scholarly journals Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

2013 ◽  
Author(s):  
John Pratapas ◽  
Daniel Mather ◽  
Anton Kozlovsky
Author(s):  
Su Ling ◽  
Zhou Longbao ◽  
Liu Shenghua ◽  
Zhong Hui

Experimental studies have been carried out on decreasing the hydrocarbon (HC) and carbon monoxide (CO) emissions of a compressed natural-gas (CNG) engine operating in quasi-homogeneous charge compression ignition (QHCCI) mode at low loads. The effects of three technical approaches including partial gas cut-off (PGC), intake air throttling, and increasing the pilot fuel quantity on emissions and the brake thermal efficiency of the CNG engine are studied. The results show that HC and CO emissions can be reduced with only a small penalty on the brake thermal efficiency. An increase in the brake thermal efficiency and reductions in HC and CO emissions can be simultaneously realized by increasing the pilot fuel quantity. It is also indicated from experiments that the HC and CO emissions of the engine can be effectively reduced when using intake air throttling and increasing the pilot fuel quantity are both adopted. However, nitrogen oxide (NOx) emissions increase with increase in the throttling and the pilot fuel quantity. Under PGC conditions, NOx emissions are lower than those in the standard mode; however, they increase and exceed the values in the standard mode in increases in the load and natural-gas supply.


2008 ◽  
Vol 9 (5) ◽  
pp. 399-408 ◽  
Author(s):  
T Shudo

A homogeneous charge compression ignition (HCCI) engine system fuelled with dimethyl ether (DME) and methanol-reformed gas (MRG), both produced from methanol by onboard reformers using exhaust heat, has been proposed in previous research. Adjusting the proportions of DME and MRG with different ignition properties effectively controlled the ignition timing and load in HCCI combustion. The use of the single liquid fuel, methanol, also eliminates the inconvenience of carrying two fuels while maintaining the effective ignition control effect. Because reactions producing DME and MRG from methanol are endothermic, a part of the exhaust gas heat energy can be recovered during the fuel reforming. Methanol can be reformed into various compositions of hydrogen, carbon monoxide, and carbon dioxide. The present paper aims to establish the optimum MRG composition for the system in terms of ignition control and overall efficiency. The results show that an increased hydrogen fraction in MRG retards the onset of high-temperature oxidation and permits operation with higher equivalence ratios. However, the MRG composition affects the engine efficiency only a little, and the MRG produced by the thermal decomposition having the best waste-heat recovery capacity brings the highest overall thermal efficiency in the HCCI engine system fuelled with DME and MRG.


1999 ◽  
Author(s):  
Y. Kawabata ◽  
K. Nakagawa ◽  
F. Shoji

Abstract Recently, a new design of engine combustion that achieves higher efficiency and less NOx emission has been proposed. Some researchers have started studying the concept, which is called Homogeneous Charge Compression Ignition (HCCI), but there have been few reports on investigations using a future prospective alternative fuel, natural gas. In this study, natural gas fueled operation of HCCI using a single cylinder gas engine was conducted. Operating and exhaust characteristics were obtained. Experimental data confirmed the potential of higher efficiency and less NOx emission, though THC and CO were higher. Based on these data, the feasibility of this concept for gas engines is also examined.


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