Braking for the Climate

When it comes to reducing greenhouse gases, the EU is putting the pedal to the metal – and threatening to run over the automotive industry. The first European CO₂ emissions standards for trucks and other heavy-duty commercial vehicles call for a reduction in CO₂ emissions from new trucks by an average of 15 % by 2025 and as much as 30 % by 2030. These ambitious targets come with draconian fines – the “excess emissions penalty” of 4,250 to 6,800 euros per gram of CO₂ per ton-kilometer could potentially jeopardize the viability of even large commercial vehicle manufacturers, as the German Association of the Automotive Industry has already warned.

The industry is caught in a dilemma. The EU emission targets can only be achieved through significant additional reductions in fuel consumption. Because fuel is one of the main cost factors in the logistics sector, it has long been included on the specs sheet anyway. This means that great leaps are highly unlikely. As such, manufacturers have no choice but to think beyond the diesel engine and include alternative drive systems in their planning, as well as components that play a role in increasing efficiency and therefore reducing CO₂ emissions.

In the (partially) electrified trucks of the future, the drivetrain will play a key role. “Eliminating the conventional combustion engine also involves eliminating its engine brake – which means the customer will need a replacement braking element that ideally also dissipates energy as soon as it can no longer be stored,” explains Gunther Kraft, Vice President Truck OEMs at Voith. The company’s latest, particularly environmentally friendly, continuous braking system is a good example of what this could look like. The Voith ECO Retarder – an efficiency-optimized, next-generation version of the popular Voith Retarder – can be adapted to alternative drives and features a built-in, electronically controlled unit for speed synchronization between the retarder drive shaft and rotor shaft. With their help, the rotor can be mechanically decoupled from the drivetrain when the retarder is switched off, preventing power dissipation when the rotor shaft is stationary. “This reduces fuel consumption and, as a result, also CO₂ emissions,” Kraft emphasizes.

Despite these improvements, however, the executive primarily focuses on the fundamental benefits of using the Voith ECO Retarder in “green” trucks. “On the one hand, in order to continue to meet legal requirements, such as the Type IIa test, manufacturers will have to replace the engine brake that is not available on heavy electric trucks because of the potentially fully charged battery. On the other hand, the sale of electric trucks gives manufacturers a further advantage in terms of fleet consumption, which earns them bonus points with customers of conventionally powered trucks as well,” argues Kernke. “This results in multiple benefits for them.”

In order to help OEMs integrate the unit into the respective drivetrain, Voith has created a modular system that is precisely designed for use with electrified vehicles and, for example, controls the interaction between the Voith ECO Retarder and the energy management and recovery systems. “We have to meet both mechanical and electronic requirements and also ensure that the unit can be optimally integrated into the system, and adapt the solutions to each OEM,” summarizes Kraft. The concept and its flexibility are impressive. Customers are already expressing interest in using the new ECO Retarder, particularly with water technology, in alternative drives, emphasizes the expert from Voith.

His colleague Joachim Kernke also believes the continuous braking system has a bright future. “We’re currently conducting market research. Today, about four out of ten trucks in Western Europe are sold with retarders – we expect a significantly higher retarder penetration with electric-powered heavy trucks, especially those powered by fuel cells.”