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Hydroforming and new welding methods help reduce vehicle weight

New CAFE standards have automakers reaching for any technology they can find to help improve fuel economy. Many manufacturers are going to electric vehicles or hybrids to increase their overall fleet mileage averages. The problem with focusing only on hybrids and electric vehicles, however, is that most consumers aren't in the market for that type of vehicle.

On traditional gasoline-powered vehicles, automakers are increasingly turning to weight savings as a way to help improve fuel economy. The lighter a vehicle can be made, the less weight the engine has to push or pull around and the less fuel it uses because engines could be made smaller without sacrificing performance.

Some automakers are even turning to removing some features of cars such as CD players and the spare tire to reduce weight according to the Detroit News. Both General Motors and Ford are turning to new processes in vehicle assembly to help remove weight from the body of mainstream vehicles.

2013 Ford Fusion
Many automakers are using aluminum rather than steel to help reduce the weight of their vehicles. Hoods, trunks, and lift gates as well as door skins are commonly made from aluminum today. Ford is also experimenting with carbon fiber on the Focus.

Switching to lighter materials isn't the only way automakers are going about reducing the weight of the vehicles they produce. They're also reducing weight by changing the manufacturing processes used. Ford, for instance, is using hydroforming on the steel structural pillars of its 2013 Fusion.

One of the big benefits of hydroforming is that it allows the forming of complicated and larger parts that don't need to be welded together. Traditional stamping produces multiple parts that have to be welded at joints. Those joints are points of weakness and add weight. Using hydroforming, rather than other forms of stamping, sheds 18 pounds from each car by eliminating the additional welds.

GM is also doing its part testing a thermal-forming process for lightweight magnesium that weighs 75% less than steel. GM also plans to use a patented welding technology to allow the company to integrate more aluminum into automotive bodies by saving the company from using rivets to join aluminum body panels. The use of the welding process rather than rivets will cut nearly 2 pounds from parts such as hoods, lift gates, and doors.

Source: Detroit News

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RE: Hilarious
By Solandri on 10/25/2012 12:17:19 PM , Rating: 2
That's BS. A bigger, heavier vehicle has higher inertia,

The greater inertia is why it's safer. In a collision between two vehicles, the resulting motion is the momentum of both vehicles combined. The heavier vehicle dominates the momentum balance.

In other words, when a heavy vehicle and a light vehicle hit each other head-on, the heavier vehicle slows down during the collision. The lighter vehicle bounces back, subjecting its occupants to higher accelerations.

Those government safety ratings you see? They're done with tests into fixed objects. In reality, you frequently collide with other cars. So a heavier vehicle which gets an B rating is actually much safer than a lighter vehicle which gets a B rating.
which translates to longer stopping distance

Nope. Friction at the tires is proportional to the coefficient of friction of the tires times the weight of the vehicle. So the greater inertia of a heavier vehicle while stopping is exactly canceled out by the increased friction it can generate with the road due to its greater mass.

If you increase the weight of a particular vehicle, its stopping distance increases because the brakes are only able to generate a fixed maximum amount of friction. But with a larger vehicle you simply install larger brakes.

higher risk of rollover (SUV's and pickup trucks lead the statistics of rollover deaths in America), slower response overall.

This one's correct. The risk of death due to rollover in an SUV almost exactly counteracts their increased safety due to greater mass.

However, we're not talking about converting sedans into SUVs. We're talking about converting sedans into lighter sedans.

Emergency avoidance response has more to do with rotational inertial and wheelbase (and tire width) than weight.

RE: Hilarious
By zephyrprime on 10/25/2012 12:35:43 PM , Rating: 1
That's bs about the tires. Yes, it's true according to simplified physics but in the real world, tires are not an ideal material at all. They behave non-linearly and changes to friction characteristics happen when they heat up while braking.

RE: Hilarious
By freedom4556 on 10/25/2012 12:40:50 PM , Rating: 2
But with a larger vehicle you simply install larger brakes.

Ever heard of a thing called brake fade? Sit there and tell me that you can consistently stop an SUV fitted with Brembos in less distance than a Porsche or a Lambo. More mass = longer stopping distances. Read a car comparison review for heaven's sake. It has nothing to do with tires.

RE: Hilarious
By FITCamaro on 10/25/2012 1:34:30 PM , Rating: 3
If brake fade is an issue for you in your normal commute, you might look in the mirror as to the problem.

RE: Hilarious
By 91TTZ on 10/25/2012 4:47:21 PM , Rating: 2
Ever heard of a thing called brake fade? Sit there and tell me that you can consistently stop an SUV fitted with Brembos in less distance than a Porsche or a Lambo

First of all, you're not going to encounter brake fade during a panic stop at highway speeds. Secondly,a large vehicle often has larger wheels than can hold larger rotors. Larger rotors are able to dissipate heat better than smaller rotors.

Car and Driver did a test about this. You can read it here:

"The amount of heat that brakes must dissipate is directly related to a vehicle’s weight, thus the brakes fitted to these heavyweight steeds face a tough mission. The FX50S was the lightest at 4643 pounds, the SRX came next at 4762 pounds, and the Cayenne S was the heavyweight, posting a brake-killing 5476 pounds.

The Porsche’s brakes, however, shrugged off the 2.75 tons with little effect. After 25 stops, we simply gave up because the pedal feel changed little (it grew just an inch), and the last stop, at 356 feet, was only 20 feet longer than the first. Clearly, the 90 seconds of cool-off time between runs was enough to keep the Cayenne’s brakes from overheating."

RE: Hilarious
By FITCamaro on 10/25/2012 1:38:54 PM , Rating: 2
Crash tests done with other vehicles are also usually against vehicles in the same class. They don't really test a Civic against an F-150 for safety ratings.

How anyone buys a SMART is beyond me. Even against regular midsize cars it does terribly. Thank you but I enjoy having legs to walk with.

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