James W. G. Turner

King Abdullah University of Science and Technology | KAUST · Clean Combustion Research Center (CCRC)

div class="section abstract"> Light-duty vehicle emissions regulations worldwide impose stringent limits on particulate matter (PM) emissions, necessitating accurate modelling and prediction of particulate emissions across a range of sizes (as low as 10 nm). It has been shown that the decision tree-based ensemble machine learning technique known as...

The maritime industry serves a pivotal role in global trade and transportation, yet its contribution to environmental pollution, notably emissions, poses a critical concern. Addressing and mitigating the carbon footprint of this industry has become imperative amidst the challenges posed by climate change. This study presents a thermodynamic analysi...

Growing global concern over the impact of carbon emissions has spurred many nations to aim to achieve net-zero carbon emissions within the 2030 to 2050 timeframe. A significant contributor to these emissions is the transport sector, responsible for a substantial 23% of total carbon emissions, with heavy-duty (HD) transport accounting for 40% of thi...

Prechamber-assisted combustion reduces emissions and improves engine performance through lean and knock limit enhancement. The spark plug ignition is replaced by multiple, high-temperature, radical-rich jets that entrain and ignite the main chamber charge, enabling the engine to operate at leaner air–fuel mixtures. Current work reports first cycle...

div class="section abstract"> Engine knock is a major challenge that limits the achievement of higher engine efficiency by increasing the compression ratio of the engine. To address this issue, using a higher octane number fuel can be a potential solution to reduce or eliminate the propensity for knock and so obtain better engine performance. Metha...

The urgent need to combat global warming has spurred legislative efforts within the transport sector to transition away from fossil fuels. Hydrogen is increasingly being utilised as a green energy vector, which can aid the decarbonisation of transport, including internal combustion engines. Computational fluid dynamics (CFD) is widely used as a too...

div class="section abstract"> Amid escalating concerns over climate change and emissions, this study presents a novel approach to develop sustainable fuels, leveraging advanced process modeling that uses waste CO₂ streams from the biological ethanol fermentation process to produce e-methanol. Using Aspen Plus software, this research focu...

Global warming is a major environmental issue caused by the release of greenhouse gases, such as carbon dioxide into the atmosphere. Light-duty vehicles (LDVs) including passenger cars and light-duty trucks, are a significant contributor to greenhouse gas emissions. The transportation sector is responsible for approximately 23% of global CO 2 emiss...

Methanol is a promising renewable fuel for achieving a better engine combustion efficiency and lower exhaust emissions. Under exhaust gas recirculation conditions, trace amounts of nitrogen oxides have been shown to participate in fuel oxidation and impact the ignition characteristics significantly. Despite numerous studies that analyzed the methan...

Opposed-piston two-stroke engines (OP2S) have demonstrated high thermodynamic efficiencies due to reduced heat losses and high volume-to-surface area ratios. This leads to remarkable advantages over four-stroke conventional diesel engines, as well as superior combustion characteristics. Therefore, combining this concept with renewable fuels and adv...

To understand key physical aspects of volume in narrow-throat pre-chambers, computational fluid dynamics simulations were performed using CONVERGE™. A major advantage of a narrow-throat feature is to allow for drop-in replacement of a diesel injector, hence facilitating technology deployment. Despite broad literature on conventional pre-chambers, t...

Prechamber-assisted internal combustion engines allow lean limit extension by replacing the spark plug with multiple, high-temperature, radical-rich jets that entrain and ignite the main chamber charge. This work reports the first investigation of active ultra-lean, active rich, and passive prechamber assisted prechamber engine operation (with a fi...

div class="section abstract"> Ammonia as a fuel suffers from a high ignition energy requirement making it hard to ignite in stoichiometric mixtures, especially with normal spark plugs. On the other hand, pre-chambers are proven to provide high ignition energy by producing multiple ignition spots in the main chamber. A pre-chamber is usually categor...

div class="section abstract"> Amongst all the hybrid-vehicles technologies and layouts, range-extended electric vehicles are the ones with the real prospect to reduce the emissions produced by the thermal machine when in driving conditions, while assuring an adequate range for the common user. The BMW i3 represents one of the most successful series...

