Emissions as functions of fuel oxygen and load from a premixed low-temperature combustion mode

Abstract

Soot, mono-nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbon emissions are investigated as functions of fuel oxygen and engine load in a single-cylinder diesel engine operated in a premixed low-temperature combustion mode by isolating fuel oxygen from other fuel properties and removing or minimizing variations in engine combustion parameters. It is found that at high loads (high global equivalence ratios), soot is reduced as fuel oxygen increases. Over the load range tested, CO and hydrocarbon emissions are not affected by fuel oxygen fraction. NOx emission increases as load is decreased because intake composition changes. NOx emission is not directly affected by fuel oxygen. The difference in NOx emission among the different oxygen fuels is indirectly caused by different exhaust composition affecting intake composition. Combustion efficiency and indicated thermal efficiency are similar for the test fuels with different oxygen fractions.

Analysis of the role of altitude on diesel engine performance and emissions using an atmosphere simulator

“…simulated altitude is below engine location one. A cyclonic separator (13) is installed downstream of the VGT to separate the ice or water generated because of very low temperature. Then, part of the air mass flow is aspirated by the engine intake (1a).…”

“…Due to the fact that at low ambient pressure the intake air mass flow decreases, some studies are driven to analyse the potential of enriched oxygen fuel (12) as a way to improve the engine performance. NOx emissions have been discussed not to be directly affected by fuel oxygen (13), so that can be proposed as potential improvement. Another solution is based on two-stage sequential turbocharging system to increase maximum available pressure ratio so that boosting pressure at sea-level conditions can be kept at high altitude (14).…”

Impact of Fuel and Injection Timing on Partially Premixed Charge Compression Ignition Combustion

“…Steady state testing was conducted using a single cylinder engine based on a GM/Isuzu 1.7 L, 4-cylinder, common-rail, direct injection diesel engine (Table ). As has been described previously by Zhu et al, the compression ratio was reduced from 19:1 to 15:1 to achieve PCCI combustion. The original piston was changed to one with a larger combustion bowl.…”