Over-molded Engine Compartment Solution for Heavy Truck Manufacturer

The Heavy Truck Challenge: Equipment Failure in Extreme Temperatures

Heavy trucks are designed to be tough, and what’s going on under the hood should be a top priority for engineers. Polymer Technologies, Inc (PTI) was approached by an original equipment manufacturer (OEM) of diesel engines for heavy trucks that were having engine trouble.

The existing design inside the engine compartment was prone to freezing when condensation in the system was exposed to extremely low temperatures. The components most susceptible to freezing (leading to engine failure) were those inside the plastic crankcase cover and the inlet and outlet tubes.

After the initial assessment of engine performance and understanding of the extreme conditions in which the heavy trucks were intended to operate, we determined the OEM needed thermal materials to insulate the engine’s crankcase ventilation system.

Initial Solution: Die-Cut Foam for Thermal Insulation

A die-cut solution consisting of closed-cell foam was developed for each component of the engine: the cover, the inlet tube, and the outlet tube. The three 2D die-cut pieces of foam were applied flat with adhesive and assembled by installers on the OEM’s assembly line. The additional assembly time to add the three pieces of foam to the components was approximately 5 minutes which, at the initial low volume, was acceptable.

We were able to help the OEM meet their initial requirements with a cost-effective, lightweight solution. The manufacturer was pleased with the results and started to consider the development and lifespan of their product in a new light. The OEM realized that trucks in warm climates could potentially end up in one of the extremely low-temperature environments that caused the freezing issue.

The OEM identified that a solution was needed for every engine they produced, roughly 100,000 vehicles annually. The OEM brought us their updated requirements, and we were ready to help them take their solution to the next level by Thinking Forward with 3D foam materials.

Ultimate Solution: Custom Molded 3D Polyurethane Foam for Every Heavy Truck Produced by the OEM

The OEM needed a similar but simpler solution that could be assembled in 60 seconds to accommodate the high volume demands. We tackled the challenge head-on. Our goal was to provide the OEM with the crankcase cover and hoses with insulation already applied to streamline their assembly time.

To start developing a new solution, Polymer Molded Products (PMP), our manufacturing division for custom molded foam, was tasked with determining if the flexible hoses and rigid plastic cover could be over-molded with Polyform^® High Density Molded - Integral Skin (PHDM-IS). In doing so, the molded material would provide a precise, one-piece thermal solution.

PHDM-IS is commonly used in over-molding applications because of its durable, attractive outer skin and excellent adhesion to a variety of substrates. Through prototyping, we determined both the flexible hoses as well as the plastic cover could be effectively over-molded. The OEM had limitations on size and configuration of the foam part. Through experimenting with pour patterns and mold articulation, we were able to meet the OEM’s requirements.

Over molding engine component for thermal control in heavy trucking

Precision molded PHDM-IS foam fits perfectly in place to stop thermal, noise, and vibration problems at the source.

Prototype parts were precision crafted to the manufacturer’s specifications, and the project was approved for production.

Final Result: Streamlined Truck Manufacturing and Superior Engine Performance

Not only did the over-molded engine parts meet the required assembly time, thermal performance, and other durability and wear requirements of the OEM, they were also more aesthetically pleasing than the die-cut solutions. By switching from a die-cut foam solution to custom molded foam, the OEM was able to reap cost-saving benefits they hadn’t thought were possible.
Not only was the engine freezing problem solved, but their whole manufacturing process was streamlined.

The Heavy Truck Challenge: Equipment Failure in Extreme Temperatures

Molded foam products should be considered at the onset of a project so OEMs can take foam solutions into account before the development process starts. Molded polyurethane products provide engineers the opportunity to create simplified assembly processes that reduce manufacturing time and the number of assembly parts.

From creating mounts for motor housings to over-molding components, the concept of utilizing molded solutions to streamline production and improve product performance can be applied to a variety of mid to high volume manufacturing processes. If the possibilities of a molded solution excite you, then be bold and develop your own custom mold with us, the experts at PTI.

(Specifications subject to change without notice. Check with factory for the latest revisions.) The Federal Trade Commission considers no existing test methods or standards regarding flammability as accurate indicators of the performance of cellular plastic materials under actual fire conditions. Results of existing test methods, such as UL-94, MVSS-302, SAE J-369, and FAR 25.853 are intended only as measurements of the performance of such materials under specific controlled test conditions. Any flammability ratings shown are not intended to reflect hazards presented by these materials under actual fire conditions. The information contained herein is based on laboratory test data developed for PTI and is believed to be reliable, but its accuracy or completeness is not guaranteed. The buyer must test any product to determine the suitability for this specific application before use. PTI DISCLAIMS ANY RESPONSIBILITY FOR: 1) WARRANTIES OF FITNESS AND PURPOSE, 2) VERBAL RECOMMENDATIONS, 3) CONSEQUENTIAL DAMAGES FROM USE AND 4) VIOLATION OF ANY PATENTS OR TRADEMARKS HELD BY OTHERS.)

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