Sealing & Flow Control for New Designs, Additives & EV Applications
Sealing & Flow Control In Composites & Designs with Additive Manufacturing. New material types and structures require advanced solutions for EV applications.
As electric vehicle (EV) manufacturers develop new light weighting techniques to optimize system efficiency and performance, material advancements are rapidly changing designs. Carbon fiber and nylon composites, as well as parts produced through additive manufacturing, are increasingly being used in product development. These solutions place new requirements on vital system components, such as flow restrictors, check valves and seals.In EV’s, there is a critical concern for leakage and fluid control. Additionally, lifespan expectations have increased while components are expected to require little to no maintenance. In applications such as drivetrains, battery systems and thermal management, automakers are partnering with suppliers to revolutionize designs.
“Some of the world’s most recognizable automakers are developing new manufacturing centers solely focused on advanced materials and additive manufacturing,” noted David Ramirez, Application Engineer at SFC KOENIG®. “Partnering with the right sealing and flow control supplier is critically important, as reliability is crucial, and there are strict requirements for wet and dry areas.”
While new materials are being introduced, existing challenges remain, including thin walls, complex port configurations and compact designs. Engineers are carefully evaluating components – such as port plugs, flow restrictors and check valves – to ensure performance and lifecycle expectations can be achieved.
Traditional force-fit seals can easily deform these designs, especially when new, lightweight materials are used. Expander-style sealing and flow control solutions, which evenly distribute stress in the base material, are helping designers meet many requirements.
SFC KOENIG solutions, which utilize an expansion-fit design to create a secure metal-to-metal seal, are one of the industry’s most reliable choices. These parts feature a serrated exterior sleeve which evenly expands into the bore walls, applying controlled forces that pose little risk for damage. With over 5 billion parts installed, SFC KOENIG solutions report a failure rate less than 1 part per million.
Some new materials do not easily accept machining operations, such as threading of drilled holes. Where machining can occur, it is often difficult and costly. In these applications, traditional seals, such as cup plugs and threaded screws, are not optimal solutions.
Solutions such as the KOENIG EXPANDER®, KOENIG CHECK VALVE® and KOENIG RESTRICTOR® eliminate the need for additional machining. These parts can be directly installed into the bore and require no sealant – which decreases risks for contamination.
EV designs are also increasingly being developed with additive manufacturing techniques. While effective in weight reduction, these new part structures present challenges. Instead of solid metal construction, 3D printed parts often feature a layer of solid material on the outside, which is internally supported by a honeycomb-like framework. Installation of seals and flow control components in these unique designs presents additional challenges.
“While our standard components support many new, unique materials, our precisely-controlled installation process reliably seats components in thin wall applications as well as unique base structures, such as those being produced with additive manufacturing,” continued Ramirez. “While many of these designs are years away from full-scale production, our ability to provide the very best product reliability and advanced engineering support, is providing new opportunities for automakers to advance their designs.
SFC KOENIG also offers a full line of installation solutions to provide additional control, precisely regulating installation pressures and distances. This equipment allows manufacturers to correctly position and expand seals and flow control components, and the company will also assist with automation, so automakers can easily design-in new solutions.
“EV design is advancing at a rapid pace,” continued Ramirez. “Long lifespans, complete reliability, and optimized performance is required of every component. At SFC KOENIG we are excited to partner with automakers on these advanced designs – it’s why we are recognized as the ‘Leader in Sealing and Flow Control’ – and how we will remain that leader.”
KOENIG EXPANDER® plugs feature a serrated exterior sleeve which expands into the base material, forming a secure seal without the need for sealant.
With their expansion design, SFC KOENIG® solutions apply controlled installation pressures, as shown in this image with a polarizing filter, where colorization reflects stress in the base material.
Additive manufacturing is increasingly replacing solid metal part construction, and requires precise installation of sealing and flow control components.
SFC KOENIG® expander plugs, check valves and flow restrictors are available in a variety of materials which support many new material composites.
CUSTOM CHECK VALVES HELP REGULATE FLUID PRESSURE, PROVIDING PRECISE SYSTEM CONTROL TO REDUCE FUEL CONSUMPTION AND EMISSIONS.
