PTO Clutch Hydraulic Performance Evaluation Methodology Development & Correlation

This paper presents an analysis methodology developed to understand the impact of pressure spikes in off-highway applications, particularly during PTO (Power Take-Off) clutch engagement. These pressure spikes can adversely affect hydraulic subsystem components such as seals, gaskets, and valve operations. Assessing hydraulic system performance through physical trials can be cumbersome, resulting in longer development times and increased costs. To address this, a methodology was developed in a virtual environment to evaluate hydraulic system performance. The virtual method outlined in this paper is created in a 1D environment using an analytical approach to replicate the transient behavior of the system. The hydraulic system primarily includes a relief valve, solenoid valves, a pump, and a clutch. An analytical model was developed for the hydraulic system components with the right fidelity to accurately capture the transient behavior and magnitudes of pressure spikes. This methodology has been validated by instrumenting the vehicle, yielding a strong correlation of over 90% with the acquired data. The correlated analytical model was then leveraged to conduct a Design of Experiments (DOE) on various subsystem components, including accumulators, orifices, and engagement rates, to analyze their effects on hydraulic system pressure spikes. This methodology has facilitated the development of an analytical workflow to optimize the system early in the product development cycle. Keywords: PTO Clutch, Pressure spike, Simulation Methodology, 1D