Experimental analysis of hydrotreated vegetable oil (HVO) and commercial diesel fuel blend characteristics using modified CFR engine

ArticlePerformance parameters of different commercial diesel fuels is a subject of interest for fuel consumers. Fuel retailer Neste recently introduced a new brand of WWFC 5th grade diesel fuel in Baltic market, consisting of diesel fuel and hydrotreated vegetable oil (HVO) blend. Fuel samples have been recently tested on chassis dynamometer, measuring wheel power and torque and in road conditions, measuring fuel consumption. Evaluation of fuel consumption and performance parameters in road or laboratory conditions may yield uncertain results due to complexity of modern automobile engine management and emission reduction systems. To better evaluate the combustion, fuel samples have been tested in modified CFR engine at various intake air pressure, temperature and compression ratio settings. Engine indicated performance parameters and combustion phasing of regular diesel fuel and diesel fuel-HVO blend are presented. Comparing to regular diesel fuel, fuel blend with HVO showed reduced apparent heat release rate (AHRR) during premixed combustion phase at low inlet air temperature and low compression ratio conditions, comparing to regular diesel fuel. Premixed combustion phase AHRR of diesel-HVO blend increased above AHRR of regular diesel fuel at higher inlet air temperature and higher compression ratio conditions. Diffusion controlled combustion phase AHRR of diesel-HVO blend increased above AHRR of regular diesel fuel at higher inlet air temperature, higher compression ratio conditions and supercharged air supply

Research into the 3d roughness of a rough surface

Abstract One of the most important parameters in determination of the deformation associated with roughness is its height on the surface. The authors study the density of probability distribution as related to the surface peak height (SPH) and estimate the mathematical expectation (ME) of SPH for the roughness values above a determined deformation level. In the contact theory, the surface is modelled as a normal random field described by the Nayak SPH formula. Since this formula is practically inapplicable in the engineering tasks, the authors propose to replace it by a simpler distribution law. For this purpose the former is compared with two other formulas obeying the most known probability distribution laws: of normal distribution (Gauss’) law and Rayleigh’s law. Comparison of these three formulas made it possible to derive a simpler yet sufficiently precise one. In the work, the numerical values of the density of SPH probability distribution and the relevant ME values at different deformation levels for all three formulas.</jats:p