By John Barlage, Director of Product Strategy, BorgWarner PowerDrive Systems

Recognizing the potential of mild hybridization in terms of fuel efficiency and performance, BorgWarner is developing innovative technologies for future vehicles in order to expand ist portfolio with advanced solutions for vehicles with 48V power supplies.

Hybridization gains ground

Figure 1: BorgWarner’s 48V eFan improves efficiency and fuel economy by adjusting its performance on demand.

In order to adapt to changing markets and a growing demand for hybrid systems featuring both an electric motor and a combustion engine, automakers rely on experienced suppliers and their solutions. As a global leader in clean and efficient technology Solutions for combustion, hybrid and electric vehicles, BorgWarner uses its extensive know-how to provide state-of-the-art 48V technologies for hybrid vehicles while also developing Systems for the complete range of hybrid architectures.

Changing requirements – future technologies

Equipping vehicles with 48V power supplies offers multiple benefits compared to traditional high-voltage power supplies. A key advantage of introducing 48V systems is cost-effectiveness, since mild hybridization provides up to 70% of the fuel efficiency and emissions benefits at only 30% of the cost of conventional high-voltage power supplies. Moreover, by utilizing the same type of 48V motor/generator unit in different applications and architectures, automakers are able to achieve rapid economy of scale. Multiple technologies such as BorgWarner’s 48V eFan, a sophisticated airflow solution, the eBooster® electrically driven compressor and the innovative one-way clutch (OWC) for electrified drivetrains already take advantage of These power supplies.

The 48V eFan (Figure 1) for SUVs and Commercial vehicles facilitates superior airflow and cooling performance even under rough conditions. It also features a highly developed electric motor design and a lightweight modular package and offers precise temperature control and quiet Operation through outstanding fan speed responsiveness. By adjusting its performance on demand and immediately responding to the engine’s cooling needs, BorgWarner’s innovative airflow technology saves energy and contributes to improved fuel efficiency.

Figure 2: BorgWarner’s eBooster® electrically driven compressor improves performance and fuel efficiency by taking advantage of the 48V power supply.

With regard to advanced turbocharging solutions, BorgWarner developed the 48V eBooster electrically driven compressor (Figure 2). It is independent of the exhaust gas flow and drives the compressor turbine with an electric motor, delivering excellent low-end engine torque and almost instant acceleration while enabling further downsizing and fuel economy enhanced by 5 to 10%. Moreover, BorgWarner’s advanced solution allows larger conventional turbochargers to be used to deliver increased power and efficiency at high engine speeds. The eBooster system thus leverages the full benefits of the 48V power supply for improved performance and fuel efficiency.

Due to the increasingly complex powertrain structures of hybrid electric vehicles, Transmission technologies also need to be developed further to allow optimal system integration. BorgWarner’s innovative OWC replaces the engine disconnect clutch and supports the whole spectrum of hybrid drive functionalities such as electric driving, boosting, load point shift, coasting, regenerative braking and recuperation. In addition, it improves clutch control and offers major packaging benefits.

Boosting hybridization

Figure 3: The Organic Rankine Cycle waste heat recovery system scavenges energy from the exhaust gas flow.

To further expand its portfolio of 48V technologies, BorgWarner is extensively developing several technologies that enable active energy recovery. The eTurbo™, for example, is an electrically assisted turbocharger able to either add power to the shaft for improved time-to-torque at low engine speeds or use its integrated electric machine as a Generator to recover energy from the exhaust gas flow. The eTurbocompound generator, on the other hand, recovers energy from the exhaust gas flow via a turbine generator. Besides providing cost-effective recovery of heat energy, the technology has minimal effects on engine operation and vehicle packaging. By contrast, the Organic Rankine Cycle (ORC) waste heat recovery System (Figure 3) uses a purely thermal approach by recovering heat energy from the vehicle’s exhaust flow and sending it back to the vehicle via a heat engine. In this way, the ORC can contribute to improved fuel economy by using the regenerated energy to assist the vehicle’s engine.

Figure 4: BorgWarner’s 48V eAWD provides all-wheel drive traction and stability along with an electric hybrid function.

In cooperation with vehicle manufacturers, BorgWarner is currently developing additional Solutions for a broad range of 48V hybrid architectures. These include the integrated Belt Alternator Starter (iBAS), the off-axis P2 module, the electric Rear Drive Module (eRDM) and the electric All-Wheel Drive (eAWD). Stop/start Systems such as BorgWarner’s iBAS, an alternator equipped with integrated power electronics, offer significant fuel economy advantages by shutting off the engine when the vehicle stops. The iBAS is designed to combine fast and quiet engine startup with high-efficiency energy generation, torque assist and regenerative braking. Additionally, BorgWarner is developing an off-axis module for P2-type hybrid systems that facilitates various hybrid functionalities including regenerative braking, boosting and pure electric driving. Achieving a more compact package compared to conventional on-axis modules through a chain-driven off-axis motor, this innovative solution is expected to enter production in 2021. On the other hand, BorgWarner’s eRDM is made for P3-type hybrid systems and provides excellent driving characteristics by combining electric torque vectoring with a full-function mechanical allwheel drive. Finally, BorgWarner’s 48V eAWD Technology (Figure 4) provides all-wheel drive traction and stability as well as electric hybrid functionality in a highly compact and robust package by driving the rear axle via an electric motor and a 2-speed transmission. Slated for series production after 2020, the system is near cost-neutral when compared to conventional AWD solutions while potentially reducing fuel consumption by up to 9%.

Recognizing the potential of 48V power supplies, BorgWarner is actively developing leading-edge technologies designed to take full advantage of the benefits of these systems.

Images: © BorgWarner

(Source: OEM&Supplier, Edition 2/2017)