down weight, but also help in reducing carbon-di-oxide emissions. Facts say that reduction of 10% weight in the vehicle can lower fuel consumption by about 5%. In fact, for every kilogram reduced from the car, the environment is spared 25 kg of CO2 emissions over the entire service life of the car. Hence, in addition to improving performance in the engine, transmission and ancillary components, use of plastics in automobile construction makes sense from an environmental point of view as well.

"Automotive manufacturing plastics are steadily taking over more and more tasks that used to be the exclusive domain of metals," Althoff said, adding, without plastic, cars would have offered less comfort and safety and would have weighed even more. For example, chrome bumpers are a thing of the past. Instead of a piece of metal screwed to the front of the vehicle, nowadays cars cruise the streets sporting a complex high-tech ensemble of plastics such as polyurethane, engineering plastics and polypropylene. A mid-size car today contains chemical products including paints, plastics and fuel additives to the value of some Euro 800. In Europe, a car on an average has 20% plastic material, which in India goes down to 10%.

By 2020, the figure of plastic material in vehicles is expected to go up to 25%.