Stealing a move from the hybrid playbook, Volvo will present three cars at the Geneva auto show that improves fuel efficiency by turning the engine off when the car is at a standstill.
The European DRIVe versions of the C30, S40, and V50 are equipped with 1.6-liter diesel engines, paired with manual transmissions, and feature Volvo's Start/Stop system. When a driver puts the car in neutral while stopped and releases the clutch, the engine automatically turns off. The engine automatically restarts the next time the driver presses the clutch. The Start/Stop technology reduces fuel consumption by 4 percent to 5 percent in mixed driving conditions, and as much as 8 percent in urban traffic.
It's a simple enough concept and can be achieved by turning the engine off at any stop (you may have seen your grandparents or cab drivers doing this in traffic), but one of the challenges is maintaining the electrical systems without draining the battery. When the engine is off, Volvo sets the HVAC on standby mode to save fuel. However, a monitoring system constantly checks the temperature, and if it dips above or below a comfort setting, a second smaller battery reactivates the HVAC. In another hybrid similarity, both batteries are charged using kinetic energy rather than fuel, which provides an additional 2 percent to 3 percent fuel savings.
However, don't expect to see this technology from Volvo stateside anytime soon. Because Start/Stop is tied to diesel engines--which do not pass California's stricter emissions standards--with manual transmissions (not a huge seller in the States), it doesn't make a lot of business sense. Plans are in the works for Volvo to improve the fuel efficiency of their automatic transmissions by 5 percent to 7 percent in the next two years, so maybe the next round of advancements will jump the pond.