Roger M. Hoy

Agricultural Industry Advanced Vehicle Technology: Benchmark Study for Reduction in Petroleum Use

agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness, of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. References herein to any specific commercial product, process, or service by trade name, trade mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof.

TESTING FUEL EFFICIENCY OF A TRACTOR WITH A CONTINUOUSLY VARIABLE TRANSMISSION

A John Deere 8530 IVT tractor (Waterloo, Iowa) with a continuously variable transmission (CVT) that could be operated in automatic (CVT) or manual (fixed gear ratio) mode was tested for fuel consumption at a setpoint travel speed of 9 km·h-1 with 17 different drawbar loads. Linear regression analysis results showed that with the throttle set to maximum in both transmission modes, operating the tractor with the transmission in the automatic mode was more fuel efficient than operating with the transmission in the manual mode when the drawbar power was approximately 78%, or less, of maximum power. When load transition portions of the data were filtered out, there was no significant effect of load sequencing in the remaining data. On the other hand, there was a noticeable effect of travel direction which could occur due to a minor slope of the test track in the direction of travel. Testing of more tractor models from different manufacturers and at different travel speeds is needed to determine if these results can be applied to different tractor models produced by the same and/or other manufacturers.

Testing Fuel Efficiency of Tractors with both Continuously Variable and Standard Geared Transmissions

A John Deere 8295R IVT tractor with a continuously variable transmission (CVT) and a John Deere 8295R PowerShift (PST) tractor (Waterloo, Iowa) with a standard geared transmission (GT) were tested for fuel consumption at three different travel speeds with six different load levels applied per speed. The JD 8295R PST tractor was tested both at full throttle (FT) and shifted up two gears and throttled back (SUTB) to achieve the same travel speed as at full throttle conditions. For each travel speed with each transmission mode, fuel consumption was determined to be linearly related to drawbar power. Linear regression results showed that the tractor with the CVT was more fuel efficient than the tractor with the GT at FT when the power was below 76% to 81% of maximum drawbar power depending on the travel speed. The results also showed that above 37% to 52% of maximum drawbar power, the GT at SUTB was more fuel efficient than the CVT equipped tractor. As travel speed increased, the percent of maximum power below which the CVT was significantly more fuel efficient than the GT at FT decreased slightly. Likewise, the percent of maximum power above which the GT at SUTB was more fuel efficient than the CVT decreased as speed increased. In order to determine differences in fuel consumption between the tractor transmission operating modes, testing with at least three loads and at least three travel speeds is recommended. Additional testing is needed on other models of tractors from other manufacturers to determine whether the trends found in this study pertain to all CVT equipped tractors or if they are specific to this tractor model and manufacturer.

Validation of machine CAN bus J1939 fuel rate accuracy using Nebraska Tractor Test Laboratory fuel rate data

All error between the SAE J1939 and NTTL fuel rates less than ?5%.Higher fuel flow rates resulted in a lower error of ?1%.Lower fuel flow rates resulted in higher error (up to 5%).Lower fuel flow rates generated higher standard deviations in error. A pilot study concluded that there was a difference (up to a 6.22% error) between data collected using the machine controller area network (CAN) bus Society of Automotive Engineers (SAE) J1939 standard fuel rate and data collected from a physical measurement system utilized by the Nebraska Tractor Test Laboratory (NTTL). This indicated a need to perform further studies on the accuracy of the CAN fuel rate message.The SAE J1939 standard fuel rate message utilized by the machine CAN bus has a theoretical value, however little work has been done to verify the accuracy of this value. Reported fuel flow rate values are rarely measured directly on field equipment using a flow meter, instead these values are estimated from other operating parameters (e.g., engine speed, number of cylinders, injector timing and pulsation, etc.). The goal of this study was to compare fuel rate values collected from the CAN bus to the physically measured fuel rate value from tractor performance tests conducted at the NTTL. The fuel rate values were collected simultaneously and then synchronized to confirm accuracy of results. The parameters for comparison in this study were comprised of the performance test points as described in the Organization for Economic Co-operation and Development (OECD) Code 2, Section 4.1.1. The NTTL has a certified fuel rate measuring system with an accuracy of ?0.5%.Results from this study indicated fuel rate as recorded from the CAN bus resulted in a ?5% error of actual physically measured fuel rates. Errors for higher fuel rates within the torque curve were closer to ?1%. This produced knowledge of machine fuel rate accuracy for in-field efficiency and/or spatial fuel usage for additional analysis, whether used for research or grower cost analysis with an accurate knowledge of actual fuel consumed during operation.

