Measurement and Analysis of Underhood Ventilation Air Flow and Temperatures for an Off-Road Machine

Abstract

To gain insight into the ventilation needs for an enclosed engine compartment of an off-road machine, a prototypical test-rig that includes an engine and other installation hardware was built. Well controlled experiments were conducted to help understand the effects of ventilation air flow on heat rejection and component temperatures. An assessment of 1-D and 3-D simulation methods was performed to predict underhood ventilation air flow and component temperatures using the experimental data. The analytical work involved development, validation, and application of these methods for optimized ventilation air flow rate in the test-rig. A 1-D thermal-fluid network model was developed to account for overall energy balance and to simulate ventilation and hydraulic system response. This model was combined with a 3-D CFD model for the ventilation air circulation in the test rig to determine the flow patterns and the distributed surface heat transfer. The tests conducted at Caterpillar and the complementary analyses performed at Argonne provide an opportunity to understand the isolated effect of ventilation air cooling on underhood thermal management.