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The maximum thermal efficiency of gasoline engine has been improving and recently the maximum of 40% has been achieved. In this study, the potential of further improvement on engine thermal efficiency over 40% was investigated. The effects of engine parameters on the engine thermal efficiency were evaluated while the optimization of parameters was implemented. Parameters tested in this study were compression ratio, tumble ratio, twin spark configuration, EGR rate, In/Ex cam shaft duration and component friction. Effects of each parameter on fuel consumption reduction were discussed with experimental results. For the engine optimization, compression ratio was found to be 14, at which the best BSFC without knock and combustion phasing retardation near sweet spot area was showed. Highly diluted combustion was applied with high EGR rate up to 35% for the knock mitigation.

The effects of fuel composition and engine operating parameters on high-pressure, direct injection gasoline (DIG) injector plugging and deposit formation have been studied. The engine used was a conventional dual-sparkplug, 2.2-liter Nissan engine modified for direct injection using one of the spark plug holes. The engine was run under 20% rich conditions to accelerate deposit formation. A ten-fuel test matrix was designed around T90, sulfur level, and olefin levels indicated in the European gasoline specifications for year 2000. The gasolines, containing no detergents, were formulated using refinery stream blends to match the specified targets. Injector flow loss was monitored by fuel flow to the engine and monitoring oxygen sensors on each of the four cylinders. The impact of fuel composition on deposit formation and injector plugging is discussed. Injector flow loss was strongly influenced by injector tip temperature.

The statistical analysis of relations of properties of common fuels, the main component of gasoline and gasoline sold on market was carried out. It is obtained that the equations of the density and low heating value, the density and hydrogen carbon ratio H/C, the density and stoichiometric air-fuel ratio. According to these equations, we can improve the precision of thermal analysis, measurement and control of air-fuel ratio in gasoline engines.

The urban mobility electrification has been proposed as the main solution to the vehicle emission issues in the next years. However, internal combustion engines have still great potential to decarbonize the transport sector through the use of low/zero-carbon fuels. Alcohols such us methanol, have long been considered attractive alternative fuels for spark ignition engines. They have properties similar to those of gasoline, are easy to transport and store. Recently, great attention has been devoted to gaseous fuels that can be used in existing engine after minor modification allowing to drastically reduce the pollutant emissions. In this regard, this study tries to provide an overview on the use of alternative fuels, both liquid and gaseous in spark ignition engines, highlighting the benefits as well as the criticalities. The investigation was carried out on a small displacement spark ignition engine capable to operate both in port fuel and direct injection mode.

The various methods for calculating AFR from exhaust gas analysis do not always produce identical results. This paper presents exhaust gas analysis data from a four-stroke SI engine burning two different fuels - unleaded gasoline and LPG. Exhaust gas concentrations are measured both upstream and downstream of the three-way catalyst. All four sets of data are analysed using established algorithms due to Spindt, Urban, Uyehara and Fukui. The results of each algorithm are compared with the AFR obtained using direct measurement of air and fuel mass flows.

Typically the combustion in a direct injected compression ignited internal combustion engine is open-loop controlled. The introduction of a cylinder pressure sensor opens up the possibility of a virtual combustion sensor which could enable closed-loop combustion control and thus the potential to counteract effects such as engine part to part variation, component ageing and fuel quality diversity. Closed-loop combustion control requires precise, robust and preferably cheap sensors. This paper presents a virtual cylinder pressure sensor based on the signal from the inexpensive but well proven knock sensor. The method used to convert the knock sensor signal into a pressure estimate included the stages: Phase correcting the raw signal, Filtering the raw signal, Scaling the signal to known thermodynamic laws and provided engine sensors signals and Reconstructing parts of the signal with other known models and assumptions.

Methanol produced from coal or natural gas can be converted over ZSM-5 class zeolite catalyst to high quality gasoline. Process reactions and yields are shown to be viable, thus providing a unique way to manufacture liquid transportation fuels from solid or gaseous energy sources. The hydrocarbon composition and physical properties of the gasoline are very similar to those of conventional petroleum-derived gasolines. No engine or vehicle modifications are required to use it. Laboratory and vehicle tests show the performance characteristics of the finished gasoline to compare very favorably in all aspects with commercial premium gasolines.