SFC KOENIG® engineers are increasingly developing customized check valve components to achieve precision requirements, utilizing both forward and reverse style designs.
As performance standards in the U.S., Europe and Asia continue to become more stringent for automakers, stop/start systems are increasingly important in reducing emissions and improving fuel economy. Precisely regulating fluid pressure enables the stop/start function to be as seamless as possible and ensures the driving experience remains high, while emissions and fuel consumption remain low.
Due to the complexity in advanced stop/start system designs, automakers are increasingly turning to custom components – such as customized check valves from SFC KOENIG® – to regulate and optimize fluid pressure, all of which can now happen in the fraction of a second.
Stop/start systems have two critical data points that check valves must achieve – the sealing pressure and the release pressure. Because of the complexity of surrounding assemblies and systems, customizing the check valve component is often the best way to adapt to design and performance requirements.
SFC KOENIG engineers work within geometric allowances and make adjustments to the check valve design, modifying the orifice size and cracking pressure to achieve the desired outcome.
“First, we work directly with the automaker to design a part that will achieve the correct performance criteria. While all of our designs are proven ‘on paper,’ SFC KOENIG has developed advanced in-house testing procedures to provide performance results that automakers can fully rely on,” noted David Ramirez, Application Engineer at SFC KOENIG. “Our in-house process often includes putting the part into a manifold and testing it. In the case of a start/stop system, we precisely record the time it takes to achieve and hold a pressure, and the time it takes to release a pressure, with computerized systems. We graphically-chart the results to show how the pressure is held or released over time. This testing is highly accurate and provides the results automakers require.”
Stop/start system fluid pressure requirements are often unique, and achieved using customized solutions, which are engineered to meet the requirements of surrounding systems. In this cutaway image, we see an installed KOENIG CHECK VALVE®, with its serrated sleeve forming a secure metal-to-metal seal with the fluid port walls.
After in-house testing, often a series of check valve protypes will be installed by the automaker, with SFC KOENIG engineers there to assist in process development, installation and review.
“With a global team of engineers experienced in the latest automotive design innovations, our team works with customers throughout the process to ensure our parts perform as expected,” continued Ramirez. “Beyond part customization, customers know SFC KOENIG components are often the best solution when evaluating total costs. Our commitment to quality extends well beyond our components, but to service and support until the final stage of design, avoiding performance and warranty problems down the road.”
Custom-engineered solutions are often required to solve challenges in advanced automotive designs, particularly with the ever-increasing complexity of systems. SFC KOENIG increasingly receives requests for custom solutions, in fact, these requests have more than doubled in recent years, with the number of custom projects expected to continue to rise.
With the ability to not only provide custom products and prototypes, but to provide highly accurate data and testing documentation, solutions that improve automotive performance and at the same time promote sustainability are keeping pace with this fast-moving industry.
INSTALLATION, ERROR AND WARRANTY COSTS ALL AFFECT THE TOTAL VALUE OF A COMPONENT. As engine designs continue to advance, units become smaller, more complex, and increasingly reliant on new materials. While improving performance and efficiency, these changes have led to new concerns for engineers and manufacturers, as components that once were commonly-used are no longer appropriate.
The plugs used to seal fluid ports are a notable example of increased complexity in cost evaluation. In the past, balls, threaded screws and cup (freeze) plugs were often selected. These traditional methods – while offering a low cost per piece – are often inappropriate for new designs when installation, performance and warranty factors are evaluated. Engineered seals, such as the KOENIG EXPANDER® from SFC KOENIG®, often prove to be the most cost-effective choice.
Installation is often the first indicator of savings. Both ball plugs and cup plugs require boring, usually with a fine surface finish, as well as reaming. While a simple bore is acceptable for threaded screws, these components require thread tapping and surface chamfering. With each additional step in port preparation, process and labor costs increase. Comparatively, KOENIG EXPANDER plugs can be directly installed in a standard bore and require no counterboring.
A number of factors affect the total cost of a sealing solution.
Once installed in the hole, traditional seals require additional labor and processing. Ball plugs must be secured by deforming the housing after installation, and contamination generated during installation is a risk. Both cup plugs and threaded screws typically require the application of sealants. While this adds to process costs, the risk of contamination also increases, as excess compound and metal shavings can enter the fluid system. This can lead to critical performance issues for the customer and increased warranty costs for the manufacturer.
