The paper focuses and develops issues raised by the SAE paper ‘THE FUTURE OF VEHICLE ELECTRICAL POWER SYSTEMS AND THEIR IMPACT ON SYSTEM DESIGN’ [1] and describes the realisation of a vehicle with a 12 V architecture of flexible configuration and a power management function.
The paper describes the methodology, reasoning and mission behind the creation of the vehicle, developed after collaborative exercises in Europe and the USA, and resulting in a joint programme involving a major vehicle manufacturer and a European system supplier.
The electrical system is becoming the focus of activity world-wide due to rapid changes in vehicle requirements, in the areas of safety, environmental and functional demands.
There are opportunities for:-
- (a)
Improved starting
- (b)
Integrated management of power generation and demand.
- (c)
Higher system integrity
- (d)
Higher efficiency
- (e)
Improvement of the vehicle electrical environment, giving benefits in component cost.
These areas have formed the main objectives for the programme. The emphasis of the discussion will be on the development of the existing 12 V vehicle systems. The focus of the programme will be the needs and requirements as seen today and for the foreseeable future, together with the possible functions of a Power Manager System (PMS).
The outline workplan for the vehicle is described and proposals for further development are discussed, including the use of simulation in the analysis of existing systems and in the evaluation of promising alternatives.
The important message from the paper is that an integrated vehicle systems approach to the management of electrical power on the vehicle is essential, together with understanding the complex interactions between the electrical power supply and the rest of the vehicle, whilst recognising the practical constraints and risk involved in making wholesale changes.
Twelve volts will be here to stay for sometime yet; it will need to be considered in a more systematic manner.