Wireless Sensors Could Help Diesel Engines Burn Fuel More Efficiently

Wireless devices just might lead to a future with greener diesel engines.

Sensors using radio frequency signals are being utilized to measure soot and ash buildup in diesel engine exhaust filters. So far the sensors shown improvement in filter regeneration during their engine and field tests

During a two-year study using New York City Department of Sanitation trucks, the sensors cut the time and frequency of filter regeneration in half.

This could mean a one to two percent savings in fuel, which is a substantial amount considering that some heavy-duty trucks use up to 8,000 gallons of fuel a year.

Cordierite diesel particulate filter on a 2008 C7500 GM class 7 truck with a 7.8 inline 6 Isuzu diesel.

The sensors communicate with the vehicle’s emissions-control system using radio frequency signals. As soot clogs the filter, the strength of the signal weakens. This weak signal alerts the onboard engine-control system that the filter is clogged and initiates a self-cleaning procedure. Once it is complete, the self-cleaning shuts off automatically.

This saves fuel and lowers fuel costs.

After the Environmental Protection Agency put strict emission limits into effect for diesel engines, ceramic filters became more popular. Ceramic filters catch more than 95 percent of soot produced by diesel engines, but they also need to be cleaned once or twice a day depending on how frequently the engine is used.

Two-year study shows the sensors cut the frequency and duration of filter regeneration in half. (Photo courtesy of MIT.)

This process is called filter regeneration. When the filter needs to be cleaned, the engine regenerates the filter by using fuel to bring the exhaust to high temperatures, burning the soot. This method is effective, but uses extra fuel because there is no way to accurately tell when the filter needs to be cleaned.

This means that heavy-duty trucks are using more fuel than they need to and if the diesel can’t burn efficiently due to build-up in the filter then it can damage the engine.

The sensors were developed by researchers at MIT start-up, Filter Sensing Technologies (FST). FST was acquired by large vehicle, electronics and sensors manufacturer CTS Corporation in October. CTS expects to manufacture the new sensors for OEM applications.

For more information about FTS sensors, visit their website.