With its expansion design, KOENIG EXPANDER plugs create a secure and leak-proof metal-to-metal seal. The plug’s serrated expansion sleeve directly sets into the as-drilled bore walls, and no additional operations or sealants are needed.
The expansion design of KOENIG EXPANDER® plugs creates a secure metal-to-metal seal without sealant or extra machining, lowering process costs and the risk of contamination.
Error and scrap rates must also be evaluated. Ball and cup plugs utilize force-fit installation processes. Threaded seals apply rotational installation forces. These pressures can affect the base geometry, pushing into nearby passages and even creating cracks in the base. This can lead to scrapped parts, rework and potential warranty costs.
Misalignment more easily occurs with threaded seals and cup plugs. A threaded seal must carefully set in the port to avoid cross threading, and the small height of a cup plug can easily be inserted at an incorrect angle. An improperly set plug not only leads to errors, scrap and waste, but can decrease a seal’s long-term effectiveness – leading to leakage and warranty costs. Comparatively, KOENIG EXPANDER plugs apply even and controlled pressures, with process stability that supports strict requirements as well as thin wall applications.
Threaded screws and cup plugs are also difficult to integrate into automated assembly operations, leading to additional investment and labor. KOENIG EXPANDER plugs are widely proven in automated installations, and SFC KOENIG offers setting equipment that controls installation forces and distances. As production lines increasingly integrate IOT, automated process further supports and increases expander seal benefits.
KOENIG EXPANDER® plugs often prove to be more cost effective when factors such as installation, performance and warranty are included in total value calculations.
While installation and rework costs are more easily calculated in seal value, long-term warranty issues can also have dramatic affects. Performance issues, damage and system failure have significant consequences and costs. With more than 5 billion parts installed and failure rates less than 1 PPM, the reliability of KOENIG EXPANDER seals is proven.
While traditional cost considerations often focus on the per-piece cost, modern designs and manufacturing environments require a detailed review of total costs when evaluating return. SFC KOENIG has created a calculator that easily allows users to compare their current solution to a KOENIG EXPANDER plug.
Evaluating Critical Factors in Engine Seal Installation
Installing seals in fluid system ports is critical to the engine manufacturing process. Choosing the right seal can streamline production, save time and money, and maximize system reliability. Today, advanced technologies such as the KOENIG EXPANDER® offer distinct advantages in installation performance versus traditional sealing methods, especially in modern production environments.
KOENIG EXPANDER® plugs are available in a variety of sizes and materials, in both push and pull types, and are proven reliable in metal-to-metal seal applications. These engineered solutions outperform many traditional sealing methods.
Traditional port sealing methods include ball plugs (a metal ball pressed into the port opening), set screws/threaded plugs (tapped and threaded into the port sometimes with an additional sealant applied), cup/freeze plugs (pressed and/or chemically bonded in place), and welding. While often selected for their low per-piece cost, these simple sealing options have distinct disadvantages in modern engine designs and high-speed production lines, which often increases total costs and results in errors.
During installation, controlled forces are applied to a fitted ball or mandrel which expands the serrated shell of a KOENIG EXPANDER®. This creates a secure metal-to-metal seal without the need for sealant or additional machining.
Engineered sealing solutions, such as the metal-to-metal expander seal design of SFC KOENIG® products, are rapidly becoming the preferred solution for precision applications. KOENIG EXPANDER® seals feature a serrated metal sleeve that is expanded radially by an integrated metal ball (push-type expander) or mandrel (pull-type expander). On installation, the sleeve’s serrations press against the port wall forming a leak-proof seal with uniform pressures, even in thin wall applications, with no sealant required.
As engineers improve the efficiency and performance of modern engines, new design challenges arise. Thin port walls and lightweight metal alloys are challenging for simple sealing solutions, as their installation can cause detriment to the base housing. From heat deformation created during the welding process to deformation created by installation forces, traditional methods pose a variety of concerns.
Comparatively, engineered solutions such as the KOENIG EXPANDER® effectively solve many installation concerns – reducing installation stresses, reducing contamination from sealant or machining processes, and allowing for installation in unique locations, such as thin walls and deep in ports.
