Identification of maximal cyclic pressure with the non-motorized method based on specific refraction

ВACKGROUND: Russian scientists constantly deal with the issues of the engine performance evaluation with non-standard methods, as they are commonly called “express methods”. In many cases, if the initial components retain the relative constancy of their physicochemical properties, the determination of performance indicators can be carried out with simple classical methods of refractometry, magneto-optics, densimetry, interfacial tensiometry or their combination (aggregation).

AIM: Identification of the maximal cycle pressure of an operating diesel engine with the non-motorized method based on the values of specific refraction for each type of biofuel.

METHODS: The object of research was the D-245.5S2 turbocharged four-stroke engine with intercooler. Mixtures of DT with ethanol, rapeseed oil and surep oil were prepared for the study. The mass fraction of oils and ethanol in the mixture varied from 0% to 50%. Density d and refractive index were measured for each sample. The measurements were carried out at an ambient temperature of 20˚C. The refractive index of the samples was measured using the IRF – 454b refractometer. The density was determined using the PZh-2-25 pycnometer and the VIBRAAJH-620CE laboratory scales according to GOST 3900-85 “Oil and petroleum products. Methods for determining density”.

RESULTS: Data analysis showed that there is a strong correlation between the specific refraction sR and the maximal pressure in a cylinder P_z (MPa). Linear regression models for various alternative fuel mixtures have been developed to determine the maximal cycle pressure during diesel operation.

CONCLUSION: The application of the proposed dependencies makes it possible to identify the maximal cycle pressure of an operating a diesel engine with sufficient accuracy in a non-motorized way.