CUSTOM CHECK VALVES HELP REGULATE FLUID PRESSURE, PROVIDING PRECISE SYSTEM CONTROL TO REDUCE FUEL CONSUMPTION AND EMISSIONS.

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.”

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.

Learn more about our custom solutions.

DAMAGE PREVENTION, EMISSIONS CONTROL AND EFFICIENCY IMPROVEMENTS CAN BE ACHIEVED BY ALLOWING THESE COMPONENTS TO REDUCE DEBRIS IN FLUID SYSTEMS

Fluid contamination presents a growing concern for engineers in the automotive industry. Today’s designs rely on complex fluid systems to optimize performance and control emissions. While flow restrictors provide the precision fluid control needed, contamination in lubricant not only affects the performance of the flow restrictor, but can be detrimental to downstream components, parts and assemblies, often the most expensive to replace. By designing-in a screened flow restrictor, engineers can improve fluid cleanliness, protect systems and optimize designs, all while helping to meet performance targets.

While not a filter, screened restrictors help prevent contaminants – such as rubber, plastic, compounds and metal debris from circulating in a fluid system. These contaminants can damage components and affect performance, leading to warranty costs and reduced efficiencies. The permanent addition of the screened restrictor not only precisely controls the flow rate, but it also helps to ensure prolonged circuit functionality and fluid quality. Engineers are increasingly looking to these parts to provide performance gains and design changes that help meet emission targets and efficiency goals.

“Screened KOENIG RESTRICTOR® solutions are an effective tool for many of our automotive customers. We’ve worked on applications where they are used in diesel exhaust dosing – helping to reduce harmful NOX emissions – as well as a critical component within an all-wheel drive disconnect system – which increased fuel efficiency by regulating when a vehicle would be driven by two wheels instead of four, depending on road conditions,” said Nathaniel Moore, Product Manager for SFC KOENIG®. “The push to meet ever-expanding and more exacting global standards means we are continuously finding new opportunities to leverage the benefits of a screened flow restrictor.”

Parts reduction is an effective method to achieve lighter weights. Often times within a fluid circuit, there may be a component or a sub-system which cannot handle the volume of flow that the rest of the circuit operates on. By permanently reducing the flow rate with a screened restrictor, the same circuit can be used for lubrication, eliminating the need for a separate circuit and/or additional components, such as pumps.

“Engineers know SFC KOENIG parts for their proven reliability, precise flow control and fast, easy installation even in high-speed manufacturing environments,” said Moore. “With our one-piece screened restrictor design they get all those benefits, and it allows one small component – between 4 to 10mm in outer diameter – to potentially eliminate the need for large system components or additional independent circuits.”

While the screen itself helps to eliminate contamination in the fluid, since KOENIG RESTRICTOR solutions do not require thread machining, reaming, sealants or adhesive compounds, they also do not create any additional contamination.

To achieve the desired flow rate, as well as eliminate fluid debris, it is typically recommended one work directly with the screened restrictor manufacturer, as there are a wide variety of considerations to each application.

“Though screens in the 125-micron range are often utilized, our recommendations are really based on thorough knowledge of their requirements,” continued Moore. “Base material, fluid medium, pressure, temperature and operating conditions affect the flow rate and impact of the screen. We work with customers to help develop the screened KOENIG RESTRICTOR solution, and even to provide a sealing solution for the same circuit, if needed. Our company’s global operations really help customers achieve their goals – no matter where they are located. That, combined with our advanced flow testing capabilities, allows engineers to achieve even greater results, knowing their system is optimized down to the component level.”

By designing-in a screened flow restrictor, engineers are realizing performance benefits, as well as new opportunities to improve efficiency and reduce emissions.

Learn more about our standard orifice flow restrictor models as well as our custom solutions, or contact us and speak to our engineering team about your application. Our flow control experts can develop a screened flow restrictor for your specific requirements.

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.

 

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.

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.

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.

Learn more about SFC KOENIG expander plugs, or submit our quick Value Calculator form for a total cost comparison calculation, and learn how KOENIG EXPANDER plugs compare to your existing seal products.