Tractor hydraulic power data acquisition system

A portable tractor hydraulic power measurement system (DUT) was developed.DUT was tested at different hose bend angles, flow rates and operating pressures.Pressure deviations from the base line ranged between 10.56kPa and 32.2kPa.Flow rate differences (<167mLmin-1) were determined to be negligible (<0.5%).Calculated power differences (<33W) were less than 1% full scale power measured. Tractor hydraulic power is used on a wide range of agricultural implements; however, the availability of operational hydraulic data at points other than full engine throttle position is limited. Operators could utilize this hydraulic data to maximize field efficiency and minimize machinery costs when determining suitable machinery for field operations. A field usable hydraulic test apparatus capable of measuring tractor hydraulic pressure and flow rate data was developed. The goal of this study was to determine if a hydraulic flow and pressure measurement device could be installed on the rear of a tractor to provide implement hydraulic power consumption at different hydraulic hose orientations. The measurement system installed allowed hydraulic lines from the tractor hydraulic remote ports to be attached to the flowmeter and pressure sensors at multiple angles of 0°, 45°, and 90° in different configuration layouts. Tests were performed at different flows and pressures for each hose configuration. The pressures were compared across configurations to a base line reading from a hydraulic pressure and flow rate measurement apparatus used by the Nebraska Tractor Test Laboratory (NTTL). Pressure deviations from the base line were small and ranged between 10.56kPa and 32.2kPa. Flow rate differences (<167mLmin-1) were determined to be negligible (<0.5%). Calculated power differences (<33W) were less than 1% full scale power measured. This small power loss suggested that using the hydraulic measurement apparatus developed as part of this study would enable accurate measurements of tractor hydraulic power provided to implements regardless of hydraulic hose bend angles.

Comparing various hardware/software solutions and conversion methods for Controller Area Network (CAN) bus data collection

Machine CAN bus digital data accuracy could vary based on collection methods.Frame and waveform (i.e., averaged) datasets were collected and compared.Frame data logging techniques resulted in much larger file sizes compared to waveform data.Differences between digital data values logged using frame or waveform methods were minimal.Based on measured parameters, waveform data would be acceptable for most field research in agriculture. Various hardware and software solutions exist for collecting Controller Area Network (CAN) bus data. Digital data accuracy could vary based upon different data logging methods (e.g., hardware/software timing, processor timing, etc.). CAN bus data were collected from agricultural tractors using multiple data acquisition solutions to quantify differences among collection methods and demonstrate potential data accumulation rates.Two types of data were observed for this study. The first, CAN bus frame data, represents data collected for each line of hex data sent from an ECU. One issue with frame data is the resulting large file sizes, therefore a second logging format collected was an averaged frame signal, or waveform dataset. Because of its smaller file size, waveform data could be more desirable for long periods of collection. Percent difference was calculated from two sets of frame data logs using different hardware/software combinations, and a frame data log was also compared to a waveform data log.The resulting difference was less than 0.0025 RPM for engine speed comparisons, zero for fuel rate and fuel temperature comparisons, and the mean percent difference was less than 0.08% between the methods of data collection. The error production could have resulted from noise in hardware and processor times, but was not found to increase as time progressed. This showed that even though errors existed between logging methods, the magnitude of errors would not negatively impact any practical agricultural field research applications. Thus, data logged by the different devices was similar and files requiring less memory would be desired. Selecting a waveform CAN bus data logging option would likely maintain digital data accuracy while reducing file storage and processing needs.

Verifying Power Claims of High-Power Agricultural Tractors Without a PTO to Sell in Nebraska

Nebraska law requires the Nebraska Tractor Test Board of Engineers to compare results of the tests of an agricultural tractor model with the manufacturers claims regarding power, fuel use, and other performance ratings in order to recommend a permit to sell that tractor model in the state. PTO tests are conducted to verify the manufacturers PTO power and fuel claims for tractor models. In recent years, several tractor manufacturers have been producing models of large tractors either without a PTO or with a PTO not capable of transmitting the full engine power and, therefore, have chosen to advertise engine power. The objective of this project was to determine a reasonable alternative to removing engines from these tractors for tests to determine whether these tractors met their power claims. Linear regression analyses of advertised engine power claims and OECD Code 2 drawbar power test results from 48 tracked (R2 = 0.98) and 43 4WD tractors (R2 = 0.99) were used to establish two linear relationships to verify the engine power claims for these tractors. These relationships provide a reasonable means of verifying engine power claims for large agricultural tractors without a PTO, or without a PTO capable of transmitting full engine power.

Development of a Calibration Procedure for Diesel Fuel Flow Measurement with a Coriolis Effect Meter

Reports in the literature indicated several factors that can influence the accuracy of Coriolis Effect mass flow meters. A Coriolis Effect mass flow meter is used to verify tractor manufacturers’ fuel consumption claims at the Nebraska Tractor Test Laboratory. The accuracy requirements placed on the flow meter by the Organization for Economic Co-operation and Development (OECD) in the Code 2 tractor performance test procedure are not clear, but were interpreted to be ±0.5% of each flow rate measured. Calibration tests conducted on the flow meter using a static weighing system showed it was capable of achieving this accuracy requirement for flow rates at or above 31.8 kg/h, and only slightly outside this accuracy for lower flow rates. The calibration determined by the testing deviated from the flow meter manufacturer’s calibration by a maximum of only 0.11 kg/h at a flow rate of 106 kg/h.

Verifying Power Claims of High-power Tractors Without a PTO at the Nebraska Tractor Test Lab

Nebraska law requires agricultural tractors of 29.8 kw (40 hp) or more to be tested and tractor power claims to be verified. In recent years, several tractor manufacturers have been producing models of large tractors either without a PTO or with a PTO not capable of transmitting the full engine power and, therefore, have chosen to advertise engine power. As the primary test the Nebraska Tractor Test Lab has used to verify manufacturers’ power claims has been the PTO power test, the manufacturers asked the University of Nebraska Board of Tractor Test Engineers to clarify how power claims for these tractors will be verified. Analyses of advertised engine power claims and drawbar power test results from 48 tracked and 43 4WD tractors were used to establish two linear relationships to verify the engine power claims for these types of tractors.