Effects of direct injection timing and blending ratio on RCCI combustion with different low reactivity fuels

Abstract

ElsevierBenajes Calvo, JV.; García Martínez, A.; Monsalve Serrano, J. (2015). Effects of direct injection timing and blending ratio on RCCI combustion with different low reactivity fuels. Energy Conversion and Management. 99:193-209. doi:10.1016/j.enconman.2015.04.046. Effects of Direct injection timing and Blending Ratio on RCCI combustion with different Low Reactivity FuelsEnergy Conversion and Management, Volume 99, 2015, Pages 193-209. http://dx.doi.org/10.1016/j.enconman.2015 AbstractThis work investigates the effects of the direct injection timing and blending ratio on RCCI performance and engine-out emissions at different engine loads using four low reactivity fuels: E10-95, E10-98, E20-95 and E85 (port fuel injected) and keeping constant the same high reactivity fuel: diesel B7 (direct injected). The experiments were conducted using a heavy-duty single-cylinder research diesel engine adapted for dual-fuel operation. All the tests were carried out at 1200 rpm. To assess the blending ratio effect, the total energy delivered to the cylinder coming from the low reactivity fuel was kept constant for the different fuel blends investigated by adjusting the low reactivity fuel mass as required in each case. In addition, a detailed analysis of the air/fuel mixing process has been developed by means of a 1-D in-house developed spray model.Results suggest that notable higher diesel amount is required to achieve a stable combustion using E85. This fact leads to higher NOx levels and unacceptable ringing intensity. By contrast, EURO VI NOx and soot levels are fulfilled with E20-95, E10-98 and E10-95. Finally, the higher reactivity of E10-95 results in a significant reduction in CO and HC emissions, mainly at low load.

An experimental investigation on the influence of piston bowl geometry on RCCI performance and emissions in a heavy-duty engine

“…In addition, physicochemical properties of E85 resulted in a particular combustion behavior with narrow operating range, limited by misfire and excessive knocking at low and high load, respectively. By contrast, minor portions of ethanol (10%-20%) showed clear potential to reach EURO VI NOx and soot levels with improved HC and CO emissions from low to high load [38].…”

Effects of low reactivity fuel characteristics and blending ratio on low load RCCI (reactivity controlled compression ignition) performance and emissions in a heavy-duty diesel engine

“…Thus, several investigations have been conducted with the aim of insight into the RCCI phenomena. First of all, the effects of the gasoline percentage in the blend and direct injection timing were widely studied [25][26] [27]. These works revealed that RCCI concept allows to reach ultra-low NOx and soot emissions levels, together with improved fuel consumption compared to conventional diesel combustion (CDC).…”

Current trends on combustion control methods using fuel reactivities

“…It was reported that delay in direct injection leads to a two stage heat release since the premixed combustion takes place initially, followed by the diffusion combustion whereas advanced direct injection leads to a single stage heat release [84]. It was reported that by keeping Start of Ignition (SOI) constant around -30° ATDC and increasing the LRF proportion, it improves the ignition delay, whereas keeping SOI around -10 ATDC and increasing the LRF proportion has no significant effects on delayed ignition.…”