Case: Electrification of the Hydraulic Powertrain for a Municipal Street SweeperWe developed an electrified powertrain concept for a municipal street sweeper by replacing the diesel engine used to drive the hydraulic pump with a battery–inverter–electric motor system. The goal was to keep the machine’s hydraulic functionality and “operator feel” familiar, while meeting city-driven requirements for lower noise and reduced emissions. A key challenge was designing a battery system that fits the machine packaging and reliably supports up to an 8-hour shift without relying on mass-produced, off-the-shelf battery modules.
What we engineered1) Energy sizing & duty-cycle modeling- Calculated required battery energy and power based on real operating cycles, load levels, and shift length targets (up to ~8 hours on a single charge).
- Defined the power envelope for the electric motor/inverter driving the hydraulic pump.
2) Custom battery pack design (packaging + electronics)- Battery placement concept inside the machine (space/packaging driven).
- Mechanical enclosure + cell layout + internal wiring/harnessing.
- BMS (Battery Management System) integration: cell monitoring, diagnostics, and CAN communication.
- Support for both standard and fast charging strategies (where applicable).
3) Electric motor + inverter integration for pump drive- Selected and integrated inverter + electric motor to drive the hydraulic pump as the new “heart” of the machine.
- Implemented speed-hold behavior so the operator experiences predictable “engine-like” response (set a speed → system maintains it under changing load).
- Two control paths depending on inverter capability:
- using built-in closed-loop speed regulation, or
- adding external control electronics to command the inverter (increase/decrease torque/current) to maintain target RPM.
4) Hydraulic system alignment (function preservation)- Preserved conventional hydraulic architecture for working functions: brush drives, vacuum fan drive, and multiple cylinder functions (lift/lower, width adjustment, positioning).
- Control of multi-section valve blocks for auxiliary functions (multiple options/attachments typical for sweepers).
5) Drivetrain notes for 4×4 municipal platforms (where part of the machine concept)- Support for typical sweeper mobility architecture with four driven wheels for curb climbing and traction on slippery surfaces.
- Speed management via pump control and motor speed-range switching to meet transport vs working requirements.
RESULTThe machine retains its familiar hydraulic functionality and operator workflow, while the diesel-driven pump power unit is replaced by a quiet, battery-electric system. This delivers a significant noise reduction and enables city-ready operation with modern electrification requirements—without redesigning the full machine around electric wheel drives. The solution provides a structured, engineering-based path to an 8-hour shift target through duty-cycle sizing, custom battery packaging, BMS-driven diagnostics, and controlled motor RPM behavior that feels consistent for the operator under varying hydraulic loads.
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