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BMW has outlined a series of fuel-saving technologies which will appear in its production cars in the near future. The company says that "progress must not be limited to small niches in a manufacturer's model range", and that reducing fuel consumption, even if by only a few percent, across the line-up will have the most far-reaching benefits.
Showcase for BMW's efforts, however, was the X3-based Active Hybrid, which combines a converter-free automatic transmission system with an electrical power unit and high-performance capacitors ("supercaps") for extra acceleration boosts. This is claimed to reduce fuel consumption and emissions by up to 20percent, as well as enhancing performance - the prototype could potentially achieve 146mph and acceleration 0-60mph in 6.7 seconds, with up to 442lb ft of torque on tap. The supercaps are compact and easy to install, as is the Active Transmission system.
To feature in otherwise conventional powertrains, BMW's High Precision Injection system is claimed to be "the world's first direct-injection system offering significant benefits in fuel economy under regular driving conditions." HPI is said to save up to 10percent of fuel in test procedures, and between five and 15percent under typical customer driving conditions, over and above the economy already achieved by the Valvetronic petrol engines. It uses ceramic piezo-injectors rather than solenoids, which are repositioned between the valves and the spark plugs. The system is also known as jet-guided injection, as the fuel/air mixture ignites right by the injection jet, which controls the injection of fuel itself rather than creating a mix in a swirl. A lean fuel-air mix can thus power the engine all the way up the rev range without compromising output or performance. It will be available in Europe within a couple of years, and in other markets once supply of sulphur-free petrol is assured.
BMW is also looking at using technogies usually seen in hybrid petrol-electric vehicles in combination with conventional powertrains. Brake Energy Regeneration recaptures energy lost under deceleration and feeds it back into the battery, relieving pressure on the alternator and providing power for auxilliary functions such as air conditioning, meaning that full engine power can be focussed on acceleration or performance. The Auto Start/Stop system is just as it sounds: automatic switch-off of the engine when idling, and re-starting again when the clutch or throttle is pressed.
BMW also stressed its continuing development of hydrogen-powered vehicles - which it has been studying since 1978. Board member Professor Burkhard Goschel said that "we will be offering customers a hydrogen car within the next three years able to run not only on hydrogen but also on gasoline" - a new type of bi-fuel model, based on the 7-Series saloon. Further into the future, BMW is working on an Auxiliary Power Unit fuel cell, which can generate its own electricity on-board to power functions such as the air conditioning or heating; "it is fair to assume that the APU will be ready for use in the next generation of hydrogen cars", it says.