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.

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.

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.

Find out more at www.sfckoenig.com.

 

 

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.

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.

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.

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.

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.

Learn more about KOENIG EXPANDER plugs and our engineering support.

 

PROPER SEAL SELECTION ELIMINATES AIR SPACE IN AUTOMATIC TRANSMISSION

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.”

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.

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 5 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.

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.

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.

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 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

MORE THAN LEAKAGE – PROPER METAL-TO-METAL SEAL SELECTION CAN AFFECT SAFETY, PERFORMANCE, LIFESPAN & COST

In any solid block of metal, where multiple ports have been drilled to allow for cross-channel fluid or gas conveyance, proper sealing of the drilled port is critical to performance. When evaluating seal options engineers must consider much more than the potential for leakage, but also installation, cleanliness requirements and materials. Proper metal-to-metal seal selection ensures reliable performance, long-life and lower total costs.

Many common metal-to-metal seals – such as screw plugs, ball bearings and cup plugs – are not well-suited for today’s precision transmission systems. Metal-to-metal seal selection has become a more complex decision because of hydraulic fluids with unique viscosities, very thin port wall thicknesses, and materials with low elasticity moduli that are being used more frequently.

Expander seals are an increasingly popular metal-to-metal seal option. Their unique design features a serrated sleeve and internal element, such as a ball or mandrel. When force is applied, the internal element expands the serrated sleeve to engage the base, forming a reliable and secure seal. System designers can be more confident when choosing an engineered sealing solution.

Proper Metal-to-Metal Seal Installation & Damage Prevention

Modern transmission system design often results in very small port wall thicknesses, and most transmission components have little tolerance for deformation. These factors can be especially challenging for seals that require high installation forces – such as the stresses caused by ball bearing insertion, or the axial forces created by screw plug insertion. Both of which can result in cracks and other damage.

“Expander seals evenly distribute installation stresses,” said Tom Ryan, Head of Product Management at SFC KOENIG®. “The plug is inserted into the channel and then expanded, forming a tight seal with the base metal. Pull-style plugs eliminate axial forces and radial forces can be engineered based on the installation, making them ideal for thin-wall applications and softer base metals.”

Transmission ports can also be difficult to access, and housings can be large, which results in complex handling and positioning of the seal. Many expander seals uniquely support installation at difficult angles without the need for elaborate fixtures. Their design also allows for plugs to be easily set deep within the channel, which can eliminate dead space within the port where air pockets can occur.

Eliminating the Risk of Contamination

Different metal-to-metal seal types have different contamination sources, such as:

• ball bearings – interference press-fit can result in metal debris


• screw plugs – tapping threads can result in metal debris


• cup plugs & screw plugs – often require sealant, which can be applied incorrectly or in excess, and contaminate the lubricating fluid or potentially block the port.

Expander seals require no additional machining processes or sealant, significantly reducing the risk of contamination.

Preventing Corrosion

Many transmission materials, such as cast iron, are not compatible with aluminum or other common seal metals. The engineer must consider the potential for corrosion between the seal and base, as well as between the seal and the fluid being sealed, especially after long lifecycles.

“Corrosion is an important factor in contamination and seal failure,” noted Ryan. “It is why SFC KOENIG offers a variety of material types, and why we have performed tests that demonstrate the effectiveness of our parts in corrosive environments. It is important to consider long-term corrosion factors when selecting the seal.”

Cost

When comparing the per-piece cost of sealing options, the less expensive options are screw plugs, cup plugs and ball bearings. Ryan noted that cost evaluation is more complex.

“When total costs are calculated, common seal types often turn out to be more expensive.” For example, our KOENIG EXPANDER® requires no additional machining processes and, with its one-piece design, requires no assembly, reducing error, scrap and labor costs. There is also significantly less risk of contamination, damage and seal failure. When total costs are calculated, expander plugs are often not only one of the most reliable, but also one of the most economical, metal-to-metal seal options available for drilled holes.”

