The paper deals with a brief bibliography survey and experimental activity concerning an unconventional combustion process for two-stroke gasoline engines. Auto-ignition is an interesting combustion process which takes place at light loads and turns the effect of residual gas from negative aspect to positive since their thermal energy is used to prime auto-ignition of the fresh gas. This leads to very good combustion quality with very small cycle to cycle variations, to low specific fuel consumption and to low exhaust emissions of carbon monoxyde and unburned hydrocarbons. The name A.T.AC. (Active Thermo Atmosphere Combustion) was chosen by Onishi et al. who presented the first industrial application of this unconventional combustion process to a portable generator (NICE 10) in 1979. Research work on the auto-ignition combustion have been carried out since early 1970’s. More recently, a famous demonstration of the potential of an engine designed with a wide range of controlled auto-ignition combustion process (Activated Radicals Combustion) has been performed by the HONDA EXP2 motorcycles during the 1995 Grenada Dakar Rally. Today, more and more stringent legislations for highly polluting two-stroke engines appear and this auto-ignition combustion process is a promising way to help to cope new regulations. In order to better understand and control this combustion process far a wide industrial application, it seems necessary to study this phenomenon thoroughly. The experimental work presented in this paper was performed on both loop and cross scavenged two-stroke engines. Different engines parameters and setting as well as compression ratio, transfer duct configuration and air/fuel ratio have been investigated to evaluate their effect an the autoignition. Furthermore, optical cylinder heads have been designed far combustion visualization and both A.T.A.C. and S.I. combustion photographic images are presented and described in this paper. A video film has also been realized.
Investigation on controlled auto-ignition combustion (A.T.A.C.) in two-stoke gasoline engine
GENTILI, ROBERTO
1996-01-01
Abstract
The paper deals with a brief bibliography survey and experimental activity concerning an unconventional combustion process for two-stroke gasoline engines. Auto-ignition is an interesting combustion process which takes place at light loads and turns the effect of residual gas from negative aspect to positive since their thermal energy is used to prime auto-ignition of the fresh gas. This leads to very good combustion quality with very small cycle to cycle variations, to low specific fuel consumption and to low exhaust emissions of carbon monoxyde and unburned hydrocarbons. The name A.T.AC. (Active Thermo Atmosphere Combustion) was chosen by Onishi et al. who presented the first industrial application of this unconventional combustion process to a portable generator (NICE 10) in 1979. Research work on the auto-ignition combustion have been carried out since early 1970’s. More recently, a famous demonstration of the potential of an engine designed with a wide range of controlled auto-ignition combustion process (Activated Radicals Combustion) has been performed by the HONDA EXP2 motorcycles during the 1995 Grenada Dakar Rally. Today, more and more stringent legislations for highly polluting two-stroke engines appear and this auto-ignition combustion process is a promising way to help to cope new regulations. In order to better understand and control this combustion process far a wide industrial application, it seems necessary to study this phenomenon thoroughly. The experimental work presented in this paper was performed on both loop and cross scavenged two-stroke engines. Different engines parameters and setting as well as compression ratio, transfer duct configuration and air/fuel ratio have been investigated to evaluate their effect an the autoignition. Furthermore, optical cylinder heads have been designed far combustion visualization and both A.T.A.C. and S.I. combustion photographic images are presented and described in this paper. A video film has also been realized.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
