One of the solutions has been to make the front sub-frame out of aluminium which offers good energy absorption characteristics in the event of an impact. Aluminium is also used in the engine-mount torque rod which is attached to the sub-frame. Areas of significant additional stiffening include across the width of the front panel, the dash lower panel, the C-pillar and around the tailgate opening.

The resulting structure together with retracting foot pedals, double pre-tensioners on the front seatbelts and side curtain airbags (standard on all models) has delivered very reassuring results in the 64km/h frontal crash test against a deformable barrier (with a 40 per cent offset), as well as on the 50km/h side impact and the 29km/h stationary pole side impact tests.

The Civic has also met Honda's car-to-car impact criteria even though the testing used a much larger and heavier Honda Legend.



Advanced Compatibility Engineering

A key element in Civic's outstanding crash performance is Honda's recently developed Advanced Compatibility Engineering (ACE) body structure, a major innovation in the drive towards ever greater vehicle safety. ACE offers significantly enhanced occupant protection, improved compatibility between vehicles of different sizes and because of its improved energy absorption abilities, less damage to another vehicle.

In a conventional body structure the loads from a frontal collision are generally concentrated through two pathways running longitudinally through the lower portion of the frame. The Civic instead employs a new front-end frame structure that disperses the crash energy through multiple load bearing pathways and away from the passenger compartment.

Its highly efficient, energy-absorbing lower main frame performs the role of a conventional impact absorbing structure, sending energy back into the floor frame and side sills. However, the ACE frontal structure also incorporates an upper cross member located behind the front panel and, on either side, upper longitudinal side members that feed into the front bulkhead and A-pillars. Each end of the cross member curves downwards ahead of the wheelarch to meet the lower frame, as do the leading edges of the upper side members; the cross member is also joined to each upper side member by a diagonal strut.

The resulting polygonal arrangement helps to reduce the potential for vertical or lateral misalignment between the Civic and the other vehicle's safety structures, so maximising the full energy absorbing potential of both vehicles. And the multiple energy absorbing paths mean that the impact force is distributed from the front of the vehicle through the side sill, floor frame and A-pillar, thus reducing cabin deformation.

The box section construction of the longitudinal elements also ensures that they crush progressively, their controlled collapse further minimising the risk of damage to the all important passenger safety cell.


Fuel tank protection

An important consideration for Honda's engineers was the way in which impact energy is dispersed throughout the floor frame, given the central location of the fuel tank beneath the front seats. As well as surrounding the tank by a protective frame on all four sides, the front cross member has been specially strengthened directly ahead of the tank; since the tank does not occupy the full width of the floor, the space either side of it is used as an energy absorption area, the frame structure designed to direct the impact energy around it.

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