KOENIG EXPANDER® LK950-100 series pull-style expansion seals, made of case hardening steel, improved performance and eliminated contamination in the aluminum block engine.

As the popularity of aluminum block engines has increased, engineers are challenged with unique concerns, balancing performance, weight and production costs.

SFC KOENIG recently worked with an automotive customer to analyze and solve performance and warranty issues. Engineers had identified contaminant in the oil as a major source of problems.

A UNIQUE AUTOMOTIVE CHALLENGE:

SFC KOENIG focused on threaded pipe plugs used to seal oil journal holes as the issue. The plugs required the port to be tapped, a machining process which created debris. In some instances, this debris was not properly cleaned and created micro-size particle contaminants.

Additionally, the pipe plugs required sealing compound to improve seal integrity. This sealant was often applied in excess and then circulated in the oil, which affected lubricant integrity and leading to a build-up of debris.

During the assessment, engineers noted failure rates increased when production capacity was at higher levels. It was realized that installation equipment and personnel could not maintain pipe plug alignment consistency at high speeds. This resulted in cross-threaded plugs, leakage and expensive rework.

THE SFC KOENIG SOLUTION:

KOENIG EXPANDER® LK950 series 10mm plugs replaced the threaded seals. The LK950 plugs utilize a metal-to-metal expansion design that does not require machining, tapping or sealing compound, and easily withstood the 100+ psi pressures.

“As systems become more advanced, old sealing solutions have become less effective,” said Tom Ryan, Head of Product Management at SFC KOENIG. “Our high performance products are more reliable than other seals, but when total costs are evaluated, they are most often the best solution.”

With its one-piece design and a variety of SFC KOENIG installation equipment, the customer quickly integrated the KOENIG EXPANDER into the automated environment and immediately realized improvement.

SFC KOENIG EXPANDER PLUGS PROVIDE CRITICAL RELIABILITY IN AUTOMOTIVE BRAKE AND TRACTION CONTROL SYSTEM

SFC KOENIG recently completed a project with a major automotive manufacturer to develop seals for new anti-lock brake and traction control systems.

Preliminary evaluations of the new design, which had originally sealed holes with ball plugs, showed debris was created during the press-in installation processes, as well as a high rate of seal failures. The designer identified the need for a superior, engineered solution to seal multiple critical ports within the central manifold and contacted SFC KOENIG, which worked with the customer to create a reliable seal that would prevent pressure loss and eliminate fluid leakage.

“Seal performance was critical to the successful operation of this new system, and selection was made more complex due to the anodized aluminum manifold base material,” said Nate Moore, Product Manager at SFC KOENIG. “Installation of the existing ball plug seals was resulting in cracks and leaks. Initially the customer increased the amount of sealant, which led to contamination, added assembly time, and increased costs. Our team worked with the customer’s engineering department to identify the best sealing components and installation equipment to provide reliability, safety and performance, while easily integrating into their high-speed production environment.”

SFC KOENIG assisted the customer in the selection of a MB 850-040E KOENIG EXPANDER® plug based on size requirements, materials, pressures, installation processes and the overall safety-critical nature of the application. As opposed to ball plugs, that were simply force fit into the port, the KOENIG EXPANDER utilized an engineered expansion principle. When inserted, the plug’s serrated sleeve was expanded into the base material and formed a reliable, secure and leak-free seal that required no sealant or additional machining processes.

During seal selection, SFC KOENIG engineers gave special consideration to ensure the anodized aluminum base material would not wear or deteriorate after repeated thermal and pressure cycles. In addition, plugs needed to perform with vigorous 160 bar air leak testing. While this testing simulated unusually high-pressure situations and exceeded normal operating tolerances, it was critical that seal integrity was maintained both in high-pressure situations as well as after pressures returned to normal ranges. SFC KOENIG engineers successfully demonstrated the effective design of KOENIG EXPANDER components.

