Nebraska Tractor tests don't test "real world conditions"
Before the advent of CVT (Continuously Variable Transmission) and computer technology, tractors were operated in the same way that they are tested at the University of Nebraska. In essence, the operator selected a gear and an engine RPM to most closely match the load and desired ground speed that was best suited to the operation. Throughout the "ups and downs" of the field operation the tractor engine and transmission would remain at the static levels pre-set by the operator.
With the advent of Power shift-style and Automatic-shift transmissions, operators could begin to apply some performance variability to the operation using the transmission (i.e. shift up in light ground and down in heavy ground). This variability has been one of the reasons that the tractor fuel usage has steadily decreased in the last 20 years (4.8% annual decrease)1 The Nebraska testing has some provisions for variable operational patterns with their addition of testing under partial loads and lower engine RPMS but these tests become woefully inadequate when compared to what CVT technology brings into the equation.
Challenger/Fendt CVT uses a computer-controlled transmission AND throttle. In a nutshell, when the computer is controlling the engine and transmission together it is always trying to idle the engine down and shift the transmission up. These variable adjustments are happening at multiple times /second and the computer never gets tired or forgets to do its job. This feature can be turned off but when it is on it is always working to give the best possible performance. The Nebraska test engineers don't test using "real world" conditions and therefore cannot test the tractor's ability to respond to these "real world" conditions.
The first thing that you will notice when scrutinizing the Nebraska tests is that they are all done at static engine RPM (meaning the test engineers set the engine at a certain RPM and then run the test; most of the testing is done at full throttle). We train our customer to utilize the computer control on the Challenger and Fendt tractors and when the tractor is under computer control the engine is always trying to idle down and the transmission is always trying to shift up. Since the computer is always doing this (multiple times/second) we can see a vast advantage in most conditions with fuel economy. The competitor's IVT does this as well and the logic of this process is adjustable by the operator on both the Challenger and non-Challenger tractors (Power-vs-economy). One of the advantages of the Challenger tractors is that Challenger allows an infinite adjustment range and the competitors only allow one of three settings.
Real world conditions are widely varied in terms of load demand and operational requirements. The problem with the Nebraska tests is that they do not simulate the actual variable conditions that are addressed by the computer control integrated into a Continuously Variable drive train. Much of this is addressed in the research paper, “The Application and Modeling Possibilities of CVT in Tractor(s).”2 Where the researchers compared power shift transmissions to the Fendt CVT (used by Challenger) and the Deere IVT. The tested fuel savings support the claims from our customers that Challenger tractors are averaging 22% or better fuel economy over the average power shift tractor in our trade area (95% of the competitive tractors in our trade area are power shift).
Challenger tractors are shipped with fuel flow meters and non-resettable volume counters to track and report fuel usage. These flow meters are calibrated at the factory and have been checked in several instances by Farm Depot customers and staff to validate the volume measurements from the tractors. Farm Depot continues to collect empirical data to support the fuel efficiency claims from our customers and this data is available upon request. The empirical data shows that the "real world" results are much different than what the Nebraska test engineers are reporting and in this case it is because the test engineers are trying to fit a "square-peg" tractor into a "round-hole" standardized test and it just won't fit.