Effects of Injection Timing on the Lean Misfire Limit in an SI Engine

1997 ◽  
Author(s):  
I. Y. Ohm ◽  
K. S. Jeong ◽  
I. S. Jeung

In this world, the population is increased and the number of vehicles increased. Not only population the pollution is increased lot by vehicles in the world harmful pollutant is realized from the vehicles like CO, HC, NOx and smoke particulates. It is inevitable to find some new technology, which increases the better performance and emission characteristics. Partially premixed compression ignition (PCCI) is the best technology for the reducing of harmful pollution in the vehicle, which uses the diesel as fuel it, gives the advantages of both CI and SI engine. This paper investigates the performance and emission characteristics of partially premixed diesel engine. Diesel engine has two injectors of port fuel injector (PFI) and direct injector (DI) to inject the fuel in different timing and electrical control unit (ECU) passes the power to PFI; it can control the injection timing and increases the fuel content from the fuel pump. The main aim in this paper is studied is effect of partially premixed ratio, performance of engine and emission characteristics of diesel engine


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5223
Author(s):  
Guanting Li ◽  
Xiumin Yu ◽  
Ping Sun ◽  
Decheng Li

Split hydrogen direct injection (SHDI) has been proved capable of better efficiency and fewer emissions. Therefore, to investigate SHDI deeply, a numerical study on the effect of second injection timing was presented at a gasoline/hydrogen spark ignition (SI) engine with SHDI. With an excess air ratio of 1.5, five different second injection timings achieved five kinds of hydrogen mixture distribution (HMD), which was the main factor affecting the engine performances. With SHDI, since the HMD is manageable, the engine can achieve better efficiency and fewer emissions. When the second injection timing was 105° crank angle (CA) before top dead center (BTDC), the Pmax was the highest and the position of the Pmax was the earliest. Compared with the single hydrogen direct injection (HDI), the NOX, CO and HC emissions with SHDI were reduced by 20%, 40% and 72% respectively.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rui Liu ◽  
Haocheng Ji ◽  
Minxiang Wei

Purpose The purpose of this paper is to investigate power performance, economy and hydrocarbons (HC)/carbon monoxide (CO) emissions of diesel fuel on a two-stoke direct injection (DI) spark ignition (SI) engine. Design/methodology/approach Experimental study was carried out on a two-stroke SI diesel-fuelled engine with air-assisted direct injection, whose power performance and HC/CO emissions characteristics under low-load conditions were analysed according to the effects of ignition energy, ignition advance angle (IAA), injection timing angle and excess-air-ratio. Findings The results indicate that, for the throttle position of 10%, a large IAA with adequate ignition energy effectively increases the power and decrease the HC emission. The optimal injection timing angle for power and fuel consumption is 60° crank angle (CA) before top dead centre (BTDC). Lean mixture improves the power performance with the HC/CO emissions greatly reduced. At the throttle position of 20%, the optimal IAA is 30°CA BTDC. The adequate ignition energy slightly improves the power output and greatly decreases HC/CO emissions. Advancing the injection timing improves the power and fuel consumption but should not exceed the exhaust port closing timing in case of scavenging losses. Burning stoichiometric mixture achieves maximum power, whereas burning lean mixture obviously reduces the fuel consumption and the HC/CO emissions. Practical implications Gasoline has a low flash point, a high-saturated vapour pressure and relatively high volatility, and it is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. The authors adopt a low volatility diesel fuel for all vehicles and equipment to minimise the number of different devices using various fuels and improve the potential military application safety. Originality/value Under low-load conditions, the two stroke port-injected SI engine performance of burning heavy fuels including diesel or kerosene was shown to be worse than those of gasoline. The authors have tried to use the DI method to improve the performance of the diesel-fuelled engine in starting and low-load conditions.


Author(s):  
K. A. Subramanian ◽  
B. L. Salvi

Hydrogen utilization in spark ignition (SI) engines could reduce urban pollution including particulate matter as well as greenhouse gas emission. However, backfiring, which is an undesirable combustion process of intake charge in hydrogen-fueled SI engine with manifold-based injection, is one of the major technical issues in view of safety of engine operation. Backfiring occurs generally during suction stroke as the hydrogen–air charge interacts with residual gas, resulting in flame growth and propagation toward upstream of engine's intake manifold, resulting in stalling of engine operation and high risk of safety. This work is aimed at analysis of backfiring in a hydrogen-fueled SI engine. The results indicate that backfiring is mainly function of residual gas temperature, start of hydrogen injection timing, and equivalence ratio. Any hot-spot present in the cylinder would act as ignition source resulting in more chances of backfiring. In addition to this, computational fluid dynamics (CFD) analysis was carried out in order to assess flow characteristics of hydrogen and air during suction stroke in intake manifold. Furthermore, numerical analysis of intake charge velocity, flame speed (deflagration), and flame propagation (backfiring) toward upstream of intake manifold was also carried out. Some notable points of backfiring control strategy including exhaust gas recirculation (EGR) and retarded (late) hydrogen injection timing are emerged from this study for minimizing chance of backfiring. This study results are useful for development of dedicated SI engine for hydrogen fuel in the aspects of elimination of backfiring.


Author(s):  
Huan Lian ◽  
Jason Martz ◽  
Niket Prakash ◽  
Anna Stefanopoulou

The classification between a sequence of highly variable combustion events that have an underlying deterministic pattern and a sequence of combustion events with similar level of variability but random characteristics is important for control of combustion phasing. In the case of high cyclic variation (CV) with underlying deterministic patterns, it is possible to apply closed-loop combustion control on a cyclic-basis with a fixed mean value, such as injection timing in homogeneous charge compression ignition (HCCI) or spark timing in spark ignition (SI) applications, to contract the CV. In the case of a random distribution, the high CV can be avoided by shifting operating conditions away from the unstable region via advancing or retarding the injection timing or the spark timing in the mean-sense. Therefore, the focus of this paper is on the various methods of computing CA50 for analyzing and classifying cycle-to-cycle variability. The assumptions made to establish fast and possibly online methods can alter the distribution of the calculated parameters from cycle-to-cycle, possibly leading to incorrect pattern interpretation and improper control action. Finally, we apply a statistical technique named “permutation entropy” for the first time on classifying combustion patterns in HCCI and SI engine for varying operating conditions. Then, the various fast methods for computing CA50 feed the two statistical methods, permutation and the Shannon entropy, and their differences and similarities are highlighted.


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