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The Lean NOx Trap (LNT) is an aftertreatment device used to attain a reduction in nitrogen oxide emissions for Diesel and lean burn engines. The LNT is typically used as a storage device, capturing NOx during lean engine operation. The trap can be regenerated by controlling the exhaust air-fuel ratio to create a rich gas mixture. Under rich conditions, the stored NOx is released and catalytically converted. This way, tailpipe emissions can be significantly reduced by properly modulating the lean (storage) and rich (regeneration) periods. To maintain the LNT operate with high conversion efficiency, an optimized control of the regeneration scheduling is required. In addition, LNT systems require fault diagnostic schemes to detect and isolate failures, typically related to sulphur and thermal damages. The paper presents a control-oriented model of a Lean NOx Trap which captures the most relevant phenomena driving the storage and regeneration dynamics.

The matching of a starter alternator and an internal combustion engine is an easily realizable hybrid electric vehicle (HEV) configuration to achieve significant fuel economy savings in urban driving. Many examples are found today in production or near-production gasoline hybrid vehicles, with implementation through either belted starter/alternators or integrated starter/alternators. One of the key factors in the successful implementation of the starter alternator technology is the ability to start and stop the engine quickly and smoothly, without compromising the Noise, Vibration and Harshness (NVH) vehicle signature. This issue becomes even more critical in case of Diesel hybrids, as the peak compression torque is much larger than any Spark Ignition (SI) engine. The paper presents modeling and experimental results on a recent production, 1.9l Common-Rail Diesel engine belt-coupled to a 10.6kW permanent magnet motor.

Homogeneous Charge Compression Ignition (HCCI) is currently considered one of the most promising concepts to achieve low NOx and particulate matter emissions in traditional Compression Ignition Direct Injection (CIDI) engines. In spite of these benefits, understanding and controlling the complex mechanisms which govern the onset of combustion process are still extremely difficult, especially because there is little or no direct control on the combustion development as in Spark Ignition or Compression Ignition engines. The proposed paper describes a mean-value model of a HCCI Diesel engine with external mixture formation fitted with Variable Geometry Turbocharger, Intercooler and Cooled EGR. The effort is aimed at understanding and controlling the complex combustion phenomena in order to identify the influence of the control parameters on the auto-ignition process.

To attain a reduction in NOx emissions, various aftertreatment technologies are being developed. In addition to the emission control, these systems require fault diagnostic schemes to detect failure and diagnose faults. For detecting faults, one approach is to measure NOx emissions using a NOx sensor that serves the purpose of control and diagnostics for these systems. Moreover, an alternative approach has been developed for Lean NOx Trap (LNT) catalysts which use substrate temperatures for feedback and diagnostics. This paper will exploit both approaches using an experimental setup up.

The simulation and evaluation of land vehicle performance requires accurate representations of driving conditions. Currently, many driving cycles have been developed and used in the determination of vehicle fuel economy and emission performance. These driving cycles are typically defined as vehicle speed and power trajectories over time. However, most of the standard driving cycles are short in duration and distance and inadequate in representing a wide range of actual driving conditions. There are also many specialized driving cycles designed for specific types of vehicles, but these are often not applicable to more than a specific class of vehicles. Moreover, more detailed driving schedules are often kept as proprietary information within the vehicle manufacturers.

Flow fields generated during the intake stroke of a 4-stroke I.C. engine are studied experimentally using water analog simulation. The fluid is seeded by small flow tracer particles and imaged by two digital cameras at BDC. Using a 3-D Particle Tracking Velocimetry technique recently developed, the 3-D motion of these flow tracers is determined in a completely automated way using sophisticated image processing and PTV algorithms. The resulting 3-D velocity fields are ensemble averaged over a large number of successive cycles to determine the mean characteristics of the flow field as well as to estimate the turbulent fluctuations. This novel technique was applied to three different cylinder head configurations. Each configuration was run for conditions simulating idle operation two different ways: first with both inlet ports open and second with only the primary port open.