The current SI engine designs submit the engine to operating conditions that require an improved performance of its components. The increase of the engine speed is a trend that generates a significant change in the engine components design approach.
During validation tests, some engines have presented blow-by spikes at high speed and low load operating conditions. The reason is an abnormal ring package motion due to the influence of the high inertia and small gas pressure loads.
This work presents a numerical simulation of a SI engine considering high speed and no load operating conditions, which showed blow-by spikes during engine tests. The numerical simulation tends to reproduce the blow-by spikes and identify the involved phenomena.
Based on the numerical simulation, other engines were analyzed and some guidelines for the piston and the piston rings were developed in order to minimize the blow-by spikes at the mentioned operating condition. Some engine tests have been done to support the guidelines.