Audi Unveils MHEV Plus Technology in A5 and Q5 Series

Audi’s A5 and Q5 series now feature MHEV Plus technology, improving performance, reducing emissions, and enabling partial electric driving with efficient energy recovery.

Ingolstadt, Germany- Audi AG., has unveiled its new A5 and Q5 series, built on the Premium Platform Combustion (PPC), featuring the groundbreaking MHEV Plus technology. This advanced 48-volt mild hybrid system seamlessly integrates a powertrain generator (PTG), belt alternator starter (BAS), and a lithium iron phosphate battery to enhance performance, reduce carbon emissions, and improve agility. The PTG, equipped with integrated power electronics and an electric motor, offers the ability to fully couple or decouple from the drivetrain, enabling partial electric driving. This innovative design not only lowers fuel consumption but also ensures a smoother, more refined driving experience.

“With MHEV Plus technology, we are advancing electrification in our combustion-engine vehicles on the Premium Platform Combustion, tailored to customer needs,” says Mr. Geoffrey Bouquot, Audi's Board Member for Technical Development. This system, debuting in the A5 and Q5, integrates a powertrain generator (PTG), 48-volt battery, and belt alternator starter (BAS). Liquid cooling ensures optimal performance, while the architecture supports front and quattro drivetrains. MHEV Plus enables partially electric driving, boosting efficiency, comfort, and agility, reducing fuel consumption and CO2 emissions, and offering purely electric operation in specific scenarios.

Audi’s MHEV Plus system enhances performance and comfort with its compact PTG, delivering up to 18 kW (24 PS) and 230 Nm of torque. Positioned behind the gearbox, it supports speeds up to 140 km/h and minimizes power losses for both front- and all-wheel drive. Liquid cooling ensures optimal operation from -40 to +75°C. Offering emission-free coasting, electric driving for low speeds, and improved agility, MHEV Plus meets modern electrification demands with advanced efficiency and responsiveness.

Operating between 0–140 km/h, the PTG offers up to 18 kW of additional power and can recover up to 25 kW through regenerative braking, minimizing friction brake usage. An electric air-conditioning compressor ensures consistent cooling even when the combustion engine is off, enhancing comfort during stops.

In Audi’s MHEV Plus system, the belt alternator starter (BAS) starts the engine, charges the battery, and improves starting comfort with quieter operation and higher starting speeds. It also recovers energy and optimally positions the cylinders for restarting.

The lithium iron phosphate (LFP) battery, Audi’s first in a mild hybrid system, offers 37 Ah capacity (1.7 kWh gross) and 24 kW discharge power. Integrated into a low-temperature cooling circuit, it operates efficiently between 25–60°C.

The integrated brake control system (iBRS) maximizes energy recovery with regenerative braking, achieving deceleration without mechanical brakes, which engage only under stronger braking, maintaining a consistent brake feel.

Audi’s MHEV Plus system optimizes efficiency and performance with a 48-volt battery cycling between 50-60% charge for rapid energy recovery and propulsion. Control software adjusts the PTG, BAS, and combustion engine based on driving mode and conditions. Mode D prioritizes efficiency, with a 50-55% SoC target and PTG decoupling at higher speeds, while mode S focuses on sportiness with a 70% SoC target and constant PTG engagement. The system supports pure electric driving at low speeds and dynamically balances energy use, enhancing range, comfort, and suitability for long-distance travel.