Unveiled at the 2004 Paris Motor Show, the C4 made its market debut in November 2004. Continuing to move forward, Citroën has designed a mid-range hatchback and coupé with distinctive exterior styling and identical interior space.
Looking beyond styling and space, the C4 is designed to bring customers a more relaxed drive. The engines, running gear and many driving aids considerably enhance on-board comfort. In all these areas, the on-board technology works with the driver and passengers to set new standards in driveability and safety in this segment.
The C4 is the first Citroën vehicle to be produced at the Mulhouse production site. Over the past five years, the Marque has invested heavily to develop the plant’s industrial infrastructure and to upgrade platform 2.
A wide range of advanced technology powerplants
The C4 is available with a wide choice of new-generation engines. It offers a choice of five petrol engines: the 1.4i 16V (90 bhp DIN), the 1.6i 16V (110 bhp DIN), the 2.0i 16V (138 bhp DIN), the new 2.0i 16V (143 bhp DIN) recently introduced on the C5 and available with the C4 Hatchback and the 2.0i 16V (180 bhp DIN), installed on a Citroën vehicle – the C4 Coupé – for the first time. The three HDi diesel engines available with the C4 are all equipped with second-generation common-rail. The HDi 92 is making its debut on a PSA Peugeot Citroën Group vehicle, while the new HDi 110 and HDi 138 engines were recently introduced in the Citroën range.
Most of these engines already satisfy the Euro IV emission standard. With the C4, Citroën is also expanding the range of vehicles equipped with the diesel particulate filter system (DPFS). This technology rounds out the benefits of HDi engines in the field of environmental protection.
Exceptionally polished road manners
The C4 boasts impeccable road manners, with its MacPherson type suspension at the front and flexible transverse beam at the rear, associated with ABS, emergency braking assistance and ESP.
The braking system is among the best in the segment, with finely regulated ABS and ESP.
Modern, innovative equipment for relaxed drive
The C4 features a range of modern, efficient driving aids designed for easy, relaxed driving.
The lane departure warning system (LDWS) is a major step forward in driving safety. At speeds of over 80 kph, this system warns the driver if the car crosses a continuous or broken lane marking, if the indicator has not been activated. A vibrating mechanism mounted in the car seat is triggered on the side corresponding to the direction of vehicle drift, enabling the driver – who may have suffered a moment’s distraction – to take corrective action in time.
Xenon dual-function, directional headlamps (dipped and full beam), generally reserved for vehicles further up the market, provide improved lighting for cornering.
The C4 also features equipment more rarely found in this segment, such as a speed limiter, cruise control, front and rear parking assistance with manoeuvres displayed on the multifunction screen, and a low tyre-pressure warning system.
New features for protecting passengers and pedestrians
The C4 passed EuroNCAP crash tests with flying colours, taking 5 stars and 35 points out of a possible maximum of 37. The C4 also becomes the standard in pedestrian impact tests with a score of three stars, along with four stars for child protection. With its array of equipment and features, the C4 sets high standards in active and passive safety.
In particular, the C4 boasts the world’s first anatomically shaped driver airbag. This feature, which uses the fixed central section of the steering wheel, improves driver protection.
The C4 is also designed to protect pedestrians in the event of frontal impact. The vehicle is designed to limit the consequences of possible pedestrian impact (impact absorbers on the upper and lower part of the front end, aluminium bonnet with an inner panel perforated in the centre to absorb energy more effectively, etc.).
A new expression of onboard comfort
The interior design of the C4 places the emphasis on relaxation, with:
- discreet, high-tech interior styling, reflected in the understated dashboard design,
- innovations for simplicity of use and ergonomics.
For example, the multifunctional fixed-centred controls steering wheel brings the main comfort functions (audio system, telephone, etc.) and driving aids (speed limiter, cruise control, etc.) within easy reach. This ergonomic feature, which places the emphasis on easy-to-use controls, promotes driving pleasure.
The steering wheel is associated with an instrument cluster of new design, which displays driving information (vehicle speed, speed limiter and cruise control settings, etc.) on a translucent strip in the centre of the dashboard. The display contrast adjusts instantly to ambient light conditions to ensure a clear read-out at all times.
All these advanced functions create a relaxed atmosphere in the passenger compartment, further enhanced by the scented air freshener styled to match the interior, and the laminated side windows for acoustic comfort. In terms of practical features, the C4 features a host of stowage compartments including a boot foldaway partition to hold objects firmly in place.
A coupe and a hatchback different styles, same interior space
The C4 Hatchback and the C4 Coupé each have their own distinctive style. However, they share the same generous interior space, contributing to the comfort of the passenger compartment.