Installation performance of KOENIG EXPANDER® sealing systems verses traditional port sealing methods.
The need for sealing solutions to support automated production lines is rapidly increasing with the integration of IOT and smart factories. Modern production environments, coupled with precision engine design, require calibration, control and compliance. Engineered sealing technologies, such as the KOENIG EXPANDER®, are quickly becoming the preferred solution for today’s manufacturers.
TRADITIONAL FLUID SEALS ARE NOT SUITABLE FOR THIN-WALLED, HIGH-PRECISION PARTS FAVORED IN MODERN ENGINE AND TRANSMISSION DESIGNS. As appeared in Today’s Motor Vehicle.
KOENIG EXPANDER® plugs feature a serrated outer shell that expands when force is applied to the integrated ball or mandrel, creating a leak-proof seal with evenly distributed pressure.
Make it lighter. Make it smaller. Make it more efficient. And make it reliable. Oh, and did we mention, don’t sacrifice performance? Today, automotive engineers and project managers must produce powertrains that deliver optimum fuel efficiency and long-term reliability without sacrificing performance. Meanwhile, global initiatives to reduce emissions and improve energy conservation have expanded the role of hybrid powertrains. Working with hybrids presents additional challenges, as engineers must combine gas and electric systems inside the limited space afforded by modern, aerodynamically designed frames and bodywork.
In response, auto designers have initiated comprehensive lightweighting programs combined with compact powertrain designs. Engine and transmission housings are smaller and made with lightweight metal alloys. The geometries of ports and passages that carry critical fluids within powertrain housings are more complex, and ports are closer together, with thinner walls.
Sealing ports inside thinner, lighter base materials pose several challenges:
Stresses that sealing elements apply to base materials
Using enough force to properly set seals while minimizing effects on surrounding systems
Production factors: potential contaminants from manufacturing processes; time, resource requirements for port machining, sealing element installation
Reliability, warranty costs, quality, consistency of sealing elements; related production costs for sealing solutions
Greg Kozlowski, application engineer at metal-to-metal sealing and flow control products producer SFC KOENIG has worked with major automotive manufacturers to provide critical sealing solutions for drilled ports in a wide variety of compact, lightweight alloy powertrain applications.
In the past, Kozlowski explains, products such as cup plugs, ball plugs, and threaded fasteners (screw plugs) were the most common methods of sealing ports. Those low-cost solutions, however, are not suitable for thin-wall applications. The high-stress installation forces needed to seat a cup, ball, or screw can deform and crack the surrounding material. Also, screws require tapping the port and may need sealant application, adding production steps that can lead to contamination from debris or sealant entering the fluid system.
Many low-cost plugs have less-precise production tolerances, resulting in part-to-part size variation. In a high-volume production environment, where port diameters are drilled to exact tolerances across multiple assemblies, size variation in the sealing plugs can prove costly. A plug that is too small will leak, and one that is too large may damage the base as it is installed.
“Customers who relied on cup, ball, or threaded fasteners have realized these products are no longer appropriate,” Kozlowski says, adding that more-advanced sealing methods, such as KOENIG EXPANDER expansion-style plugs, are taking the lead in providing low-stress sealing solutions in compact, lightweight engines and transmissions.
KOENIG EXPANDER® plugs feature a serrated outer shell that expands when force is applied to the integrated ball or mandrel, creating a leak-proof seal with evenly distributed pressure.
EXPANSION PLUGS
Expansion plugs employ an expandable, serrated outer shell that is activated by a pre-assembled, metal ball or mandrel. The plug is positioned in the port and then set into place by pushing the ball or pulling the mandrel into the shell with a hand-held or automated tool. The shell expands radially, causing its serrated edges to press against the port wall, creating a leak-proof metal-to-metal seal with evenly distributed pressures.
“In addition to their low stress capabilities, expander plugs are generally easy to position and install, with precisely controlled stroke distances,” Kozlowski notes. “They’re especially valuable for deep or angled ports, or for complex port layouts where alignment is difficult or additional machining is not possible.”
Installing plugs without detriment to surrounding materials is critical when working with today’s lightweight metal alloys and thin-wall ports. Kozlowski points out that expansion-style plugs are manufactured to precise tolerances, allowing for tightly controlled stresses on surrounding materials, while providing a proven leak-proof seal.
