scholarly journals Natural gas-diesel reactivity controlled compression ignition with negative valve overlap and in-cylinder fuel reforming

2019 ◽  
Vol 254 ◽  
pp. 113638 ◽  
Author(s):  
Maciej Mikulski ◽  
Praveen Ramanujam Balakrishnan ◽  
Jacek Hunicz
Keyword(s):  
Natural Gas ◽  
Compression Ignition ◽  
Fuel Reforming ◽  
Reactivity Controlled Compression Ignition ◽  
Negative Valve Overlap ◽  
Valve Overlap

scholarly journals HCCI with standard and alternative fuels at moderate compression ratios

2006 ◽  
Vol 124 (1) ◽  
pp. 3-20
Author(s):  
Miroslaw WYSZYNSKI ◽  
Hongming XU
Keyword(s):  
Natural Gas ◽  
Power Systems ◽  
Compression Ratio ◽  
Alternative Fuels ◽  
Global Solutions ◽  
Fuel Reforming ◽  
Hydrogen Addition ◽  
Land Rover ◽  
Negative Valve Overlap ◽  
Valve Overlap

Work with different fuels: gasoline, natural gas, biogas, ethanol, propane, mixtures of gasoline and diesel at the authors’ Future Power Systems Group in Birmingham University reveals great potential for the use of moderate compression ratio engines (from 10.4 to 15), particularly when additional engine facilities such as EGR (external and internal via negative valve overlap and low lift cams), some degree of intake heating and/or hydrogen addition (from fuel reforming) are employed. Possibilities, benefits and demands of these technologies are outlined, additional challenges specific to application of HCCI in multi-cylinder engines in vehicle applications are discussed and on-going work on the CHASE (Controlled Homogeneous Autoignition Supercharged Engine) is outlined. The team who contributed to this work includes colleagues from Birmingham University, Jaguar Land Rover, Johnson Matthey plc, National Engineering Laboratory and Shell Global Solutions.

Numerical study on combustion characteristics of six-stroke-cycle gasoline compression ignition engine with continuously variable valve duration valve technology

2019 ◽  
Vol 22 (1) ◽  
pp. 165-183 ◽  
Author(s):  
Oudumbar Rajput ◽  
Youngchul Ra ◽  
Kyoung-Pyo Ha ◽  
You-Sang Son
Keyword(s):  
Numerical Study ◽  
Power Stroke ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Wide Range ◽  
Negative Valve Overlap ◽  
Variable Valve ◽  
Valve Overlap

Engine performance and emissions of a six-stroke gasoline compression ignition engine with a wide range of continuously variable valve duration control were numerically investigated at low engine load conditions. For the simulations, an in-house three-dimensional computational fluid dynamics code with high-fidelity physical sub-models was used, and the combustion and emission kinetics were computed using a reduced kinetics mechanism for a 14-component gasoline surrogate fuel. Variation of valve timing and duration was considered under both positive valve overlap and negative valve overlap including the rebreathing of intake valves via continuously variable valve duration control. Close attention was paid to understand the effects of two additional strokes of the engine cycle on the thermal and chemical conditions of charge mixtures that alter ignition, combustion and energy recovery processes. Double injections were found to be necessary to effectively utilize the additional two strokes for the combustion of overly mixed lean charge mixtures during the second power stroke. It was found that combustion phasing in both power strokes is effectively controlled by the intake valve closure timing. Engine operation under negative valve overlap condition tends to advance the ignition timing of the first power stroke but has minimal effect on the ignition timing of second power stroke. Re-breathing was found to be an effective way to control the ignition timing in second power stroke at a slight expense of the combustion efficiency. The operation of a six-stroke gasoline compression ignition engine could be successfully simulated. In addition, the operability range of the six-stroke gasoline compression ignition engine could be substantially extended by employing the continuously variable valve duration technique.

An experimental study on reactivity controlled compression ignition engine fueled with biodiesel/natural gas

Energy ◽  
2015 ◽  
Vol 89 ◽  
pp. 558-567 ◽  
Author(s):  
Ayatallah Gharehghani ◽  
Reza Hosseini ◽  
Mostafa Mirsalim ◽  
S. Ali Jazayeri ◽  
Talal Yusaf
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Reactivity Controlled Compression Ignition

Controlling combustion with negative valve overlap in a gasoline–diesel dual-fuel compression ignition engine

2015 ◽  
Vol 17 (3) ◽  
pp. 354-365 ◽  
Author(s):  
Kohei Kuzuoka ◽  
Takashi Kondo ◽  
Hirotsugu Kudo ◽  
Hiroyoshi Taniguchi ◽  
Hiroshi Chishima ◽  
...  
Keyword(s):  
Dual Fuel ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Negative Valve Overlap ◽  
Valve Overlap

Internal Residual vs. Elevated Intake Temperature: How the Method of Charge Preheating Affects the Phasing Limitations of HCCI Combustion

2012 ◽  
Author(s):  
Laura Manofsky Olesky ◽  
Jiri Vavra ◽  
Dennis Assanis ◽  
Aristotelis Babajimopoulos
Keyword(s):  
Constant Load ◽  
Combustion Stability ◽  
Residual Fraction ◽  
Compression Ignition ◽  
Hcci Combustion ◽  
Final Study ◽  
Temperature Constant ◽  
Negative Valve Overlap ◽  
Burn Rate ◽  
Valve Overlap

Homogeneous charge compression ignition (HCCI) has the potential to reduce both fuel consumption and NOx emissons compared to normal spark-ignited (SI) combustion. For a relatively low compression ratio engine, high unburned temperatures are needed to initiate HCCI combustion, which is achieved with large amounts of internal residual or by heating the intake charge. The amount of residual in the combustion chamber is controlled by a recompression valve strategy, which relies on negative valve overlap (NVO) to trap residual gases in the cylinder. A single-cylinder research engine with fully-flexible valve actuation is used to explore the limits of HCCI combustion phasing at a constant load of ∼3 bar IMEPg. This is done by performing two individual sweeps of a) internal residual fraction (via NVO) and b) intake air temperature to control combustion phasing. It is found that increasing both variables advances the phasing of HCCI combustion, which leads to increased NOx emissions and a higher ringing intensity. On the other hand, a reduction in these variables leads to greater emissions of CO and HC, as well as a decrease in combustion stability. A direct comparison of the two sweeps suggests that the points with elevated intake temperatures are more prone to ringing as combustion is advanced and less prone to instability and misfire as combustion is retarded. This behavior can be explained by compositional differences (air vs. EGR dilution) which lead to variations in burn rate and peak temperature. As a final study, two additional NVO sweeps are performed while holding intake temperature constant at 30°C and 90°C. Again, it is seen that at higher intake temperatures, combustion is more susceptible to ringing at advanced timings and more resistant to instability/misfire at retarded timings.

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