div class="section abstract"> The Wankel rotary engine has been an attractive alternative for transportation due to its unique features of lightweight construction, small size, high power density, and adaptability to various fuels. This paper aims to investigate the performance of air-fuel mixing in a hydrogen-fuelled Wankel rotary engine using dif...

div class="section abstract"> To understand key practical aspects of ammonia as a fuel for internal combustion engines, three-dimensional computational fluid dynamics (CFD) simulations were performed using CONVERGE^TM. A light-duty single-cylinder research engine with a geometrical compression ratio of 11.5 and a conventional pentroof com...

div class="section abstract"> Hydrogen-fueled homogeneous charge compression ignition (HCCI) engines have shown the ability to provide a cleaner and more efficient alternative to conventional fossil fuels. The use of hydrogen as a fuel has the potential to reduce greenhouse gas and promote sustainability. In this study, a modified single-cylinder C...

div class="section abstract"> This paper presents results from an extended analysis of a supercharged gas turbine concept initially proposed by Ford Motor Company in the 1960s. The concept was augmented through individual component improvements and utilization of new technologies developed over the 60 years since the inception of the original conce...

div class="section abstract"> Ammonia (NH₃) is a carbon-free fuel, which could partially or completely eliminate hydrocarbon (HC) fuel demand. Using ammonia directly as a fuel has some challenges due to its low burning speed and low flammability range, which generates unstable combustion inside the combustion chamber. This study investig...

Phenols are recalcitrant compounds that constitute the majority of organic contaminants in industrial wastewaters. Their removal at large scales require a combination of various processes to reach the desired discharge quality. An extensive body of work has already been published in the area of phenol removal from wastewater, however none of them h...

This paper investigates the performance of hydrogen-fueled, spark-ignited, single-cylinder Cooperative Fuel Research using experimental and numerical approaches. This study examines the effect of the air–fuel ratio on engine performance, emissions, and knock behaviour across different compression ratios. The results indicate that λ significantly af...

Over the past few decades, criteria emissions such as carbon monoxide (CO), hydrocarbons (HCs), nitrogen oxides (NOx) and particulate matter (PM) from transportation have decreased significantly, thanks to stricter emission standards and the widespread adoption of cleaner technologies. While air quality is a complex problem that is not solely depen...

Hydrogen is most easily used as combustion engine fuel in a spark ignition engine. This chapter starts from the properties of hydrogen and hydrogen mixtures to present the various options for running spark ignition engines on hydrogen, reviewing the power density potential, emissions and efficiency. This is then linked to past and present research...

Despite the growing sales of electric vehicles and electrification as a means to alleviate the growing problem of climate change, it is largely overlooked that internal combustion engine-driven vehicles still account for 99.8% of the global transportation fleet. These vehicles pose a significant demand for liquid fuels, which is typically met by fo...

Ammonia is an attractive carbon-free fuel that has the potential to reduce the need for conventional hydrocarbons (HC) and reduce emissions of undesirable pollutants such as CO, CO2, particulates, and unburned hydrocarbons. However, ammonia has different combustion characteristics than conventional HC fuel. Ammonia is difficult to ignite and has a...

Pre-chamber combustion (PCC) has the potential to extend the lean-burn limit in spark-ignition engines, which can promote engine efficiency and relieve the concern of emissions of nitrogen oxides. This work assessed the effects of pre-chamber (PC) and piston geometries on the combustion characteristics of an optical methane PCC engine with both exp...

To provide fundamental insights into the underlying mechanisms of knock occurrence in a spark-ignition (SI) engine, optical diagnostic measurements were performed at advanced spark timing under boosted conditions. Employing high-speed imaging, deflagration-to-detonation transition (DDT) processes were recorded. The states and locations of the unbur...

