Maruti Suzuki, Mahindra, others revisit metallurgy, chemistry lessons to prune kerb weight

Written by Anil Sasi | New Delhi | Updated: Sep 28 2014, 14:37pm hrs
Maruti SuzukiMaruti?s Ciaz weighs around 200 kg less than the SX4. (CarDekho)
Three of the newest car launches in India point to a discernible trend that manufacturers are optimising automotive body structures of their models in the singular pursuit of pruning kerb weight, and thereby improving mileage figures.

The new launch by the countrys largest carmaker Maruti Suzukis Ciaz in the mid-segment sedan category has been developed on an all new modular ultra lightweight platform that deploys Suzukis Total Effective Control Technology or S-TECT.

The new technology, according to CV Raman, Maruti Suzukis R&D head and executive officer (engineering), incorporates a liberal use of high-tensile steel across the body panels for a lighter, yet more durable body and a wide wheelbase for stability.

As a result, the Ciaz weighs in at just 1,010 kg for the petrol and 1,105 kg for the diesel. Compare that with a kerb weight of 1,200 kg for the petrol and 1,245 kg for the diesel variants of Marutis SX4, the car that the Ciaz has replaced.

With lower weight, Maruti is claiming mileage figures of 26.21 kmpl (ARAI-certified) for the diesel and 20.73 kmpl for the petrol, giving Ciaz the top billing in the mileage listings.

Utility vehicle maker Mahindra (M&M), which has just launched its second-generation Scorpio SUV, has also pruned the vehicles kerb weight. While the new vehicles body is broadly similar to the older version, the most crucial change is an all-new chassis incorporating a new modular ladder construction that uses a hydroforming manufacturing technique a cost-effective way of shaping ductile metals such as aluminium, brass, low alloy steels, stainless steel into lightweight, structurally stiff and strong pieces. Compared to the old ladder chassis, the new Scorpios frame is visibly thicker but is in fact 2 kilograms lighter and almost 100 per cent stiffer.

The New Generation Scorpio, comes on an altogether new platform, with a new chassis frame, new front and rear suspension, new higher efficiency transmission and a new rear axle, Rajan Wadhera, chief executive, truck, power train division & head Mahindra Research Valley, M&M Ltd, said at the launch.

Automobili Lamborghini, which has launched the all-new Huracan LP 610-4 in India last week as the replacement for the Gallardo, uses a new hybrid chassis of carbon fibre and aluminium, as a result of which, the car weighs in at a modest 1,422 kg, making it lighter than the Gallardo and thus quicker on its feet.

While the Indian consumers obsession for mileage, even evident in premium segment cars, is pushing manufacturers to try and improve fuel efficiency numbers of new models, globally carmakers are already pushing the limits of technology to derive the most from the internal combustion engine. A lower weight vehicle has better acceleration, better braking and better handling.

One of the consequences is the increasing use of automotive aluminium, making it second only to steel as the most used material in vehicle construction. In Detroit, carmakers are pushing technology further by putting cars together by using glue as are airplanes, phones and a lot of household items.

According to reports, Ford Motors new F-150 pickup (to be launched next year) has an aluminium body and more than three times as much adhesive as prior models of the top-selling US vehicle. BMWs new Project i-electric and electric-hybrid cars are reported to have passenger compartments made of carbon fibre joined with adhesives, eliminating metal fasteners. General Motors Corvette already comes with a carbon fibre roof glued to a magnesium frame.