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Simultaneous crank-angle-resolved measurements of gasoline concentration and gas temperature were made with two-color mid-infrared (mid-IR) laser absorption in a production spark-ignition engine (Nissan MR20DE, 2.0L, 4 cyl, MPI with premium gasoline). The mid-IR light was coupled into and out of the cylinder using fiber optics incorporated into a modified spark plug. The absorption line-of-sight was a 5.3 mm optical path located closely adjacent to the ignition spark providing spatially resolved absorption. Two sensor wavelengths were selected in the strong bands associated with the carbon-hydrogen (C-H) stretching vibration near 3.4 μm, which have an absorption ratio that is strongly temperature dependent. Fuel concentration and temperature were determined simultaneously from the absorption at these two wavelengths.

NH3 and CO2 concentration measurements performed on a Biological Water Processor (BWP), under development at NASA-JSC for water recycling, using near infrared laser diode absorption spectroscopy are reported. The gaseous effluents from the bioreactor are a concern for potentially introducing harmful amounts of NH3 in a spacecraft environment. Furthermore, NH3 and CO2 monitoring is important for understanding the nitrogen and total organic carbon (TOC) balance and conversion dynamics in the BWP, and real time continuous monitoring could reveal dynamic situations that are hard to detect otherwise. Diode lasers operating at wavelengths that access NH3 and CO2 absorption lines near 1.53 μm and 1.99 μm are used in a portable and automated gas sensor system. Concentration measurements were performed during a 16 day period starting in August 25, 2000, and a 5 day period starting in November 10, 2000.

High bandwidth control of the air-fuel ratio is necessary in order to minimize the exhaust emissions of spark-ignition engines with three-way catalytic converters. A new approach is to implement a control structure based on modern control and estimation theory. This work describes the implementation of an estimator-based controller which uses the feedback from an on-off zirconia exhaust oxygen sensor of the type currently used in production vehicles. The limit-cycle associated with the on-off oxygen sensor in conventional systems is eliminated with the estimator-based control structure. Furthermore, the in-cylinder air-fuel ratio tracks the commanded value, so that if a limit cycle is desired in some areas of the engine's operating range for better catalyst operation, its amplitude and frequency can be set arbitrarily.

Tracer-based PLIF temperature diagnostics have been used to study the distribution and evolution of naturally occurring thermal stratification (TS) in an HCCI engine under fired and motored operation. PLIF measurements, performed with two excitation wavelengths (277, 308 nm) and 3-pentanone as a tracer, allowed investigation of TS development under relevant fired conditions. Two-line PLIF measurements of temperature and composition were first performed to track the mixing of the fresh charge and hot residuals during intake and early compression strokes. Results showed that mixing occurs rapidly with no measureable mixture stratification remaining by early compression (220°CA aTDC), confirming that the residual mixing is not a leading cause of thermal stratification for low-residual (4-6%) engines with conventional valve timing.

This SAE EDGE™ Research Report identifies key unsettled issues of interest to the automotive industry regarding the new generation of sensors designed for vehicles capable of automated driving. Four main issues are outlined that merit immediate interest: First, specifying a standardized terminology and taxonomy to be used for discussing the sensors required by automated vehicles. Second, generating standardized tests and procedures for verifying, simulating, and calibrating automated driving sensors. Third, creating a standardized set of tools and methods to ensure the security, robustness, and integrity of data collected by such sensors. The fourth issue, regarding the ownership and privacy of data collected by automated vehicle sensors, is considered only briefly here since its scope far exceeds the technical issues that are the primary focus of the present report. SAE EDGE™ Research Reports are preliminary investigations of new technologies.