Automotive System and Component Contamination Sensitivity

Experienced SwRI engineers use a variety of contaminant dusts to evaluate their effects on a transmission valve body.

Excessive wear and malfunctions in automotive systems are often caused by contaminants or small particles that may be built-in, self-generated, or ingested from the environment. In addition to premature abrasive wear, these contaminants may cause blockage, lockup, and premature failure of valves, pumps, seals, fuel injectors, and other automotive components. Results may include machine performance degradation, shortened service life, customer dissatisfaction, and catastrophic failure. Southwest Research Institute (SwRI) engineers and scientists address these contamination problems using a multidisciplinary approach that employs failure analyses, laboratory testing, experimentation, field work, modeling, predictive correlation, design elaboration, and concurrent engineering.

The Institute's areas of focus include:

• Contaminant characterization
• Accelerated life testing (Key-Life testing)
• Material compatibility
• Modeling and simulation
• Test procedure development
• Lubricity, friction, and wear
• Environmental evaluation
• Filtration
• Emissions and safety issues
• Component and systems development

Because SwRI does not manufacture or endorse products, all investigations are impartial. In addition, client confidentiality is protected. SwRI's Engine and Vehicle Research Division has achieved certification to ISO 9001, ensuring compliance with stringent quality control procedures in design, development, and research.

Contaminant Characterization

Contamination significantly affects the performance and durability of fuel, air, and lubricant components and systems, especially with respect to automotive safety, vehicle performance, and warranty issues. SwRI uses advanced analytical tools, testing techniques, and simulation methodologies to assess the contamination sensitivity of fuel system, engine, and powertrain components. Institute services include:

• Functionality testing
• Contamination sensitivity and durability testing
• Contaminant chemical composition determination
• Contaminant particle size evaluation

SwRI engineers evaluate changes in surface characteristics at critical boundaries as illustrated in these micrographs of a fuel injector tip. (Top left: 250-hour test; Bottom right: 750-hour test)

Accelerated Life Testing (Key-Life Testing)

Working closely with industry, SwRI engineers develop accelerated-life testing methods to determine the expected life of components and systems, particularly those subject to premature failure. In establishing accelerated-life testing programs, engineers may: 

• Use pre- and post-test boundary analyses to identify and evaluate critical parameters
  
  
• Apply classical or modern accelerated-life assessment methodologies
  
  
• Interrogate machine performance through introduction of controlled contaminants 
  
  
• Evaluate component and systems design and construction to determine vulnerability 

Institute engineers have developed a series of fuel-system simulations representing 36,000 to 150,000 miles of vehicle operation.

In this contamination sensitivity evaluation, staff members introduce controlled amounts of contaminant into the fuel delivery subsystem assemblies as they undergo severe laboratory testing.

Material Compatibility

Today's automotive components must be compatible with numerous environments, operating conditions, and automotive and industrial fluids. For example, fuel system components must be compatible with various fuel types, such as diesel, gasoline, ethanol, methanol, and blends, from all geographic regions. To help industry investigate these fuel-related issues, SwRI offers a variety of services, including:

• Contamination control strategy development, implementation, and evaluation
• Specialty fuel formulation
• Hot and cold soak with specialty fuel
• Scanning electron microscopy (SEM) examination 
• Material and failure analyses
• Fuel property and contamination analyses
• Fuel compatibility studies
• Lubricity and wear property evaluation
• Filtration analysis

After changing fundamental models of deterministic systems to stochastic models, SwRI scientists simulate the influence of contaminants in a system.

Modeling and Simulation

During component and system development, performance predictions are often based on specific physical characteristics and deterministic operating parameters. System contaminants often modify operating performance, resulting in a change of deterministic equations to stochastic models involving time-varying, probabilistic random variables. Using contamination sensitivity analysis, testing, modeling, and simulation methodologies, SwRI engineers help manufacturers:

• Design components to function
  • at given contamination levels
  • for suitable periods of time, and 
  • with acceptable performance
• Identify contaminant-sensitive components
• Develop realistic service-life estimates
• Achieve targeted service life for final designs

Test Procedure Development

Measurement of contaminant sensitivity is becoming more important as vehicle longevity requirements increase and production processes leave internal residue in the component. SwRI staff members, with extensive experience in measuring system and component responses to internal contamination, work with automotive manufacturers and their suppliers to develop effective simulants and test procedures. Institute engineers provide testing methods to evaluate contaminant impact on performance and longevity of automotive components such as:

• Fuel pumps
• Seals
• Fuel injectors
• Engines and transmissions
• Hydraulic control valves

SwRI uses contamination analysis, testing, modeling, and simulation methodologies to assist industries in developing specialty test procedures that determine how contaminants affect the performance of automotive components such as filters, pumps, seals, and fuel injectors.

Lubricity, Friction, and Wear

Engines and other automotive components, especially air, fuel, and lubrication systems, are continually subjected to wear-causing environments. Because fuel has a low viscosity, the ability of a system to maintain engine lubricity to reduce friction and wear is important. To measure friction and wear at critical components, SwRI offers a variety of services, including:

• Fuel lubricity assessment 
• Commutator friction measurement
• Wear measurement
• Brush contact voltage drop testing
• Surface wear measurement in real-time using radioactive tracer technologies

SwRI engineers use radioactive tracer technology to measure piston ring and connector rod wear in response to engine speed, load, and coolant temperature.

Environmental Evaluation

SwRI scientists and engineers subject components, subsystems, and final assemblies to simulated environments that are sufficient to measure acceptable performance and longevity. For production verification, sufficient environmental stresses are added to detect workmanship or process faults. SwRI offers numerous services to study and evaluate the durability of fuel, air, and lubricant systems and components. These services include:

• Thermal cycle testing
• Vibration and resonance evaluation
• Pressure cycle testing
• Flow cycle testing
• Durability simulation

Institute scientists develop test protocols that combine contamination, pressure cycle, thermal cycle, and vibration in a single test, providing close to real-world test data in a timely and cost-effective manner.

Filtration

Filtration plays an important role in delivery systems for fuel, air, and lubricants. Proper filtration strategies help industry reduce or eliminate malfunctions of air induction, fuel delivery, and lubrication components. Using advanced small particle and filtration-assessment technologies, Institute engineers provide the following services:

• Particle-loading pattern analysis
• Dust-loading pressure drop testing
• Dust-loading capacity measurement
• Filtration efficiency testing
• Media testing

Using up-to-date instrumentation and laboratory facilities, Institute staff members design and test air, fuel, and lubrication filtration systems and components.

Emissions and Safety Issues

Understanding fuel properties, material compatibility, and component capabilities is essential to providing robust and environmentally friendly automotive fuel systems. SwRI engineers evaluate fuel-delivery components and systems with respect to a wide range of emissions and safety-related issues. The Institute provides the following services:

• Helium- and fuel-leakage testing
• Hot-fuel handling
• Permeation testing
• Hydrocarbon compound analyses
• Upper and lower flammability limit determinations

Component and Systems Development

SwRI has extensive experience in fuel and lubricant delivery systems, air induction systems, and automotive component testing. Engineers possess a comprehensive understanding of flow dynamics, contamination tolerance, and material life expectancy. Institute staff members provide component and system design and fabrication services for air, fuel, lubricant, and other engine and powertrain systems and components. These services include:

• Prototype component design
• Computational fluid dynamics analysis
• Prototyping
• Statistical analysis

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