The hatchback has rounded forms, while the coupé favours a sharper line. Both vehicles share smooth, fluid lines for outstanding aerodynamics, one of Citroën’s traditional strengths (Cd of 0.28 for the coupé and 0.29 for the hatchback). The two vehicles also share the same interior space. Knee room for passengers at the rear is among the best in the segment (17 cm when the seat is pushed back to the maximum).
By offering a hatchback and coupé, Citroën is pursuing the strategy initiated in the supermini segment, where it has three complementary offers (C2, C3, and C3 Pluriel), each with distinctive styling to address wide-ranging customer tastes.
Two vehicles of distinctive styling
C4 styling:folowing lines and stong aerodynamics
The C4 Hatchback and the C4 Coupé have very different styling, while also sharing a number of features that identify them as members of the same family.
The style of the C4 is characterised by decisive architectural choices. Its height is limited in order to optimise aerodynamics, road behaviour and fuel consumption. In consequence, power and fluid design lines emerge as the key traits qualifying the C4.
However, the real signature of the C4 can be read in its strong exterior features, some of which are common to both the hatchback and the coupé.
These distinctive signs can be seen on the front end in particular, with the chrome chevrons spanning the full width of the radiator grille, and the boomerang-shaped lights extending up to the vehicle wings.
Other distinctive and stylish features include the flag-shaped rearview mirrors on the front doors, which give prominence to the sides of the C4.
Looking beyond these shared attributes, Citroën is offering two clearly differentiated body styles:
a hatchback of fluid, dynamic lines with strong curves
- a coupé of longer, sharper lines with a spectacular plunging tail.
In both cases: smoothly flowing contours with an ever-present emphasis on aerodynamics.
A hatchback of assertive design
The C4 Hatchback boasts smooth, protective bodywork, with unique exterior styling.
The profile of the hatchback is traced in a single line, with a strongly raked windscreen that extends the taut lines of the bonnet, before moving smoothly on to the curve of the roof.
Similarly, the high, arched waist line reinforces the feeling of safety and protection enjoyed by the passengers. At the same time, the elongated windows draw out the cabin and accentuate the fluid lines of the hatchback.
The body style of the C4 Hatchback shows distinctive lines of force, which underline its dynamic character. In addition to the headlamps placed either side of the double chevron on the radiator grille, other particularly striking styling features include:
- the rear lights, whose geometric shape expresses dynamic power. The lower part underlines the vehicle’s stability, while the upper part runs along the rear window up to the lip at the top of the tailgate,
- the quarter windows and waist line suggesting controlled power.
A coupe with a difference
The exterior styling of the C4 Coupé owes its force to the dynamic fluidity of its proportions, which combine a long wheelbase and long front overhang with a short rear overhang.
The profile of the coupé expresses the pursuit of optimal aerodynamic design. The receding lines converging towards the rear of the vehicle suggest movement and fluidity. The waist line – slightly curved towards the rear – and the prominent wings, suggest stability and good roadholding.
The C4 Coupé possesses a distinctive style, with a flowing, easily recognisable profile, and a reverse-sloping rear window with a spacious passenger compartment. Its styling is a mix of sportiness and interior space.
Architecture combining aerodynamic design and generous volume
The C4 was designed to meet stringent aerodynamic targets, while also offering class-leading space at front and rear.
Best Cd in its category
Extensive aerodynamic studies were conducted on the C4 in order to obtain a drag coefficient (Cd) of up to 0.28 for the coupé, a record in this segment. The hatchback boasts a Cd of up to 0.29. These values promise acoustic comfort, along with reduced fuel consumption and lower pollutant emissions.
They are achieved by:
the exceptionally fluid body styles, with:
- limited height (1.46 m),
- a windscreen placed well to the front, continuing the line of the bonnet,
- a long roof with a dramatic drop at the rear,
- sides narrowing at the rear.
The presence of exterior features designed to smooth the air flow:
- flag-shaped exterior rearview mirrors,
- aerodynamic undertrays to smooth out the airflow under the body,
- a rear spoiler extending the flow-line of the roof to the maximum extent,
- bumpers designed to improve the airflow over the wheels,
- front windscreen wipers integrated in the scuttle aperture to avoid disrupting the air flow.
Class-beating interior space
In both hatchback and coupé form, the C4 combines style and aerodynamics with a level of interior space that ranks it among the best in its segment.
Identical interior space on the hatchback and the coupé
Although the C4 Hatchback and the C4 Coupé are very different in terms of styling, they share the same interior space.
They have the same dimensions, viewed from the side, with a wheel base of 2.61 m and a height of 1.46 m. Only their length differs slightly (by 1.3 cm) owing to the style of the rear bumper.
