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Electric axle for commercial vehicles

Periodic Reporting for period 2 - ELECTRIC_AXLE (Electric axle for commercial vehicles)

Reporting period: 2017-11-01 to 2018-10-31

E-mobility is one of the most relevant trends on the commercial vehicle market, which is driven by two major factors:
• To protect the environment, especially the atmosphere by zero emission
• To decrease the Total Cost of Ownership of a vehicle
Since kinetic energy can not be fully regenerated even at electric vehicles, decreasing gross weight is the viable way, which helps to reach both the above goals. A lighter vehicle needs less amount of batteries, which is a direct cost decrease, moreover the batteries’ manufacturing and recycling consumes less energy and emits also less pollutant. The electric vehicles’ market is rapidly changing, new technologies and respectively suppliers emerge and traditional ones lose their importance and market share. Despite of the very turbulent technological changes, electric commercial vehicles’ components are still mostly based on the established diesel value chain. Currently there are no critical components available, which would be required by the designers of light weight commercial vehicles. Typical example of this situation is the axle system of city buses. While a 12.7 solo bus, carrying 95 passengers weights currently 18 ton in total, the same amount of passengers can theoretically be transported by a 13 ton composite bus. While an 18-19 ton electric bus requires a 12-13 ton rear electric axle, a 13 ton electric bus needs only 8.5-9 ton at its rear. Problem is that there is no such an axle on the market, which causes a chicken and egg situation. Since still there are no 13 ton weight vehicles, there is no 8.5 ton electric axle available and because there are no 8.5 ton electric axles, no manufacturer could reach the 13 ton gross weight so far.

Goal of the project is to develop an electric axle for 8.5 ton load and introduce it on the market.

The project’s societal importance can be formulated as follows:
Electric power train is the key element for every electric vehicle. The rationale of the project is to provide a leading edge technology for:
• Bus and other commercial vehicle manufacturers, to increase their competitiveness on the world market, by decreasing their vehicles’ total cost.
• Bus operators, to decrease their operation costs (a lighter vehicle consumes less energy)
• Cities, to provide an environment friendly, high passenger comfort service at lower cost

The project’s overall objectives are:
• To develop and test the 8.5 ton electric axle, install it in vehicles
• Introduce the product into the market
• Transform Silex from a small company, to a medium sized, technology oriented organisation, which is active on the world market
"From the beginning of the project the following work has been performed:
• Silex’s management is elaborating and managing the change process to transform the company from the existing state to a real organisation, with internal processes, well defined roles, duties and obligations. This is essential in order that Silex can become partner of vehicle manufacturing OEMs, which require this level of company structure.
• The first version of the axle mechanics, including body, gearbox and additional parts needed to the break system has been completely designed
• Tool chain has been elaborated to design and simulate the electric motors, which are needed for the electric axle. The first version of the electric motor, which needs further optimisation, is under manufacturing
• Since the final parameters of the axle, including the technical data of the motor have been settled, the development is in progress
• Axle controller development is ongoing and in parallel to this the role of the controller has been extended, so respectively the controller’s technical specification has also changed. This development work is also in progress.
• The test facility has been completely designed and plans are being corrected according to the changes of the axle to be tested.
• The first version of the 8.5 ton electric axle has been exhibited in Kortrijk, Belgium, on the Busworld 2017 exhibition. Silex has been awarded with the ""Sustainable mobility"" price, issued by a jury, which is a great honour for Silex. First feedbacks from customers are positive, so Silex is currently making changes on the axle based on the received customer information and is preparing projects with them together.
During the course of the project as a consequence of discussions with customers the role of the axle controller has been extended to a vehicle wide, ISO 26 262 qualified controller. This is a value for customers, since in this way they can comply with the newly adopted ISO standard (they do not have to spend engineering time and money on the vehicle’s qualification) and thus opens new markets for Silex too.

The expected result of the project is that Silex grows from its current 400 k€/year turnover to an annual 25-30 m€ turnover company, with a strong technological background and international presence.

The socio-economic impact of the project is to contribute to the electro mobility in the city traffic, by buses (and in a broader sense other commercial vehicles), which comply with operators’ daily 250 km distance expectation, increase vehicle comfort by low floor and wide corridor at the rear axle, moreover decrease the TCO of the vehicles.
First version of the electric axle on the Busworld exhibition