SUPPORTS CONSERVATOIRE VISIT
- Citroen Advanced Comfort (CAC) program sets parameters for 21st Century ride comfort
- All-new suspension system featuring Progressive Hydraulic Cushions™ (PHC) to launch on all-new C5 Aircross
- CAC Program takes holistic view of vehicle including ergonomics, ride and handling, practicality and versatility, along with cabin atmosphere
- For Citroen, Comfort is the new cool!
When it comes to comfort, Citroën has long been a pioneer and innovator. Few car manufacturers can evidence such a consistent history of innovation for the sake of comfort, an attribute that has been a defining hallmark of the company's cars since the first Citroën took to the roads in 1919.
Historically, the concept of 'comfort' has led to the development of seats that are softer and more supportive, and suspension systems that soak up bumps and shocks, and isolate passengers from the worst road surfaces.
Citroën has consistently set new standards in each of these areas, to enhance comfort and driver enjoyment. Innovations include the company's famous hydro-pneumatic suspension, ergonomic cabin controls, advanced seating arrangements, low-drag (and so low-noise) aerodynamics, revolutionary new vehicle architectures, and new cabin materials, all serving to improve comfort.
In the 21st century, however, comfort covers a wider range of features. The modern approach to comfort has seen the arrival of new materials and advanced technologies to create new experiences for drivers and passengers.
To address the ongoing development of 'Citroën comfort' in the 21st century, the company has framed its expertise in comfort under a new development project, known as the Citroën Advanced Comfort® programme. The programme seeks to define a new dimension of comfort in vehicles, and pursues four objectives to enhance comfort in its latest cars:
- Driving comfort – filtering out exterior interferences for a smooth ride and calm, quiet cabin
- Living comfort – simplifying life on-board with functional storage compartments, intelligent packaging, and generous space
- Functional comfort – creating a more comfortable drive with intuitive technologies, driver aids, and connectivity
- Comfort of mind – ensuring the peace of mind of driver and passengers, with clear information displays and a relaxed interior ambience to enhance driving pleasure
Citroën has always focused on suspension and seating as key elements in improving ride comfort.
Today however, ergonomics, ride and handling, practicality and versatility, and even the atmosphere of the cabin, are all vital elements in making a car as comfortable as possible, for driver and passengers alike.
Each of the themes under the Citroën Advanced Comfort® programme builds on the historic innovations that have contributed to Citroën's reputation for comfort over the last 99 years.
Guided by changing customer expectations, the programme supports the design process in terms of both styling and technology. It is visible on current models and will continue to be a mainstay in the future.
THE "CITROËN ADVANCED COMFORT ® LAB'": UNEQUALLED DAMPING QUALITY
The "Citroën Advanced Comfort® Lab'" focuses on one of the many and varied aspects of comfort. Designed to filter out bumps and dips on the road, it groups Citroën innovations in this field. When a car drives over a bump or dip, the effect is passed on to the cabin and the occupants in three stages:
a) the suspension takes action
b) the vibrations are transferred to the body
c) the vibrations are felt by the passengers through the seats.
Reflecting this process, the "Citroën Advanced Comfort® Lab'" prototype features three innovations, one for each form of transmission, in order to reduce the vibrations felt by the occupants and thus significantly improve driving comfort.
Citroën has filed more than thirty patents for the technologies implemented by this prototype, but they were all developed to be applicable, from both a cost and production standpoint, to all the vehicles in the Citroën range.
SUSPENSION WITH PROGRESSIVE HYDRAULIC CUSHIONS ™ (PHC)
New C4 Cactus, launched early 2018, was the first model in Europe to be equipped with an all-new suspension system.
Locally, the forthcoming all-new C5 Aircross will be the first model to feature Citroen's ground-breaking Progressive Hydraulic Cushions™ (PHC), a Citroën innovation that will be rolled-out on future range vehicles.
Citroën's expertise in suspension is undisputed. For 99 years, suspension comfort has been embedded in the Brand's genes. And over the years, customers have grown attached to Citroën's comfort, which is unique on the market.
Drawing on its expertise and the know-how of its engineers, Citroën developed the new suspension system to improve the filtering quality typical of Citroën and so dear to its customers.
Some 20 patents were filed in the development of the new suspension.
The way it works is quite simple. While conventional suspension systems comprise a shock absorber, a spring and a mechanical stop, the Progressive Hydraulic Cushions™ (PHC) system adds two hydraulic stops on either side, one for compression, the other for decompression. The suspension therefore works in two stages to match how the car is used.
- For light compression and decompression, the spring and shock absorber control vertical movements together with no assistance required from the hydraulic stops. But these stops gave engineers greater freedom in the car's clearance, providing a "magic carpet ride" effect giving the impression that the car is gliding over uneven ground.
- During major impacts, the spring and shock absorber work together with the hydraulic compression or decompression stops, which gradually slow the movement to avoid jerks at the end of the range. Unlike a traditional mechanical stop, which absorbs energy but returns a part of it, the hydraulic stop absorbs and dissipates this energy. This means there is no bouncing.
STRUCTURAL BODY BONDING
When the suspension has completed the damping process, the energy created by the irregular road surface is transferred to the body. The use of the structural bonding technique will significantly reduce this occurrence thanks to a global stiffness input.
Using an industrial process specific to Citroën, the structural parts of the vehicle are bonded together using a discontinuous line of adhesive. An electrical welding is positioned wherever the line of adhesive is interrupted. This bonding technique ensures a hard-bonding assembly without toxic smokes generated by bonding welds.
This special bonding technique has a number of advantages:
The first is significantly higher body stiffness. The improvement in stiffness is around 20% on average : this contributes to isolate it from external vibrations phenomena. A stiffer body will reduce the level of vibrations transferred by driving conditions.
Another significant benefit concerns weight. Bonding makes the body stiffer without making it heavier. The heavier the vehicle, the more complex the suspension damping process for improved comfort.
The third and final advantage of this bonding technique concerns the bead bonding process: this technique allows to reduce the electrical welding work numbers and to control costs. It will not be reserved solely for executive vehicles, but could be used on all Citroën models.
SEATS INSPIRED BY THE WORLD OF BEDDING
Seats are the part of the vehicle most frequently in contact with passengers. It is the seats that provide the first impressions of comfort, when you look at them or get into the car. As well as providing support, they naturally contribute to damping out the various vibrations from the vehicle and the road surface.
As part of the development process, engineers study the lines of the seat, in order to respect the curve of the back for a better driving position, and the choice of materials used in manufacture. Foam of different densities and hardness will be used depending on the role of the seat component concerned: support or cushioning.
Adding in a new factor, Citroën looked at practices in the bedding industry, a sector in which shape memory materials represent the latest in comfort.
By using several layers of special materials (polyurethane foam, viscoelastic or textured foam), Citroën has been able to develop shape memory seats that adapt perfectly to the body shape of each passenger and offer an innovative comfort experience in the automotive field. With these properties, the seats regain their original shape from one passenger to the next.
In summary:
With its progressive hydraulic cushions, structural body bonding and innovative seats, Citroën Advanced Comfort® combines three innovations that significantly improve the vehicle's ability to filter out the bumps and dips of the road.
These innovations reassert all the Citroën expertise regarding comfort. Particular emphasis was placed on the need to make all these innovations gradually applicable to the entire Citroën range, whatever the price of the model.
The brand's future models will go further in each of these areas, as illustrated by the "Citroën Advanced Comfort® Lab" demonstration vehicle in the field of suspension comfort.