, Land Line senior technical editor | Monday, August 01, 2016
With Phase I of the new Environmental Protection Agency greenhouse gas reduction mandate bearing down on the trucking industry, Cummins unveiled its newest engines recently. The latest advancement from Cummins is the X15, the soon-to-be successor to the ISX15.
Available in two configurations, the Efficiency Series and the Performance Series, Cummins officials say the X15 will exceed EPA standards for 2017 greenhouse gas emissions and fuel efficiency. It will be in production in January 2017.
X15 Efficiency Series engines, with ratings from 400 to 500 horsepower, provide up to 1,850 lb-ft peak torque, also from 1,000 rpm. They are engineered for typical line-haul, long-haul and regional applications.
The X15 Performance Series engines are rated from 485 to 605 horsepower. They’re designed for vocational and emergency vehicles and heavy-haul applications, providing up to 2,050 lb-ft peak torque from 1,000 rpm through a wide rpm range.
Both engine series offer improved throttle response. Their engine brake develops 450 retarding horsepower at 1,500 rpm and up to 600 horsepower at 2,100 rpm.
The X15 Efficiency Series is optimized when integrated with the Cummins and Eaton SmartAdvantage Powertrain. Computers measure and adjust for vehicle weight grade and driver input (by measuring throttle position) and shift gears accordingly. Fuel efficiency is improved a further 3 percent by incorporating ADEPT, SmartCoast and predictive cruise control functions.
Since model year 2010 emission-controlled engines were introduced, Cummins officials say the ISX engines have averaged 2 percent better fuel economy each year. They expect the X15 Efficiency Series to improve on that because of significant re-engineering. For example, thermal efficiency was improved by optimizing the cam profile to minimize parasitic losses and by allowing the engine to breathe easier. In addition, Cummins officials say the industry’s highest compression ratio, improvements to Cummins VGT Turbo and XPI fuel system help improve engine response while improving fuel economy.
Steps were taken to minimize internal friction losses. Re-engineering included the water pumps, gear train, lube system, pistons and exhaust gas recirculation (EGR) system.
Maintenance requirements were reduced to minimize owner’s total cost of ownership. Cummins officials project overall maintenance costs to be just over half the costs of 2010 engines for the first 500,000 miles. Oil drain intervals will vary by application, but could be up to 50,000 miles in typical line-haul service. Trucks signed-up for Cummins’ soon to be introduced oil analysis program, OilGuard, may be able to extend oil drain to up to 80,000 miles. The new engines take the new API licensed CK-4 oils as well as the new FA-4 oils, with better fuel economy anticipated with the FA-4 oils. Crankcase breathers need no maintenance on X15 engines.
Cummins’ redesigned Single Module aftertreatment combines all exhaust cleaning functions in a one-piece design that is up to 40 percent lighter and 60 percent smaller than previous designs. Improvements to the DEF doser provide a more precise spray pattern to reduce DEF consumption. The diesel particulate filter (DPF) has an increased capacity extending the need for ash cleaning up to 800,000 miles, depending on duty cycle.
Both engines will be built in Cummins’ Jamestown, N.Y., engine plant.
In 2018, the X15 will be joined by a redesigned 12-liter engine, the X12. It will provide 350 to 475 horsepower and up to 1,700 lb-ft peak torque, also starting at 1,000 rpm. The X12 weighs in at just 2,050 pounds, giving it the highest power-to-weight ratio of any 10- to 16-liter engine. Weight reduction was accomplished by re-sculpturing the block, removing excess mass without reducing strength or rigidity. Composites replace metal in the oil pan and valve cover. Drivers with heavy sleepers or others needing to lower steer axle loading may opt for the X12.
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