Optimization of piston bowl and valve system in compression ignition engine fueled with gasoline/diesel/polyoxymethylene dimethyl ethers for high efficiency

Abstract

Polyoxymethylene dimethyl ethers, with excellent volatility and oxygen content of up to 49%, have great potential to improve engine performance and emission characteristics. In this study, experiments were carried out in a single-cylinder engine fueled with gasoline/diesel/polyoxymethylene dimethyl ethers blend fuel using multiple premixed compression ignition combustion mode along with engine optimization to exploit the high-efficiency potential. The thermal efficiency was increased by 9.4 percentage points after transforming the combustion mode from conventional diesel mode to gasoline/diesel/polyoxymethylene dimethyl ethers multiple premixed compression ignition mode. A fully variable valve system and a redesigned low-heat-transfer piston were used to further improve the thermal efficiency. The low-heat-transfer piston had a 15% lower area–volume ratio compared with the original ω-type piston. By replacing the original ω-type piston with the low-heat-transfer piston, the heat transfer loss was reduced by 2.29 percentage points and thus indicated thermal efficiency could be increased by 2.37 percentage points, which was up to 50.03%. On the basis of the low-heat-transfer piston, indicated thermal efficiency could be further increased to 51.09% with the application of fully variable valve system due to the longer ignition delay and more premixed combustion. At the same time, NOX emissions could be controlled below 0.4 g/kW·h using high exhaust gas recirculation ratio, which equaled the NOX emission limit of Euro VI standard. Although soot emissions could be increased due to weak turbulence and insufficient intake charge using the low-heat-transfer piston and fully variable valve system, it was still lower than those of the original diesel engines.

An experimental and modeling study on polyoxymethylene dimethyl ether 3 (PODE3) oxidation in a jet stirred reactor

“…However, with increasingly stringent emissions regulations, seeking environmentally friendly fuels for diesel engines is of urgency. Studies have shown that the usage of oxygenated alternative fuels can improve diesel engines’ combustion and emissions performance, without significantly affecting their power output [1] , [2] , [3] .…”

Enabling robust simulation of polyoxymethylene dimethyl ether 3 (PODE3) combustion in engines

“…Meanwhile, PODE 3 has a very high CN, which can potentially overcome the drawbacks of GD blends when gasoline/diesel/ PODE 3 (GDP) blends are applied. 129 Moreover, with the soot reduction potential expected of PODE 3 , GDP blends can be anticipated to further reduce soot emissions, possibly forming ideal concoctions for clean combustion. Liu et al 1 experimentally investigated GDP blends and realized GDP blends produce less HC, CO and soot emissions as compared to GD blends.…”

Conjugate heat transfer study of the impact of ‘thermo-swing’ coatings on internal combustion engines heat losses

“…The main goal is to achieve an engine with lower emissions and higher efficiency. [1][2][3] Among the solutions that are being explored to improve thermal efficiency, one is the development of innovative insulating materials to coat some engine parts, [4][5][6] such as the combustion chamber walls and the exhaust pipes manifold. However, the real global impact of coating these surfaces on the final engine performance is not clear.…”