Remote Combustion Sensing in Diesel Engine via Vibration Measurements

An efficient control of the combustion process is required in order to comply with regulations on pollutant emissions from internal combustion engines. Literature presents investigations devoted to explore the potentiality of externally mounted sensor (speed sensor, microphone, and accelerometer) for combustion diagnosis. A relationship exists between the combustion event measured via an in‐cylinder pressure transducer and engine block vibration measured via an accelerometer. Time and frequency domain processing of acquired signals highlighted the correlation between parameters able to characterize the combustion development and features derived from the engine block vibration data. A methodology was developed by the authors that demonstrated to be suitable for real‐time estimation of combustion progress based on engine vibration. A two‐cylinder common rail diesel engine of small displacement was tested; two configurations were investigated, naturally aspirated, and turbocharged. The in‐cylinder pressure and block vibration signals were acquired and processed in time and frequency domains. The vibrational components mainly related to the combustion process were extracted, and indicators of the combustion positioning were computed. The angular positions of start of combustion (SOC) and MFB50 computed via the heat release curve by means of the in‐cylinder pressure measurements were compared to those obtained by means of the accelerometer signal. High correlation coefficients were obtained for the data acquired during the testing of both naturally aspirated and turbocharged configurations in the complete engine operative field

Effect of Waste Cooking Oil Biodiesel Blends on Performance and Emissions from a CRDI Diesel Engine

The employment of biofuels in blends with diesel oil proved to attain a reduced environmental impact without compromising the engine performance. Among biofuels, waste cooking oil offers the advantages of its reduced raw material cost in comparison with fresh vegetable oil cost; it also eliminates the environmental impacts caused by its disposal. Although a great number of researches has been devoted to biodiesel combustion in engines and pollutant emissions, few studies can be found on light duty diesel engine equipped with up-to-date technologies. This work aims at investigating the impact of waste cooking oil percentage in blends with diesel oil on the performance and emission characteristics of an up-to-date light and compact common rail diesel engine whose main application is in microcars and in urban vehicles. A comprehensive experimental activity was performed in the engine complete operative field. The comparison of the results with those obtained with standard ultralow-sulfur diesel highlighted that the engine performance was quite similar for B20 and diesel oil. B40 suffered for the lower caloric value in regard to diesel. A reduction in CO and HC was obtained with biodiesel blends, along with an increase in NOx. Particulate emissions were also reduced for biodiesel blends; the mean size of particles was smaller as regards diesel oil

Soot Particles Experimental Characterization During Cold Start of a Micro Car Engine

Abstract Substantial amount of pollutants is emitted during the vehicle start-up, since the engine has not reached its optimal operating temperature. In urban traffic environment, the engine emissions during its warming up until it reaches a hot stabilized mode are an important source of major air pollutants. Existing literature indicates that: - in recent years the vehicle emissions have been reduced significantly, while those related to engine cold starts still remain high; - emission levels during engine start-up are deeply influenced by the vehicle characteristics. Most of studies are related to diesel engines equipped with high efficiency DPFs, gasoline port fuel injected and gasoline direct injected engines equipped with three-way-catalysts. This paper aims at characterizing pollutants and solid particles emissions from a low displacement two cylinder diesel engine, whose main application is in city cars and urban vehicles. During tests, measurements started at the time of the engine cold start-up; transient conditions of load and speed were imposed to the engine. A characterization of solid particle was performed, in terms of particle number and size distribution for three engine thermal conditions: cold, warm and hot starts