Gasoline particulate filters (GPF) have become a standard aftertreatment component in Europe, China, and since recently, India, where particulate emissions are based on a particle number (PN) standard. The anticipated evolution of regulations in these regions towards future EU7, CN7, and BS7 standards further enhances the needs with respect to the filtration capabilities of the GPFs used. Emission performance has to be met over a broader range in particle size, counting particles down to 10nm, and over a broader range of boundary conditions. The requirements with respect to pressure drop, aiming for as low as possible, and durability remain similar or are also enhanced further. To address these future needs new filter technologies have been developed. New technologies for uncatalyzed GPF applications have been introduced in our previous publications.

The fuel marking is widely accepted method to check the fuel integrity at any stage in the large and complex road-fuel supply-chain. Not any longer these sophisticated technologies are employed in the developed countries only, governments and fuel marketing companies in developing countries are increasingly leveraging these systems to control the supply chain to ensure fuel integrity to the consumers. Over a decade of experience in this field enforces the value of on-spot, accurate, and user-friendly testing systems due to lag between sampling and laboratory testing and hence complexity of corrective action. In association with IOC R&D Center and oil companies, Rohm and Haas Company demonstrated its accurate, quantitative and instrument based SpecTrace Technology and conducted a large scale field trial at HPCL’ Vashi terminal by marking Gasoline.

Several predictive equations based on the chemical composition of gasoline have been shown to estimate the particulate emissions of light-duty, internal combustion engine (ICE) powered vehicles and are reviewed in this paper. Improvements to one of them, the PEISimDis equation are detailed herein. The PEISimDis predictive equation was developed by General Motor’s researchers in 2022 based on two laboratory gas chromatography (GC) analyses; Simulated Distillation (SimDis), ASTM D7096 and Detailed Hydrocarbon Analysis (DHA), ASTM D6730. The DHA method is a gas chromatography mass spectroscopy (GC/MS) methodology and provides the detailed speciation of the hundreds of hydrocarbon species within gasoline. A DHA’s aromatic species from carbon group seven through ten plus (C7 – C10+) can be used to calculate a Particulate Evaluation Index (PEI) of a gasoline, however this technique takes many hours to derive because of its long chromatography analysis time.

Injector nozzle deposits can have a profound effect on particulate emissions from vehicles fitted with Gasoline Direct Injection (GDI) engines. Several recent publications acknowledge the benefits of using Deposit Control Additives (DCA) to maintain or restore injector cleanliness and in turn minimise particulates, but others claim that high levels of DCA could have detrimental effects due to the direct contribution of DCA to particulates, that outweigh the benefits of injector cleanliness. Much of the aforementioned work was conducted in laboratory scenarios with model fuels. In this investigation a fleet of 7 used GDI vehicles were taken from the field to determine the net impact of DCAs on particulates in real-world scenarios. The vehicles tested comprised a range of vehicles from different manufacturers that were certified to Euro 5 and Euro 6 emissions standards.

IT is the purpose of this paper to present a chart by means of which the vapor-locking characteristics of a gasoline (represented by a curve showing the quantity of vapor formed as a function of the temperature) can be estimated with moderate accuracy for gasolines in the current commercial distillation ranges from the conventional Reid vapor pressure and A.S.T.M. distillation tests on the gasoline. Interpretation and consolidation of car data are facilitated by means of the chart and, in this respect, vapor-lock test data are given for eight 1934, eleven 1935, and several 1936 model cars. The use of the chart and car data is illustrated by a group of sample problems which are specially designed to show the degree of assurance that may be placed on the use of either Reid vapor pressure or A.S.T.M. 10 per cent point alone as a criterion of vapor lock. The problem of evaporation losses from the fuel system, which can be roughly treated by means of the chart, is also discussed briefly.

THIS paper gives a brief resumé of the development of the Rolls-Royce Kestrel engine and then analyzes the requirements of the high-performance engine of the future, developing at least 1500 b.hp. and operating on fuels of high knock ratings. The problems investigated include those of engine form, fuels, detonation, waste-heat disposal, cooling drag, cooling medium, and the mechanical and operational features. Conclusions deduced from the arguments are: (a) Compression ratios, charge density, and rotational speeds will need to increase and, therefore, cylinder bores and strokes will decrease; it may be necessary to adopt the sleeve-valve type. (b) The arrangement of the engine will tend to multithrow crankshafts with more than two pistons per crankpin.