Generous interior dimensions
The interior dimensions of both vehicles meet customer requirements concerning the essentials of on-board comfort. The two C4s are standards in their segment concerning knee room for passengers at the rear (17 cm when the front seat is pushed back to the maximum).
In terms of elbow room at the front (1.44 m) and rear (1.43 m), the C4 is on a par with most of its competitors in this segment.
Innovations for onboard comfort and relaxed driving
The interior of the C4 boasts a host of innovations in driving ergonomics, life on-board and functional convenience. The C4 is also available with an array of high-tech communication equipment.
The C4 features a dashboard of pure design lines and a fixed-centred controls steering wheel bringing driving aids within easy reach. At the same time, for enhanced safety and comfort, some instruments are located in the centre of the dashboard, so that the passengers can contribute to the ride.
The multifunctional fixed-centred controls steering wheel
The fixed centre of the steering wheel features the main comfort functions and driving aids. This layout places the emphasis on ergonomics and easy use, thus promoting driving pleasure.
The main characteristic of the C4 steering wheel is its fixed hub. The centre of the wheel no longer turns with the rim. The technical principle is simple: a toothed ring linked to the steering wheel engages an inner pinion, itself linked to the steering column. The space between the ring and the pinion is used to couple the fixed components: the steering wheel hub and the steering column mounting.
A host of advantages
The multifunctional fixed-centred controls steering wheel offers the following advantages:
• controls are grouped in the centre of the steering wheel, thus freeing up space on the dashboard, and giving it a simpler, uncluttered look,
• significant improvements in ergonomics, since the controls are grouped in a stable and easily accessible position, so that the driver does not have to take his hands off the wheel,
• as the controls are on the steering wheel, they remain easily visible, even at night, thanks to the use of illuminated pictograms,
• in terms of safety, the fixed-centre design of the steering wheel makes it possible to install an airbag designed to match the driver’s body shape.
A balanced distribution of controls
The steering wheel controls are split into four different areas: each with four buttons and a knob:
- the top right-hand area groups the radio controls, with volume and station settings, the memorised station search function, and the mute function;
- the bottom right-hand area provides access to the multifunction screen, with in particular – the on-board computer and the NaviDrive navigation system;
- the top left-hand area is dedicated to the speed limiter and cruise control. If the driver opts for one of these driving aids, a pictogram will appear on the translucent instrument cluster, showing the mode selected and the programmed speed;
- the bottom left-hand area groups the controls for vehicle options. For example, the voice control of the NaviDrive navigation system, the telephone controls, the driver-configured button offering "black panel" lighting as the default function, or the air recycling function.
The horn is on the lower part of the steering wheel. Conventional driving functions (lighting and wiping) maintain their usual layout, with standard stalk switches.
Driver-dedicated steering-wheel display
Driving information intended specifically for drivers is displayed immediately in front of them. This is the case, for example, of the rev counter, the indicator and headlamp settings, and the mode /gear speed selected on versions equipped with an automatic gearbox. Also, the background of the rev counter turns red when the vehicle reaches maximum engine speed.
Fitted on the steering column, this display unit moves with the steering wheel to remain easily legible at all times.
A dashboard designed to promote relaxed driving and shared information
The clean, soft lines of the dashboard create an uncluttered look that is relaxing on the eye. Enhancing this effect, curves and relief are kept to a minimum. The choice of colours and materials reflects the same approach to design.
The dashboard is designed to share information, in the same way as on a people-carrier. The centre features three display units:
- a translucent instrument cluster,
- a multifunction screen with the on-board computer and NaviDrive navigation system,
- an air-conditioning display unit for vehicles equipped with automatic air conditioning.
The translucent instrument cluster
Driving panel information is displayed on a translucent strip in the centre of the dashboard.
The translucent instrument cluster provides the following information:
- vehicle speed,
- petrol gauge and range,
- water temperature
- total and partial mileage,
- oil level,
- speed settings for the cruise control and speed limiter,
- a maintenance indicator.
Indicators corresponding to the seatbelt warning lights, the child safety function, and ESP disablement are displayed on either side of the translucent instrument cluster.
As the instrument cluster is located in the centre of the dashboard, the translucent strip captures the light perfectly. The display contrast adjusts instantly to the light to provide perfect legibility is perfect in all circumstances, by day and night, in full sunlight or in darkness.
Life on board
The cabin of the C4 is designed to optimise passenger comfort. The cabin layout, the ergonomics and characteristics of the seats and the soundproofing – essential vehicle qualities – have all been addressed in such a way as to create a relaxing interior ambience.
