Europe's population is increasingly urban-centred and Toyota research into commuting patterns shows that in the UK and France, more than 80 per cent of car journeys cover a distance of less than 25km; in the UK around 80 per cent are less than 10km long. These figures confirm the potential for electricity in providing short to mid-term sustainable mobility.
The environmental benefits of electric cars for urban commuting are well-documented, but vehicle development has been hampered by the drawbacks of the weight, size and cost of the large capacity batteries needed to provide even a modest driving range, and the lack of an adequate recharging infrastructure.
Toyota is addressing both these issues with the launch of the Prius Plug-in Hybrid Concept. It believes that progress in battery technology makes plug-in hybrid architecture the most workable solution for an electrified powertrain. The system overcomes the issue of a limited cruising range by enabling an automatic switch to a traditional full hybrid petrol-electric system once the vehicle reaches the limit of its EV (electric vehicle) driving range.
The concept model is a development of the new, third generation Prius, and builds on the core technology of Hybrid Synergy Drive specifically to meet the needs of urban motorists. It is a full hybrid vehicle in which both the electric motor and petrol engine can drive the wheels: a fully electric EV mode is used for shorter distances, while the petrol engine provides a true long-range capability.
As well as avoiding the limited range traditionally associated with electric vehicles, Toyota has also achieved a compact and practical packaging design for the battery pack. Prius Plug-in can be also be quickly recharged, from a conventional household electricity point, or a public charging post.
More than 500 Prius Plug-in cars will be released around the world early next year for lease programme, with more than 150 of these on the road in Europe. This will let Toyota evaluate all the technical aspects of the new model in a real-world environment, an essential step in preparing the vehicle for a potential market launch. The lease programme will also yield valuable intelligence on market response and which characteristics drivers find appealing, and why.
The Prius Plug-in Concept's powertrain is similar in format to the Hybrid Synergy Drive used in the new Prius, but with the nickel-metal hydride battery pack replaced by a new, high-output lithium-ion battery – a first for a Toyota hybrid vehicle. The new battery is more compact and has a higher volumetric energy density, so it does not compromise vehicle weight and packaging. Perhaps more importantly, it can be recharged much more quickly than the nickel-metal hydride type: the battery in the Prius Plug-in can be fully recharged in one-and-a-half hours from a 230v power supply.
The battery allows strong, seamless acceleration up to a maximum 62mph (100km/h) in EV mode. On a full charge, it can cover approximately 12.5miles (20km) in EV mode, six miles further than the nickel-metal hydride battery in the latest Prius model. Over longer distances, the car operates as a regular full hybrid.
The car's extended EV performance has a significant impact on emissions, with CO2 output dropping to less than 60g/km and, as with other full hybrid models, reduced NOx and particulates (PM) levels. Even greater CO2 savings can also be gained if the electricity used to charge the battery is drawn from renewable sources, such as windmills and solar panels. Simply put, the lower the percentage of energy derived from fossil fuels, the better the car's well-to-wheel CO2 performance.
The Prius Plug-in Concept is every bit as comfortable, convenient and practical as the latest generation Prius. As in its sister model, the air conditioning can be activated remotely, when the vehicle is plugged, enabling the cabin to be brought to the right temperature before setting off.
To help drivers maximise the benefits of driving in EV mode, it is equipped with a Hybrid System Indicator, which includes information on the EV driving range, based on the level of battery charge. An engine starting point display has also been added to emphasise the increase in EV driving range.
The Electro Multi-Vision screen on the dashboard also offers a display that highlights the plug-in hybrid's contribution to reducing CO2 emissions, showing a computer graphic image of single tree that gradually increases to whole forest as the battery charging process takes place.