Gasoline Two-Stroke HCCI Combustion Controlled by Residual Gas (Second Report)~Effect of Scavenging Pressure and Fuel Injection Timing

Author(s):  
Naoki Baba ◽  
Kiyomi Kawamura ◽  
Yoshiyuki Mandokoro ◽  
Michio Nakano
Author(s):  
Sok Ratnak ◽  
Jin Kusaka ◽  
Yasuhiro Daisho ◽  
Kei Yoshimura ◽  
Kenjiro Nakama

Gasoline Direct Injection Homogeneous Charge Compression (GDI-HCCI) combustion is achieved by closing early the exhaust valves for trapping hot residual gases combined with direct fuel injection. The combustion is chemically controlled by multi-point auto-ignition which its main combustion phase can be controlled by direct injection timing of fuel. This work investigates the effect of single pulse injection timing on a supercharged GDI-HCCI combustion engine by using a four-stroke single cylinder engine with a side-mounted direct fuel injector. Injection of primary reference fuel PRF90 under the near-stoichiometric-boosted condition is studied. The fuel is injected during negative valve overlap (NVO) or recompression period for fuel reformation under low oxygen concentration and the injection is retarded to intake stroke for the homogeneous mixture. It is found that the early fuel injection in NVO period advances the combustion phasing compared with the retarded injection in the intake stroke. Noticeable slower combustion rate from intake stroke fuel injection is obtained compared with the NVO injection due to charge cooling effect. Zero-dimensional combustion simulations with multiple chemical reaction mechanisms are simulated to provide chemical understanding from the effect of fuel injection timing on intermediate species generations. The species such as C2H4, C3H6, CH4, and H2 are found to be formed during the NVO injection period from the calculations. The effects of single pulse injection timings on combustion characteristics such pressure rise rate, combustion stability, and emissions are also discussed in this study.


Author(s):  
S. Juttu ◽  
S. S. Thipse ◽  
N. V. Marathe ◽  
M. K. Gajendra Babu

The objective of this work is to study the effect of different control parameters viz. EGR, fuel injection pressure and start of injection timing on exhaust emissions from diesel fueled HCCI combustion concept. A 4-cylinder LCV engine has been selected for experiments and FIRE 3D CFD software was used for simulation study. The basic idea of the simulation study is to find the suitable EGR ratio to run the engine on HCCI combustion mode so as to avoid any damage to the engine during testing. From simulation study, it was observed that the minimum EGR required for running the engine at 5.6 bar BMEP @ 2500 rpm in HCCI mode is approximately 45%. The trends of simulation results viz. soot and NOx emissions are closely following the experiments. The experiments were conducted at different loads at 2500 rpm and EGR varied from 0% to 60%. With increased EGR ratio, soot bump was observed at 50%, 75% and 100%. The BTE dropped to 24.5% from 33.5%. The effect of fuel injection pressures (750bar, 1000bar and 1500bar) were studied to improve the BTE and to control soot bump over a wide range injection timings EGR ratio. Detailed experiments were conducted at 2.8 bar BMEP @ 2500 rpm to study simultaneous reduction of NOx, SOOT, UHC and CO emissions from diesel HCCI combustion. At injection pressure (1500 bar), advanced fuel injection timing and high EGR ratio, the soot CO and THC emissions were reduced significantly without penalty on NOx emissions. The BTE was improved from 24.5% to 31% against 33.5% of convention diesel combustion.


Author(s):  
Steven G. Fritz ◽  
John C. Hedrick ◽  
Tom Weidemann

This paper describes the development of a low emissions upgrade kit for EMD GP20D and GP15D locomotives. These locomotives were originally manufactured in 2001, and met EPA Tier 1 locomotive emission regulations. The 1,491 kW (2,000 HP) EMD GP20D locomotives are powered by Caterpillar 3516B engines, and the 1,119 kW (1,500 HP) EMD GP15D locomotives are powered by Caterpillar 3512B engines. CIT Rail owns a fleet of 50 of these locomotives that are approaching their mid-life before first overhaul. Baseline exhaust emissions testing was followed by a low emissions retrofit development focusing on fuel injection timing, crankcase ventilation filtration, and application of a diesel oxidation catalyst (DOC), and then later a diesel particulate filter (DPF). The result was a EPA Tier 0+ certification of the low emissions upgrade kit, with emission levels below EPA Line-Haul Tier 3 NOx, and Tier 4 HC, CO, and PM levels.


2008 ◽  
Vol 22 (09n11) ◽  
pp. 1846-1852 ◽  
Author(s):  
HYUN-BAE JEON ◽  
TAE-HOON SONG ◽  
SUNG-HO PARK ◽  
SUN-CHUL HUH ◽  
WON-JO PARK

This experimental study investigates the fracture characteristics of the camshaft made with newly developed SM53C material. As part of the countermeasure, use the surface hardening heat treatment. Cam shaft which is a part of automobile engine is very essential when traveling and significant to fuel injection timing. Stiffness and efficiency are important for automobile sash which have a durability of the engine. High hardness and durability are necessary, because engine output is affected by cam shaft directly. So, high-frequency induction hardening is very important because of increasing the surface strength. The shape of hardening depth, hardened structure, hardness, and fracture characteristics of SM53C composed by carbon steel are also investigated.


Author(s):  
Zuohua Huang ◽  
Seiichi Shiga ◽  
Takamasa Ueda ◽  
Nobuhisa Jingu ◽  
Hisao Nakamura ◽  
...  

Abstract Effect of fuel injection timing relative to ignition timing on natural gas direct-injection combustion was studied by using a rapid compression machine. The ignition timing was fixed at 80 ms from the compression start. When the injection timing was relatively earlier (injection start at 60 ms), the heat release pattern showed slower burn in the initial stage and faster burn in the late stage, which is similar to that of flame propagation of a premixed gas. In contrast to this, when the injection timing was relatively later (injection start at 75 ms), the heat release rate showed faster burn in the initial stage and slower burn in the late stage, which is similar to that of diesel combustion. The shortest duration was realized at the injection end timing of 80 ms (the same timing as the ignition timing) over the wide range of equivalence ratio. The degree of charge stratification and the intensity of turbulence generated by the fuel jet is considered to cause these behaviors. Earlier injection leads to longer duration of the initial combustion, whereas the later injection does longer duration of the late combustion. Earlier injection showed relatively lower CO emission while later injection produces relatively lower NOx emission. It was suggested that earlier injection leads to lower mixture stratification combustion and later injection leads to higher mixture stratification combustion. Combustion efficiency maintained high value over the wide range of equivalence ratio.


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