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This paper presents the use of a second life battery pack in a smart grid-tied photovoltaic battery energy system. The system was developed for a single family household integrating a PV array, second life battery pack, grid back feeding, and plug-in hybrid electric vehicle charging station. The battery pack was assembled using retired vehicle traction batteries. The pack is configured with 9 cells in each parallel bank, 15 banks in series featuring 48V nominal and a 12kWh nominal capacity. Limited by the weakest bank in the pack, the second life battery pack has an accessible capacity of 10kWh, or 58% of its original condition. A battery management was developed to handle the bank-to-bank imbalance and ensure the safe operation of the battery pack. An energy management algorithm was established to optimize the energy harvest from PV while minimizing the grid dependence.

Emissions, fuel economy, and performance are determined over a light and a heavy driving cycle designed to represent the vehicles in-use driving patterns. The vehicles are 2010 class 8 Freightliner tractor trucks equipped with Cummins engines with Selective Catalytic Reduction and Diesel Particulate Filter emission control systems. The hybrid has lower carbon dioxide emissions, better fuel economy, and nitrogen oxide emissions statistically the same as the conventional. The CO emissions are well below the standards for both vehicles, but they are higher from the hybrid. The higher CO emissions for the hybrid are primarily related to the cooling of the Diesel Oxidation Catalyst (DOC) during the standard 20 minute key-off soak between repeats of the driving cycles. With a 1 minute key-off soak the CO emissions from the hybrid are negative.

Previous work has demonstrated the capabilities of gasoline compression ignition to achieve engine loads as high as 19.5 bar BMEP with a production multi-cylinder diesel engine using gasoline with an anti-knock index (AKI) of 87. In the current study, the low load limit of the engine was investigated using the same engine hardware configurations and 87 AKI fuel that was used to achieve 19.5 bar BMEP. Single injection, “minimum fueling” style injection timing and injection pressure sweeps (where fuel injection quantity was reduced at each engine operating condition until the coefficient of variance of indicated mean effective pressure rose to 3%) found that the 87 AKI test fuel could run under stable combustion conditions down to a load of 1.5 bar BMEP at an injection timing of −30 degrees after top dead center (°aTDC) with reduced injection pressure, but still without the use of intake air heating or uncooled EGR.