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How is PSA doing on plug-in hybrid (PHEV) technology?

In 2014, PSA Group announced that it would be introducing a plug-in hybrid solution by 2019, as part of its global product strategy. What is the project’s status two years down the line? What do we already know about this new technology? In Movement interviewed Olivier Salvat, head of the plug-in hybrid electric vehicle (PHEV) project, to learn all about it.

What is plug-in hybrid technology?

When we talk about plug-in hybrid technology, we’re referring to a system that combines two different powertrains on the same vehicle:

  • an internal combustion engine designed to run on fuel
  • an electric motor coupled with a high-capacity battery

What’s special about this technology is that the battery can be charged externally simply by connecting it to a home power network. With a fully charged battery, the vehicle can meet your needs for your daily errands in urban driving conditions. Given that half of daily car journeys are under 12 km, most travel needs can be met in electric mode, which doesn’t consume any fuel or generate any emissions.

How does the plug-in hybrid system work?

The two powertrains can be used separately or together. If the battery is charged, the vehicle travels in electric mode by default. When the battery is almost empty, the system automatically switches to hybrid mode – meaning the internal combustion engine is assisted by the electric motor. Alternatively, the “on-demand” mode allows the driver to move from one power source to another.

  • Electric mode: A zero-emissions, zero-fuel mode appropriate for most daily journeys.
  • Hybrid mode: A traditional powertrain assisted by an electric motor (as on the DS 5 hybrid), allowing you to travel long distances, such as when you’re getting away for the weekend. It is also equipped with Stop & Start technology to optimise fuel consumption. The plug-in system is separate from the internal combustion system, and it can work with either petrol or diesel engines.
  • Combined mode: The petrol and electric powertrains work together on a continuous basis, which boosts vehicle performance in certain situations, such as overtaking.

You also have the option of charging the battery when the vehicle is operating in engine mode. This is a backup solution, however, because it’s much more cost-effective to charge the battery by connecting it to a power grid. The key advantage is knowing that you will always be able to drive in zero-emissions mode wherever legally required.

What are the advantages of the plug-in hybrid?

First and foremost is operating range. Whether you compare it to an all-electric or Hybrid4 vehicle, range is the main differentiating factor. Charging your car every day using a home wall socket gives you an electric range that covers virtually all of your daily travel needs.

Second is savings. The savings are considerable, particularly in terms of energy costs. With a traditional engine, the fuel cost per 100 km is between €6 and €8. With the plug-in hybrid operating in electric mode, you can cover 100 km for an electricity cost of about €2.

The electric powertrain also delivers savings when it comes to brake system maintenance. In electric mode, the vehicle uses a zero-friction regenerative braking system. Electrical resistance is used to counter the vehicle’s forward motion, recapturing the energy in the process rather than letting it dissipate. So there’s no wear and tear on the brake pads or rotors.

How have we managed to improve operating range?

The challenge we faced was to limit vehicle mass, because this is the number one contributor to fuel consumption. We also looked for the most compact solution, the idea being to save space inside the vehicle as well as fit the battery into existing models to limit the cost of converting conventional vehicles. We achieved this thanks to improvements on new-generation batteries and the modular platform we are using to develop our plug-in hybrids.

Does the plug-in hybrid also reduce CO2 emissions?

Yes, of course. But it’s a multi-purpose vehicle that can cover all types of user needs, so emissions vary according to use.

Driving in electric mode, particularly in urban environments, you can get around for months without emitting any CO2. As for the engine, it performs at the same emissions levels as on non-hybrids. The potential for reducing CO2 emissions is huge. As I mentioned earlier, half of all car journeys are under 12 km. With the appropriate battery charging infrastructure in place, well over half of journeys could be made without generating any CO2 emissions.

Do we already know which vehicle line-ups will be equipped with PHEV technology?

Not yet. What I can tell you is that, since plug-in hybrids are fitted with two powertrains, they will be more expensive up front, while being nicely cost-effective over time. This is why PHEV technology will initially be targeted to high-power segments. Then, as with all new technologies, prices will fall as volumes rise, gradually making the PHEV more broadly accessible, just like air conditioning 20 years ago and brake assist systems in the last decade.

Could you tell us more about how the vehicles are charged?

Of course. There are three different scenarios.

  • You can charge the battery at home using a regular wall socket. A small adaptor will be delivered with the vehicle. No at-home adjustments are required. The battery charges at a rate of 8 amps per hour using a standard domestic socket, so a full charge takes around seven hours.
  • A 16 amp socket can also be used to charge the battery. You can easily change one of your home sockets to raise its capacity to 16 amps, which will allow you to charge your car in four hours.
  • Alternatively, you can install special equipment at home to give you a capacity of 32 amps, which would reduce total charging time to two hours.

These are all home charging solutions. But in the future, high-performance charging stations are likely to be installed by cities and businesses for general use, to encourage zero-emissions travel.

Aside from reducing emissions and user costs, does PHEV technology deliver any other key breakthroughs?

Yes, we’re working on a solution to pre-set the temperature of the vehicle cabin. On a standard vehicle, you have to turn on the engine to get the air conditioning or heating going. But one of the properties of the PHEV system is thermal resistance through the battery. So the user can set the vehicle’s temperature before even getting into it. There’ll be no more waiting for the windows to defrost or opening the door to a blast of heat from a sun-baked car!

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