Improving Engine Coolant System Performance with the Science of Sealing Technology; Part II Compact Seal Design 2004-01-0056
Constant improvements to automotive engines have required continuous improvements to components that define the engine as a system. Greater demands in performance require that sub systems such as the coolant systems, are smaller, more efficient, more reliable, and are designed for maximum life. The water pump seal is the most critical component within the coolant system. As the pump shaft begins to turn, the seal faces are in sliding contact and subject to changing conditions for temperature, pressure, and speed. The type of engine coolants must be considered in the seal design. For this liquid will cool and lubricate the seal faces. The basic function of the coolant is to maximize heat transfer and prevent boiling or freezing during normal operating conditions. Such a liquid is not the most desirable lubricant for the seal. This must be taken into account in the design of the seal and the materials of construction.
The Society of Automotive Engineers (SAE) in standard J780 has defined existing water pump seals. This standard defines the basic space, design and nomenclature for the seal.
The available space for the seal has been redefined by industry to make the water pump a more compact component within the coolant system. This has required a complete redesign of all the individual parts of the seal. Results of this work have lead to the development of a unique seal that exceeds the performance requirements in all types of coolants while meeting the restrictive space requirements.
Finite Element Analysis (FEA) is presented which verifies the seal design. Extensive laboratory and field tests are presented that confirm the design and material for automotive use. This new design is 30% smaller in length than existing water pump seals. This reduction in length has resulted in a more compact and cost effective pump and seal.