| Summary: | Hybrid Electric Vehicles (HEVs) improve fuel economy by taking advantage of the peak efficiency operating envelope of the Internal Combustion Engine (ICE), together with an energy storage system to supply drive power when the ICE has lower efficiency. They also attempt to minimize engine idling. To achieve this improvement, a hybrid design requires an ICE, a generator/motor, motor controllers, and an electric energy storage system (battery or ultra-capacitor) which are connected together in various ways such as Series, Parallel, and Series-Parallel configurations.
Multiple strategies have been developed to manage energy use by hybrid electric vehicles in which decisions are made based on input variables such as battery state of charge, driver torque demand, vehicle speed, and transmission gear. For example, as the state of charge of the battery decreases, it becomes more costly to use electricity, and so, the control system tends to transition the power source from battery to fuel.
Although diesel-electric mine haulage trucks are in use today, energy storage is not a feature of these systems. Such trucks are typically arranged in a Series configuration in which the engine is completely decoupled from the wheels and used to provide electric energy through a generator to power electric motors on each wheel. The lack of a battery pack is a lost opportunity to improve fuel economy through regenerative braking and/or engine-off operation. This thesis discusses the fuel economy question with respect to road topography and distance data, conditions that can be predicted for mine haulage with relative ease. Access to such data in real-time can be put to advantage to maximize fuel economy on a given cycle. This thesis finds the HEV system can provide fuel savings due to 1) elevation change and 2) engine Brake Specific Fuel Consumption (BSFC) optimization on the order of 22 per cent on a typical open pit mine, which for a haul truck can provide substantial cash flow returns in addition to paying off for the extra capital cost of the hybrid electric system. === Applied Science, Faculty of === Mining Engineering, Keevil Institute of === Graduate
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