Effect of Bioethanol on Combustion and Exhaust Emissions in a Diesel–Bioethanol Dual-Fuel Combustion Engine

Abstract This paper investigated the effect of different substitution ratios of neat ethanol (E100) and ethanol–gasoline blend E85 on in-cylinder combustion, engine efficiency, and exhaust emissions, in a dual-fuel diesel engine, using the ethanol–diesel blend (DE95). Experimental studies realized at 1400 rpm, 1600 rpm, and 1800 rpm engine speeds under constant engine load of 50% (20 Nm). For each engine speed, the injection timing of diesel and E95 fuels at 24 °CA bTDC kept constant while low-reactivity fuels (i.e., E100 and E85) substitution ratio changed in the range of 59–83%. The results showed that premixed fuels in different SRs have an impact on shaping engine emissions, ignition delay (ID), in-cylinder pressure, and heat-release rate. Also, at the dual-fuel experimental studies in all engine speeds, NOx about 47–67% decrease compared to single fuel conditions of reference diesel and DE95, and smoke opacity remained unchanged around 0.1 FSN, whereas HC and CO increased in the range of 20–50%. However, E85/DE95 and E100/DE95 dual-fuel combustion achieved lower brake thermal efficiency (BTE) and combustion efficiency compared to single diesel fuel combustion. On the other hand, in dual-fuel combustion conditions, despite the low combustion efficiency, premixed E85 fuel offered higher engine efficiency and lower exhaust emissions than E100.

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Closed-loop control of a dual-fuel engine working with different combustion modes using in-cylinder pressure feedback

International Journal of Engine Research ◽

10.1177/1468087419835327 ◽

2019 ◽

Vol 21 (3) ◽

pp. 484-496 ◽

Cited By ~ 2

Author(s):

Carlos Guardiola ◽

Benjamín Pla ◽

Pau Bares ◽

Alvin Barbier

Keyword(s):

Closed Loop ◽

Combustion Engine ◽

Fuel Combustion ◽

Operating Conditions ◽

Dual Fuel ◽

Maximum Pressure ◽

Cylinder Pressure ◽

Pressure Derivative ◽

Combustion Modes ◽

Dual Fuel Combustion

This work presents a closed-loop combustion control concept using in-cylinder pressure as a feedback in a dual-fuel combustion engine. At low load, reactivity controlled compression ignition combustion was used while a diffusive dual-fuel combustion was performed at higher loads. The aim of the presented controller is to maintain the indicated mean effective pressure and the combustion phasing at a target value, and to keep the maximum pressure derivative under a limit to avoid engine damage in all the combustion modes by cyclically adapting the injection settings. Various tests were performed at steady-state conditions showing good abilities to fulfil the expected operating conditions but also to reject disturbances such as intake pressure or exhaust gas recirculation variations. Finally, the proposed control strategy was tested during a load transient resulting in a combustion switching-mode and the results exhibited the closed-loop potential for controlling such combustion concept.

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