Into the future with 48V:
Can new on-board electrics make powertrains smarter and more efficient?
When Henry Ford introduced his legendary Model T …
… the on-board electrics were still rudimentary: all the 6-volt battery did was support the ignition when starting. There was a starter handle, not a starter motor, and the headlights were acetylene lamps. By contrast, the 12V systems in modern automobiles have a wide range of electric ’consumers’ to feed, and engineers have been calling for a more performant system for years. Currently, the chances of a new 48V system asserting itself are stronger than ever.
As numerous talks and papers at the 10th CTI Symposium 2016 in the USA showed, almost all automobile manufacturers and suppliers have identified the need. And thanks to hybridization, they already have solutions ready to enter serial production in 2017.
Experts say 48V Mild Hybrids have the edge
One thing seems certain: the only way to meet ever-stricter CO2 targets like the ones set for Europe, the USA and China is through stepwise powertrain electrification. In the mild hybrids that experts favour, the internal combustion engine (ICE) still does most of the work. However, it’s assisted by an electric motor that uses recuperation, boosting and all-electric drive to reduce CO2 emissions.
In a way, a 48V second electrical system offers the best of both worlds. The voltage is four times higher than with a 12V battery, and it provides significantly more power. That means electric aggregates work more efficiently, and can be made more compact. It also permits sophisticated solutions such as start/stop coasting or electric torque vectoring – both formerly reserved for high voltage hybrids.
And all at affordable prices well below the costs incurred by complex high voltage technology. Contact protection, for example, is not required. The system is relatively easy to install in conventional-drive automobiles. At steady or low speeds, the electric motor can take over completely for trips with zero local CO2 emissions.
Intelligent Start/Stop Coasting: Standstill is progress!
An ICE that isn’t running uses no fuel, and emits no CO2. At the 10th CTI Symposium 2016 in the USA, Continental presented its 2nd-generation Gasoline Technology Car (GTCII), which takes that insight to extremes. At the heart of its 48V hybridization is a belt-drive starter generator, placed between the ICE and the transmission for higher efficiency. This ‘P2’ position enables the ICE to decouple completely from the drive train, and also permits the electric motor to run independently.
The moment you take your foot off the accelerator, the ICE shuts down. It also decouples from the drive train, eliminating energy loss from engine drag. Since the electric motor also decouples, the vehicle basically freewheels when in ’start/stop coasting’ mode, and can coast briefly in traffic without a single engine shaft having to rotate.
In ’sailing’ mode, the electric motor engages first to maintain road speed. Touching the brake pedal prompts recuperation. The electric motor functions as a generator, which provides a ’smart’ braking effect. Recovered energy is fed into the system and stored in the compact Li-on battery – and the brakes stay cold throughout. The ICE only restarts when you accelerate; thanks to the 48V electrics, ignition is smooth and extremely fast (<0.2 seconds). Altogether, the GTC II’s internal combustion engine can stay off almost a third of the time. That means fuel savings of more than 25% compared to the reference vehicle (NEDC).
Next-level efficiency in torque vectoring too
At this year’s CTI Symposium USA, BorgWarner showed an innovative torque vectoring system that offered further proof of 48V Hybrid technology’s potential.
An electric motor on the rear axle shares torque dynamically between the two wheels, based on their current needs and taking factors such as yaw rate, wheel velocities, steering angle or accelerator position into account. The result: first-class driving dynamics and driving stability. Besides torque vectoring mode, there is also a hybrid mode that offers the benefits of recuperation and boosting. As a result, higher performance and lower CO2 emissions go hand-in-hand here too. Again, implementation is decidedly affordable because the solution foregoes costly high voltage technology.
Welcome to Shanghai!
China remains the most exciting growth market for the automobile sector. This year marks a modest anniversary for CTI Symposium China in Shanghai (21 – 23 September 2016): it will be the fifth time respected experts and top decision-makers from around the world meet up to get the facts, discuss developments and connect.
Once again, this year’s CTI Symposium China will be the ideal platform for people to share insights and ideas on 48V Hybrid technology – and a wealth of other interesting topics too. What specific wishes do Chinese automobile customers have? What mistakes should you definitely avoid when dealing with Chinese business partners? At the 5th International CTI Symposium China, participants can find answers to these questions too. Like in 2015 numerous speakers and guests who are at home in the Chinese market will attend.