A split injection of wet ethanol to enable thermally stratified compression ignition

Abstract

Thermally stratified compression ignition is a new advanced, low-temperature combustion mode that aims to control the heat release process in a lean, premixed, compression ignition combustion mode by controlling the level of thermal stratification in the cylinder. Specifically, this work uses a mixture of 80% ethanol and 20% water by mass, referred to as “wet ethanol” herein, to increase thermal stratification via evaporative cooling of areas targeted by an injection event during the compression stroke. The experiments conducted aim to both fundamentally understand the effect that a late cycle injection of wet ethanol has on the heat release process, and to use that effect to explore the high-load limit of thermally stratified compression ignition with wet ethanol. At an equivalence ratio of 0.5, injecting just 8% of the fuel during the compression stroke was shown to reduce the peak heat release rate by a factor of 2, subsequently avoiding excessive pressure rise rates. Under pure homogeneous charge compression ignition using wet ethanol as the fuel, the load range was found to be 2.5–3.9 bar gross indicated mean effective pressure. Using a split injection of wet ethanol, the high-load limit was extended to 7.0 bar gross indicated mean effective pressure under naturally aspirated conditions. Finally, intake boost was used to achieve high-load operation with low NOx (oxides of nitrogen (NO or NO2)) emissions and was shown to further increase the high-load limit to 7.6 bar gross indicated mean effective pressure at an intake pressure of 1.43 bar. These results show the ability of a split injection of wet ethanol to successfully control the heat release process and expand the operable load range in low-temperature combustion.

Intelligent Oil Production Stratified Water Injection Technology

“…China's rapid economic development over the years, the demand for oil and gas resources, oil field production scale, and supporting technology are relatively perfect; the number of oil wells and water content is constantly improving; stratified water injection technology has also put forward higher performance requirements. Since the 1950s, waterflood oil recovery has been gradually understood by domestic industry and academia [10][11][12][13][14][15]. After years of development, an independent waterflood oil recovery technology system has been formed.…”

Tailoring thermal stratification to enable high load low temperature combustion with wet ethanol on a gasoline engine architecture

“…Typically, the naturally aspirated highload limit of HCCI with wet ethanol would be ;4 to 4.5 bar IMEPg when an RI limit of 2.5 MW/m 2 is considered. 11 Similarly, the HCCI high-load limit is ;4 bar IMEPg on this engine when fueled with gasoline. 28 The known mechanism of heat release elongation from wet ethanol in LTC is an increase in thermal stratification.…”

Experimental Study of the Effect of Start of Injection and Blend Ratio on Single Fuel Reformate RCCI

“…Thermally stratified compression ignition is a combustion mode that aims to control the heat release process in LTC by controlling the in-cylinder thermal stratification. Thermally stratified compression ignition uses the evaporative cooling of a compression stroke injection of a noncombustible liquid, like water [6,7], or a high latent heat of vaporization, low equivalence-ratio-sensitive fuel, like wet ethanol [8][9][10], to modify the thermal stratification profile in the combustion chamber. Contrarily, combustion modes like partial fuel stratification [11][12][13], gasoline compression ignition [14,15], and premixed charge compression ignition [16][17][18] use a compression stroke injection of an equivalence-ratio-sensitive fuel to create an equivalence ratio stratification in the cylinder, where the rich regions will have a shorter ignition delay than the lean regions, staging the heat release process.…”