Volkswagen Mild Hybrid Technology: First Drive

The world’s automobile manufacturers are moving towards lower emission values every year with the help of electric, hybrid or plug-in hybrid technologies. Along with these additional power trains and alternative fuels, there is a growing demand globally for technology that can aide the basic internal combustion engine to perform better than ever before. In Europe for instance, where most travel time is spent on motorways, autostradas and autobahns, there is a lot of potential to save fuel and cut down on CO2 emissions, especially while cruising at higher speeds.

Although there are existing technologies that help shut off a few cylinders depending on throttle pedal position, Volkswagen has gone one step ahead and will soon introduced a system called the Mild Hybrid. Essentially, the Mild Hybrid is an advanced version of the Stop-Start technology that we have become so used to in recent years. However, where traditional Stop-Start technology works when the car comes to a complete stop, the Mild Hybrid technology works at any speed when it detects the driver’s foot off the throttle for a certain pre-stipulated amount of time.

This can be extremely useful in cases where the driver is coasting down an incline or has lifted off the throttle in anticipation of a stop. Shutting the engine off results in both zero emissions and fuel saving. In this case, a message, ‘Coasting’ appears on the multifunction display along with the symbol for the active ‘Stop-Start’ system. This coasting with engine-off function essentially extends the availability of the Stop-Start system to any driving speeds.

We did get the chance to test the function at Volkswagen’s legendary Ehra Lessien test facility and although the Mild Hybrid does feel slightly weird at first try, the system eventually does grow on you. This system also differentiates itself from current Stop-Start systems with one big difference. In today's Stop-Start systems, the engine must first reach zero revs before it can be restarted. However, in the Volkswagen Mild Hybrid, the engine can be restarted at any engine speed with the aid of an electric oil pump. So, this system can conveniently handle situations such as when the driver releases the accelerator pedal, but then suddenly presses it again, say to get through an intersection while the traffic light is still orange. An electric oil pump that feeds the engine and the DSG also ensures that the gearbox can still shift while the combustion engine is deactivated, so that the proper gear ratio is immediately available at restart.

Get latest updates on
the automobile community

Login Now

In addition, the system also uses regenerative braking to recover energy that is then stored in a lightweight lithium-ion battery. The recovered energy is then used in the Mild Hybrid system to supply the car with electrical energy when the engine is shut off and also more importantly to restart the engine. On the whole, expect to see this technology in the next generation Volkswagen Passat very soon with the likes of the high powered 2-litre twin turbo diesel engines. Along with lower CO2 and particulate emissions, Volkswagen engineers also claim that the system will save upto 20 percent of fuel, which for a mileage sensitive country like India is good news.