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Series production of Tevva’s truck began earlier this year at the company's London facility. (Tevva)

Tevva & ZF integrate brake-by-wire regen system for last mile BEV

Tevva’s integration of ZF’s brake system enables up to180 kW of regen for extended driving range.

UK-based EV manufacturer Tevva recently completed development of a regenerative braking system on the company’s 7.5-ton battery-electric truck. Tevva collaborated with ZF to adapt its Electronic Brake System (EBS) for use in the truck. The system reportedly utilizes a blend of regenerative and compressed-air brakes to provide a high level of safety and responsiveness for drivers.

"Our broad product portfolio, including ZF's standardized Electronic Braking System, enables faster time-to-market for new, innovative market players such as Tevva,” said Heiko Eggers, head of commercial vehicle EMEA application engineering for braking and ADAS for ZF. “Their commitment and agile engineering expertise allowed us to meet our stringent safety requirements and complete our project. We look forward to seeing the first Tevva trucks on the road."

Tireless testing
Tevva said its engineers successfully met a strict range of testing criteria for the company's truck to receive ZF's seal of approval. Development included fine-tuning the truck’s vehicle control unit (VCU) and maximizing compatibility with ZF’s EBS. Testing of the system took place at ZF’s facility in Jeversen, Germany and reportedly involved a variety of conditions, grades and surfaces.

Tevva's Uzair Jilani, lead engineer, drive and brake systems, said in a statement "We have worked hard to secure a ringing endorsement from arguably one of the world's most significant Tier 1 suppliers. Working with ZF is a crucial step in the momentum we are building as a truck manufacturer. The system has been adapted for use with our regen system; when the brake pedal is pushed, most of the 'braking' is handled by regen, meaning that the drive system slows the vehicle down.”

Jilani continued, “The conventional braking system is still needed to bring the truck to a complete stop, but this double layer of safety is an excellent aid to more efficient driving. It also means that the hardware undergoes less strain to extend the braking system's life in the long run."

Focused friction
According to Tevva, the result of this integration is a system that recaptures up to four times more energy than conventional compressed-air braking, thus optimizing the total range of range of the Tevva truck. The regenerative braking system is reportedly capable of up to 180 kW of regen, compared to traditional air-brake systems that usually hover around 40 kW of maximum regen.

Modern EBS systems can control and blend friction braking with an electric motor, which reduces overall brake wear. The system transfers the driver's deceleration request electronically to all braking components to shorten response time, balance braking forces and provide ease of braking and efficient brake management.

Tevva claims a maximum driving range of up to 140 miles (227 kilometers) from a 105-kWh battery on a full charge. The company’s truck is intended for use as a last-mile and urban-delivery vehicle. Series production of the truck began earlier this year at the company's London facility.

Scalable system
ZF’s first EBS, or brake-by-wire, system was developed in the 1990s and there are more than four million units sold and on the road to date, according to company sources. The system functions by transmitting electronic pressure commands from ECU to pressure modulators that facilitate a sensitive dosage of the applied air pressure according to a wide range of vehicle information such as axle load status, vehicle speed and vehicle mass, and trailer brake-system information.

ZF also states that the system balances brake forces between axles of a truck-trailer combination during braking and provides efficient brake management between service and endurance brakes. The system is principally based on two pneumatic and one electronic circuit for highly reliable braking performance.

The design reportedly meets current regulatory requirements for braking systems (ECE R13) and is a standardized modular arrangement that can seamlessly incorporate with various OEM systems. ZF’s EBS also features scalable software for a wide range of upgrade options and has integrated diagnostic functionality to constantly monitor system performance.

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