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Diesel Particulate Filters (DPF) are a key component in many on- and off-road aftertreatment systems to meet increasingly stringent particle emissions limits. Efficient thermal management and regeneration control is critical for reliable and cost-effective operation of the combined engine and aftertreatment system. Conventional DPF control systems predominantly rely on a combination of filter pressure drop measurements and predictive models to indirectly estimate the soot loading state of the filter. Over time, the build-up of incombustible ash, primarily derived from metal-containing lubricant additives, accumulates in the filter to levels far exceeding the DPF's soot storage limit. The combined effects of soot and ash build-up dynamically impact the filter's pressure drop response, service life, and fuel consumption, and must be accurately accounted for in order to optimize engine and aftertreatment system performance.

Turbocharging, increasing the compression ratio, and downsizing a spark-ignition engine are well known strategies for improving vehicle fuel economy. However, such strategies increase the likelihood of engine knock due to higher in-cylinder pressures and temperatures. A high octane fuel, such as E85, effectively suppresses knock but is not necessary in most parts of the engine operating map. To better utilize a high octane fuel, dual fuel injection has been suggested where high octane fuel is injected only when the engine is about to knock. However, the effects of downsizing, retarding spark timing, and increasing compression ratio on dual fuel applications are not well understood. To investigate these questions, GT-power simulations along with engine experiments and engine-in-vehicle simulations for a passenger vehicle and a medium-duty truck were conducted.

Efficient aftertreatment management requires accurate sensing of both particulate filter soot and ash levels for optimized feedback control. Currently a combination of pressure drop measurements and predictive models are used to indirectly estimate the loading state of the filter. Accurate determination of filter soot loading levels is challenging under certain operating conditions, particularly following partial regeneration events and at low flow rate (idle) conditions. This work applied radio frequency (RF)-based sensors to provide a direct measure of the particulate filter soot levels in situ. Direct measurements of the filter loading state enable advanced feedback controls to optimize the combined engine and aftertreatment system for improved DPF management. This study instrumented several cordierite and aluminum titanate diesel particulate filters with RF sensors. The systems were tested on a range of light- and heavy-duty applications, which included on- and off-road engines.