Additives for Spark Ignition and Compression Ignition engine fuels

Author(s):  
John Bennett

Fuel additives for automotive applications have been in use for almost as long as the automobile has existed. They provide significant benefits, both in making fuels fit for purpose and to deliver protection and performance benefits. Performance benefits can range from protection against degradation, through recovery of lost performance, all the way to enhanced engine function. This has become particularly important with the tension between increasingly stringent long emissions requirements, the encouragement of renewable biofuel content and the drive to improved engine efficiency and reduce fuel consumption. The paper discusses where performance fuel additives provide their benefits and how they are evolving to work with latest generations of fuel and engines, and provides an overview of the current and upcoming industry engine tests for fuels and their additives.

2020 ◽  
Author(s):  
Jinlong Liu ◽  
Christopher Ulishney ◽  
Cosmin E. Dumitrescu

Abstract Partial conversion of the large inventory of compression-ignition engines to natural-gas (NG) spark-ignition lean-burn operation can reduce U.S. dependence on imported petroleum and enhance national energy security. This paper describes some of the observations made during such an engine conversion and proposes some solutions to alleviate some of the potential issues. The engine conversion in this study consisted from replacing the diesel injector with a spark plug and adding a port fuel injection system for NG delivery. The results indicated that the retrofitted engine performed reliably at lean-burn conditions, despite the different combustion characteristics compared to conventional SI engines. However, the squish region will trap an important fuel fraction (∼30%) and experience less-optimal burning conditions, hence a slower burning rate. This affected the engine efficiency and increased the unburned hydrocarbon and carbon monoxide emissions. From a combustion point of view, the operation of such converted engines can be optimized by increasing the bowl-to-squish volume ratio, optimizing the piston shape (e.g., by removing the central protrusion and avoiding 90-degree edges inside the bowl). The original compression ratio may also need to be reduced to avoid knocking. Moreover, direct gas injection and/or intake charging will increase the volumetric efficiency, which will benefit engine efficiency and emissions.


2021 ◽  
pp. 146808742110342
Author(s):  
Francisco Payri ◽  
Jaime Martín ◽  
Francisco José Arnau ◽  
Sushma Artham

In this work, the Global Energy Balance (GEB) of a 1.6 L compression ignition engine is analyzed during WLTC using a combination of experimental measurements and simulations, by means of a Virtual Engine. The energy split considers all the relevant energy terms at two starting temperatures (20°C and 7°C) and two altitudes (0 and 1000 m). It is shown that reducing ambient temperature from 20°C to −7°C decreases brake efficiency by 1% and increases fuel consumption by 4%, mainly because of the higher friction due to the higher oil viscosity, while the effect of increasing altitude 1000 m decreases brake efficiency by 0.8% and increases fuel consumption by 2.5% in the WLTC mainly due to the change in pumping. In addition, GEB shows that ambient temperature is affecting exhaust enthalpy by 4.5%, heat rejection to coolant by 2%, and heat accumulated in the block by 2.5%, while altitude does not show any remarkable variations other than pumping and break power.


2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Jinlong Liu ◽  
Hemanth Kumar Bommisetty ◽  
Cosmin Emil Dumitrescu

Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) operation can reduce the dependence on petroleum-based fuels and curtail greenhouse gas emissions. Such an engine was converted to premixed NG spark-ignition (SI) operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector. Engine performance and combustion characteristics were investigated at several lean-burn operating conditions that changed fuel composition, spark timing, equivalence ratio, and engine speed. While the engine operation was stable, the reentrant bowl-in-piston (a characteristic of a CI engine) influenced the combustion event such as producing a significant late combustion, particularly for advanced spark timing. This was due to an important fraction of the fuel burning late in the squish region, which affected the end of combustion, the combustion duration, and the cycle-to-cycle variation. However, the lower cycle-to-cycle variation, stable combustion event, and the lack of knocking suggest a successful conversion of conventional diesel engines to NG SI operation using the approach described here.


2016 ◽  
Vol 817 ◽  
pp. 47-56 ◽  
Author(s):  
Maciej Mikulski ◽  
Sławomir Wierzbicki ◽  
Andrzej Piętak

Improving the efficiency or work and reducing the emissions of toxic substances into the atmosphere are the two key directions of development of modern combustion engines. Improvement of engine efficiency is feasible only by increasing the precision of control thereof, which necessitates long-term operating tests. Regrettably, due to complexity of processes taking place during the combustion of fuel, these phenomena can only be tested on simulation models, based on a mathematical description of the phenomena.This paper presents the results of verification tests of the developed fuel combustion model in a multifuel compression-ignition engine for an engine running only on diesel fuel.


2015 ◽  
Vol 75 (8) ◽  
Author(s):  
Helmisyah Ahmad Jalaludin ◽  
Mohd Ruysdi Ramliy ◽  
Nik Rosli Abdullah ◽  
Salmiah Kasolang ◽  
Shahrir Abdullah ◽  
...  

The sudden increase in fuel prices due to diminishing petroleum resources and the pollution resulting from its use has resulted in research into alternative fuels such as biodiesel. In addition, the faster combustion and high temperature in the combustion chamber which results from petroleum diesel fuel leads to higher nitrogen oxide (NOx) and Particulate Matter (PM) emissions. Therefore, this research was conducted to investigate the effect of using palm oil methyl ester (POME) blends as alternative fuels on the performance and emission of a compression ignition engine. The performance of POME blends and diesel were compared by manipulating the load of the engine at 1800 rpm. The results obtained show that fuel consumption rate is higher for the POME blends compared to the diesel fuel and increases as the POME concentration increases. The increment of brake specific fuel consumption and the reduction of CO emission exhibit a relation to the increase in percentage of POME. This is mainly contributed by the higher oxygen content of POME which promotes complete combustion of the blends. However, efficient combustion from the blends as compared to diesel fuel resulted from higher oxygen content and cetane number leads to significant increase in exhaust temperature. This in turn increases NOx emissions since using POME blends is highly related to high temperature of combustion chamber. The experimental results proved that POME in compression ignition engine is a possible substitute to diesel.


2018 ◽  
Vol 41 (4) ◽  
pp. 511-520 ◽  
Author(s):  
Felipe Fernandes Klajn ◽  
Flávio Gurgacz ◽  
Anderson Miguel Lenz ◽  
Giuseppe Eugenio Peruzo Iacono ◽  
Samuel Nelson Melegari de Souza ◽  
...  

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