Knock in a spark-ignition (SI) engine is a complicated combustion phenomenon that stimulates high-pressure oscillations inside the combustion chamber and restricts engine performance. This study presents a high-speed OH* chemiluminescence imaging technique to investigate the knock mechanism resulting from firing multiple spark plugs. The experiment...

div class="section abstract"> In passenger car development, extreme ICE downsizing trends have been observed over the past decade. While this comes with fuel economy benefits, they are often obtained at the expense of Brake Mean Effective Pressure (BMEP) rise time in transient engine response. Through advanced control strategies, the use of Fully V...

div class="section abstract"> The pre-chamber combustion (PCC) concept is a proven lean or diluted combustion technique for internal combustion engines with benefits in engine efficiency and reduced NOx emissions. The engine lean operation limit can be extended by supplying auxiliary fuel into the pre-chamber and thereby, achieving mixture stratifi...

div class="section abstract"> The future of the internal combustion (IC) engine relies on carbon-free fuels to mitigate climate change. Ammonia (NH₃) is a promising carbon-free fuel, which can be used as an energy carrier for hydrogen (H₂) and directly as a combustible fuel inside the engines. However, burning pure ammonia fue...

div class="section abstract"> Throughout its history, the internal combustion engine has been continuously scrutinized to achieve strict legislative emission targets. With the dawn of renewable fuels fast approaching, most Internal Combustion Engine (ICE) equipped hybrid electric vehicles (HEVs) face difficulty in adjusting their precise control st...

With the passing of every second we get closer to a society that is more cognizant of the effect carbon dioxide emissions are having on our planet, and that is more willing to take part in sustainable efforts to combat this and ever more interested in investing in cleaner technologies like electric vehicles (EVs). EVs are marching strongly into a m...

Lean operation increases the efficiency of the Otto-cycle internal combustion engine and decreases its emissions. However, increasing the air-fuel ratio beyond stoichiometry requires higher ignition energy to maintain the stable operation of the engine. The pre-chamber emerges as one of the promising enablers of lean operation, providing much large...

Pre-chamber combustion (PCC) modeling has been progressing in recent years, while there are lingering questions on fundamental modeling aspects, whether a flame-based or an ignition-based model predicts the combustion with higher fidelity. This mode of ignition concept is known to enable a stable engine operation at ultralean conditions with a shor...

This study is geared toward generating highly stabilized partially premixed flames at various levels of turbulence and partially premixing. Therefore, with the help of the laser-induced breakdown spectroscopy (LIBS) technique, a new burner was constructed and employed to quantitatively estimate the mixture equivalence ratio (Φ) within the flame. Tw...

div class="section abstract"> The present work extends the performance analysis of a rotary Wankel engine for range extender applications already introduced in the companion papers of this series. Specifically, in this work, an overall balance was carried out on mechanical and thermal parameters inferred from the indicated pressure cycles and those...

div class="section abstract"> Lean combustion is one of the most applied methods to increase engine efficiency and maintain a good trade-off with engine emissions. The pre-chamber combustion (PCC) is one of the most promising combustion concepts to extend the lean operating limits of the engine. The Narrow throat pre-chamber has shown better lean l...

The pre-chamber combustion concept (PCC) concept shows promises for lean combustion to achieve improved combustion stability and engine efficiency. The KAUST narrow-throat pre-chamber design, which can readily fit into the diesel injector pocket of a heavy-duty engine, has demonstrated an increased lean limit extension compared to conventional pre-...

div class="section abstract"> Pre-chamber combustion (PCC) has re-emerged in recent last years as a potential solution to help to decarbonize the transport sector with its improved engine efficiency as well as providing lower emissions. Research into the combustion process inside the pre-chamber is still a challenge due to the high pressure and tem...

To date, 59 countries, representing 54% of global greenhouse gas emissions have made pledges for net-zero emissions targets within this century. This will require cleaner and more efficient sources of energy which is driving research into small-scale engines and auxiliary power units for hybrid vehicles and stationary power generation. A suitable c...

Engine knock is an abnormal combustion phenomenon that limits the thermal efficiency and service life of spark-ignition engines. A better understanding of the knock mechanisms and characteristics is beneficial to knock alleviation and engine efficiency improvement. In this study, a metal liner with four evenly-spaced spark plugs in the periphery of...

