Road Ready
By Ted Worroll and Mike Gardiner, Product Managers at ITT Interconnect Solutions

Rugged connectors are meeting the rapidly changing requirements of the modern automotive platform. Today’s vehicles are heading into new territory, thanks to smart and adaptable interconnect products.

There is one requirement in the automotive industry that remains steadfast — reliability. While consumer demands drive many trends in the dynamic automotive industry, including cost, comfort, size, style, safety, and functionality, the need for advanced, rugged components in this harsh-environment application remains a constant. Many automotive connecters were developed based on industrial connector designs. The original industrial designs were developed to address many of the same environmental factors that are found in the automotive environment, including high temperatures, vibration, shock, and fluid exposure. Engineers adapted the industrial designs to meet automotive requirements; however, the increasing complexity of automotive electronics — particularly control systems and sensors — has created demands for interconnect solutions that vary greatly from the traditional pin-and-socket connectors.

Designers utilizing the latest technologies to enhance systems such as safety features, user interfaces, and electric vehicle charging must implement high-performance, ultra-dependable connectors. In addition to meeting reliability and quality standards, connectors in today’s vehicles are required to have an increased I/O count and density, while reducing their PCB footprint and cost.

Reliability and Ruggedness
A significant challenge in the evolution of the automotive connector is meeting reliability and durability standards. Today’s vehicles rely heavily on electronics to control critical systems, including steering, braking, airbags, and GPS. This means that electronic components used in safety-critical electronic systems must be ultra-reliable and durable. Failures in any critical system could have disastrous results. While today’s electronic systems have demonstrated reliability, they cannot be visually inspected and physically tested like traditional rod-and-gear mechanics. As electronic designs continue to replace mechanical control systems, connectors must evolve to eliminate reliability concerns.

Temperature: Under-the-hood applications must perform on both ends of the temperature spectrum, from sub-freezing temperatures prior to ignition to high operating temperatures when an engine is running. Temperature stresses are common in automotive applications, and these stresses require connectors that can operate at temperatures between -55ºC to +125ºC, but these aren’t the only concerns. Current electronic fabrication processes require connectors that can withstand processing temperatures for RoHS compliance up to +260ºC (for a limited time during processing). This elevated processing temperature requirement has emerged in response to the European initiatives that eliminated lead from soldering operations, thus elevating the processing temperatures during electronics fabrication.

Shock and Vibration: Interconnects for automotive electronics have incorporated much of the experience from industrial applications with regard to shock and vibration. It can be challenging to find interconnect solutions that are able to withstand both low and high frequency vibrations typical of automotive applications; hence, the critical need to find an interconnect partner with the ability to work on a project from the beginning to ensure that a reliable solution ends up in the finished product.

Examples of vibration include low frequency sources caused by out-of-balance wheels on a vehicle; to high frequency vibration caused by engines. Shock loads vary, with some extreme, undampened shock resulting in hundreds of Gs of force on impact surfaces.

Sealing: Many electronics traditionally used in automotive applications were developed for environments not typically subjected to moisture and chemicals. Fortunately, some manufacturers have been able to use their industrial experience to implement sealing techniques designed to meet IP65 (splash), IP67 (submersion), and IP69 (spray) specifications. Manufacturers have employed anti-corrosive materials to ensure connectors survive in wet and corrosive environments for applications found on vehicle engines, batteries, and on systems exposed to the external environment.

Quality
Beyond the performance and environmental exposure issues for connectors, there are important quality concerns as well. Conditions, such as bent pins from connector misalignment during assembly, are an old problem that affects reliability, raises assembly costs, and leads to production delays. However, even this issue is being addressed through the latest plug-only landed contact designs, which minimize these types of quality issues. There has been a significant move away from traditional pin-and-socket connectors towards newer pressure contacts that can be better controlled in under-hood environments.

These plug-only landed contact systems include pressure contacts designed to mate directly to pads on a PCB, yet are able to withstand the thermal shock, vibration, and hostile environments common in automotive applications. In these systems, all of the contacts are in a plug-side connector, so OEMs can have receptacles integrated into their housing with essentially no connectors and no contacts. The advantages include:

• Increased density (due to requiring only a pad on the PCB);

• Cost reduction (from the removal of contacts);

• Simplification of the connection in the plug-side to provide the total solution

New connector designs provide a plug-only solution that is scalable, sealed, rugged, high-density, smaller, and with lower total installed costs.

Innovations
Environmental concerns and the rising cost of oil have spurred consumer demand for more compact, fuel-efficient vehicles. Technological advancements have enabled automobile manufacturers to address this demand with the mass-production of environmentally friendly vehicles, such as hybrid and electric cars. Since the introduction of electric vehicles, a primary concern from many skeptical consumers has been the reliability of the charging solution. Not only is the operating life of the rechargeable lithium-ion battery being questioned, but the lengthy battery recharging process is also an issue. These obstacles have undoubtedly delayed the mass-production of electric vehicles by major automotive manufacturers. With recent interconnect technology advancements, however, the charging of a lithium-ion battery can be significantly reduced from the standard eight hours down to four hours.

With the release of the SAE Electric Vehicle J1772 charging specification in January 2010 (a standard adopted in both the U.S. and Japan for Level 1 and Level 2 electric vehicle charging), the automotive market needed a robust coupler capable of passing the stringent UL 2251 certification. In addition, the application required a high amperage charging solution that could provide fast, easy, safe charging of any electric vehicle.

Manufacturers have provided a high amperage solution that reduces the Level 2 charge time by 50%. With a single inlet design that allows for Level 1 and Level 2 charging, this advanced interconnect system has proven its ability to meet both electrical and mechanical UL specifications. It features high-efficiency power contact technology to provide flexible functionality, with minimal modifications, across a power curve ranging from a low of 15 amps/120 volts to a high of 75 amps/240 volts. The interconnect solution utilizes standard ITT VEAM CIR Series backshells, flange gaskets, and mounting plates, providing for an enhanced cable management system that incorporates robust and proven technology and ground pin contacts on the inlet side. Anti-freeze drain holes enable outdoor use in extreme environments.

Conclusion
Manufacturers are continuously developing new connector designs and technologies to keep pace with automotive demands. When designing for the automotive industry, engineers must always take into account the severe environmental conditions that connectors are subjected to every day. As electronics are increasingly used in safety-critical automotive applications, it is even more important that connectors are rugged and reliable.

Mike Gardiner is a product manager at ITT Interconnect Solutions, and has more than 30 years of experience in the connector industry. Mike received his B.S. degree from Saint Louis University. Mike can be reached at mike.gardiner@itt.com.

Ted Worroll is a product manager at ITT Interconnect Solutions and has been with the company for 22 years. Prior to joining ITT, Ted spent 9 years with LFE Corporation and 6 years with WALSCO.