In addition, the C4 features a range of equipment to create a feel-good ambience, such as the glazed panoramic roof and the scented air freshener.
The scented air freshener
A scented air freshener, styled to match the dashboard design, also contributes to the restful onboard atmosphere.
A choice of nine fragrances
Nine fragrances are available: Citrus and Passion, Amber and Sandalwood, Cinnamon and Ginger, Lotus Flower, Vanilla, Jasmine and Mimosa, Soft Lavender, Mint and Musk, Ylang and Bamboo.
All these fragrances were developed by Robertet, a company specialising in the creation of perfumes.
Customers will receive a kit with three fragrances (Vanilla, Mint and Musk, Ylang and Bamboo) on delivery of their car.
A fully integrated system
Placed on the central air vent, the scented air freshener diffuses the fragrance selected through the air conditioning system. A knob lets the user switch the system off or adjust the quantity of perfumed air.
The perfumes come in the form of sealed, individual cartridges, so the fragrance can be changed at any time. A cartridge lasts around two months, based on one hour of daily use. Refills are available from the Citroën network.
Seats tailored to a full range of tastes and body shapes
Looking beyond their styling, which is an explicit statement of their qualities, the seats of the C4 are designed to ensure outstanding levels of comfort and support.
Firm support, adapted to everybody’s tastes
To reflect customers’ tastes more effectively, the C4 is equipped with "comfort" or "vitality" seats, depending on the trim level selected.
"Comfort" seating ensures excellent damping and also provides sufficient support to hold the occupant firmly without being restrictive.
Placing the emphasis on comfort in use, it is perfect for smooth, relaxed driving.
"Vitality’ seating is firmer to the touch with more pronounced support. It corresponds to the pursuit of stronger driving sensations and a more dynamic driving style.
In addition to the conventional seat settings (fore-and-aft adjustment, angle of back rest), the C4 also includes a number of other settings to ensure that all the occupants can find a position to suit their body shape and driving habits:
- steering wheel adjustable for height and reach,
- a driver’s seat adjuster that can be raised over 50 mm,
- manual lumbar adjustment on the driver’s seat.
The C4 can also be fitted with an electrically controlled driver’s seat with a memory function, allowing different drivers to immediately find their preferred settings.
Focus on acoustic comfort
To optimise acoustic comfort on board the C4, extensive studies were conducted on sealing, and sources of wind noise.
The main factors contributing to sound insulation are:
- the flag-shaped exterior rearview mirrors,
- the laminated windscreen with a damping film between two sheets of glass,
- the thick glass used for the side windows (3.82 mm instead of the 3 mm usually found on vehicles in this segment),
- the windscreen wipers integrated with the scuttle aperture,
- the anti-turbulence windscreen seal,
- the double door seals,
- the treatment and filling of box sections.
Available as an option, the laminated side windows reinforce the filtering of wind noise and external nuisances.
Individual thermal comfort
To satisfy requests for individual comfort functions at the front, the C4 features automatic two-zone air conditioning. The driver and front passenger can thus choose their own temperature settings.
The automatic air conditioning system is equipped with:
- a particulate and pollutant gas filter,
- an air recycling function, activated using the controls on the steering wheel and air conditioning panel,
- a heat-reflecting windscreen, which considerably increases the reflection of ultraviolet rays.
With its many stowage compartments, easily adaptable, modular passenger compartment and boot partitioning system, the C4 is an easy-going car that adapts to the requirements and needs of the moment.
A host of practical and well designed stowage compartments
From the dashboard to the consoles and door panels, the interior of the C4 possesses generous stowage, including: a vast glove box, bins in the doors, can-holders, a drawer under the front passenger seat and nets on the backs of the front seats.
Evenly distributed around the passenger compartment, these stowage compartments were designed for practical use. The closed stowage compartments have a damped opening, the drawers are of the push/pull type and the ash tray is illuminated, as is the glovebox, which may also be cooled. Some compartments are intended for specific purposes, such as the handbag hook on the passenger side of the central console or the overhead eyewear holder on the driver’s side.
Some compartments are closed, thus contributing to the uncluttered look of the cabin. For example, the front central armrest, with fore-and-aft adjustment, has a stowage compartment for CDs or the CD stacker. The console is also equipped with a 12V socket and a cigar lighter
The C4 features a 60/40 split-folding rear seat back and cushions. Simple attachments make it easy to take advantage of the C4’s modular interior.
The seat backs unlock easily and can be folded down:
- directly onto the seat cushions,
- with the seat cushions raised, in order to obtain additional space and a virtually flat load floor,
- using clips, after the fast-fit seat cushions are removed. In this configuration, the loading space extends up to the front seats.
