The aluminium chassis provides the best of both worlds when it relates to chassis design and manufacturing. A chassis, being the frame of the vehicle has to be rigid or strong to absorb and retain movements and vibrations from the engine, suspension and axles. It should also be as light as possible to improve the vehicle’s performance and fuel efficiency.
Aluminium provides both strength and lightweight properties. The drawback is their cost and that additional cost contributes to the overall cost of the vehicle but high end vehicle buyers are usually willing to pay the increased overall cost if their preference is performance and above average driving dynamics.
Pure aluminium weighs around one third the weight of steel but pure aluminium is not always used for chassis components. In many instances an aluminium alloy is used allowing different parts of the frame to be stiffer than others depending on the percentage of the mixture of the materials.
A lightweight chassis results in a safer car as the weight the vehicle has to move around is less the easier it can be controlled. It also assists the vehicle in having a better power to weight ratio as a fully aluminium chassis can slash several hundred lbs off the weight of the vehicle. In fact an aluminium chassis is more than 50% lighter than a steel chassis.
The chassis does not only mean the frame itself. Other parts of some high end vehicles where aluminium makes an appearance is the front and rear axles and suspension components. Any part or sub frame that connects to the suspension, steering and brakes is in many cases considered to be part of the chassis and will be considered a lightweight chassis if aluminium is used on these parts.
The aluminium chassis have moved away from the traditional chassis, the passenger safety cage is sometimes integrated into the frame with stronger and/or stiffer alloys being used on certain parts such as the b-pillars to add more rigidity or to enhance safety.
The 2010 Jaguar XJ has most of its monocoque chassis and body panels made out of aluminium and an aluminium space frame has been used in all generations of the Audi A8. The current Rolls Royce Phantom also uses an aluminium space frame.
The design of a chassis can also affect factors such as the center of gravity, better weight distribution and other performance attributes. The design and dimensions of the chassis determines the wheelbase of the vehicle and possibly the track (the distance between the center of the left and right wheel) for increased stability.
All of the above factors that the chassis contributes to indicates that the chassis forms an integral part of a vehicle’s platform. These factors and benefits can be incorporated when using a lightweight chassis.
Source: http://www.whyhighend.com/aluminium-chassis.html downloaded 2016/01/30
Jaguar XJ (X351)
Production of the successor model (X351) started end of 2009 with first deliveries being made in 2010. The current XJ features a lightweight aluminium body with 50% recycled material content based on the X350 chassis and retaining a large proportion of the earlier floor pan.
The weight saved – an average of 150kg compared to its competitor models – also has benefits with respect to performance and agility of the car.
Source: http://european-aluminium.eu/wp-content/uploads/2011/12/1_AAM_Body-structures.pdf downloaded 2016/01/30
Jaguar XK (X150)
The second generation XK has an aluminium monocoque body shell as introduced by Jaguar with the XJ sedan.
The new XK takes the Light Weight Vehicle concept a step further with extended use of lightweight aluminium castings and extrusions as well as the stamped aluminium panels.
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