Cummins; 1355286117 | Hasan As Ari | Getty Images
Spotlight On Powertrain 63d88058163bb

How to improve engine efficiency and service life

March 20, 2023
Engine experts discuss ways to hit higher levels of efficiency, whether that's through the right product, the right maintenance cycle, or the right drivers.

Every fleet strives to achieve two things when it comes to engines. The first is to maintain efficiency in order to reduce operating and service costs. The other is to ensure the longest possible service life.

The first objective is a long-standing and important one. With the supply chain and new vehicle production issues of the past few years, the latter has taken on even greater importance.

For engine manufacturers, such as Detroit Diesel, it begins with product design.

“Typically, it takes all engine systems to support the most efficient maintenance practices,” said Len Copeland, Detroit marketing manager. “One specific design feature is the coolant system because optimized distribution keeps the engine cool where it needs to be cool and hot where it needs to be hot—with minimal restriction. That allows the engine oil to be stable for long periods and is a big contributor to extended oil drain intervals.”

Designing for less fuel in the aftertreatment system will also extend diesel particulate filter maintenance intervals, Copeland said, as this prevents soot and ash buildup in the DPF.

“We also recommend fleets follow prescribed maintenance intervals for each engine and proper fluids recommendations,” he said. “Intervals are much longer these days than they were years ago, and the newest diesel technologies require the most up-to-date and advanced fluids to keep them operating at peak performance.”

See also: International S13 Integrated Powertrain set for vocational applications

Mark Ulrich, director of customer support at Cummins, also pointed to control system features that reduce ash load as a way to promote longer DPF life. This allows manufacturers to accurately predict when to maintain the DPF versus a preset interval, he explained.

“Today’s aftertreatment systems also have fewer failures, which is no small feat considering the increased number of parts, system complexity, and controls required to meet emissions regulations,” said Kris Ptasznik, powertrain TCO and consultancy leader at Cummins.

Duane Tegels, product marketing manager–powertrain / VHD, VNX, VAH at Volvo Trucks North America, noted the importance of turbo compounding. This technology brings the added benefit of more efficient heat recovery because it allows the engine to produce horsepower from wasted heat in the exhaust stream.

“That not only increases efficiency but also reduces pressure on the engine’s revolving assembly, resulting in fewer revolutions per mile,” he explained.

Reaching optimal performance

Proper maintenance is critical to achieving optimal performance and reliability, said Mike Furst, director of contract service and business technology solutions at Mack Trucks.

“Items that can reduce performance if not maintained properly include engine air and fuel filters, drivetrain fluids, exhaust and intake systems, and DPFs,” Furst explained.

When in doubt, just follow the OEM recommendations.

“Not following published maintenance intervals can decrease operational efficiency when it leads to either unplanned downtime due to avoidable failures or, in some cases, performing maintenance too frequently,” Cummins’ Ulrich stated. “In addition, in winter months, it’s important that fleets ensure their fuel is properly treated. Improperly treated diesel fuel can lead to unplanned downtime due to fuel gelling and fuel filter plugging.”

See also: Maintenance and repair costs rise, but rate of increase slows

In spite of how cliché it may sound, always return to the basics, noted Tegels. Regardless of the component, using the correct oil or lubricant is always a good place to start. Make sure your filters are clean and adjust the overhead per manufacturers’ recommendations. Too much valve clearance can result in poor performance and, over the long term, cause damage to valves, camshaft lobes, or rocker arms.

“HVAC maintenance is a common area that is often overlooked,” Tegels continued. “A dirty or unmaintained HVAC system can cause the compressor to run longer than it should. Make sure the evaporator and condenser coils are clean, allowing for correct temperature transfer, and ensure the refrigerant level is correct. Additionally, be sure the fan clutch is operating correctly, so the fan runs only when needed.”

Impact of the driver

Service life and maintenance intervals are also affected by how a driver treats the engine on the road and before taking off.

“When thinking about driver behavior and efficiency, we typically view the correlation between the foot and the throttle, often underestimating that small inputs have a big effect,” Tegels stated.

Heating the cab in the winter just to get it warm before starting a route takes a significant amount of time, related Ptasznik, but the best way to generate cab heat is to get the engine under load.

See also: Steer-axle specs must be followed—or safety is put at risk

“The best way a driver can increase efficiency is also the safest way to drive,” Ptasznik added. “Leaving a proper following distance reduces engine and foundation brake use where kinetic energy is dissipated as heat. A steady state is always more efficient than throttle-brake-throttle operation.”

When the drivetrain is tuned optimally, Furst added, driver behavior becomes the major contributor to efficiency. Driving smoothly, maintaining speed, and avoiding abrupt changes in speed are all behaviors that optimize efficiency, he said.

“Some things drivers have an effect on include throttle aggressiveness, brake usage, and idle time,” Copeland said. “All of these factors will cause hydrocarbons, which will need to be dealt with sooner rather than later.”

Follow the data

Fuel economy is one of the best indicators of an optimally performing engine, and it can be monitored via a telematics system that also detects problems, Furst noted. A dealer can also provide benchmarking data and check to see if the truck’s settings are optimized for maximum performance, he added.

“Fleets can pull data remotely to gain insights by using a comprehensive suite of connectivity systems that provide real-time, actionable information about vehicle performance,” Copeland said. “That empowers effective decision-making, resulting in less downtime and a better bottom line.”

As to the future, Ptasznik emphasized the importance of updated maintenance monitors on next-generation products to maximize efficiency, time between intervals, and long engine life.

“Modern advances with prognostics provide the ability to predict a hardware failure before unexpected downtime occurs,” he said. “Combined with future maintenance monitors, an unexpected repair turns into a one-stop service event when it is convenient for your business.”

This article originally appeared in Fleet Maintenance, a FleetOwner sister publication.

About the Author

Seth Skydel

Seth Skydel, a veteran industry editor, has more than 36 years of experience at fleet management, trucking, and transportation and logistics publications. Today, in editorial and marketing roles, he writes about fleet, service and transportation management, vehicle and information technology, and industry trends and issues. 

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