A new boot foldaway partition
The boot of the C4 features an original partitioning system. This system is designed to isolate and securely hold the objects placed in the boot. A simple function lets the user fold out the partitions integrated in the boot sill to create three separate compartments.
When folded, these partitions disappear totally into the thickness of the boot sill. When partitioning is not used, the boot regains its full loading volume.
The boot of the C4 can also be fitted with a stowage bin, a stowage net and a range of hooks to hang bags up.
High-tech communication equipment
To increase on-board comfort, the driver can install a range of high-tech equipment including:
• the NaviDrive telematics system for stress-free driving,
• the JBL hi-fi system for high-level acoustics,
• the Bluetooth hands-free telephone system to make and receive calls safely.
Stress-free driving with NaviDrive
The C4 is available with the new-generation NaviDrive telematics system.
It offers a number of essential functions: a GPS navigation system, a GSM dual-band hands-free telephone with access to the address book and audio system (radio and 5-CD stacker). At the same time, passengers can use the screen or voice synthesis function to read SMS messages received over the phone.
The main functions can be accessed easily using the steering-wheel controls, which can also be used for the voice recognition and synthesis functions. NaviDrive can be controlled by the user’s voice without any preliminary learning time. This feature is very useful for making phone calls, finding your way, or accessing the address book without risk. The system can also be operated directly using the unit built into the dashboard. The functions are displayed on a black-and-white screen or large 16:9 colour screen.
NaviDrive was also designed to offer a number of additional customer services. The services available to users are: Citroën Emergency, Citroën Assistance and Citroën On line.
Working with the GPS and telephone functions, Citroën Emergency makes it possible to locate the vehicle if the driver has an accident or is ill, for example, and to access the services of a call centre.
A customised hi-fi function
JBL, one of the world’s leading audio specialists, has developed a hi-fi system specially for the C4. The new system is designed to offer customised acoustics of superb quality.
The hi-fi system comprises ten loudspeakers in six locations, together with a subwoofer that is fitted in the boot. The presence of the subwoofer in the boot provides wraparound sound quality and an extremely faithful reproduction of musical material. The system is controlled by an amplifier located under the front passenger seat. This unit is parametered with the acoustic settings defined and optimised for the cabin of the C4. Driver and passengers enjoy excellent sound quality, with an acoustic reproduction that is tailored to their environment in all circumstances.
Bluetooth, to make and receive telephone calls safely
The C4 features a Bluetooth hands-free telephone in which the address book is displayed on the vehicle’s multifunction screen. This hands-free telephone system, based on Bluetooth wireless technology, is integrated with the passenger compartment.
Bluetooth is a convenient and safe option for making personal in-car calls from a mobile phone, since drivers can make and receive calls without taking the phone out of their pocket. In this way, they keep both eyes on the road and both hands on the wheel.
To make a hands-free call, drivers uses the ergonomic control function on the wheel, and the microphone built into the roof. Conversations are relayed over the C4’s audio system.
Drivers select the name of a correspondent from the address book of their mobile phone, using the steering wheel controls. They can also use the "voice recognition" function to initiate a call.
The phone directory and the name of the correspondent are displayed on the vehicle’s multifunction screen.
Arange of advanced technology engines
The C4 offers a choice of five petrol engines, including the new 143 bhp 2.0i recently introduced on the C5, and three HDi diesel engines developed in cooperation with Ford. These are the HDi 92 – fitted for the first time on a PSA Peugeot Citroën vehicle – and the new HDi 110 and HDi 138 recently introduced in the Citroën range.
A wide choice of petrol engines
Five petrol engines are available: the 1.4i 16V (90 bhp DIN), the 1.6i 16V (110 bhp DIN), the 2.0i 16V (138 bhp DIN), the new 2.0i 16V (143 bhp DIN) also introduced on the new look C5 and available with the C4 Hatchback, and the 2.0i 16V (180 bhp DIN), installed on a Citroën vehicle – the C4 Coupé – for the first time. All the engines feature a cylinder head with a double overhead camshaft, four valves per cylinder and a motor-driven throttle, controlled electrically by the engine control unit. All the engines are equipped with a five-speed manual gearbox, except for the 143 bhp 2.0i 16V engine, which is mated with an automatic gearbox. The 110 bhp 1.6i 16V engine is also available with an automatic gearbox.
The 1.4i 16V engine is the entry-level model. It develops 65 kW EEC (90 bhp DIN) at 5,250 rpm and maximum torque of 133 Nm at 3,250 rpm. Continuously variable valve timing optimises filling of the combustion chambers at all engine speeds.
Variable valve timing offers more torque at low engine speeds and contributes to the respect of the Euro IV emission standard. Torque of 118 Nm – 90% of maximum torque – is available from 1,800 rpm.
