Vocational Truck & Trailer

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Tighter Standards & Today’s Engines

By Marek Krasuski

Tighter emissions regulations spearheaded by the EPA (Environmental Protection Agency) continue to force engine builders to design new builds that meet, and even exceed EPA requirements while maintaining power output. Better fuel economy and raw power set the parameters for new builds, and 2017 is another watershed year marking the introduction of continuous engine improvements.
Last January for example PACCAR, a leading engine manufacturer of HD trucks under the nameplates of Kenworth, Peterbilt, and DAF, met these fuel efficiency and power benchmarks through enhancements to its MX-13 and MX-11 engines. Company Vice President Landon Sproull said the modified engines deliver best performance & fuel economy as well as durability and low cost of ownership. Both engines have been ramped up with power and torque. The MX-13 engine output has increased to 510 hp and 1850 lb.-ft. of torque. The MX-11 now stands at 430 hp and 1,650 lb.-ft. of torque. MX engines have a rating of B10, meaning that 90 percent of these builds are expected to reach one million miles without requiring any major overhauls.
Among the advantages of these redesigns are better fuel economy due to a single cylinder air compressor, variable displacement oil pump, and variable speed coolant pump. Extended oil and filter changes now range in intervals of between 60,000 and 75,000 miles, culminating in significant savings over the life of the vehicle. Improvements to the after treatment system reduce overall weight by 100 pounds. By year end Paccar will have produced 135,000 MX engines for the North American market. PACCAR claims the industry has embraced the MX engine, evidenced by the fact that 50 percent of Kenworth trucks will be powered by Paccar engines.
2017 is the year in which new green house gas regulations have come into effect, building on the 2014 regulations from the EPA in conjunction with the National Highway Traffic Safety Administration (NHTSA). The 2014 regs looked to reduce the entire carbon footprint in the whole vehicle through a combination of low rolling resistance tires and aerodynamic changes. This year’s rules focus on CO2 reduction from engines.
Mack Trucks has met this most recent standard through upgrades to the MP engine for vocational trucks. Enhancements include better fuel economy ranging from 2 to 8.8 percent. Additional power has been configured into the 11-liter MP7 with 425 horsepower, 1560 lb.-ft. of torque, and a reduction of 25 pounds on the MP7 and 44 pounds shaved off the MP8.
Mack says a critical improvement has been to the fuel injection which has been replaced with a high pressure common rail system that more efficiently delivers fuel to the cylinders, providing better fuel economy and cleaner combustion. A cleaner burn, in line with the 2017 GHG regs, also comes from a newly designed piston that produces less soot. Other updates include a double wall venturi tube attached to the EGR system for better cold starts and shut off, a new camshaft and a two speed coolant pump, all of which add to better fuel mileage, more power, quieter running and lighter weight in the MP engines.
Joining the lineup of cleaner engines is the Cummins X15 turbodiesel engine which has exceeded the EPA’s 2017 GHG requirements thanks to a number of innovations. Cummins built on the best features of the ISX15 with additional refinements culminating in an engine with better fuel economy, more power and durability. These features include a new cam profile that minimizes loss during combustion and provides a cleaner burn. Heat transfer, too, is reduced to the engine oil thanks to new piston design. Lower heat to the engine translates into less oil breakdown and extended service intervals. Cummins uses a common rail fuelling system that provides for a smoother, quieter and more durable engine. Fuel mileage is also enhanced by integration with the Eaton SmartAdvantage Powertrain that aligns the engine with vehicle weight and road grade that helps reduce fuel consumption. The ADEPT system, a handful of high tech features, helps drivers by making minor adjustments to speed, power and gear selection. Cummins also redesigned gear trains, pistons, and water pumps to decrease drag and maximize power.
A discussion of engines wouldn’t be complete without commentary on the push toward electric trucks. For about 10 years Tesla Trucks has been promising a fully electric heavy duty truck. And now, according to its Master Plan, the Tesla semi is expected to go into production within the next two years. The Tesla Semi will have a range of 200 to 300 miles. Its limited range takes it out of the long haul market for the time being since it can’t keep pace with diesel alternatives that run about 1000 miles between fuel ups. Predictions are that the electric truck will bite into the regional sector, taking up as much as 30 percent of that market in the US.
Still, company CEO Elon Musk remains confident that their truck is, or soon will be, suitable for long haul applications. “It is a heavy-duty; long range semi-truck, so it has the highest weight capability for the range. Essentially it’s meant to alleviate the heavy-duty trucking loads. This is something which people do not, today, think is possible. They think the truck doesn’t have enough power, or it doesn’t have enough range. With the Tesla semi, we want to show that no, an electric truck actually can out-torque any diesel semi, and if you had a tug-of-war competition, our truck will tug the diesel semi uphill,” he said. Analysts predict that an autonomous electric truck can reduce operational costs by 70 percent over diesels, a massive saving that could change the face of the industry.
This year the commercial truck builder Nikola Motor Company introduced the Nikola One electric Class 8 truck, along with its plans to establish a network of 1000 fueling stations to support its hybrid electric truck. The Nikola One is a hydrogen-powered electric vehicle with a range for 800 to 1,200 miles. The company believes that hydrogen powered generation is preferable to a plug-in for electrical charging coming in at around $3.50 per kilogram which is half the current market price.
By comparison, Tesla plans to charge vehicles with batteries by adopting a battery leasing model which means drivers could exchange batteries at designated stations which will get drivers back on the road quicker. Swapping batteries would take about 5 minutes. Tesla estimates fuel costs would drop by 50 percent.
The new technology is not without its problems, which is why electric and hybrid trucks are used mainly in the regional pickup and delivery markets. There is also the age-old resistance to change, and until electric trucks, particularly long hauls, have proved their mettle in real life applications, wholesale acceptance is likely to come later than sooner. Yet from a global perspective the trend toward electrically driven and hybrid vehicles is unmistakable. For example China, never known in the popular imagination as a leader in green technologies, surprises as the leading market for electric commercial vehicles. Fully 95 percent of its buses – 100,000 in all – are electrically driven.
In Europe, truck suppliers are coming under increasing pressure to fill the market with low emission commercial trucks. And even though purchase costs for such vehicles remain high in North America, operational costs are low, making electric vehicles a feasible alternative in the near future.

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