How to recognize and address air contamination that can impact connected vehicle systems

How to recognize and address air contamination that can impact connected vehicle systems

With the increasing adoption of automated manual transmissions (AMTs) and advanced safety technologies supported by electronically controlled braking systems, protecting a commercial vehicle’s air system performance has never been more important.

Many AMTs on the market utilize a mechatronic shifter, which combines the intelligence of electronic controls with the reliability and high power density of pneumatics. The compressed air to control these AMTs is supplied by the engine’s existing air compressor. Furthermore, most automated air controls on trucks utilize multiple electronically operated solenoids, which require both cleaner and dryer air than traditional manual brake valves, and are sensitive to both small particulate and oil contamination.

As part of its Bendix Tech Tips series, Bendix Commercial Vehicle Systems offers maintenance insight on protecting these systems by recognizing and addressing air quality issues.

Poor Air Quality: Know the Signs

Early indicators of poor air quality can occur downstream of the compressor and air dryer, in the systems that rely on effective functioning of components such as solenoid valves for pneumatic automation and emissions controls.

“These components have very tight tolerances, and if there’s too much of that ‘toxic brew’ of contaminants, engine oil, and water, it leads to mechanical malfunctions due to fouling within valves, for example,” said Richard Nagel, director of marketing and customer solutions, air charging for Bendix. “That’s actually how many customers first realize there’s a problem with the air system: Drivers will report noticeable performance changes, like malfunctioning brake valves or an AMT not engaging or operating as smoothly as expected.”

Other signs include an excess of oil mixed with water found when regularly draining the air system tanks, and the need to replace air dryer cartridges more frequently than expected. cartridgeWhat steps can you take to address an air contamination issue? From a practical standpoint, the two key points within the air system for controlling air quality are the compressor and the air dryer.

Compressor Ins and Outs

Every compressor is designed to pass a small amount of oil in order to lubricate the piston. Depending on the compressor’s design and other factors—including duty cycle, operating temperature, age, and whether the engine is turbocharged—the amount of oil passed through can vary widely. Even a high-quality, brand-new compressor can pass a significant amount of oil per year, and poorly rebuilt compressors run the risk of passing even more.

When oil passes around the compressor piston, it mixes with moisture drawn into the engine through the truck’s air intake system, creating the potential for emulsions to build up in the air system. A compressor passing too much oil with elevated ambient temperatures can result in carbon buildup in its unloading valves, resulting in a malfunction of the unloading system. The oil and water mixture can also restrict the air passage in the discharge line.

“If the compressor is passing too much oil, you can replace the head or the unloader valves, or replace the entire compressor with a new or remanufactured unit,” Nagel said. “But it’s like anything else: If you work a compressor hard, over the years, that piston-to-bore clearance gets wider, and more oil is going to get through. That’s where the capability of the air dryer comes in.”

Dryer Importance

Standard air dryers utilize an adsorption process to bind the moisture in the air to a dessicant during the charge cycle, and exhaust air mixed with water during the regeneration or purge cycle. Clean dessicant has a potential life of millions of charge cycles, if it remains uncontaminated.

Oil that passes through the compressor, however, can foul the dessicant, preventing the dryer from operating as efficiently and effectively as it should. Bendix recommends using oil-coalescing dryer cartridges, which include an additional filter that extracts the oil from the air and collects it in the cartridge sump, where it is exhausted during the purge cycle. (The Bendix PuraGuard design actually removes oil from the air before reaching the desiccant, which alsoextends the dryer’s capability.) If a truck manufacturer specifies an oil-coalescing cartridge to protect an AMT or other system, it’s even more important to stick with an oil-coalescing replacement, since using a standard cartridge would leave those components vulnerable to higher levels of contamination. Repairing a system affected or damaged by contaminated air can cost multiple times the added expense of an oil-coalescing cartridge.

Biannual air dryer cartridge replacement is often suitable, but air system quality may depend on more frequent changes, depending on the vehicle’s design, usage, and operating environment. Running the compressor harder means consuming more air and increasing the system’s number of cycles, so vehicles with multiple axles, or vocational vehicles like gravel haulers, will have higher air consumption rates than an over-the-road truck running cross-country.

“For a long time, the design of many valves and other components in the truck’s air supply remained relatively unchanged, with internal clearances designed to operate under higher levels of contamination,” Nagel said. “Today, trucks often have more complex pneumatic systems which are more mission-critical—placing even more importance on maintaining the quality of the air they use to operate.”

This article was contributed by Bendix Commercial Vehicle Systems.

You May Also Like

Volvo on Demand battery electric truck adoption program launches

Volvo Trucks North America (VTNA) launched Volvo on Demand, a Truck-as-a-Service (TaaS) business model focused on battery electric trucks in collaboration with Volvo Financial Services (VFS). Volvo says Volvo on Demand was designed as a solution to simplify the acquisition and reduce the major upfront investment in battery-electric vehicles. Volvo on Demand provides qualified customers

Volvo Trucks North America (VTNA) launched Volvo on Demand, a Truck-as-a-Service (TaaS) business model focused on battery electric trucks in collaboration with Volvo Financial Services (VFS). Volvo says Volvo on Demand was designed as a solution to simplify the acquisition and reduce the major upfront investment in battery-electric vehicles. Volvo on Demand provides qualified customers with flexible term options as short as 12 months and includes Volvo Trucks’ Gold Contract and the option to bundle vehicle insurance for physical damage and collision, route planning and optimization guidance, as well as consultation to find the best charging solution and incentives that might be available.

Hino, Hexagon Purus launch Tern zero-emission truck brand, RC8 Class 8 truck

Hino Trucks and Hexagon Purus announced the launch of Tern, a new zero-emission truck brand along with their inaugural truck model, the RC8, a battery electric Class 8 tractor. Related Articles – Hyundai previews enhanced Xcient fuel cell truck – New Penske Energy initiative to advise, support fleets on electric truck infrastructure – Eaton to

Daimler announces battery repairing, remanufacturing, repurposing and recycling program

DTNA says the circular economy approach strives to extend the usability of rare-earth materials and products.

Daimler-Truck-North-America-Logo-1400
Kenworth T680, T880 trucks with Cummins X15N to begin production

Production of Kenworth T680 and T880 models with the new Cummins X15N natural gas engine will start in Q3 2024.

Kenworth-PACCAR-Cummins-X15N-Class-8-prudction-schedule
ACT Research numbers: Heavy-duty down, medium-duty up

ACT says after a year of unexpected growth, March orders may finally indicate a slowdown in capacity additions.

ACT-class-8-net-march-2024-orders

Other Posts

Daimler Truck reports good start to 2024

Despite lower Group unit sales, Daimler Truck says it continued toward a robust profitability in normalizing markets for Q1 2024.

Daimler-Truck-Q1-2024
Vipar Heavy Duty announces Latin America expansion plans

Plans include focusing on new locations, stockholders, and suppliers to serve the growing market.

VIPAR-Heavy-Duty-Latin-America-Expansion
41 Volvo VNR EV trucks deployed by 4 Gen Logistics

The zero-emissions fleet will help the drayage company haul freight in southern CA, while advancing its commitment to sustainability.

4-Gen-logistics-Volvo-VNR-EV-electric-trucks
Performance Food Group, partners unveil sustainable distribution center

PFG tells us Advanced Energy Machines, FreeWire, GridMarket and Volvo Trucks North America played key roles in facility transformation.

Performance-food-group-PFG-Earth-Day-volvo-vnr-electric-carb-ev