The angular variation with respect to crankshaft timing is managed by the engine control unit, in line with the engine oil temperature, engine load and speed.
This engine also features a stiffened cylinder block to meet high standards of acoustic comfort. Fuel consumption is low (6.4 l/100 km over a standard combined cycle), and emissions satisfy the future Euro IV standard.
The 1.6i 16V engine develops 80 kW EEC (110 bhp DIN) at 5,800 rpm and maximum torque of 147 Nm at 4,000 rpm. Highly responsive from the lowest engine speeds, this engine offers torque of 132 Nm – 90% of the maximum amount – from 2,000 rpm.
This mid-range engine strikes an excellent balance between performance and fuel consumption in combined use (7.1 l/100 km over a standard combined cycle).
The 2.0i 16V engine develops 100 kW EEC (138 bhp DIN) at 6,000 rpm with torque of 190 Nm at 4,100 rpm. The high engine torque available from low engine speeds ensures a smooth response to driver input. This engine offers torque of 165 Nm from 2,000 rpm, almost 87 % of the maximum torque available. The power of the engine combined with the strong, steady increase in engine speed make the C4 138 bhp 2.0i 16V a pleasant and relaxing drive, offering superior responsiveness and acoustics.
The 2.0i 16V engine is also available with the C4 Hatchback, in a version offering output of 103 kW EEC (143 bhp DIN) at 6,000 rpm. It is coupled with an automatic gearbox.
Recently introduced on the C5, this new variant of the 2.0i 16V engine offers maximum torque of 200 Nm at 4,000 rpm. It features continuously variable valve timing to optimise filling of the combustion chambers at all engine speeds. Torque of 170 Nm, almost 85% of the maximum torque available, is supplied from 2,000 rpm.
This engine also meets the requirements of the Euro IV emission standard.
The 2.0i 16V engine, developing 130 kW EEC (180 bhp DIN) at 7,000 rpm is the most powerful engine in the range. The C4 Coupé is the first Citroën vehicle to offer this engine, which combines dynamic driving thrills with a high level of safety and comfort in daily use. Maximum torque is 202 Nm at 4,750 rpm. On this engine, the intake camshaft is also equipped with a continuously variable valve timing system. This characteristic makes for a powerful, responsive engine.
Three diesel engines offering exceptional performance and fuel consumption
The three HDi diesel engines available with the C4 are all equipped with second-generation common-rail. The HDi 92 is making its debut on a PSA Peugeot Citroën Group vehicle, while the new HDi 110 and HDi 138 engines were recently introduced in the Citroën range.
The characteristics and performance of these compact, low-weight engines are exceptional: driving pleasure, reduced fuel consumption and pollutant emissions, along with acoustic comfort and vibration control. The engines are also remarkable for their verve, and for the temporary torque increase of 20 Nm supplied by the overboost function, which is present on the two most powerful versions.
The HDi 138 engine is coupled with the six-speed manual gearbox, recently introduced on the C5.
The new 1.6. HDi engine develops 66 kW EEC (92 bhp DIN) at 4,000 rpm for torque of 215 Nm at 1,750 rpm. Based on the HDi 110, this "all-aluminium" engine is making its debut in the Citroën range. With low fuel consumption (4.7 l/100 km over a standard combined cycle) and CO2 emissions of just 125 g/km, this engine satisfies the Euro IV standard.
The 1.6 HDi engine is also available in a version offering output of 80 kW EEC (110 bhp) at 4,000 rpm, introduced on the Xsara Picasso in February 2004. It supplies maximum torque of 240 Nm at 1,750 rpm. Torque can be increased to 260 Nm at 1,750 rpm on the three highest gearspeeds, thanks to the overboost function. For strong bursts of acceleration, the "overboost" function kicks in, delivering up to 20 Nm of additional torque by increasing the fuel injection rate.
This new engine therefore combines a fast response with a linear increase in power, and excellent acceleration at low engine speeds. The HDi 110 features a second-generation injection system delivering injection pressure of 1,650 bars, controlled by piezoelectric-type injectors. A variable-geometry turbocharger enhances driving pleasure and performance. This engine makes full use of the potential offered by the common-rail system with its multiple injection technology and the enhanced management of fuel injection into each cylinder, providing four injections per engine cycle:
- two pilot injections to reduce combustion noise,
- two main injections to reduce nitrogen oxide emissions at source.
When the DPFS is fitted, two additional post-injections improve regeneration efficiency.