In recent years, an abnormal combustion phenomenon called low-speed pre-ignition (LSPI) has arisen from the downsizing of gasoline engines in order to improve fuel economy and comply with global CO2 legislation. The type and quality of the fuel and lubricant has been found to influence LSPI occurrence rates. A methodology for studying LSPI has been implemented, and a rigorous statistical approach for studying the data from a stationary engine test can provide consistent results as shown in Part 1 of the series. LSPI events can be determined by an iterative statistical procedure based on calculating the mean and standard deviation of peak pressure (PP) and crank angle location of 2% mass fraction burned (MFB02) data, determining cycles with parameters which exceeded n standard deviations from the mean and identifying outliers. Outliers for the PP and MFB02 metrics are identified as possible LSPI events.

IN the testing method described in this paper the moment of ignition is determined by a mechanism consisting of a diaphragm in the cylinder head, a phonograph “pick-up,” a short stiff wire transmitting the motion of the diaphragm to the pick-up, a thyratron relay, and a neon lamp protractor. When ignition occurs in the cylinder the flexing velocity of the diaphragm is sufficiently high so that the voltage generated in the coil of the pick-up trips the thyratron tube and permits a high-tension condenser discharge to be sent through the neon lamp which by its flashes then indicates the time of ignition. Because of the absence of friction and arcing the action of the pick-up is more regular than that of a bouncing pin. A similar pick-up is used for indicating injection timing. Using this apparatus and the “fixed-ignition-lag method” the Diesel fuel testing in the C.F.R. engine has been so simplified that seven to eight fuels can be tested in an hour with a high degree of reproducibility.

Low temperature heat release (LTHR) has been of interest to researchers for its potential to mitigate knock in spark ignition (SI) engines and control auto-ignition in advanced compression ignition (ACI) engines. Previous studies have identified and investigated LTHR in both ACI and SI engines before the main high temperature heat release (HTHR) event by appropriately curating the in-cylinder thermal state during compression, or in the case of SI engines, timing the spark discharge late to reveal LTHR (sometimes referred to as pre-spark heat release). In this work, LTHR is demonstrated in isolation from HTHR events. Tests were run on motored single-cylinder engines and inlet air temperatures and pressures were adjusted to realise LTHR from n-heptane and iso-octane (2,2,4-trimethylpentane) without entering the HTHR regime. LTHR was observed for a lean n-heptane-air mixture at inlet temperatures ranging from 60°C to 100°C and inlet pressures of 0.9 bar (absolute).

Laminar burning velocity is a fundamental combustion property of any fuel/air mixture. Formulating gasoline fuel blends having faster burning velocities can be an effective strategy for enhancing engine and vehicle performance. Formulation of faster burning fuels by changing the fuel composition has been explored in this work leading to a clear correlation between engine performance and fuel burning velocity. In principle a gasoline vehicle should be calibrated to give optimal ignition timing (also known as MBT - minimum spark advance for best torque) while at the same time avoiding any possible engine knock. However, modern downsized/boosted engines frequently tend to be limited by knock and the spark timing is retarded in respect of the optimum. In such scenarios, faster burning fuels can lead to a more optimum combustion phasing resulting in a more efficient energy transfer and hence a faster acceleration and better performance.

The Octane Index (OI) relates a fuel's knocking characteristics to a Primary Reference Fuel (PRF) that exhibits similar knocking characteristics at the same engine conditions. However, since the OI varies substantially with the engine operating conditions, it is typically measured at two standard conditions: the Research and Motor Octane Number (RON and MON) tests. These tests are intended to bracket the knock-limited operating range, and the OI is taken to be a weighted average of RON and MON: OI = K MON + (1-K) RON where K is the weighing factor. When the tests were established, K was approximately 0.5. However, recent tests with modern engines have found that K is now negative, indicating that the RON and MON tests no longer bracket the knock-limited operating conditions. Experiments were performed to measure the OI of different fuels in a modern engine to better understand the role of fuel sensitivity (RON-MON) on knock limits.

Recent studies have shown that for a given RON, fuels with a higher sensitivity (RON-MON) tend to have better antiknock performance at most knock-limited conditions in modern engines. The underlying chemistry behind fuel sensitivity was therefore investigated to understand why this trend occurs. Chemical kinetic models were used to study fuels of varying sensitivities; in particular their autoignition delay times and chemical intermediates were compared. As is well known, non-sensitive fuels tend to be paraffins, while the higher sensitivity fuels tend to be olefins, aromatics, diolefins, napthenes, and alcohols. A more exact relationship between sensitivity and the fuel's chemical structure was not found to be apparent. High sensitivity fuels can have vastly different chemical structures. The results showed that the autoignition delay time (τ) behaved differently at different temperatures. At temperatures below 775 K and above 900 K, τ has a strong temperature dependence.