While there have been continual improvements to the design of a commercial truck’s aftertreatment system, this system is still one the most challenging areas of a vehicle to maintain for fleets. Mark Hawkins, technical manager for Redline Detection – maker of diagnostic leak detection equipment – discusses the current challenges fleets face with aftertreatment system issues, the tools and processes are available to find leaks early and accurately, and how these processes can be employed as part of a preventive maintenance program.
Transcription of the interview:
Erica Schueller, Fleet Maintenance: Hello and welcome to VSP News: Uptime Update. I am your host Erica Schueller, editorial director for Fleet Maintenance magazine, covering all maintenance, all vehicle classes, all management, all the time.
While there have been continual improvements to the design of a commercial truck’s aftertreatment system, this system is still one the most challenging areas of a vehicle to maintain for fleets. One reason is because intake and exhaust system issues can be caused by problems further upstream or downstream in the vehicle – and not always with the aftertreatment system itself.
The Technology & Maintenance Council’s Recommended Practice 375, Leak Detection in Engine Systems Utilizing Visible Vapor Technology, highlights best practices fleets can implement to find aftertreatment leaks. The RP provides guidance on how to use a smoke machine in order to quickly diagnose problem areas of the aftertreatment system, even for small leaks before they become critical failures.
We talked with, Mark Hawkins, technical manager for Redline Detection – maker of diagnostic leak detection equipment – to discuss the current challenges fleets face with aftertreatment system issues, and what tools and processes are available to find leaks early and accurately.
Mark Hawkins, Redline Detection: Technicians today, they need the ability to be able to see air leaks, whether that’s in the intake system, which is what we refer to as upstream leaks, or in the exhaust system – downstream leaks.
Any leak in that system can cause a variety of problems. For instance, upstream leak and air getting into that system would cause an air-fuel mixture problem. An air-fuel mixture problem would go downstream and then cause an overtaxing of the aftertreatment system.
When trucks come from the factory, they’re tight, they’re sealed, and they’re supposed to stay that way through [the vehicle’s] life. But the problem is they get used and abused and they develop these leaks. The leaks can start out small and develop into larger leaks, affecting the system and triggering the “check engine” light.
On the downstream side, a leak in that system causes sensor data problems like getting bad data from the sensors and ECU to adjust the air-fuel mixture. This causes, again, over-taxation of the aftertreatment, the use of excess fuel, excess diesel exhaust fluid (DEF), and not cleaning the air properly.
A mechanic needs something in their arsenal to visually inspect the system.
Schueller, Fleet Maintenance: Hawkins talks more about specific tools offered by Redline that can help with this process.
Hawkins, Redline Detection: We’ve developed a product, the HD Powersmoke, that’s able to find these leaks in minutes.
You put an expandable bladder in the intake, you put one in the exhaust, you seal the system, you put the visible vapor in [the system]. It only takes a few minutes.
Schueller, Fleet Maintenance: While the aftertreatment diagnosis is more of a reactive measure, a smoke machine can also be used for preventive maintenance. Hawkins and other representatives from Redline Detection provided guidance in the development of RP 375, which also highlights how smoke machines can be implemented as a best practice for PMs.
Hawkins, Redline Detection: On the preventive maintenance (PM) side, changing the oil, changing the air filters, checking the air pressure in the tires, that’s a common thing. The next common thing needs to be checking the engine system for air leaks.
A small air leak, upstream or downstream, may not trigger the “check engine” light right away, but small leaks develop into large leaks. A small leak starting out can cause fuel consumption problems and can lead to over-taxation of the aftertreatment system – clogging the DPF (diesel particulate filter), causing excessive regeneration, those types of events.
It starts out as small and grows into a bigger problem with more maintenance down the line, and also can leave you alongside the road. You may as well fix it upfront when it’s a small, inexpensive problem before it turns into a large problem.
If you rolled an air leak inspection into your PM, which several fleets have done, it saves money in the long run on fuel and roadside assistance problems. It increases the vehicle’s uptime.
Schueller, Fleet Maintenance: What continuing trends can we expect with regards to engine and exhaust aftertreatment system service for the commercial vehicle industry? Hawkins shares more.
Hawkins, Redline Detection: With emissions regulations getting tighter, fuel economy increasing, it’s getting harder and harder to meet those criteria. Manufacturers then make the engine management system do a lot of that heavy lifting.
Part of that is, you have to have a sealed intake and exhaust system. It’s a must. That’s one of the reasons why TMC came out with a new RP (Recommended Practice) directly related to this issue; RP 375 deals directly with using visible vapor to find air leaks in truck systems.
Schueller, Fleet Maintenance: If you’d like more information about aftertreatment service and maintenance, check out the link below for a recent story from Fleet Maintenance on this topic.
Thank you for tuning in to VSP News: Uptime Update, I’m your host Erica Schueller.
Until our next broadcast, keep up with this, and other industry topics, by visiting us online at VehicleServicePros.com.