Knock research is an essential study because knock limits spark-ignition (SI) engine power output, durability, noise, fuel consumption, and emission performance. The thermal efficiency of an engine can be improved by increasing the compression ratio, but at the same time it leads to the possibility of end gas autoignition inside the chamber. The ob...

Stable internal combustion (IC) engine operation with a lean mixture allows improved thermal efficiency and reduced engine-out emissions. However, lean limits in IC engines are challenging due to poor ignitibility. Narrow throat pre-chamber as an ignition source allows extending the lean limit through a robust multi-reactive jet ignition and in-cyl...

This chapter focuses on the use of biofuels in spark-ignition and compression-ignition engines. The use of biodiesel in the form of fatty acid methyl ester and hydrogenated vegetable oil is discussed briefly before centring on the use of low carbon- number alcohols, methanol and ethanol; the use of butanol is also discussed. The physicochemical pro...

Renewable liquid fuels provide an opportunity for nations to increase energy independency or reduce greenhouse gas emissions by supplying energy-dense fuels which are miscible with petroleum gasoline and diesel. This chapter shows how liquid fuels are the most pragmatic way to increase the renewable energy content in the transport sector, enabling...

The benefits of pre-chamber combustion (PCC), such as improved engine efficiency and reduced NOx emissions, are primarily observed when operating at lean conditions with an active pre-chamber, where auxiliary fuel is supplied directly to the pre-chamber. Estimating the pre-chamber excess air ratio (λ) is important in the active pre-chamber concept...

The Wankel rotary engine offers unrivalled power density as a consequence of having a combustion event every revolution, as well as lightness, compactness and vibrationless operation due to its perfect balance. These attributes have led to its success as a powerplant for unmanned aerial vehicles, and which should also make it an attractive proposit...

The demand for cleaner, more efficient, and durable sources of electricity is driving research into small-scale power generation. Micro gas turbines are especially suitable by virtue of their high power density and reliability, but a major drawback is their poor overall efficiency due to increasing parasitic energy losses relative to net power outp...

Engine knock has long been one of the major obstacles for improving thermal efficiency of spark-ignition (SI) engines. An in-depth understanding of the engine knock mechanism and characteristics is vital for controlling knocking combustion. Experimental investigation of knock events is challenging given their stochastic nature. We employ a single-c...

Opposed-piston, two-stroke engines reveal degrees of freedom that make them excellent candidates for next generation, highly efficient internal combustion engines for hybrid electric vehicles and power systems. This article reports simulation results that explore the influence of key control and geometrical parameters, specifically crankshaft phasi...

div class="section abstract"> In a previous study it was shown that a production vehicle employing a Wankel rotary engine, the Mazda RX-8, was easily capable of meeting much more modern hydrocarbon emissions than it had been certified for. It was contended that this was mainly due to its provision of zero port overlap through its adoption of side i...

At the beginning of the 20th century the operational issues of the Otto engine had not been fully resolved. The work presented here seeks to chronicle the development of one of the alternative design pathways, namely the replacement for the gas exchange mechanism of the more conventional poppet valve arrangement with that of a sleeve valve. There h...

This paper follows on from an earlier publication on high-blend-rate binary gasoline-alcohol mixtures and reports results for some equivalent ternary fuels from several investigation streams. In the present work, new findings are presented for high-load operation in a dedicated boosted multi-cylinder engine test facility, for operation in modified...

div class="section abstract"> The Wankel rotary engine historically found limited success in automotive applications due in part to poor combustion efficiency and challenges around emissions. This is despite its significant advantages in terms of power density, compactness, vibrationless operation, and reduced parts count in relation to the 4-strok...

The work presented here seeks to compare different means of providing uniflow scavenging for a 2-stroke engine suitable to power a US light-duty truck. The three different configurations which could utilize this type of scavenging system that were investigated are (1) the opposed-piston engine, which has been applied to aircraft propulsion as well...

Gasoline Direct Injection (GDI) engines equipped with a turbocharger or supercharger (known as boosted engines) have achieved significant market penetration due to their advantages in reducing CO 2 emissions compared to Port Fuel Injection (PFI) engines. These engines are known to emit particulate matter and recent studies have characterized these...