Engineers can further adjust the pressures applied to port walls by slightly increasing the diameter of the port bore, relative to the expander plug. If the resultant port bore diameter is not larger than a specified limit of the shell’s expansion range, a secure seal is typically possible.
“We take a collaborative three-level approach in working with customers to arrive at a reliable and cost-effective sealing solution for low-stress applications,” Kozlowski says.
Level 1: Apply off-the-shelf products from standard inventory for the lowest-cost solution. If installation stress levels are too high, the engineering team may recommend design adjustments to the base component, such as increasing port bore diameters to allow the standard solution to work.
Level 2: A custom solution based on a minor design derivative of the standard sealing product to meet application requirements.
Level 3: SFC KOENIG engineers can develop a completely custom part using expander technology.
TOLERANCES Even with advanced sealing technologies, engineers must be vigilant when specifications call for installation of a plug in thin-wall ports, especially when ports are located near other fluid pathways or moving parts. A slight deformity in a port wall can protrude into a neighboring section, causing misalignment of moving components, premature wear from friction, and restrictions in fluid transmission, Kozlowski says.
KOENIG EXPANDER® plugs are available in a wide range of sizes and metals to meet specific, low-stress, metal-to-metal sealing application needs.
The company’s engineers recently developed a custom solution, working with a major automaker, to seal ports in an aluminum alloy transmission housing that contained a bearing shaft. Due to the position of installation and the stress requirements, engineers designed a custom expander utilizing a low stress pin design instead of a ball. This custom expander solution created a reliable seal with very low stresses on port walls – sealing ports in the housing and preventing sidewalls from deforming and interfering with the bearing shaft.
Testing is essential when developing such sealing solutions.
“We work closely with customers to thoroughly test solutions before making any recommendations,” Kozlowski says. “When we receive designs and specifications from the customer, we go through an extensive evaluation process. We begin with theoretical testing and modeling. We identify potential products that meet application requirements and calculate the effects of installation and the expected performance. If our theoretical tests are successful, we move to practical tests. We work with customers to source base materials and test the performance of the sealing products in the alloys the customer will be using in final production.”
PRACTICAL LIMITS Any plug that relies on friction and outward pressure to form a seal will apply stress to the base material. To minimize stress and maximize seal performance, there are limits to how thin a port wall can be to maintain its integrity during plug installation and subsequent pressurized operation. According to Kozlowski, “Installations in applications with wall thicknesses that are less than 65% of the bore diameter can be achieved, but they require special consideration.”
Application engineers often conduct destructive tests on base alloys to identify the physical limits of the sealing product and the base materials. Destructive tests that take materials to their limits help engineers understand and optimize long-term reliability of sealing solutions. This is important because a leaking seal, especially across an entire product line, can lead to increased warranty costs for automakers.
Engineers also must consider production costs in their specification process. Scrapping components damaged during seal installation adds time and material costs, so low-stress expansion seal technologies can reduce waste by lowering scrap rates.
Pull type expander plugs use an integrated mandrel to expand the outer shell and are ideal for sealing deep or angled ports.
One-piece plugs arrive ready for installation with a flexible tolerance range up to 0.12mm for pull-style expander plugs and up to 0.10mm for push-style plugs. While advanced sealing technologies typically cost more per part than the traditional cup, ball, and screw methods, costs are offset by the reduction in waste and production time.
“The No. 1 objective of all sealing methods is providing a reliable, leak-proof seal,” explains Kozlowski. “While our expander plugs provide a variety of benefits in lightweighting projects, at the end of the day, it’s all about seal effectiveness and reliability. KOENIG EXPANDER plugs have a field failure rate of less than one part per million (ppm), with more than 5 billion parts installed.”
Advances in sealing technology and the ongoing development and re-engineering of the smallest system components contribute to success in modern vehicle lightweighting and space-saving programs. As engineers continue to collaborate to find the best methods of designing and manufacturing assemblies with lightweight alloys and compact designs, automakers can expect to achieve the goals of reduced emissions, energy conservation, and optimum vehicle performance.