As a result of its low fuel consumption – 4.7 l/100 km over a standard combined cycle – and its 60-litre tank, this engine offers a range of more than 1,200 km. CO2 emissions are also very low at 125 g/km. The Euro IV version, available in some countries from the launch of the C4, is equipped with the diesel particulate filter system (DPFS), which traps and destroys particulates.
The 2.0 HDi engine complies with the Euro IV standard and is coupled with the diesel particulate filter system (DPFS). It develops 100 kW EEC (138 bhp) at 4,000 rpm. Offering maximum torque of 320 Nm at 2,000 rpm, it also features an overboost function that raises torque temporarily to 340 Nm. This new engine is coupled with a six-speed manual gearbox already available with the C5. Like the HDi 110, the HDi 138 features a second-generation injection system and a variable-geometry turbocharger.
Exceptionally polished road manners
Efficient running gear
The running gear of the C4 offers precise handling, while also effectively contributing to active safety.
The MacPherson type front suspension features lower wishbones and an anti-roll bar. The rear suspension features a flexible transverse beam associated with an anti-roll bar.
Damping control is adapted to optimise comfort and handling. Depending on the level of trim and the engine, the C4 is available with 15-inch wheels and 195/65R15 tyres, 16-inch wheels with 205/55R16 tyres, or 17-inch wheels with 205/50R17 tyres.
An electric pump unit controls the variable power steering, fitted as standard. The level of assistance varies with the vehicle speed and angle of the wheel.
The C4’s braking system features ventilated discs at the front and discs at the rear, combined with ABS and electronic brakeforce distribution (EBD).
To further improve braking safety, the C4 is fitted as standard with emergency braking assistance (EBA) and automatic hazard warning lights. ESP (electronic stability programme) is also available with all engines. It is coupled with traction control to prevent skidding. This last system can be disconnected with the 180 bhp 2.0i 16V engine.
Braking performance is among the best in the segment, with finely regulated ABS/ESP.
Relaxed, enjoyable driving
The C4 boasts a range of innovations in driving comfort, which also contribute to vehicle control.
New technologies have been applied systematically in order to develop new services and functions that provide drivers with more information while letting them concentrate on the road.
Innovative and modern driving
C4 drivers have access to a range of modern and innovative driving aids which, combined with the interior comfort and uncluttered design of the cabin, let them take to the road with a relaxed mind.
The lane departure warning system (LDWS)
The lane departure warning system detects a lane change on a motorway or fast road from speeds of 80 kph. It warns the driver if the car crosses a continuous or dotted lane marking, if the indicator is not activated. A vibrating mechanism mounted in the car seat is triggered on the side corresponding to the direction of vehicle drift, enabling the driver – who may have suffered a moment’s distraction – to take corrective action in time.
Six pairs of infrared sensors located under the front bumper monitor and detect any lane changes. Each pair is made up of an infrared emitting diode and a detection cell. The detection function relies on variations in the infrared beam reflected by the diode on the road surface.
A control unit receives the information and activates a vibration mechanism in the driver’s seat, on the side corresponding to the drift. Alerted by the vibrations on the left- or right-hand side, the driver can then steer the car back on course. This system, which can be activated or deactivated from the dashboard does not disturb the passengers, and leaves the driver free to perform manoeuvres.
Taking a significant step forward in terms of safety, this innovation is one of the solutions developed to make up for a loss of concentration or a moment’s distraction on the part of the driver.
Xenon dual-function directional headlamps
The C4 is also available with a feature that remains rare in this segment: Xenon dual-function directional headlamps (low beam and high beam).
When the car takes a corner, the beam lights up the inside of the curve, at an angle of up to 15° (8° for the headlamp on the outside of the bend and 15° for the headlamp on the inside). This feature lets the driver see where he is going and to distinguish other road users and possible obstacles. This is an important advantage in terms of safety since, at a speed of 110 km/h, the car covers more than 30 metres every second. When Citroën developed this function for the DS, the controls were mechanical. Today, they rely on electronics.
This swivelling beam enhances the lighting quality of the Xenon dual-function discharge lamps, which are active in both the low- and high-beam positions.
By improving driver visibility and reducing visual fatigue, this feature brings significant gains in safety and driving pleasure.
Front and rear parking assistance
The C4 brings customers an effective parking aid, with the introduction of front parking assistance, alongside the rear parking assistance function.
The sensors work in the same way at the front as at the back. Four sensors located in the bumper inform the driver that an obstacle is present in their detection area when vehicle speed is lower than around 10 kph. The system emits a series of bleeps whose frequency increases as the vehicle approaches the obstacle, becoming a continuous tone when the object is just a few centimetres away.
The system lets the driver view the distance separating the car from the obstacles at both front and rear. The multifunction screen displays the silhouette of the vehicle, along with six detection areas. The parking assistance function can be disabled from the dashboard.
