Search Results

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.

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.