PROPER SEAL SELECTION ELIMINATES AIR SPACE IN AUTOMATIC TRANSMISSION
In the previous transmission, a cup plug sealed the cross-drilled channel at the edge of the shaft. Its position created dead space and allowed air pockets to form.
As 8, 9 and even 10-speed automatic transmissions become more common, system complexity and sensitivity has increased. With additional speeds comes the requirement for additional clutch actuation ports to be added to the transmission shaft, resulting in less space between ports and thinner port walls. While delivering increased fuel economy and better performance, these modern transmission systems have much less operational tolerance.
When a major automotive manufacturer noted noise and rough shifting in their new multi-speed automatic transmission systems, engineers began a system-wide analysis. They eventually focused on dead space within the cross-drilled channels that connected the clutch actuation ports. These channels allowed for even distribution of transmission fluid, but created approximately 6-inches of space between an actuation port and the transmission shaft seal. The dead space became an area where air would collect, which was determined to be a major source of the performance issues.
The manufacturer brought the project to SFC KOENIG® for evaluation. SFC KOENIG engineers reviewed the cross-drilled channel design, and noted that the manufacturer had continued to use the same cup plug seals that had been used in their older, less advanced transmissions.
The cup plugs, which sealed holes at the surface of the transmission shaft, resulted in the dead space that allowed air pockets to form. While these air pockets were not problematic in the operation of their older designs, the new transmission systems were much more sensitive.
“While often selected for their low price, cup plugs present a number of challenges, especially in precision and deep bore applications,” said Nate Moore, Product Manager at SFC KOENIG. “In this project we knew that sealing at the surface was not a good solution, and cup plugs couldn’t be installed deep within a drilled shaft, deep in the transmission. Ensuring proper installation of a cup plug in that type of location would be extremely difficult. In this design there would be no way to visually inspect the seal integrity or to access an improperly installed seal for a repair. A failed seal would result in complete transmission failure.”
The new multi-speed transmission design featured a KOENIG EXPANDER® plug installed deep in the cross-drilled channel. A removable pin was used to align the plug during installation.
Cup plug installation offers little tolerance for variation. The installation system must provide accurate alignment, apply even and controlled pressure, and deliver a precise stroke to create a secure seal. The aspect ratio of cup plugs, which tend to be large in diameter but “short” in height, make alignment more difficult. Additionally, pressure points created by installation tools make the cup plugs susceptible to deformation and can lead to a reduction in seal effectiveness. There is also an inherent risk of contamination from sealant, which most cup plugs require to maintain seal integrity.
Other common sealing solutions, such as threaded pipe plugs, were also not viable options. Even if the threaded plug was long enough to fill the dead space, the forces applied to the port walls during installation would be high and would likely damage the shaft. Other sealing solutions required additional machining processes, such as drilling and tapping, which would increase costs, production effort, and the risk of contamination from metal debris.
Working with the customer, SFC KOENIG suggested a solution that could be reliably positioned deep within the bore. A push-type KOENIG EXPANDER® MB 850 Series would be installed at the edge of the clutch actuation port, eliminating the space that allowed air pockets to form.
A push-type KOENIG EXPANDER® inserted into a shaft, before expansion.
KOENIG EXPANDER plugs featured a unique serrated sleeve and ball. During installation, the ball would be forced into the sleeve, causing the plug to expand into the base material. This would create a permanent metal-to-metal seal that would not require sealant, and could be installed in the existing gun-drilled port without additional machining operations.
“Our KOENIG EXPANDER® plugs were the type of engineered sealing solution a high-performance application like this requires,” continued Moore. “Our components are proven. We have installed more than 3 billion components with field failure rates less than 1 PPM (part per million). We were confident the component could be installed deep within the transmission block without concern. After testing and evaluation our customer was also able to realize the value in our one-piece, engineered expander seal.”
SFC KOENIG worked directly with the manufacturer, not only providing the sealing technology, but also to develop a solution to integrate their products in the manufacturer’s production environment.
An installed KOENIG EXPANDER® plug. The ball has been inserted into the sleeve, which has expanded into the base to form a secure, metal-to-metal seal.
While high-speed installation tools were accurate, there was concern for variation caused by positioning tolerances in the automated environment. SFC KOENIG engineers developed an additional positioning method to ensure optimal placement was achieved.
