Photo courtesy of Volvo Trucks North America
One benefit of cleaner burning diesel engines is less soot output. Here, a technician works on a Volvo D11 engine.

Balancing changes in engine technology and uptime commitments

Feb. 12, 2018
Advancements in engine technology provide a number of opportunities for improved vehicle serviceability.

Now that we’ve entered the latest greenhouse gas regulations - GHG ‘17 Phase 1, Step 2 - trucks are rolling off the assembly line with U.S. EPA and CARB certified engines that feature the smallest carbon footprint available to the market in our industry’s history. These ultra-clean engines also burn less fuel, so fleets will save thousands of dollars in fuel costs from the efficiency improvements.

However, it’s not all just about fuel savings. Investments in future technology are also benefitting the industry by improving uptime.

Proactively address service issues

Future technology does create reliability challenges, partially due to the aggressive regulatory GHG targets that must be met to achieve engine and vehicle certification. It can be a strain on engineering resources to certify one platform while engineering and testing another for the next phase and step of legislation, all the while testing and retesting vehicles in real-world situations for millions of miles to maintain quality and reliability. 

In general, trucking companies seem to be resistant to change due to risk of downtime with new technology. However, connected vehicles may provide support when adopting new processes and technologies.

Connected vehicle technology, including telematics, provides the driver and the fleet the ability to monitor vehicle health with proactive communication from the truck itself. This information can be provided to the driver directly, and be communicated remotely to the fleet. In addition, a separate support team can also aid in monitoring events 24 hours a day.

One example of this, the Volvo Uptime Center, allows the support team to work directly with the customer and the Volvo dealer network to proactively address the service issues, correcting small problems before they become critical issues and mitigating unnecessary downtime. 

Steps to cleaner burning engines

Another benefit from cleaner burning diesel engines is less soot output.

Engine manufacturers aim to introduce features on their products to lower fuel consumption. One such feature known as “wave piston” technology, available in 2017 Volvo D11 and D13 engines, turns fuel spray jets back toward the center of the piston for a more complete burn of all hydrocarbons, utilizing normally leftover oxygen in the center of the cylinder. This can result in 90 percent less soot output from the cylinder.

Less soot is less unburned fuel, which raises fuel efficiency. The exhaust gas recirculation (EGR) valve and cooler are also more reliable because less soot is present to potentially cause clogging issues.

Another maintenance benefit of a cleaner engine, coupled with higher performing engine oil, is a 25 percent increase in oil drain intervals. Longer diesel particulate filter (DPF) cleaning intervals are also under evaluation.

All other maintenance item change intervals, like coolant, primary and secondary fuel filters, and diesel exhaust fluid (DEF) filters have remained at the same intervals as their predecessors. Valves should be adjusted every 300,000 miles after the first 150,000 miles. Valve lash on the new engines can be adjusted without using shims, which saves time and reduces complexity, another uptime improvement.

Other engine efficiency improvements

The next level of GHG regulations starts in 2021 – less than five years away.

One way for engines to meet this target is to increase the percentage of BTUs in a gallon of diesel that are used as available power at the wheels, also known as Brake Thermal Efficiency, or BTE.

Today, on average, only 43 percent of available BTUs from a gallon of diesel are used. The rest is wasted heat out of the exhaust system or transferred into the atmosphere via the radiator or charge air cooler. Some form of waste heat recovery system, like turbo compounding, will be necessary to improve BTE to meet future stringent regulatory targets.

As technology advancements continue, the engine and transmission will work together to ensure performance is maintained while providing maximum fuel efficiency. Lower engine rpm at cruise lowers engine friction, saving fuel and increasing the reliability and the useful life of the engine.

Engine manufacturers like Volvo are working to offer products that will meet this need. One example includes the introduction of the D13 Turbo Compound (D13TC) engine.

The 13L D13TC engine will use a compound turbo, fixed geometry intake turbo and an exhaust compounder turbo that takes otherwise wasted heat and converts it to up to 50hp that is delivered back into the engine via the crankshaft. Simplistic design and a fluid couple separating the compound unit from the crankshaft eliminate the need for clutches, making the turbo compound unit virtually maintenance-free.

The D13TC will provide peak torque down to 950 rpm, allowing a new level of downspeeding at a sweet spot cruise rpm of 1,000 to 1,200.

Downspeeding will continue to drive cruise speed engine rpm down as faster and faster rear axle ratios are used for interstate vehicles that predominantly operate on flat terrain.

Because vehicles find themselves in different terrain with different payloads, different trailers and even different owners, engine and transmission control unit parameters will have to be changed to meet fuel efficiency or performance expectations. Industry data indicates the average downtime for such parameter changes is up to 2.3 days.


New and future technologies will improve uptime by allowing these parameters to be programmed over-the-air, just as we’ve become accustomed to doing each time an update is available for our mobile phones. Customers will have access to a website or app that will allow them to change road speed or idle time, or pick from several templates pre-programmed to provide maximum fuel efficiency or a blend of fuel efficiency and performance. Over-the-air remote programming will also help improve uptime by allowing remote software updates to be done on electronic control units rather than going to a dealer each time an update is available.

Future technology will keep the trucking industry sustainable through increased fuel efficiency, reliability and uptime. 

John Moore is an 18-year veteran of Volvo Trucks North America ( and currently serves as North American Product Marketing Manager for Volvo and Cummins diesel engines in the Volvo chassis. John’s responsibilities include optimizing current and future integrated drivelines to specific customer applications by utilizing engineering, sales, aftermarket and other customer-related resources along with building informational tools to assist Volvo Group personnel in applying these technologies. 

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