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A numerical study was carried out to determine the relative impact of diesel engine after-treatment system placement on engine performance. The objective of the study was to investigate the advantages and disadvantages of placing the after-treatment system upstream of the turbocharger as opposed to the more conventional downstream location. The study was conducted under both steady state and transient operating conditions. The after-treatment system involved in this study consisted of a Diesel Oxidation Catalyst (DOC) followed by a Diesel Particulate Filter (DPF) directly downstream of the former. The DOC and DPF models were correlated with experimentally-obtained, individual, pressure drop and warm-up data sets for each device. In an additional step for transient studies, chemical reactions were modeled within the DOC to simulate HC and CO oxidation, and their associated exothermic behavior.

Diesel engines nowadays are faced with enhanced emission standards, which limit further improvements in fuel economy. In order to meet future emission regulations in a cost effective way, high levels of EGR are needed. One way of increasing the level of EGR with current technology boosting systems is to utilize low pressure loop EGR. This paper discusses the benefits of low pressure loop EGR as well as some of the challenges. A new component is presented which overcomes some of these challenges. Also, modifications to current technology compressor wheels are presented which enable the compressor wheel to survive ingestion of exhaust gas.

This paper gives a thorough review of the HC/CO emissions challenge and discusses the effects of different diesel oxidation catalyst designs in a pre turbine and post turbine position on steady state and transient turbo charger performance as well as on HC and CO tailpipe emissions, fuel economy and performance of modern Diesel engines. Results from engine dynamometer testing are presented. Both classical diffusive and advanced premixed Diesel combustion modes are investigated to understand the various effects of possible future engine calibration strategies.

An air intake system must satisfy three main functions: air filtration, air delivery to the engine and the minimization of orifice noise emission. At the same time, however, the intake system must satisfy the packaging conditions in the engine compartment. The same applies to the exhaust system, with the exception of the filtration function. By determining the noise emission of the source compressor through computer simulation, we were able to optimize the intake and exhaust system. The result was a noise reduction of 25dB[A]. This is sufficient for a passenger car application. As opposed to the intake system, however, the exhaust system has the problem of a high accumulation of water, which requires a drain system. Plastic is an ideal material for the mass production of air and exhaust systems in fuel cell engines for passenger car applications.

The deposits on intake valve tulips of spark ignition and diesel engines can produce an increase in fuel consumption and exhaust gas emission, a deterioration of the driving behavior as well as mechanical defects. The formation of these deposits is investigated with respect to different engine parameters and by using a commercially available leaded fuel without additives. The valve deposits are formed by composing and decomposing phenomena which occur in parallel. The composing elements are oil, particles coming from the combustion chamber via the internal exhaust gas recirculation and, partially, fuel components. The deposits are reduced by the liquid fuel coming in contact with the valve tulips and by a high rate of oil flow. To the end of a shorter test duration and less test efforts a short-time simulation to investigate the deposit formation on inlet valves will be described.