During installation, a temporary, removable pin was inserted into the actuation port. The KOENIG EXPANDER was inserted into the deep gun-drilled channel, pushed until it came into contact with the pin, and then expanded. After the seal was installed, the pin was removed. This ensured that the plug was not inserted too deep in the channel, which could block part of the actuation port, and also provided maximum contact between the plug sleeve and the port walls. The seal ensured the most direct fluid path and blocked access to the “dead space” behind the expander.
With the new KOENIG EXPANDER plugs in place, problems associated with air pockets were eliminated. Testing of the new transmission was successful and the SFC KOENIG solution was utilized in large-scale production of the transmission systems.
Given the performance and reliability of the KOENIG EXPANDER in this application, engineers have begun to work with SFC KOENIG to evaluate other opportunities where this expander seal technology can be applied, such as hydraulic manifolds, pumps, cylinder heads and engine blocks.
SFC KOENIG’S CAREFUL ANALYSIS OF REPEATED TURBOCHARGER FAILURES ON AN OEM ENGINE MANUFACTURER’S PRODUCTS ENABLED IT TO FIND A SOLUTION THAT ENSURED RELIABILITY
An engine manufacturer was receiving a high rate of warranty claims due to turbocharger failures. After extensive analysis of failed units, problems rooted in design, product selection and installation were discovered. An engineered sealing solution came to the rescue.
Unlike traditional cup plugs, SFC Koenig’s are less susceptible to pressure related deformation.
Working together, the OEM engine manufacturer and Tier 1 supplier reviewed failed systems and noted that malfunctions were concentrated where the actuator mounted to the turbo housing. It was discovered that cup plugs were leaking, allowing coolant to enter the assembly and accelerate corrosion. This was resulting in premature actuator failure.
Cup plugs, or freeze plugs, are often selected for their low cost, and are stamped from a single piece of metal to create a cup shape. Most cup plugs use a press/ interference fit and often require sealant to achieve and maintain the seal. Cup plugs have little tolerance for port imperfections, and holes must be machined with a high level of precision.
The installation of cup plugs can also be difficult. The stamped cups are susceptible to deformation due to pressure points created by installation tooling. Any deformation can reduce seal effectiveness. It is imperative that the installation system applies controlled and even pressure with proper tool alignment and precise stroke. Another installation challenge is the aspect ratio of the cup plugs, which tend to be large in diameter but low in height.
Close-up of a one-piece pull-style KOENIG EXPANDER plug. The mandrel is pulled and causes the serrated sleeve to expand into the base, forming a metal-to-metal seal. The installation mandrel breaks away when the proper stroke is achieved.
Engineers realized that it was relatively easy for production personnel to misalign the cup plug in the hole during assembly of the turbocharger system. Once the installation tool was applied, the plug was angled in the port, so a tight seal was not achieved. Failed units also showed evidence of damaged cup rings, which was likely caused during installation.
Additionally, the turbocharger systems operated at high temperatures. High heat is always a risk when relying on chemical sealants in a mechanical system. A combination of alignment, physical damage to the cup plugs and compromised sealant integrity resulted in paths for coolant to leak through.
After careful review, the engineering teams realized that the accuracy required in the cup seal installation was not feasible in the production line. While low in cost, the plugs were resulting in an extremely high total cost when warranty costs were included. Koenig Expander plugs ensure a more reliable seal than conventional fastening methods.
An expander plug being installed. The full length of the serrated plug sleeve will be in contact with the base, creating a secure seal with no sealant required.
An engineered expander seal was identified as the ideal solution. The metal-to-metal seal featured a unique serrated sleeve and mandrel. During installation, the mandrel was pulled into the sleeve to expand the plug into the base material. This formed a tight seal, even with a liberal hole diameter tolerance of 0.10mm. Engineers at SFC Koenig worked directly with the Tier 1 supplier to integrate its product into the design and production environment.
Production costs were also reduced, as the hole required less precise machining and epoxy was eliminated (which also eliminated the risk of sealant contamination). Most importantly, the Koenig Expander plug provided a safer, more reliable and more secure seal.
