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Internal combustion engine cold test is becoming one of the main tests performed during the late stage of the product development for defects inspection using the torque signatures and pressure levels in various engine components. This paper includes a lumped masses model generated for the cold test torsional system to calculate the driveline natural frequencies with a high accuracy. Calculating the natural frequency of the system is crucial for avoiding resonance excitation during the testing phase. Eigen value problem was solved; the natural frequencies and the mode shapes were obtained. The natural frequencies of the model were compared with the measured natural frequencies and 95% accuracy is achieved.

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Cold test stations are commonly arranged as sequential processes along a complete engine production line. The production line consists of several stations for engine building purposes, and before the engine exits the production line it passes through different validation and testing stations, such as leak testing stations, piston protrusion stations (known as torque to turn stations), and cold test stations. Each of these stations has a sequence of operation that is performed automatically or semi-automatic with the support of an operator. The waiting time until the engine finishes the operation in one station is called “cycle time”. The longer the cycle time the less efficient the production line. Cold testing stations are considered the most complicated and time-consuming, yet important test stations for engine and powertrain development. The lengthy cycle time affects the overall efficiency of the production line. This paper investigates the problem of the cycle time difference between consequent stations and its effect on the overall efficiency of the factory. New techniques and operations research methods are introduced aiming to recover from such a manufacturing obstacle. This research is investigating the limitations of a manufacturing operation standpoint. Each test station is treated as a block that simulates the actual station, and the overall factory workflow is described. Time-based equations governing block time, idling time, and utilization of the system are introduced, and the factory efficiencies are calculated and compared. After identifying the problem, a practical solution is explained.

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