Automotive Applications for Inflatable Seals

The Client:

A technology company specializing in the design and fabrication of test stand equipment for the automotive industry used for testing engines components during the manufacturing operation.

The Situation:

Provide a test stand to screen 4 and 6-cylinder sport utility vehicle engine blocks for porosity/cracks, and test the integrity of the oil ways that provide oil to the camshaft and harmonic balancers.

Application Requirements:

Three areas required engineered rubber technology to provide an effective seal during test conditions. The first area was the need to provide an effective seal around the oil pan interface. The second area was to seal off the oil ways supplying the camshaft bearing location and the third focus was to seal off the oil ways supplying the harmonic balancers bearing location.

The Approach:

Sealing the oil pan interface would be accomplished utilizing an inflatable seal P-1 cross section seal with a special soft bead (as shown below). The inflatable seal is molded in a "racetrack" configuration to match the lip of the oil pan interface. Sealing off the oil ways supplying the camshaft and harmonic balancers bearing location presented a number of unique challenges. Basically, multiple seals would be mounted on a shaft, inserted into the engine block, pressurized to expand radically outward and seal against the oil way locations. The unique challenge was that the seals would be inflated through an air passage in the mounting shaft and could not be fitted with a traditional standard valve.

The Solution:

The shaft seals were designed with two molded in o-rings on the inside diameter of the seal to seal against the mounting shaft during inflation. The inflatable seals were molded without inflation fittings utilizing a blow molding process that did not require an external air supply. An inflation port was mechanically "drilled" into the ID of the seal to permit inflation to occur during the testing phase of the machine's operation.

The Results:

The test stand successfully screens engine blocks for porosity/cracks, and verifies the integrity of the oil ways to the camshaft bearing and harmonic balancer bearing locations. When a defect is found, the engine block is removed and the material recycled into a new engine block thus preventing additional costly machining operations on an inferior engine block that could fail in the field.