Published on May 17th, 2018 | by Subhash Nair
Kia’s Planning a 48V Mild Hybrid Diesel Powertrain. Here’s How it Works
Kia Motors will introduce its first 48V diesel mild-hybrid powertrain in the second half of 2018. The new ‘EcoDynamics+’ powertrain reduces CO2 emissions by supplementing acceleration with electric power from an additional 48-volt battery and extending combustion engine ‘off time’ using a new Mild-Hybrid Starter-Generator unit.
In line with Kia’s aim to create innovative cars that are affordable for a broad range of buyers, EcoDynamics+ mild-hybrid technology offers a compelling cost-to-performance ratio compared to full hybrid powertrains. The compact nature of the components means the technology can be integrated into existing vehicle and powertrain architectures without impacting practicality or packaging. Kia’s mild-hybrid powertrain is designed to fit seamlessly into consumers’ lives, with no plug-in recharging required.
The Kia Sportage will be the first model to offer the new EcoDynamics+ diesel mild-hybrid powertrain later in 2018. The new third-generation Kia Ceed will be the second among a range of Kia models to offer the new powertrain from 2019.
Kia plans to launch 16 advanced powertrain vehicles by 2025, including five new hybrids, five plug-in hybrids, five battery-electric vehicles and – in 2020 – a new fuel-cell electric vehicle.
The EcoDynamics+ diesel mild-hybrid powertrain will enable Kia to offer cleaner diesel engines. The system is paired with Kia’s Selective Catalytic Reduction (SCR) active emissions control technology, reducing CO2 emissions by up to 4% on the new Worldwide harmonized Light vehicles Test Procedure (WLTP), and up to 7% on the New European Driving Cycle (NEDC). The roll-out of diesel mild-hybrid technology will contribute to the brand’s global efforts to improve whole-fleet fuel efficiency. Kia’s mild-hybrid technology features a compact 0.46 kWh 48-volt lithium-ion battery and a new Mild-Hybrid Starter-Generator (MHSG). By electronically controlling the MHSG using the inverter, the system switches seamlessly between two modes: ‘motor’ and ‘generator’. Connected by a belt to the diesel engine’s crankshaft, under acceleration the MHSG provides up to 10kW of electric power assistance to the powertrain in ‘motor’ mode, reducing engine load and emissions. In ‘generator’ mode, the system harvests kinetic energy from the vehicle during in-gear deceleration and braking and uses the power to recharge the batteries.
How EcoDynamics+ works on the road
The powertrain has been engineered to deliver greater efficiency from internal combustion engines on the road, by using electric power delivered and recuperated seamlessly.
In ‘motor’ mode the battery is discharged under acceleration, providing additional torque to the engine for a slight boost in performance under hard acceleration, or to reduce engine load during light acceleration. Under deceleration, or when driving downhill or towards a junction, the MHSG switches to ‘generator’ mode, recuperating energy from the crankshaft to recharge the battery on-the-go.
The system is controlled by an advanced Electronic Control Unit (ECU), which calculates the most efficient use of the available energy, and adjusts accordingly, taking into account the amount of charge remaining in the car’s batteries.
Battery power can also be used to provide a new ‘Moving Stop & Start’ function. If the battery has sufficient charge, the combustion engine turns off automatically during in-gear deceleration and braking. The MHSG can then seamlessly re-ignite the engine – in any situation – if the driver presses the throttle pedal.