Kia Motors Will Debut 48V Diesel Hybrid Powertrain This Year

Kia Motors Will Debut 48V Diesel Hybrid Powertrain This Year

Author: Eric Walz   

South Korean automaker Kia Motors will introduce its first 48V diesel hybrid powertrain later this year. Kia's new ‘EcoDynamics+' powertrain reduces emissions by supplementing the diesel engine with a electric-powered generator that is powered by a 48-volt battery.

The system uses a mild-hybrid starter/generator (MHSG) unit which replaces the standard alternator found in 12V vehicles. The starter generator is mounted to the engine via a belt, and provides quick starts—so the engine can remain off when the vehicle is stopped—thereby reducing emissions. The system will be available on the new Kia Sportage SUV.

EcoDynamics+ mild-hybrid technology offers a greater cost-to-performance ratio compared to full hybrid powertrains. The compact design means the technology can be integrated into many existing vehicle and powertrain architectures. Unlike a fully electric vehicle, Kia's mild-hybrid powertrain does not require plug-in recharging. The 48 volt generator recharges the vehicle's battery when the diesel engine is running.

The 48V mild-hybrid powertrain is the first new technology to be launched as part of Kia's wider powertrain electrification strategy. Kia Motors is the first manufacturer to offer consumers hybrid, plug-in hybrid, battery-electric and 48-volt technology across its model line-up.

The 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 four percent on the new Worldwide harmonized Light vehicles Test Procedure (WLTP), and up to seven per cent on the New European Driving Cycle (NEDC).


The 2018 Kia Sportage

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' or ‘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 collects kinetic energy from the vehicle during deceleration and braking and uses the power to recharge the batteries.

How Kia's EcoDynamics+ System Works

Kia's mild-hybrid powertrain has been engineered to deliver greater efficiency from internal combustion engines—either gas or diesel.

In ‘motor' mode the battery is discharged under acceleration, providing additional torque to the engine for a slight boost in performance under hard acceleration. The system also reduces engine load during normal to light acceleration. Under deceleration, or when driving downhill or coasting towards a stop light, the MHSG switches to ‘generator' mode, recuperating energy from the crankshaft to recharge the battery.

The system is controlled by an advanced Electronic Control Unit (ECU), which calculates the most efficient use of the available energy, and adjusts it 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 deceleration and braking. The MHSG can then quickly restart the engine the moment the driver presses the accelerator pedal.

The 48V battery DC/DC converter enables the battery to connect to the vehicle's on-board power supply, reducing the reliance on the vehicle's 12V battery required to power the vehicle's ancillary electronics. The adoption of the MHSG also means the conventional starter motor can be made smaller and lighter, reserved primarily for cold starts at extremely low temperatures. Charge from the 48V battery helps to start the engine in most conditions.

The system is compatible with both manual and automatic transmissions vehicles, and could be adapted for front or rear wheel drive, or all-wheel drivetrain configurations. Depending on vehicle, the 48V battery can be mounted beneath the trunk floor, freeing up interior space.

Kia will announce more detailed plans for the roll-out of its new mild-hybrid technology later this year. After the diesel mild hybrid's introduction, Kia will use the technology in a gasoline-powered vehicle.

The electrified models will be two of 16 new advanced-powertrain vehicles Kia will introduce by 2025, including a electric version of Kia's Niro SUV later this year.

Eric Walz
Eric Walz
Originally from New Jersey, Eric is an automotive and technology reporter specializing in the high-tech industry in Silicon Valley. Eric has over fifteen years of automotive experience and a B.A. in computer science. These skills, combined with technical writing and news reporting, allows him to fully understand and identify new and innovative technologies in the automotive industry and beyond. He has worked on self-driving cars and as a technical writer, helping people to understand and work with technology. Outside of work, Eric likes to travel to new places, play guitar, and explore the outdoors.
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