E-Mobility Engineering | September/October 2023 49 Some key suppliers Battery system: Webasto Motors and power electronics: Danfoss Vehicle control system: IFM Electro-hydraulic valves, operator controls and system integration: VSE Industrial Automation Dieseko Woltman pile-driller/driver | Digest Dieseko has a patent pending on this system, which improves overall energy efficiency. “We could have chosen to go with one big motor,” Legtenberg says. “Not only is this a zero-emissions machine, we also want to optimise it so it consumes less energy.” The hydraulic pumps feed manifolds that supply all the winches, motors and numerous cylinders. The leader is folded down and laid flat on the machine deck for transport, so it is raised into its operating position hydraulically. The pins that secure the battery container to the rear of the machine deck, and open to allow it to be removed for transport and maintenance, are also hydraulic. The electro-hydraulic management system also includes a suite of sensors to measure parameters such as pressure and flow and motor speeds that indicate how much power is required at any given moment, along with sensors that monitor the condition of the machinery. Operator controls and displays In terms of control, the 90DRe is essentially a drive-by-wire machine, with everything from the joysticks in the operator’s cabin to the hydraulic control valves in the manifolds generating or responding to signals processed in ECUs. The operator is provided with a comprehensive set of displays dealing with start-up and shutdown procedures, pile drilling and driving operations, performance and health of the batteries, inverters and motors, battery charging and system diagnostics, for the moment all labelled in Dutch. Among the most important displays for pile drilling and installation, for example, are two inclinometers that show the angle of the leader from the vertical in left/right and fore/aft terms. Despite the time constraints, and the electronics hardware supply problem, development was completed in good time, Legtenberg says. Dieseko signed the contract with BAM in November 2021, and the 90DRe was presented at the Bauma event. When the machine returned from the show, there was still some final testing to be done, so its first job at Schiphol Airport effectively served as an operational trial. “BAM did an extremely good job,” Legtenberg says. “It was not a big one, just to drill 30 piles in, but it was a perfect test. “We were concerned that, every day, service engineers, software engineers and mechanical engineers from the development team would have to go there or log in to the machine remotely to solve any bugs. I expected that to take 2 or 3 months, which would have been reasonable, but there was practically nothing, only a few minor things that had to be adjusted. “I was amazed, because normally Murphy’s law is on your case, but it was just one filter that had to be upgraded because it was getting a little too hot, and one cable connector proved a little weak, so we had to find a new one.” The filter was a power electronics component in the charging circuit, essentially a transformer that serves to smooth out the ripples in the charging voltage. “We went one size bigger, and that solved it. I was really impressed with the machine’s reliability because there were so many new components involved,” Legtenberg says. The Schiphol job attracted a lot of interest from potential customers and competitors. “It is a slow-moving market defined by Dutch rules,” Legtenberg says. “We see that the government and the four big cities are tightening their zero-emissions requirements and, based on that, we expect to sell more soon.” Development paths Beyond the 90DRe, Dieseko is looking to electrify a smaller machine such as the Woltman 55DR. With an eye on reducing the price of electrification, the company has started developing a batterypowered electro-hydraulic powerpack that can be connected to the hydraulic system of existing diesel-powered machines to enable them to operate in zero-emissions mode when required. Another line of development is the electrification of pile drills and vibratory hammers, which could yield an energy saving of around 20-25% over hydraulics, Legtenberg says. Of these, the vibratory hammer is the more challenging, because the motor will have to be mounted on the moving part and will therefore have to withstand sustained high-frequency 20 g accelerations, with peaks of 40 g during rebound. Pile drivers work hard. Operator’s display panel with inclinometers, caution and warning symbols, and a range of gauges for parameters such as battery charge and hydraulic pressure in the drill and winches, and the forces on the winches
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