Fast Spatially Resolved Exhaust Gas Recirculation (EGR) Distribution Measurements in an Internal Combustion Engine Using Absorption Spectroscopy

Abstract

Exhaust gas recirculation (EGR) in internal combustion engines is an effective method of reducing NOx emissions while improving efficiency. However, insufficient mixing between fresh air and exhaust gas can lead to cycle-to-cycle and cylinder-to-cylinder non-uniform charge gas mixtures of a multi-cylinder engine, which can in turn reduce engine performance and efficiency. A sensor packaged into a compact probe was designed, built and applied to measure spatiotemporal EGR distributions in the intake manifold of an operating engine. The probe promotes the development of more efficient and higher-performance engines by resolving high-speed in situ CO2 concentration at various locations in the intake manifold. The study employed mid-infrared light sources tuned to an absorption band of CO2 near 4.3 μm, an industry standard species for determining EGR fraction. The calibrated probe was used to map spatial EGR distributions in an intake manifold with high accuracy and monitor cycle-resolved cylinder-specific EGR fluctuations at a rate of up to 1 kHz.

Design and development of a probe-based multiplexed multi-species absorption spectroscopy sensor for characterizing transient gas-parameter distributions in the intake systems of I.C. engines

“…The theory of absorption spectroscopy is well established [7][8][9][10][11][12][13] and therefore, only a brief overview is given here. Laser absorption spectroscopy is a quantitative, species-specific, path-averaged, and minimally-intrusive technique that can be used to measure gas temperature, pressure and species concentration simultaneously in a medium through which the laser radiation is transmitted.…”

“…3a, is an upgraded version of the probe described in prior work [9,10]. This compact probe comprises of a 9.525-mm (3/8-inch) outer diameter (OD) stainless steel (SS) tube which houses the measurement-cell optics as well as the optical media to guide the light, i.e.…”

“…While the main intent herein is to describe the instrument, Figure 9 demonstrates an engine application of the multi-species probe. Other engine applications have been published using earlier versions of the EGR Probe [9,10]. We intend a separate publication to focus on engine applications of the multi-species probe.…”

“…Laser absorption based sensors provide a solution for resolving inter-cycle and intercylinder gas-property transients; specifically, such sensors have been shown to provide multikHz bandwidth for measurements in internal combustion engines [7][8][9][10][11][12][13][14] as well as in various other combustion systems including gas turbine engines [15], scramjet combustors [16], and flat flame burners [17]. Furthermore, both H 2 O and CO 2 have been used as combustion gas markers in these absorption studies.…”

Диодные оптопары на основе InAsSb для сенсоров углекислого газа, работающих в режиме реального времени

“…Это позволило перейти к разработке ГА СО 2 на основе оптопар с минимально возможными на-пряжением питания и энергопотреблением при высокой точности измерений и небольшом объеме пробы [9][10][11][12]. Последнее обстоятельство крайне важно при измерени-ях СО 2 в выдохе пациентов, особенно для новорожден-ных детей, имеющих малый объем легких [13].…”