News of February
BMW Group presents first car with gasoline fuel cell for on-board electricity supply
Delphi Automotives and the BMW Group present the first prototype with a gasoline fuel cell for on board electrical supply
Munich, Germany - After less than two years development time, the BMW Group presents the first car in the world whose on-board electrical power is supplied by a gasoline operated fuel cell (SOFC). The new type of fuel cell battery can be used in every conventionally operated automobile, reduces fuel consumption and permits a whole range of new safety and comfort functions. The energy system, which was developed together with Delphi Automotive, will be featured in coming BMW model generations as the so-called APU (Auxiliary Power Unit). The BMW Group is the world's leader in the development of fuel cell APUs for on-board power supply. Several of the small-series-production, hydrogen-powered 750hL models are already equipped with such a fuel cell APU featuring PEM (Polymer-Electrolyte-Membrane) technology.
SOFC fuel cell: effective, robust and reasonably priced
The new fuel cell is a so-called "Solid Oxide Fuel Cell", SOFC in short. In this solid fuel cell, hydrogen is converted into electricity at approx. 800° C via zirconium oxide ceramics. In a start and a main reformer, gasoline is evaporated and hydrogen is split off also at 800° C operating temperature. The hydrogen then reacts with the oxygen from the air, which is supplied by a fan. In the process electricity is generated and water is produced as a by-product. Non-reacted residual gas is combusted. The heat produced in this way serves to heat the air required for the reaction and the reformer, which improves overall efficiency even further.
It is not only this short process chain which makes the SOFC cell so ideally suited for operation in conventionally powered gasoline cars. Compared to the currently generally favored PEM fuel cell (polymer electrolyte membrane) the SOFC is also a lot less sensitive to impurities which are produced in a gasoline reforming process since CO can also be converted into electricity and not only hydrogen. In addition, it does not require expensive precious metal electrodes. Efficiency has been doubled compared to conventional concepts.
The task of the SOFC fuel cell unit for BMW passenger cars is to supply the vehicle electrical system with electrical energy. This "electrochemical powerplant" is to take over the function it does best: to generate electricity with a high degree of efficiency - independent of the engine. The conversion of gasoline into electricity via SOFC fuel cell is almost twice as efficient as the combination of engine, alternator and battery. For driving the car itself, the view held by BMW is that the internal combustion engine offers more benefits.
The autonomous operation of the fuel cell APU makes possible new functions: windows can be defrosted before getting in the car, seats and steering wheel can be warmed. In high outside temperatures the air conditioning can be operated optimally regardless of the engine speed. Air conditioning the car with the engine off can already be carried out using a quarter of the energy required today. With today's level of electrical consumption in a vehicle, approximately one liter per 100 kilometers of fuel can be saved in city traffic. Future "by wire" systems such as electrically operated steering or brakes require far more electrical energy which can then be efficiently provided by the SOFC fuel cell.
The use of Internet and online services in the car and the "mobile office" are facilitated considerably by fuel cell APU technology. The APU developed by BMW is ideally suited for the new 2-voltage electrical system. Existing APU vehicles not only supply the conventional 12 V system, but also the newly developed air conditioning system with 42 volts.
APU to be available in a few years: customer benefit with no compromises
The BMW Group wants to offer the fuel cell APU and the benefits involved in approx. five years. This means that BMW customers will be the first to benefit from specific advantages of fuel cell technology without any compromises involved. The aim of series development, which has already begun, is to reduce the size and optimize the overall system even further. Output will be approximately five kilowatts for which the reformer is already designed today. The compact fuel cell battery will only require approx. the space of a conventional lead battery in the future. However, the fuel cell surpasses the power and "endurance" of the lead battery by far. In the long term the fuel cell might even substitute the electric generator in the car. With the APU, a new era will begin for the automobile whose electrical power needs are ever-increasing.
(Feb. 16, 2001)