Optimization of TOC Plumbing Line Pressure Drop using 1D Modeling

The performance of the Transmission Oil Cooler (TOC) is influenced significantly by the TOC plumbing lines which transmit the oil from transmission system to the oil cooler and back. Designing the optimum TOC plumbing line with lesser pressure drop is the need of the hour considering the complex nature of the vehicle packaging. Reducing the pressure drop increases the oil flow rate through the transmission which results in optimum performance. Improved transmission efficiency in turn shall improve the engine efficiency and performance. The improvements obtained from increased transmission and engine efficiency shall result in an overall increase in vehicle fuel economy. Optimization solutions are required in the early product development cycle where the components are not readily available and/or are prohibitively expensive to do testing. In such scenarios, one-dimensional (1D) simulations shall be employed to compute the pressure drop for faster and economical solutions. In this paper, the approach of creating a modeling tool for TOC plumbing line pressure drop is discussed. Design for six sigma (DFSS) methodology is followed to optimize the modeling tool. An L18 orthogonal array of iterations are created and 1D simulation is carried out using the commercial software Flowmaster® from Mentor Graphics Corporation. Samples are manufactured and tested in the system calorimeter to validate the simulation results. The frictional coefficients of the simulation model are fine tuned to match with the test data at all operating conditions. This fine-tuned model shall be used to predict the TOC plumbing line pressure drop for the future programs with good accuracy.