2008 Hybrid Air – a key step towards the heart of the hybrid range

With the HYbrid Air technology, Peugeot confirms on the one hand its strategy of reducing fuel consumption and CO2 emissions and on the other hand its pioneering nature, with a new breakthrough solution. In fact, the HYbrid Air combines petrol with compressed air in a full-hybrid solution. This technology is a key step in achieving the goal of 2.0-litres/100km, a feature destined to become widespread due to its simplicity, durability and international character.

Hybrid strategy

Peugeot has set itself the goal of reducing the average CO2 emissions of its range to 116g/km in 2015 without sacrificing driving pleasure. To achieve this, it is investing in a range of technologies which are already present on its vehicles and permit substantial progress: continuous improvement of the efficiency of the internal combustion engines, a petrol and diesel engine down-sizing strategy, widespread use of the Stop & Start and electric vehicles, to name a few.

The accomplished HYbrid4, diesel-electric hybrid, is part of this process. Launched as a world first by Peugeot on the 3008 Crossover, it was then extended to the 508 RXH and the 508 Saloon HYbrid4. The 20,000 customers of the HYbrid4 technology have discovered a new driving experience the like of which they would not have experienced before, combining performance, simplicity of use, quiet operation while protecting the environment with CO2 emissions from 88g/km.

With the 2008 HYbrid Air, Peugeot is innovating once more in the interests of the environment and of its customers in all of its markets. In fact, this breakthrough technology is introduced on the 2008, the new urban crossover developed by and for three continents. It is the natural medium for this new drivetrain, which combines petrol and compressed air to fulfill the expectations of customers and rise to the increasing challenges of the motor industry. The HYbrid Air technology is an essential step towards the goal of reducing fuel consumption to just 2.0litres/100km. To achieve this, it combines the continuous improvements of the engine and the weight-saving available through the design of new platforms.

HYbrid Air, the facts

The specification for this technology set clear objectives: substantial reduction of fuel consumption and CO2 emissions, on all continents, by means of affordable technology which can be applied to vehicles and light commercial vehicles in the B and C segments.

In response to this, the HYbrid Air combines tried and tested technology: the new generation of threecylinder petrol engines and compressed air. Over 80 patents testify to the expertise mobilised for this important R&D (research and development) work.

Principle of operation

The HYbrid Air combines two energies to achieve the highest efficiency in various situations. So, the compressed air will assist, or even take the place of, the petrol engine during the phases, which consume the most energy: acceleration and moving off. This technology uses certain components new to the motor industry but widely tested in other sectors such as aeronautics. The HYbrid Air consists of:

* an energy tank, containing pressurised air, installed under the body in the central tunnel,

* a low pressure tank at the rear suspension crossmember, acting as an expansion bottle,

* a hydraulic unit consisting of a motor and a pump, installed under the bonnet on the transmission.

This latter consists of a EGC (Electronically Gearbox Control) epicyclic drivetrain to manage the distribution between the two motors. It replaces the mechanical gearbox and in addition offers automated gear changes.

The internal combustion engine is the latest generation 3-cylinder petrol engine. It benefits from the very latest technology: optimisation of the weight and compactness by means of maximum integration of the components, reduction of internal friction by means of the use of Diamond Carbon coating, thermo-management, split-cooling for a faster warm-up, etc. So, the HYbrid Air has the important advantage of being compatible with the existing platform benefitting occupant space, modularity and the volume of the petrol tank, which remain unchanged.

Three modes: Air (ZEV), petrol and combined

The driver controls the two energy sources to achieve the highest overall efficiency possible in the current situation. Switching between the three modes available is completely natural for the driver.

In the Air (ZEV) mode, only the energy contained in the compressed air will drive the vehicle. As it depressurises, the air occupies an increasing amount of space in the energy tank and so displaces a corresponding volume of oil. This is an energy carrier, which supplies the hydraulic motor coupled to the epicyclic drivetrain. As the internal combustion engine is switched off, the vehicle moves without consuming any fuel or emitting any CO2.

This mode comes into its own when driving in town.

In petrol mode, only the 1.2-litre VTi 3-cylinder petrol engine powers the vehicle. This engine benefits from the latest technology to offer, compared to the previous generation, a reduction in weight of 21kg, friction reduced by 30% and advanced thermo-management to reach the optimum operating temperature more quickly.

This mode is particularly suited to steady speeds on main roads and motorways. In the Combined mode, the petrol engine and hydraulic motor operate simultaneously to move the vehicle, in proportions adjusted according to the situation to achieve optimum fuel economy.

Adaptable, the HYbrid Air can supply the hydraulic motor from two sources. While the quantity of energy contained in the pressurised air tank is sufficient to fulfill the driver’s request, the hydraulic motor operates using this source. Then, if necessary, it can be supplied by the hydraulic pump directly.

This mode is intended in particular for the transitional phases in town and on the open road (moving off, acceleration).

The energy tank is filled in two ways. On deceleration (on braking or releasing the accelerator), the speed is reduced not by application of the pads to the brake discs but by the resistance to the compression of the air in this accumulator. The alternative consists of filling by restarting the internal combustion engine; in this situation, some of the energy produced by the petrol engine is used to compress the air.

In both cases, the maximum energy capacity of the pressurised accumulator is reached very quickly – in just ten seconds.