Porsche is also working on an induction charger that can be installed in a domestic garage floor. The system allows the battery to be recharged simply by being in the proximity of the charger, eliminating the need for charging cables.
Porsche’s move is part of its plans to reduce fuel use during everyday driving. Porsche says its “new parameter” for fuel saving is reducing the engine’s “revolutions per kilometre”. In the first phase, exemplified by the plug-in Panamera, reducing engine revs per kilometre involves conventional stop-start, plus coasting, engine-off coasting and running on battery power.
In the next stage, due in 2016-2017, Porsches will interact intelligently with their surroundings using information from detailed maps, including accurately measured inclines and the radius of approaching corners. This data will allow the cars to select automatically the optimum driving mode (from Electric, Hybrid, Charging and Sport modes) for the situation.
In future, it seems, Porsche’s hybrid models will be making many of the driving decisions, including deciding the balance of power between the engine, battery and the effects of kinetic energy and gravity.
The Panamera S E-Hybrid’s newly developed hybrid unit combines an electric motor and a dry clutch pack to deliver 94bhp — twice the power of the electric motor in the previous Panamera Hybrid. It is also much lighter than the old set-up and, interestingly, is claimed to be 91 per cent efficient.
The supercharged 3.0-litre V6 meets stringent EU6 emissions regs by means of a clever cold-start strategy. The engine runs for 30sec or so before it connects to the transmission, letting the catalytic converters reach their operating temperature. Only after that will the engine mesh with the drivetrain. In the meantime, the car can move off on battery power alone.
The hybrid module is installed between the otherwise conventional engine and transmission. The upshot is that the engine is mounted slightly further forward, but overall weight distribution isn’t adversely affected due to the battery pack’s location in the tail.
Porsche’s familiar eight-speed automatic has been used “without component modification”, although new shifting programmes have been developed to cope with the two power units and different drive modes.
High tension cables and cooling system
There are 54 metres of high-tension electric cables on the E-Hybrid. The next-generation version of the hybrid transmission will use aluminium cables to reduce weight. There are also three cooling circuits. A high-temperature unit deals with the engine, one low-temperature unit is for the oil cooler and power electronics module, and the third unit can both heat and cool the battery pack.
There are four driver-selectable driving modes: Full Electric, Hybrid, Charging (while driving) and Sport.
Panamera Hybrid apps
Porsche has designed an app to communicate with the E-Hybrid via smartphone. It can be used for a number of functions, including the timing of the charging, pre-cooling or pre-heating the cabin and even remotely locking and remotely folding the door mirrors.