Volvo Cars was the first carmaker to develop and produce a diesel-based plug-in hybrid powertrain with the launch of the V60 D6 Twin Engine in 2012. The new model V60 D5 Twin Engine, unveiled at the Geneva Motor Show in 2015, is receiving a lot of attention.
”The Twin Engine technology with both diesel and electric engines quickly proved popular. This is a little sibling, the concept is the same but with a little less horsepower”, says Magdalena Molin in Volvo Magazine 3/2015. Magdalena is vehicle program manager at Volvo and was involved in the development of the new model.
Super green car
With carbon dioxide emissions measured to 48 g/km according to New European Driving Cycle (NEDC), V60 D5 Twin Engine is classified as a “super green car”. In Sweden, this translates to a subsidy of 40,000 SEK per car for the purchase. ”This is Volvo’s third super green car, along with V60 D6 and XC90 T8 Twin Engine”, Magdalena Molin says.
”Many car-owners are satisfied with less horsepower, and the new model has a 2.4 liter diesel engine producing 163 horsepower, instead of the 220 HP of V60 D6. The electric motor, producing 68 horsepower, is the same in both models. The propulsion can be switched between different combinations of electric and diesel at the press of a button, and I think the smooth transition will give an aha moment to many. The performance of the engine is excellent and the reduced horsepower brings a tax relief in a few countries. The purchase price is also lower, compared to V60 D6”, Magdalena continues.
The driver selects the required driving mode via buttons that give the car entirely different temperaments: Pure, Hybrid or Power.
- In Pure mode, the car is powered solely by its electric motor as much as possible. The range is up to 50 kilometres.
- Hybrid is the standard setting whenever the car is started. The diesel engine and electric motor cooperate to achieve CO2 emissions (NEDC, mixed driving cycle for certification) of 48 g/km (1.8 l/100km).
- In Power mode, the technology is optimised to give the car the maximum possible power.
Battery improvements are what has revolutionized hybrid electric vehicles. Earlier batteries took up a lot of space, needed long time to charge, and did not last long. Volvo’s solution is custom-made batteries, providing the same amount of power but using less space. V60 D5 Twin Engine has a battery compartment under the floor cover of the trunk, which is raised 70 millimeters – the rest of the storage space is not affected. The battery can be charged in 4.5 hours from a regular 10 A outlet. If 16 A is available, charging time drops to 3.5 hours.
The driver can choose to save battery power in order to drive on pure electricity later on. When Save is activated, the on-board system ensures that there is always sufficient charge for driving later in Pure mode. If necessary, the high-tension generator will charge the battery pack so there is sufficient capacity for driving in Pure mode. It is also possible while recharging the car to heat or cool the passenger compartment to provide a more comfortable start to the journey. This also means that more battery power is available for actually propelling the car. The pre-conditioning function can also cool the batteries if necessary. Cooling prior to driving is very important in order to maximise battery charge and thus also range.
A two-stage braking system is yet another smart feature of the Volvo Twin Engine. When the driver presses the brake pedal, the system starts braking the rear axle’s electric motor. The mechanical brakes are activated only when the situation requires more braking power than the rear axle can provide. The braking energy can be used to recharge the battery.
The article was published in October 2015