BMW Concept 7-Series ActiveHybrid

BMW is back with another rendition of its ActiveHybrid system—this time in its flagship 7-series—with the world debut of the BMW Concept 7-series ActiveHybrid in October at the 2008 Paris auto show.

The automaker pairs the car’s twin-turbo, direction-injection, 4.4-liter V-8 engine with an electric drive for what is known as a mild hybrid—meaning the car cannot operate on electricity alone. Rather, the electric motors reduce fuel consumption and emissions—BMW claims by 15 percent—through such means as an automatic start-stop function that turns the vehicle off when it otherwise would be idling.

The idea is to make the car more efficient without compromising performance. The conventional version of the new 2009 7-series with the V-8 offers 400 hp and 450 lb-ft of torque and BMW says that is not diminished—in fact, the 20-hp electric motor will boost acceleration. Combining the two powertrains should produce about 415 hp and 605 lb-ft of torque, we are told. Channeling the power is an eight-speed automatic transmission.

Energy captured in brake regeneration will be used to power many of the car’s features, leaving the fuel free to make the car go fast. BMW says enough energy can be stored to power substantially more electric components than in past vehicles—which seemingly makes it possible for an endless list of creature comforts. The energy is stored in lithium-ion batteries that are located in a trough in the trunk.

Why is proper tires inflation important?

Proper tire inflation is essential for safe and efficient vehicle operation. Safety experts estimate that 25 percent of passenger vehicles are operated with tires that are under inflated. Vehicles with properly inflated tires experience optimum ride and handling characteristics, shorter braking distances, longer tire life, and improved fuel economy.

Many factors affect tire pressure including ambient temperature changes and tire damage such as punctures. Tire pressure drops about 1 psi for every 10 degrees F drop in ambient temperature. Additionally, tires lose as much as 1.5 psi per month as air escapes the tire and rim naturally.

Under inflated tires are visually difficult to detect. It is recommended that tires are inspected and checked monthly with an accurate gauge. The TPMS is not intended to be a substitute for regular tire maintenance. Drivers should consult the owner’s manual for information on replacement tires and use of the spare tire.

Vehicles with properly inflated tires consume less fuel, have longer tire life, and emit less carbon dioxide than vehicles with under inflated tires.