Pre‑turbo‑DeNO_x exhaust aftertreatment: simulation and testing

摘要

Real urban driving conditions challenge exhaust gas aftertreatment systems for diesel passenger cars. One promising approachis the transfer of the selective catalytic reduction to a pre-turbocharger position, resulting in a thermal adjustment of theboundary conditions for the system. The design and functional behaviour of two new pre-turbo concepts are discussed. Challengesarise when the dosing of a urea-water solution and thermal mass are integrated upstream of the turbocharger. Thedesign and results of these new concepts are presented using an integrated methodology. Three-dimensional computationalfluid dynamics are used as a tool to fundamentally analyse the flow fields and the preparation process of urea-water-basedsolution to the reducing agent ammonia. The preparation process includes spray injection, spray interaction phenomena,and mixing of the reducing agent. The prototypically built-up hardware is integrated into an Engine-in-the-Loop test setup.In stationary engine operation, the basic measurement of temperatures and nitrogen oxides allows for the validation of thesimulations. Using a simulated vehicle approach, the experimental test setup is capable of being operated in real drivingscenarios. An additional 48 V boosting system is integrated and operated in the air pass to analyse and overcome thermaldelay. Realistic dynamic load test results and boosted WLTC measurements of a virtual passenger car are presented.