PT  - JOURNAL ARTICLE
AU  - Šmerda, Tomáš
AU  - Čupera, Jiří
TI  - Combined loading of tractor's engine
DP  - 2014 Oct 5
TA  - Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis
PG  - 199--206
VI  - 58
IP  - 1
AID - 10.11118/actaun201058010199
IS  - 12118516
AB  - The paper deals with influence of combined load of engine on drawbar properties of a tractor. The aim was focused on determination of power consumed via PTO and the impact on drawbar pull. During the development of the tractor is assumed that certain work will transfer operations from 60 to 60% over the PTO. Combined loading of engine power significantly reduces driving force as well as drawbar pull. In general, any change in power distribution will affect power balance and overall efficiency. Nevertheless, decreasing of drawbar force enables higher efficiency due to lower resistance in transmission to PTO. Previous researches have shown that the overall loss can achieve at the most 15 %. Ordinary efficiency of pulling tractor will not cross the limit of 70 %. The contribution brings the results of experimental work where the load was changed. The combined load can be simulated with using of chassis dynamometer along with a dynamometer connected over the PTO. Basic levels of absorbed power over the PTO were set to 50, 70 and 90 kW. These points usually presents needs for main field operations. Settings of the test were carried out of constant power transferred over the PTO. Variable part of engine power is consumed to movement what means change in tractor velocity. The results of experiment have been evaluated using spreadsheet editor and statistical software and were built into plots.