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The growing demand for transportation fuels and the global emphasis on reducing greenhouse gas (GHG) emissions have led to increased interest in analyzing transport GHG emissions from the life-cycle perspective. Methanol, a potentially carbon-neutral fuel synthesized from CO2 and H2, has emerged as a promising candidate. This paper conducts a comprehensive life-cycle analysis (LCA) of the GHG emissions associated with the methanol production process, utilizing data inventory from China in 2019. To simulate the synthesis and distillation process of methanol, Aspen Plus is employed, using parameters obtained from actual plants. GHG emissions are then calculated using the GREET model, incorporating updated industry statistics and research findings. The CO2 necessary for methanol production is captured from factory flue gas.

Injector fouling is an important contributory factor to particulate matter (PM) emissions in Gasoline Direct Injection (GDI) engines. Several publications have emerged in recent years which acknowledge the benefits of injector cleanliness, but others claim that high levels of Deposit Control Additive (DCA) could have detrimental effects that outweigh the benefits of the augmented cleaning potential. The paper is divided into two parts: The first part contains a critical review of the literature linking injector cleanliness and particulate matter emissions, and studies assessing the impact of higher treat rates of additives. The second part of the paper describes new evidence of the beneficial effects of DCAs, in the form of several separate (previously unpublished) studies, using both engines and vehicles. In this newly reported work, various DCA treat rates were employed, and some of the fuels had measured UWG levels well in excess of 50 mg/100 mL.

Ethanol fuel blends with gasoline for spark ignition (SI) internal combustion engines are widely used on account of their advantages in terms of fuel economy and emissions reduction potential. The focus of this paper is to study the effects of these blends on combustion characteristics such as in-cylinder pressure profiles, gas-phase emissions (e.g., unburned hydrocarbons, NOx) and particulates (e.g., particulate matter and particle number) using both measurement campaigns and digital engineering workflows. Nineteen load-speed operating points in a 1L 3-cylinder GDI SI engine were measured and modelled. The measurements for in-cylinder pressure and emissions were repeated at each operating point for three types of fuel: gasoline (E0, 0% by volume of ethanol blend), E10 (10 % by volume of ethanol blend) and E20 (20% by volume of ethanol blend).

With increased awareness and scrutiny of greenhouse gas (GHG) emissions, the heavy-duty truck industry is on the lookout for solutions that can maximize GHG savings, through either lowering fuel consumption and lowering methane slip. This paper focuses on whether it is possible to provide a differentiated Liquefied Natural Gas (LNG) that supports the further improvement of a High-Pressure Direct Injection (HPDI) Engine. Desired improvements from this LNG blend are the lowering or substitution of the pilot Diesel use of the current HPDI engine, the lowering of the raw exhaust gas methane concentration and any additional performance improvements. Sixty-five substances were identified that could potentially be blended into cryogenic methane thus creating a differentiated LNG fuel.

Gasoline Direct Injection (GDI) vehicles now make up the majority of European new car sales and a significant share of the existing car parc. Despite delivering measurable engine efficiency benefits, GDI fuel systems are not without issues. Fuel injectors are susceptible to the formation of deposits in and around the injector nozzles holes. It is widely reported that these deposits can affect engine performance and that different fuels can alleviate the buildup of those deposits. This project aims to understand the underlying mechanisms of how deposit formation ultimately leads to a reduction in vehicle performance. Ten GDI fuel injectors, with differing levels of coking were taken from engine testing and consumer vehicles and compared using a range of imaging and engine tests. At the time of writing, a new GDI engine test is being developed by the Co-ordinating European Council (CEC) to be used by the fuel and fuel additive industry.

In Gasoline Direct Injection engines, direct exposure of the injector to the flame can cause combustion products to accumulate on the nozzle, which can result in increased particulate emissions. This research observes the impact of injector fouling on particulate emissions and the associated injector spray pattern and shows how both can be reversed by utilising fuel detergency. For this purpose multi-hole injectors were deliberately fouled in a four-cylinder test engine with two different base fuels. During a four hour injector fouling cycle particulate numbers (PN) increased by up to two orders of magnitude. The drift could be reversed by switching to a fuel blend that contained a detergent additive. In addition, it was possible to completely avoid any PN increase, when the detergent containing fuel was used from the beginning of the test. Microscopy showed that increased injector fouling coincided with increased particulate emissions.

The purpose of this work was to gain a fundamental understanding of which fuel property parameters are responsible for particulate emission characteristics, associated with key intermediate behavior in the engine cylinder such as the fuel film and insufficient mixing. Accordingly, engine tests were carried out using various fuels having different volatility and chemical compositions under different coolant temperature conditions. In addition, a fundamental spray and film visualization analysis was also conducted using a constant volume vessel, assuming the engine test conditions. As for the physical effects, the test results showed that a low volatility fuel displayed high particulate number (PN) emissions when the injection timing was advanced. The fundamental test clearly showed that the amount of fuel film on the impingement plate increased under such operating conditions with a low volatility fuel.

