OVERVIEW
Although both TL models share almost identical dimensions and
exterior body panels, they are structurally different in many crucial
areas. This was largely due to the different vibration
characteristics and weight balance of the two engines. As a result,
the chassis was developed to optimize the rigidity and crash
protection, and to minimize noise, vibration and harshness.
In developing the chassis, Acura engineers used the latest Finite Element Analysis and Modeling to achieve the highest rigidity levels at the lightest possible weight. An important tool in achieving these high rigidity targets was the NASA Stress Analysis Program (NASTRAN). This tool allows chassis designers to quickly analyze and evaluate changes in a structure and find the best solution.
UNIT BODY STRUCTURE
The carefully designed structure is designed to help keep the center
passenger section protected in the event of an impact. The center
"safety cage" is specifically reinforced, and straight frame rails at
the front and rear help absorb both direct and offset impact loads.
RADIUSED FRONT FRAME RAILS
The longitudinal engine placement has allowed the creation of a
unique front frame rail design. The front frame rails are radiused as
they meet the front bulkhead. This design imparts high torsional and
bending rigidity to the body, and also maximizes front impact
protection by dissipating the loads over a wider area and by
directing the load downward toward the floorpan.
HONEYCOMB FLOOR STRUCTURE
Instead of a conventional steel stamping for the floorpan, the 2.5TL
floorpan uses an 18-mm thick honeycomb sandwich. It consists of a
resin-impregnated honeycomb material bonded between two layers of
zinc-coated steel. This structure imparts considerable strength to
the floorpan. In addition to maximizing rigidity, the honeycomb
material also serves to block out noise and vibration.
SOUND INSULATION
While the structure effectively damps outs annoying vibrations and
ensures a tight, rigid body, blocking out road noise is accomplished
by using sound deadening material in strategic areas throughout the
body. The amount and thickness of this material is different in each
model, but a liberal amount of insulating material has been used in
the front bulkhead, the floorpan, the rear bulkhead, the rear parcel
shelf and the trunk to ensure a quieter passenger cabin. Sound
deadening foam material is used in the C-pillars, which in testing
has reduced noise in the passenger compartment by 3 decibels.
PAINT PROCESS
From bare metal body to the final inspection stage, the TL undergoes
a careful 23-step, 3-coat, 3-bake painting process. TL models with
pearl white exterior paint undergo a 4-coat, 4-bake process due to
the unique requirements of the pearlescent pigment. The process
begins by thoroughly cleaning the body of grease and other debris
that might mar the final finish or prevent paint from properly
bonding to the metal. The body is then put through an
electrodeposition coating process, washed and then dried.
At that point, the actual process of painting begins. Each successive coat of paint and the clear sealer coat is baked and washed. The final finish is glass-smooth and designed to resist fading for the life of the vehicle.
ANTI-CORROSION MEASURES
To ensure excellent corrosion protection, over 90% of the TL outer
body panels are made of double-sided galvanized steel.
In fact, the only panel that is not galvanized on both sides is the roof. In addition to this, the rocker panels and other selected cavities are filled with an oil-impregnated wax material that inhibits moisture penetration and prevents rust. This, when combined with the excellent painting process, produces a corrosion-resistant body that carries a 5-year rust-through limited warranty.