Validation of under Hood Thermal CFD Simulation for After-Treatment System with Off-Highway Application Test Data

<div class="section abstract"><div class="htmlview paragraph">Over the past few years, drastic steps have been taken to regularize emission norms for various segments in India. One of the major reforms done was separating construction equipment and agricultural vehicles to differentiate and define regulations effectively. Transition Emission Measure TREM IV emission norms have been implemented in India, and TREM V will also be launched soon. These changes to emission norms have increased the need for the implementation of after-treatment systems (ATS) in off-highway vehicle applications. Earlier, these systems were widely used for on highway vehicles. These emission norms target hydrocarbons, particulate matter, nitrogen oxide and carbon monoxide. Due to which, the demand for diesel oxidation catalysts (DOC) and diesel particulate filters (DPF) has increased in construction equipment and agricultural vehicles.</div><div class="htmlview paragraph">Although ATS has been in use for a long time, there are certain challenges associated with its integration into vehicles. As the space available on the vehicle is limited and there are high-temperature neighboring components, this can impact performance and increase safety-related risks for the end user. This study focuses on the integration challenges of ATS in tractor applications. Due to the limited available space, ATS must be integrated under the bonnet of vehicles for some applications. During static regeneration, the high temperature from the ATS heats up the bonnet and can pose a safety risk to the end user operating the vehicle. Some of the best practices to control heat rise from ATS have been discussed in this paper.</div><div class="htmlview paragraph">To understand the heat transfer in the actual application around ATS, a comprehensive repeatable test was done on the actual vehicle to collect critical information during various operating cycles of the vehicle. Air velocity was also measured during vehicle operation to understand the impact of forced convection on ATS. Validation of the actual test with steady state CFD simulation helped understand heat transfer on ATS. Validated CFD thermal model helps in comparing various design changes and identify thermal risks during high temperature conditions. A close correlation between the test and CFD simulation also helped in understanding the risk of high temperatures on the bonnet of vehicles. The modeling approach, test setup details, and critical factors affecting the performance of ATS have been discussed in detail in this study.</div></div>