In a previous study, we estimated multivariate regression models (MRM) for 12 soil properties, including chemical and biological (soil organic matter) properties, and soil maps were created by using a tractor-mounted soil analyzing system. The purpose of this study was to estimate MRMs for 25 soil properties, including exchangeable potassium and dry density, to evaluate the accuracy of the models by comparison with previous studies, and to create soil maps.
MRM estimations were applied to second-derivative pretreatment and partial least-squares regression analysis (Full Cross Validation) using a total of 334 data. The accuracies of 25 MRM were obtained, with R2 from 0.82 to 0.90 and residual prediction deviations from 2.35 to 3.25. We were able to show 25 soil properties on high-resolution soil maps. These included the three major nutrients in fertilizer, along with biological and physical information, enhancing the value of soil management information.
Biogas is used in gas engine cogeneration to obtain electricity and heat. However, only the biogas produced is stored in the plant. Hence, we developed dual-fuel biogas tractors that can be operated with biogas and diesel. Their basic performance in the steady state was tested. The results of power take-off shaft (PTO) performance tests showed that tractor operation was stable at all engine speeds and under loads. The maximum engine torque and power in the dual-fuel model were higher than the conventional values by 10%. The maximum fuel replacement rate was 86%. NOX and CO2 emissions decreased by 8% and 11%, respectively, in the dual-fuel mode. However, CO and HC emissions increased because excess biogas prevented diesel fuel combustion.
Biogas tractors were developed for agricultural purposes with the aim of partially replacing diesel with biogas. This paper mainly discusses the performance and reduction of fuel consumption of these tractors.
The results showed that dual-fuel operation reduced diesel consumption in all field tests, while realizing the same working efficiency. The maximum decrease in fuel consumption was 73% in hay rake operation. The maximum decrease in fuel replacement rate was 79% in broadcaster operation. Furthermore, by using a dynamometer to determine the actual engine power and load in field tests, we reproduced the engine speed and estimated the engine load. Finally, the fuel consumption performance of the tractors at actual engine speed and power was determined.
We studied a test method to minimize the effects of environmental test conditions on engine performance and conduct a fairer test. In this report, we investigated the effects of fuel temperature and atmospheric factors calculated based on dry atmospheric pressure and intake air temperature on engine performance and emission gases in exhaust turbocharged diesel engines. As a result, it was clarified that differences in atmospheric factor influence the test results for engine power, specific fuel consumption, particulate matter, nitrogen oxide and carbon monoxide. There is a possibility of reducing variations in test results by maintaining constant atmospheric factors. Therefore, it is necessary to research this possibility.