Search Results

A new methodology for modeling engine intake has been presented; it is based on a transfer function relating pressure response and mass flow rate that makes use of the corresponding frequency spectrum obtained on the so-called “dynamic flow bench”. This new approach provides a way to obtain fast and robust results, which take into account all the phenomena inherent to compressible unsteady flows. Recently the potential of this method has been explored by incorporating it in a GT-Power model to produce a coupled frequency - time domain simulation of a naturally aspirated engine. The method exhibited promising results. One strategy utilized to combat the increasingly stringent emissions standards and reduce fuel consumption is to employ downsized turbocharged engines equipped with charge air coolers (CAC). Therefore, research and development must focus not only on naturally aspirated engines but also on turbocharged ones.

As is well known, today's air cleaner systems have to fulfill air filtration and acoustical tasks without neglecting package and pressure loss restrictions. Simulation tools like CFD and FEM are intensively used to provide an optimum design for air cleaner systems with new - unloaded - filter elements. But, especially regarding fuel consumption and emission quality (OBD, air flow meter signal), it is becoming more and more important to predict the filtration and flow behavior over the life time of an air filter element. Here, a 3D CFD flow simulation approach is presented, which takes into account the influence of the increasing dust load on the filter element.

Unsteady intake wave dynamics have a first order influence on an engine's performance and fuel economy. There is an abundant literature particularly for naturally aspirated SI engines on the subject of intake manifolds and primary runner lengths aimed to achieve a tuned intake air line. A more demanding design for today's engines is to increase efficiency to meet the requirements of lower fuel consumption and CO2 emissions. Today's tendencies are downsizing the engine to meet these demands. And for drivability purposes, the engine is combined with a turbocharger coupled with a charge air cooler. However, when the engine's displacement is reduced, it will be very dependent on its boosting system. A particularly interesting point to address corresponds to the engine's operation in the low speed range and during transients where the engine has large pumping losses and poor boost pressure. This operation point can be optimized using acoustic supercharging techniques.