Consumer demands drive many trends in the dynamic automotive industry, whether it is cost, comfort, style, safety, reliability, functionality, or any number of other factors. These customer demands, combined with consistent technology advancements, performance enhancements, and the requirement for smaller, lighter systems and components, have shaped the evolution of the automotive connector.
Historically, 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—and can adapt to electric and hybrid vehicles.
Designers utilizing the latest electronic technologies to enhance systems such as safety features, user interfaces, and electric vehicle charging must implement high-performance connectors. In addition to meeting quality and reliability standards, connector requirements in today’s vehicles include increased I/O counts, higher densities, small PCB footprints, and lower costs. Although these requirements may appear incompatible with lowering costs, connector suppliers are responding by developing new solutions that challenge traditional parameters in regard to both technology and cost.
Reliability and durability
One of the biggest challenges 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, brakes, airbags, and GPS navigation—which means that electronic components used in key 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 the reliability concerns.
These challenges include:
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 -55 and 125C, but these aren’t the only concerns. Current electronic fabrication processes require connectors withstand processing temperatures for RoHS compliance up to 260C. 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 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 range include low frequency sources, caused by out of balance wheels on a vehicle, to high frequency vibration caused by engine turbochargers. Shock loads vary—with some extreme, undamped shocks resulting in 100s 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 systems exposed to the external environment.
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—one that not only affects reliability, but assembly costs and production delays as well. 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 tremendous move away from traditional pin and socket connectors to 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 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:
• Cost-reduction from the removal of contacts
• Increased density, due to requiring only a pad on the PCB
• Simplification of the connection in the plug-side
New connector designs provide a plug-only solution that is scalable and sealed, which increases density, reduces PCB space, and cuts total installed costs.