AUTOMOBILE ELECTRICAL SYSTEM

The automobile electrical system describes how the automobile vehicle generates, store and distributes electrical energy through distinct voltage system.

There are several automobile electrical systems and they are; 6 volts, 12volts, 24volts, 48 volts, 200-350 volts, 300-400 volts, 400 volts and 800 volts electrical system.

6 volts legacy system is a simple electrical system that can handle only a starter, motor horn and incandescent lights. Example of 6 volts system includes; pre 1955 ford and Chevrolet models, the early Volkswagen beetle, the Willys jeep MB military vehicle etc.

12 volts automobile electrical system became the universal automotive standard and this architecture remains dominant in all conventional petrol and diesel vehicles today. The architecture supports a single lead acid battery, belt driven alternator to power every load from ECUs to infotainment. Virtually every popular mass produced ICE vehicle falls into this category. Example of 12 volts automobile system includes; Toyota corolla, ford focus, Honda civic, VW Golf etc.

24 volts automobile electrical system, use two 12 volts batteries in series and are standard for trucks, buses, military vehicles and heavy construction equipment. The higher voltage halves the current for the same power output, enabling lighter wiring on large vehicles with demanding electrical loads. Example of 24 volts automobile system includes; Volvo FH16, Mercedes Actros, Scania R-series and military vehicles built to NATO STANAG standards etc.

48 volts automobile electrical system pair a conventional 12 volts body network with a 48 volts network powering a belt integrated starter generator (BSG). The BSG harvest braking energy, enables silent engine restart in start-stop systems, thus delivering 10-15% fuel savings without the complexity of a full hybrid. Example of a 48 volts automobile electrical system includes; Mercedes E-300, BMW 5 series with the B57 engine, Renault Clio Etech, Suzuki swift 48 volts etc.

200-350 volts automobile electrical systems are used predominately in full hybrid systems (HEV). At 200-350 volts, full hybrid systems (HEV) add a high-voltage motor generator that can propel the vehicle on electricity alone at low speeds, self-charging from the engine and regenerative braking without any plug in requirement. Example of a 200-350 volts automobile electrical system includes; Toyota Prius (201.6V), Toyota Camry hybrid, Honda CR-V e. HEV (305V), Lexus UX 250h etc.

300-400 volts automobile electrical systems are used mostly in plug in hybrid systems (PHEV). At 300-400 volts they extended the full hybrid concept with a larger battery and external charging port, enabling 40-60 km of pure electric driving before the ICE takes over. Example of 300-400 volts automobile electrical system includes; Mitsubishi outlander PHEV, BMW 330e, Volkswagen golf GTE, Mercedes GLC 300e etc.

400 volts automobile electrical system ( for battery electric systems) power main stream BEVs with large lithium-ion packs (40-100+Kwh) driving permanent magnet motors through silicon carbide inverters. This is the dominant EV architecture globally. Example of 400 volts automobile electrical system includes; Telsa mode 3 and model Y, Volkswagen ID.4 (MEB platform), Chevrolet equinox EV, ford mustang MACH-E etc.

800 volts automobile electrical system enables ultra-fast charging at 350 Kw or more, adding 100km of range in less than five minutes. The halved current at double the voltage also allows thinner, lighter high voltage cabling throughout the vehicle. Example of 800 volts automobile electrical system includes; Hyundai ioniq 6, kia EVQ, audi e-tron GT, lucid air etc.

The advantages of automobile electrical system are; it provides for superior vehicular performance and energy efficiency. It enables prompt precision electronic control of the automobile vital systems. It provides for reduced mechanical complexity by replacing mechanical systems with less complex electrical/electronic system. ABS, ESC and autonomous braking will br impossible without a viable electrical architecture. Electrical systems in general ensures for smooth, quiet vehicle operation. Electrical systems are usually less difficult, complex and expensive to operate and maintain.

The disadvantages of automobile electrical system are; electrical/electronic systems are prone to spontaneous fire hazards and cyber security vulnerabilities, especially with fully electric vehicles. Electrical/electronic systems contribute above 30% of the purchase cost of a vehicle. Electrical systems in automobile vehicle, because of their complexity require expertly trained electrical/electronic technicians to diagnose problems or faults and rectify them. Electrical/electronic systems can be affected by adverse weather conditions.

The application of automobile electrical system is as follows; they provide power in propulsion and drive system of an automobile. They are responsible for starting and ignition of engines. They are indispensible in automobile safety systems such as ABS, ESC, airbag, ADAS, EPAs,electric power steering systems etc.  They facilitate energy management system function such as alternator and voltage regulation, battery systems etc. they provide power for comfort and climate control in the vehicle such as electric A/C compressors, heat pumps, body electronics etc. they provide power and control for vehicular navigation (GPS), audio and multimedia, smartphones integration etc. they provide power and control for lighting both external and internal. They also provide power for powertrain control, engine control, transmission control, adaptive suspension control, connectivity and telematics systems etc.

The future of automobile electrical systems is based on the advances and development of the following technologies; electrical vehicles, offering improved safety, range and charging speeds. Software defined vehicles, with over the air updates and advanced driver assistance systems (ADAS) being standard. Autonomous vehicles becoming increasing connected, with 5G and V2X (vehicle to everything) communications. Other future advances expected are wireless charging, vehicle to grid (V2G), advanced materials and technologies like solid state batteries and advanced semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) based semiconductors.

 

SOURCES:

• Automobile electrical and electronic system by James D. Halderman.
• Electrical hybrid vehicles by Tom Denton.
• Automotive technology: A system approach by Jack Erjavec and Bob Thompson.
• Automotive electronics and computer systems by William B. Rubbens.
• Electric vehicles: Technology and applications by T. Markvart and L. Castaner.