English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The decrease of inlet charge and mismatch of air and fuel are main reasons for the decrease of engine performance at variable altitudes. Understanding coupling mechanism between two-stage turbocharging and fuel injection system is key to maximize its potential for engine power recovery at variable altitudes. This paper focused on the coupling characteristic of twin variable geometry turbocharging (Twin-VGT) and fuel injection parameters on key parameters of gas path, in-cylinder combustion, and energy flow of the diesel engine at variable altitudes. Firstly, a thermodynamic cycle model of a Twin-VGT diesel engine aiming at variable altitudes was established and validated by experimental data. Furthermore, the coupling mechanism of high-pressure variable geometry turbocharging (HVGT) and low-pressure variable geometry turbocharging (LVGT) vanes on exhaust available energy (EAE), global expansion ratio (GER) and its distribution, global boost ratio (GBR) and its distribution, isentropic efficiency of the Twin-VGT, combustion process, and energy flow of the engine were studied at different altitudes. Enthalpy drop ratio is regulated by HVGT and LVGT and the isentropic efficiency of two-stage turbine reaches to maximum when openings of HVGT and LVGT at 0.35 and 0.75, respectively, at the altitude of 5500 m. Finally, this paper investigated the coupling characteristic of turbocharging and fuel injection parameters on combustion process and engine performance, which provides the theoretical basis for collaborative controlling of the Twin-VGT and fuel injection parameters at variable altitudes. Brake thermal efficiency (BTE) is affected by exhaust temperature which is mainly controlled by HVGT openings and injection advance angle (IAA) at variable altitudes, and BTE reaches to maximum when openings of HVGT at 0.4 and IAA at −5.5°CA under fixed engine load at the altitude of 5500 m.

Thermodynamic analysis on coupling characteristic of Twin-VGT and fuel injection parameters at variable altitudes