2013 and beyond-Part 2: Downspeeding

The 2013 emissions have begat a new engine term: Downspeeding. Downspeeding is the way to improved fuel economy that is projected at 1-1.5% for the 2013 emisions engines. This will apply to the Cummins ISX15 "Family 1" engines as well as the PACCAR MX13 engines (save for the 500HP version that is new for 2013).

The downspeed is 100 RPM at cruise, i.e. the engines are designed and programed for max fuel economy at 100 RPM less than the 2010 versions. Peak torque will now start at 1000 RPM, again down the RPM band from the previous versions. As a result new, taller gear ratios will be offered by the axle manufacturers to allow your chosen cruise speed to happen in the 1200-1450 range.

This applys to linehaul applications only, not vocational trucks, etc. We will be looking at axle ratios that a few years ago would not have been considered and in fact did not exist!

 

Yes,

No real hardware added save for DEF quality sensor and sensor for ammonia degradadtion in the SCR. Both monitor the emissions and adjust the ECU accordingly.

We have not driven a downspeed unit yet although they are in production already. Yes, the "sweet spot" has moved downward and progressive shifting is being encouraged to improve economy. Also, the driver manuals for the new engines want you to hold a gear and lug some on a grade rather than downshift so long as you don't drop below the torque peak.

I agree that improved transmission technology will be the next big improvement in trucking. it has lagged behind engines and aero advancements so it will happen. More automated units and less power loss on all the transmissions is likely.

 

I was at a customer's location last week with our Eaton rep to upgrade the programming on an Ultrashift trans and on the way we talked about that issue. Eaton specs the SPL driveline which is machined shaft rather than the cast unit, they are also adding an additional carrier bearing on some wheelbases where it would not normally be required. The axle manufacturers all have "high performance, low torsional vibration" differentials and those will used in increasing numbers to combat any torsional issues.

It really is fine mix of parts to make this stuff work well...................