While the cup plug was originally selected for its low cost, the engineered Koenig Expander actually lowered total costs and provided greater seal reliability. The company reported that warranty claims caused by leaking in the turbocharger system were virtually eliminated with the new components in place.
FLUID POWER SEALING SOLUTION – WATER HYDRAULICS APPLICATION
A reliable sealing solution was needed for a water-based hydraulic system. The system controlled the operation of a dredging vessel’s hopper doors, which are located in the boat’s hull. Proper door operation ensured the doors were securely closed when filled with debris, and that dredging materials would be deposited in the correct location when doors were opened. Should the doors’ functionality become comprised, operations would stop and there was the potential for severe penalties.
Seals were needed in multiple cross-drilled ports within the hydraulic system’s logic block to control water flow between the pilot valve and a large poppet valve. While the marine application presented temperature extremes and environmental concerns, the hydraulic system also had unique spatial challenges, as the system was being developed to be smaller and more compact than the previous model.
While SAE type plugs had been used in the previous logic block, plugs with correct pressure performance capabilities were too large in diameter for the new design. The customer also noted that the SAE plugs required specific monitoring and inspection. Dredging operations created regular vibration and shock, as materials were emptied onto the doors with great force, and instances had been identified where the SAE plugs had begun to back out from the port.
SFC KOENIG engineers worked with the customer from the early stages of the hydraulic system development. Multiple KOENIG EXPANDER CV series plugs were selected, which exceeded pressure requirements and fit the smaller port configurations. The CV 173 models were constructed with an aluminum sleeve, so the plugs would not corrode with the base material, react with water in the hydraulic system or be affected by potential exposure to the exterior environment. While both 6.0mm and 10.0mm models were ultimately used in the system, parts were available as small as 3.0mm to as large as 22.0mm in the series, which provided flexibility as designs progressed.
In the previous design, space was needed between each channel to increase the strength of the base, to prevent cracks and damage that could occur from thread tapping processes and the rotational torque applied in the SAE plug installation. SFC KOENIG worked with customer engineers and advised on channel configurations and pressure considerations as they related to the sealing plugs, which allowed for a new channel design that reduced the size of the base. In addition, assembly operations were analyzed to develop ideal pressure settings, tooling alignments and installation processes using SFC KOENIG air hammers.
While size and space were the primary reasons for the switch from SAE plugs, KOENIG EXPANDER components also provided many benefits related to installation, which were fully realized during the engineering process. SAE plugs required additional drilling and tapping operations, which generated metal debris and could potentially cause contamination. Comparatively, the serrated sleeve of the SFC KOENIG component expanded into the base material when installed – no metal chips were created and a secure, leak-proof seal was formed that did not require sealing compound. Additionally, the elimination of thread tapping also eliminated the risk of cross tapping.
In the final design SFC KOENIG engineers were able to help optimize sealing plug size and installation forces, which reduced the size of the hydraulic system and resulted in a leak-free seal that could resist vibration and would remain permanently secure. KOENIG EXPANDERS plugs reduced installation time and effort required in installation, and lowered total costs.
After 5 years of use, the new water-based hydraulic system has recorded no problems due to seal failure, and the reliability of KOENIG EXPANDER models has reduced maintenance and downtime. Installation of the SFC KOENIG components is also faster than the SAE plug installations, which has reduced assembly time and costs. The plugs have been integrated into other hydraulic systems produced by the customer, and KOENIG EXPANDER plugs are now the preferred sealing solution.
The customer noted that the engineering support provided by SFC KOENIG was integral in their ability to successfully reduce the size of the hydraulic system, and that the design process provided on-going communication and support, which reduced the time required to bring the project to completion.
Technical Details
› Application: Water-based hydraulic system for marine vessel
› System Pressure: < 100 bar
› Fluid Medium: Water
› Product: CV173 Series Plug
› Volume: 10,000 Million
Product Overview
› Model: CV 173-070
› Style: Push Style Expander Seal
› Sleeve Material: Aluminum 2024-T4, QQ-A 225/6
› Ball Material: Stainless Steel, AISI 302/304, Wax Film Lubrication
› Pressure Capabilities: Up to 170 Bar
› Sizes Available: 3.0 to 22.0mm in diameter
Installation performance of KOENIG EXPANDER® sealing systems verses traditional port sealing methods.