Cruise control and the speed limiter
Cruise control and the speed limiter round out the list of new comfort and safety equipment.
Cruise control lets the driver maintain the car at a programmed speed without using the accelerator pedal.
With the speed limiter, the driver defines a maximum speed that must not be exceeded. If he wishes to exceed this speed from time to time, he presses down hard on the pedal to override the end-of-travel switch under the accelerator pedal.
For the cruise control or speed limiter functions, the driver simply programmes a required speed using the function on the fixed-centred controls steering wheel. A readout on the translucent instrument cluster then shows the programmed speed and the status (active / inactive) of each system.
The low tyre-pressure warning system
Already present on the C5 and the C8, the low tyre-pressure warning function enhances the range of safety equipment present on the C4. This system measures the pressure of all four tyres. Each tyre is fitted with an emitter and a pressure sensor, which sends information to the central control unit.
When one of the tyres drops below its set pressure level, a message immediately flashes up on the multifunction screen to warn the driver. At the same time, a buzzer sounds. In the event of a puncture, the "Stop" indicator will also come on. In this way, this feature detects any under-inflation that could have an adverse impact on the car’s stability and the safety of the passengers
In addition to improving safety, this function also encourages the driver to check tyres regularly and to correct inflation levels. These checks serve to reduce driving noise, fuel consumption and tyre wear.
A high level of passive safety
The Citroën C4 passed Euro NCAP impact tests with flying colours, taking 5 stars and 35 points out of a possible 37. It also gave an excellent performance in pedestrian-impact tests, with a score of three stars out of a possible four and 22 points. It now sets the standard in this area. The C4 also achieved an outstanding score in child-protection tests, with four stars out of a possible five.
The C4 boasts a wide array of passive safety features, including the world’s first anatomically-shaped driver airbag. This feature, which uses the fixed central section of the steering wheel, improves driver protection. The C4 also includes reinforced protection for frontal impact and a number of features designed to enhance pedestrian protection. For increased safety, the C4 is also well protected against theft and break-in.
A complete, dependable range of passive safety equipment
The C4 offers the following main passive safety features:
- an anatomically-shaped driver airbag for improved driver protection,
- driver and passenger dual-stage front airbags.
- This system adapts to the severity of impact: if impact is minor, only one stage of the airbag will deploy. The firing process is therefore less abrupt, but protection is equally effective.
- head curtain airbags standard at front and rear,
- driver and passenger chest airbags standard at front,
- seatbelts with three anchor points, a force limiter and a seatbelt warning light for all seats. The front seatbelts are fitted with pyrotechnic pretensioners and are height-adjustable on the hatchback,
- Isofix anchor points on the rear side seats.
A reinforced protective structure
Improved cabin protection in the event of frontal impact
To satisfy the most stringent passive safety evaluation requirements, Citroën conducted extensive studies on protection from frontal impact.
- The C4 features an additional impact absorber at the front end of the subframe to distribute energy more effectively in the event of frontal impact. This impact absorber is made up of a lower bumper beam and subframe extensions.
- The mechanical resistance of the front suspension and subframe has been optimised to enable, for example, energy to be transmitted under the body.
- Studies were conducted on the movement of hard incompressible objects in the engine compartment in order to limit intrusions into the cabin.
- The front doors have been reinforced in order to better stiffen the whole. Moreover, to cut the cost of repairs following minor knocks, the C4 is fitted with plastic front wings and an aluminium upper bumper beam, integral with the absorbers.
In the event of impact, the upper beam and impact absorbers crumple, without damaging the cantrails. Similarly, the lower front bumper beam crumples without damaging the engine mounting or extensions.
Focus on pedestrian projection
The C4 is designed to reduce the consequences of possible pedestrian impact. It features two impact absorbers (one on the upper part of the front end and one on the lower part) to limit leg injuries. The bonnet is made of aluminium with a perforated inner panel in the centre to absorb energy more effectively. Studies also focused on achieving a non-aggressive front end. For example, the boomerang-shaped headlamps are not only a key styling trait on the C4. They also contribute to pedestrian protection, since the headlamps are no longer on the top part of the bonnet.
Increased protection against theft and break-in
The C4 offers excellent protection against theft and break-in. Key features are as follows:
- laminated glazing on the side windows to protect the occupants and their property,
- a perimetric and volumetric alarm,
- an engine immobiliser and transponder,
- an unpickable electric boot lock,
- locking nuts for alloy wheels,
- automatic relocking thirty seconds after the vehicle is unlocked if no doors are opened,
- automatic locking of the doors and boot as soon as the car starts to move.