Many of today's vehicles and their internal combustion engines are facing a transformation as the implementation of emissions regulations force automakers to seek effective ways to reduce their vehicles' carbon emissions.

Equipped with advanced safety features, a concert-hall-like sound system, heated seats, and headlights that steer to illuminate dark curves, they've become the high-tech marvels of the automotive industry.

Many of the wonders of these technologies rely on and consume vehicle electrical energy.

"A 12-volt electrical system can deliver about 300 amps, and about 600 amps at peak, barely enough to power the traction motors and braking systems, let alone power modern infotainment systems and semi-autonomous safety. The energy load required for the function is now available," says Karl-Heinz Steinmetz, who heads the company's Hybrid, Electric Vehicle and Powertrain Systems Engineering team: "This requires a transformative step."

This disruptive change is the 48-volt electrical system. This advancement in automotive power-drive architecture meets the higher power demands of today's energy-intensive vehicles. The increased power also allows the internal combustion engine to run more efficiently, helping manufacturers meet emissions regulations faster.

Many manufacturers in the industry have embraced this change. Manufacturers of various car brands are launching mild hybrid vehicles with start-stop technology. The technology allows the engine to be temporarily shut down when the car is coasting, braking or stopped, then quickly restarted, partly powered by the new system. Low-end mild-hybrid automakers will follow suit this year with the technology. Unlike traditional hybrids, the electric motors in mild hybrids (also called battery-assisted hybrids) are used to supplement the internal combustion engine and do not power the car alone.

In addition to reducing harmful exhaust emissions and improving fuel economy, the power increase enabled by the 48-volt electrical system also addresses the growing consumer demand for vehicles with high-tech infotainment, convenience and driver-assistance safety features. Some 48-volt electrical system manufacturers claim fuel savings of up to 20 percent. (1) By 2025, carbon dioxide emissions can be reduced by 30%. (2)

Through innovations in these systems, automakers can meet tougher global fuel economy and emissions standards for a world with cleaner air and safer roads without compromising power, performance and driving safety.

Conventional 12-volt electrical systems use conventional lead-acid batteries and alternators to power an ever-increasing variety of energy-consuming functions, such as interior and exterior lighting, semi-autonomous collision avoidance and lane-shift safety features, and software that provides in-vehicle audio and video. hardware.

A 48-volt system can handle more of these power loads. The energy required to drive the turbocharger, air conditioning compressor, active suspension system, coolant pump, oil pump and power steering pump in modern vehicles is provided by the electrical system rather than the crankshaft pulley and the power steering pump that used to power the internal combustion engine. Belt drive provided.

By transitioning from an engine-driven system that previously produced carbon dioxide to a system driven by 48-volt electrical system current, a smaller size engine can be used.

"This allows you to downsize the internal combustion engine, reducing the size of a six-cylinder car to a four-cylinder car, increasing fuel efficiency and reducing CO2 emissions," Karl-Heinz said.

On a technical level, the structural changes required to switch from 12 volts to 48 volts are not that large, but even with the addition of higher voltage systems, automakers are working to ensure that this adjustment remains resilient over the long term. In a 48-volt system, the power from the engine is converted by a generator instead of the alternator used in the 12-volt system. In addition, a 48-volt high-capacity lithium-based battery and a regenerative braking system are required. Through regenerative braking or recovery braking, the generator converts the kinetic energy lost when the car decelerates into electricity, which is stored in a high-capacity 48-volt battery.

Karl-Heinz said: "With regenerative braking, when the driver goes from stopping to accelerating at a traffic light, the stored energy is used to propel the vehicle forward, resulting in a higher speed than normal. Some 48-volt electrical systems also shut down the engine when the vehicle is coasting or parked, improving fuel efficiency and reducing emissions."

The car's HVAC system will also benefit from it. Karl-Heinz said many drivers complained that the HVAC system would lose power when a car with a 12-volt system was stopped.

He said that doesn't happen with a car with a 48-volt system, and the stored energy is readily available to defrost the windows and heat the seats faster.

More and more manufacturers are using new infrared heating panels to heat the passengers directly without wasting electricity to heat the rest of the car. It's akin to putting an extra layer of clothing on for passengers to keep warm, rather than turning up the thermostat.

Karl-Heinz said: "The challenge with infrared heating panels is that each seat requires about 500 watts of power, which puts a lot of stress on the 12-volt electrical system. That's not the case with a 48-volt system."

Core systems of the car of the future

For vehicles with high levels of autonomy and driver assistance features, today's 12-volt electrical systems are nowhere near the energy needed by onboard computers to analyze and process sensor and camera data.

“Each on-board computer is expected to consume about one kilowatt to two kilowatts of electricity, which would drain the power of a 12-volt system,” Karl-Heinz said. Whether the autonomous vehicle of the future is a hybrid or a pure electric vehicle, They all require a 48-volt system to handle energy-intensive loads. "

Many automakers are converting systems such as starters and generators, DC/DC converters and battery management, and body electronics such as HVAC compressors, positive temperature coefficient heaters and junction boxes to 48-volt systems. In addition, advances in on-board charging efficiency and power density, precision current sensing, wireless battery management system technology, and isolation and power management of gallium nitride are helping to reduce vehicle weight and reduce the power required to drive automotive conditions. (Go to @TI official)