Certain diesel fuel specification properties are considered to be environmental parameters according to the European Fuels Quality Directive (FQD, 2009/EC/30) and previous regulations. These limits included in the EN 590 specification were derived from the European Programme on Emissions, Fuels and Engine Technologies (EPEFE) which was carried out in the 1990’s on diesel vehicles meeting Euro 2 emissions standards. These limits could potentially constrain FAME blending levels higher than 7% v/v. In addition, no significant work has been conducted since to investigate whether relaxing these limits would give rise to performance or emissions debits or fuel consumption benefits in more modern vehicles. The objective of this test programme was to evaluate the impact of specific diesel properties on emissions and fuel consumption in Euro 4, Euro 5 and Euro 6 light-duty diesel vehicle technologies.

Octane appetite of modern engines has changed as engine designs have evolved to meet performance, emissions, fuel economy and other demands. The octane appetite of seven modern vehicles was studied in accordance with the octane index equation OI=RON-KS, where K is an operating condition specific constant and S is the fuel sensitivity (RONMON). Engines with a displacement of 2.0L and below and different combinations of boosting, fuel injection, and compression ratios were tested using a decorrelated RONMON matrix of eight fuels. Power and acceleration performance were used to determine the K values for corresponding operating points. Previous studies have shown that vehicles manufactured up to 20 years ago mostly exhibited negative K values and the fuels with higher RON and higher sensitivity tended to perform better.

Ambient temperature has significant impact on engine start ability and cold start emissions from diesel engines. These cold start emissions are accounted for substantial amount of the overall regulatory driving cycle emissions like NEDC or FTP. It is likely to implement the low temperature emissions tests for diesel vehicles, which is currently applicable only for gasoline vehicles. This paper investigates the potential of the intake heating strategy on reducing the driving cycle emissions from the latest generation of turbocharged common rail direct injection diesel engines at low ambient temperature conditions. For this investigation an air heater was installed upstream of the intake manifold and New European Driving Cycle (NEDC) tests were conducted at -7°C ambient temperature conditions for the different intake air temperatures. Intake air heating reduced the cranking time and improved the fuel economy at low ambient temperatures.

Diesel engines are the versatile power source and is widely used in passenger car and commercial vehicle applications. Environmental temperature conditions, fuel quality, fuel injection strategies and lubricant have influence on cold start performance of the diesel engines. Strategies to overcome the cold start problem at very low ambient temperature include preheating of intake air, coolant, cylinder block. The present research work investigates the effect of coolant temperatures on passenger car diesel engine’s performance and exhaust emission characteristics during the cold start at cold ambient temperature conditions. The engine is soaked in the -7°C environment for 6 hours. The engine coolant is preheated to the desired coolant temperatures of 10 and 20°C by an external heater and the start ability tests were performed.

In recent years magnetic resonance imaging (MRI) has been shown to be an attractive method for fluid flow visualization. In this work, we show how MRI velocimetry techniques can be used to non-invasively investigate and visualize the hydrodynamics of exhaust gas in a diesel particulate filter (DPF), both when clean and after loading with diesel engine exhaust particulate matter. The measurements have been used to directly measure the gas flow in the inlet and outlet channels of the DPF, both axial profiles along the length and profiles across the channel diameter. Further, from this information we show that it is possible to indirectly ascertain the superficial wall-flow gas velocity and the soot loading profiles along the filter channel length.

In a modern diesel engine, a high fuel injection pressure is achieved by a common-rail system. Therefore, it is important to understand the effects of fuel properties on engine performances because a diesel fuel could deteriorate inside an injector at such severe conditions. The test methods so far basically use the fuel with pro-fouling agent to form deposit on injector. In this study, a novel test procedure was developed to evaluate the effect of the use of the fuel with and without zinc contaminant on injector performance. With Zn doped European specification B7 fuel (7% biodiesel) as a reference, the test result showed that an engine torque decreased almost lineally over time, and the overall torque drop was 9% after 300 hours. The investigation of the dismantled injector after the test revealed that the deposit was not formed on the sliding parts of the injector, but on the nozzle hole surface.

The large eddy simulation (LES) with Volume of Fluid (VOF) interface tracking method in Ansys-FLUENT has been used to study the effects of nozzle hole geometrical parameters on gasoline direct injection (GDI) fuel injectors, namely the effect of inner hole length/diameter (L/D) ratio and counter-bore diameters on near field spray characteristics. Using iso-octane as a model fuel at the fuel injection pressure of 200 bar, the results showed that the L/D ratio variation of the inner hole has a more significant influence on the spray characteristics than the counter-bore diameter variation. Reducing the L/D ratio effectively increases the mass flow rate, velocity, spray angle and reduces the droplet size and breakup length. The increased spray angle results in wall impingements inside the counter-bore cavity, particularly for L/D=1 which can potentially lead to increased deposit accumulation inside fuel injectors.

