Today's diesel agricultural equipment has higher heat loads than in the past. This is due to increased demand of higher horsepower and engine after-treatment components needed to meet emissions regulations. Although the number of components and heat loads has significantly increased, the size of the engine compartment, in many cases, has not. This is the challenge for design engineers, to dissipate the additional heat loads with the same amount of space as they had previously. To achieve this goal, each component of the cooling system of the machine must be optimized. This paper focuses on one component of this system, the fan shroud and its variable geometry parameters. In addition to this paper, a case study attempts to meet the additional heat loads from a Tier 4 final engine by increasing mass airflow by optimizing the fan shroud geometry.

In this paper, an engine cooling shroud's variable parameters, intended to affect airflow, is explored. The simplified design space consists of a heat exchanger, hood and engine from an AGCO Corporation RoGator T4f machine. Parameters considered for the design space include: shroud curvature, fan insertion depth, shroud depth, fan height, shroud curve center and fan tip clearance. After characterizing the design space parameters by simulating points from a sparse DoE and subsequent sampling, a response surface model is used for multi-objective optimization. A Pareto front analysis of the response surface is carried out to maximize air mass flow while minimizing fan power. Furthermore, a genetic algorithm is used for single objective optimization of the response surface. Selected optimal designs are simulated using the CFD tool, PowerFLOW, to verify results.

The results of this paper did not provide an engine shroud with the targeted increase in mass airflow needed for the additional head loads of the RoGator T4f engine. However, it does provide an insight into the shroud geometry parameters and their effect and sensitivity to the cooling system for maximizing mass airflow.