“Our team has extensive experience in automotive sealing applications,” continued Moore, “which allowed us to provide valuable support to the customer in the design process, and also to provide a solution that they could trust. The combination of our MB 850 and our installation equipment reduced the risk of contamination, streamlined seal installation, and in the long run has lowered their costs when warranty and rework expenses are considered.”

The customer’s initial testing of the MB 850 showed improved pressure performance capabilities and no pressure loss, even after anticipated lifetime cycle testing. Successful field testing of a low volume initial run showed continued reliability and success. SFC KOENIG now has begun to supply orders of more than 1 million MB series expander plugs to the automotive manufacturer, and is a trusted partner for the company’s many sealing and flow control needs.

Read about KOENIG EXPANDER expansion seals.

AS ENGINE DESIGN EVOLVES TO MEET EMISSION AND PERFORMANCE REQUIREMENTS, THINNING PORT WALLS PRESENT SEALING CHALLENGES.

Today’s automotive engineers are challenged with designing more efficient engines that operate with reduced emissions. From small displacement, 4-cylinder engines in compact cars, to large displacement engines in commercial vehicles, new designs commonly reduce the size and weight of the engine to improve fuel consumption. Engine components are much closer together, and ports and passages – such as those that deliver oil – must be integrated into the remaining available space.

This results in thin port walls. Engineers are increasingly relying on low stress expander seals, such as the KOENIG EXPANDER®, in these applications.

“Customers that relied on cup plugs or threaded screws have realized these products are no longer appropriate,” noted Greg Kozlowski, Application Engineer at SFC KOENIG. “Thin port walls in new engine designs fail under the installation forces of these older style plugs, which have a wide part-to-part variation that can result in damage to one engine, and leakage in another.”

Thinner walls are increasingly common in crankshafts, cylinder heads, wrist pins, transmission systems and cast bosses located throughout the engine block. Often these ports are located in close proximity to bearings or moving parts. A seal that affects these surrounding components, due to expansion during installation or damage to the base, can cause additional wear. The precision tolerances of engineered seal solutions, like KOENIG EXPANDER plugs, are often looked to for reliable, precision sealing.

“Engineers often think of KOENIG EXPANDER seals for their high-pressure capabilities – up to 7200 psi working pressure,” continued Kozlowski. “Due to their precision engineering, we are increasingly providing expander plugs for what could be considered lower pressure applications – like an engine with operating pressure up to 65 psi, or even a crankshaft journal and bearing which can reach a few hundred psi – to provide safe and secure sealing with minimal effect to the port wall, even in applications with very thin walls and complex geometries.”

CUP & PORT PLUGS VS. KOENIG EXPANDERS

Commodity seals, such as cup plugs and port plugs are not produced with the same precision as a KOENIG EXPANDER. This repeatable precision of the KOENIG seal is maintained across millions of installations and can prevent cracking of the base or expansion of the port into nearby components, significantly reducing the risk of leaks, wear, and effects on system performance. SFC KOENIG also provides installation equipment for seal installation, with stroke force and distance strictly applied, providing additional controls.

Cup plugs typically utilize less precise forces in their installation, with larger variation in process performance. Similarly, the installation of threaded plugs applies torque to the base, which can result in cracks and deformation. These plugs typically require additional tapping or machining operations for their installation, as well as a sealant, all of which increases the potential for contamination.

In applications with thin walls, strict tolerances and reliable installation are critical. This becomes even more important when ports are located deep within the engine, where repair and review are difficult. SFC KOENIG also offers custom designed, low force expanders. For extremely sensitive applications where the standard expander does not solve the thin wall problem, this design reduces the installation stresses even further.

When compared to other standard sealing solutions, including less precisely-engineered expansion seals, KOENIG EXPANDER seals from SFC KOENIG have been proven to provide leak-proof security.

“With over 5 billion parts installed, and failure rates less than 1 PPM, our team understands the complex geometries and thin port walls in modern engine design,” continued Kozlowski. “Our can seal a wide variety of bore sizes, pressures, base materials and temperatures with complete reliability.”

For more on KOENIG EXPANDER solutions, view our Koenig Expander plug solutions.