Wide Distillation Fuel (WDF) refers to the fuels with a distillation range from Initial Boiling Point (IBP) of gasoline to Final Boiling Point (FBP) of diesel. Polyoxymethylene Dimethyl Ethers (PODEn) have high oxygen content and cetane number, are promising green additive to diesel fuel. In this paper, WDF was prepared by blending diesel and gasoline at ratio of 1:1, by volume; the mass distribution of oligomers in the PODE3-4 product was 88.9% of PODE3 and 8.46% of PODE4. Diesel fuel (Diesel), WDF (G50D50) and WDF (80%)-PODE3-4 (20%) (G40D40P20) were tested in a light-duty single-cylinder diesel engine, combustion characteristic, fuel consumption and exhaust emissions were measured. The results showed that: at idling condition, G40D40P20 has better combustion stability, higher heat release rate, higher thermal efficiency compared with G50D50.

A study of Multiple Premixed Compression Ignition (MPCI) with mixtures of gasoline and diesel is performed on a light-duty single cylinder diesel engine. The engine is operated at a speed of 1600rpm with the same fuel mass per cycle. By keeping the same intake pressure and EGR ratio, the influence of different blending ratios in gasoline and diesel mixtures (90vol%, 80vol% and 70vol% gasoline) is investigated. Combustion and emission characteristics are compared by sweeping the first (−95 ∼ −35deg ATDC) and the second injection timing (−1 ∼ 9deg ATDC) with an injection split ratio of 80/20 and an injection pressure of 80MPa. The results show that compared with diesel combustion, the gasoline and diesel mixtures can reduce NOx and soot emissions simultaneously while maintaining or achieving even higher indicated thermal efficiency, but the HC and CO emissions are high for the mixtures.

Experimental research were carried out on a compression ignition engine with compression ratio of 17.5 with direct-run Naphtha. Exhaust recirculation ratio sweeps were carried out with three injection strategies. Premixed charge compression ignition, partially premixed combustion and low temperature combustion modes were realized and compared with each other. The first injection strategy is single injection. The injection timing is scanned to form partially premixed combustion and low temperature combustion. The second injection strategy features a large early first injection with fixed timing to form premixed charge and a small second injection near top dead center, which was scanned. The third injection strategy is similar to the traditional diesel injection strategy, which has a small pilot injection with fixed interval before the main injection. Results show that all injection strategies could realize both low NOx and low particulate matter emissions simultaneously.

Combustion behaviour and emissions characteristics of different blending ratios of diesel and gasoline fuels (Dieseline) were investigated in a light-duty 4-cylinder compression-ignition (CI) engine operating on partially premixed compression ignition (PPCI) mode. Experiments show that increasing volatility and reducing cetane number of fuels can help promote PPCI and consequently reduce particulate matter (PM) emissions while oxides of nitrogen (NOx) emissions reduction depends on the engine load. Three different blends, 0% (G0), 20% (G20) and 50% (G50) of gasoline mixed with diesel by volume, were studied and results were compared to the diesel-baseline with the same combustion phasing for all experiments. Engine speed was fixed at 1800rpm, while the engine load was varied from 1.38 to 7.85 bar BMEP with the exhaust gas recirculation (EGR) application.

This study investigates the potential of using a partial flow filter (PFF) to assist a wall flow diesel particulate filter (DPF) and reduce the need for active regeneration phases that increase engine fuel consumption. First, the filtration efficiency of the PFF was studied at several engine operating conditions, varying the filter space velocity (SV), through modification of the exhaust gas flow rate, and engine-out particulate matter (PM) concentration. The effects of these parameters were studied for the filtration of different particle size ranges (10-30 nm, 30-200 nm and 200-400 nm). For the various engine operating conditions, the PFF showed filtration efficiency over 25% in terms of PM number and mass. The PFF filtration behaviour was also investigated at idle engine operation producing a high concentration of nuclei particulates for which the filter was able to maintain 60% filtration efficiency.

Engine transient operation has attracted a lot of attention from researchers due to its high frequency of occurrence during daily vehicle operation. More emissions are expected compared to steady state operating conditions as a result of the turbo-lag problem. Ambient temperature has significant influences on engine transients especially at engine start. The effects of ambient temperature on engine-out emissions under the New European Driving Cycle (NEDC) are investigated in this study. The transient engine scenarios were carried out on a modern 3.0 L, V6 turbocharged common rail diesel engine fuelled with winter diesel in a cold cell within the different ambient temperature ranging between +20 °C and −7 °C. The engine with fuel, coolant, combustion air and lubricating oil were soaked and maintained at the desired test temperatures during the transient scenarios.