The development of a new low-gravity inertial sensor for the ESC system helps illustrate how the number of sensors in today’s underhood areas will only continue to grow.

When dealing with an expanded number of underhood electronic controls and components, the core issue can usually be traced back to a greater number of interior creature comforts, improved fuel efficiency targets, expanded power/performance specifications or safety. In this case, we’ll discuss the latter— more specifically, the impact of electronic stability control.

The development of a new low-gravity inertial sensor for the ESC system helps illustrate how the number of sensors in today’s underhood areas will only continue to grow. ESC helps drivers maintain control of their vehicles by using high-performance, two-axis sensors to measure the lateral and longitudinal acceleration of the vehicle. When sensors register potentially unstable driving conditions, data is sent to the car’s engine and braking system to automatically assist the driver in maintaining vehicle control.

Freescale Semiconductor, a manufacturer and supplier of this technology has developed a next-generation, high-aspect ratio micro-electro-mechanical system (HARMEMS) for ESC. It uses a technology similar to that of airbag sensing and deployment applications. Since the ESC system is installed in either the vehicle cabin or under the hood, over-damped HARMEMS technology enables cleaner communication between the sensing elements and the rest of the related vehicle system controls.

Essentially, these new sensor advancements now allow for responding to a wider range of driving conditions with greater accuracy than in the past. This is achieved with improvements focused on these sensors’ ability to filter out extraneous signals, such as parasitic vibrations, that could potentially interfere with the vehicle’s lateral acceleration measurement. In addition, an integrated digital signal processor (DSP) improves signal strength in communicating with the rest of the vehicle’s related systems.

Additional features and functions of these new sensors include internal self-testing to ensure a ccuracy and system-wide synchronization. They’ve also been developed with an eye towards operating in harsh conditions, as they can withstand temperatures of -40 to 125 degrees Celsius.

As is the case with many safety-focused advancements, the development of these new sensors and ESC systems has been boosted by government-mandated changes affecting new vehicles. The National Highway Traffic Safety Administration (NHTSA) is requiring ESC systems on 100 percent of passenger cars, multi-purpose vehicles, trucks and buses sold in the United States by model year 2012.

NHTSA feels that as many as 9,000+ lives could be saved, and up to 238,000 injuries prevented annually once all light vehicles (weighing 10,000 lbs. or less) are equipped with ESC systems. In particular, SUV drivers and passengers seem to especially benefit from ESC, due to lower rollover rates. According to industry experts, ESC systems implementation is expected to increase to 48 million units by 2012, up from just 23 million last year.

So while electronic stability control is nothing new for the repair shop, it had been typically associated with higher-end vehicles. This NHTSA mandate will change that. With universal implementation, the ability to maintain and service these systems will be a key component of shop’s service offerings. This translates to:

• New diagnostic codes for reading sensor output.
• New specialty tools for accessing, removing and replacing the sensor and its related parts.
• The ability to understand how ESC will impact alignment and other driveability systems.
• In the end, these systems will offer another revenue opportunity and repair challenge for the service community.
• The key is to prepare with the proper training and tool investments.