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Idle Times

It is a good time to be in the idling business, say many in the school bus industry, whether you are pushing alternative fuels, emissions control and exhaust products or engine pre-heating systems for school buses.

In the past five years or so, there has been idle-reduction legislation put in place nationwide that not only helps clean up the environment but also enables fleet managers to save money on fuel and maintenance costs.

Currently, about 25 states limit vehicle idling to five minutes or less, and another handful limit it to 15 minutes, while some local jurisdictions have even more stringent rules or conditions (see ATRi-online.org for a compendium of idling regulations).

Even when it is not mandated, idle reduction remains top of mind for fleet managers looking to increase efficiency and to promote “green” practices that stakeholders like parents and the general public appreciate.

“From the anti-idling perspective, what we’ve found is that, regardless of state legislation, a lot districts are saying they don’t want the buses idling in front of schools because of all the air intakes for the schools. So if you have buses sitting out there, idling away, all those emissions are being drawn into classrooms,” said Brian Curliss, product manager for heaters at Proheat for the past eight years. “Anti-idling campaigns have raised awareness. California really has led the way with CARB becoming the de facto standard … (and) what California does the rest of North America tends to follow.”

He noted that his company’s diesel-fired auxiliary heaters, which are EPA SmartWay Certified, aid in emissions control by reducing bus idle times.

“The idea behind it is we would replace the need for idling while the bus is sitting and waiting to pick up students in colder weather,” he continued. “The heater can be programmed ahead of time so when the driver comes to start the bus, it makes for a much easier start and the engine itself gets up to temperature quicker, which means it reduces the amount of emissions it produces.”


Sales of the Scholastic series of engine pre-heaters remain robust, according to Paul Baczewski, national account manager of Webasto’s bus products division, and a rising number of customers consider the heaters an idle-reduction tool. The company’s coolant heaters are both CARB approved and EPA SmartWay verified.

“In today’s world, fleets are slowly recognizing the benefit that pre-conditioning an engine with a Webasto has on emission-reducing aftertreatment devices such as diesel particulate filters (DPFs),” said Baczewski.

For example, if you pre-condition a school bus engine with a Webasto in a 70-degree climate environment, he explained, the particulate matter (PM) that is being introduced into the diesel particulate filter may be reduced by nearly 30 percent.

“The result to the fleet is a drastic reduction in maintenance costs, (saving) valuable time and promoting prolonged life of DPF sub-straights. This unforeseen benefit has introduced our product into areas of the country I would have never dreamed about 20 years ago,” Baczewski noted. “What is even more beneficial is the discovery that this PM reduction is proportional with the ambient temperature: At 40 degrees Fahrenheit, the reduction increases to nearly 70 percent.”

Paula Bishop, manager of transportation and environmental affairs at Espar Inc  pointed out that large and small truck fleet customers recognized the need for idle reduction several years ago, yet awareness among bus operators has lagged. The company’s entire E-Guardian family of heaters has earned EPA validation and CARB approval.

“School bus fleets have been slower to recognize the necessity for idle reduction and a warm-engine start,” she said. “Starting a warm diesel engine will prevent the cold fuel from entering the filters, and save on maintenance and premature expensive filter replacement. This factor, as well as reducing emissions and fuel savings, makes engine pre-heaters even more important today.”


Emissions reduction, fuel consumption and safety all appear to be equally important to fleet managers, Bishop added, but more education is needed on the benefits of idle reduction for school buses.

Mike Taylor of the Propane Education and Research Council (PERC) agreed, noting that most fleet managers know the anti-idling requirements in their area, but many bus drivers are either not aware of the rules or ignore them altogether, which is a challenge.

“No vehicle should ever idle, regardless of what fuel you’re using,” said Taylor, who is spreading the word nationwide on the importance of anti-idling programs for all school buses, no matter what they run on.

“I’m an anti-idling guy all around for all kinds of fuel,” he told STN. “According to the data I’ve seen for diesel, idling consumes a gallon of fuel per hour. It’s a huge waste of fuel, not to mention the damage you can potentially do to your vehicle. You run the risk of replacing some expensive parts that may be non-warranty items.”

Todd Lewis, director of sales, Exhaust and Emissions business unit, at Donaldson Company Inc., said the company produces passive and semi-active emissions systems verified by CARB for the retrofit market. Donaldson has thousands of retrofit systems in the field. The company has participated in the school bus retrofit market for nearly 10 years, he explained, and its Semi-active Electric Filter (SEF) is a key part of Donaldson’s retrofit emissions product portfolio which is ARB verified.

“Clean air regulations have driven many market changes,” Lewis said. “Funding for emissions retrofits compete with engine and vehicle replacements, alternative fuels and other developing technologies. School bus fleets have a lot of options for reducing diesel emissions. Despite these competing technology options, emissions retrofits are still one of the most cost-effective ways to reduce emissions and improve air quality on legacy fleets.”

For example, he continued, when spending $130,000, you can buy one new school bus or retrofit up to 10 existing vehicles— so you can have 10 times the clean air impact in this retrofit scenario.

Lewis also noted there are still a large number of pre-2007 school buses in California that are good candidates for retrofit emissions devices. California requires their school bus fleets to be emissions compliant by the end of calendar year 2014. “To be successful with an emissions retrofit, which requires very little vehicle down time, you need to choose the right retrofit technology for the vehicles’ duty cycle. There are very specific technologies that work well for specific vehicle duty cycles. If you apply the correct technology to the right duty cycle, the devices will work very well.”



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