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This paper investigates the effect of valve deactivation (VDA) on idling performance in port fuel injection (PFI) engine. The test was conducted on 1.6L, 4-cylinder engine with PFI configuration. One of the two intake valves in each cylinder was deactivated (zero lift on deactivated port) and fuel injector was modified to only provide fuel spray on the active intake port. In-cylinder pressure was recorded by the combustion analyzer in order to measure and analyze the combustion characteristics. From the test, there are up to 6% of fuel consumption improvements across all the test conditions. Better combustion stability is achieved at very low idling speed (throttle position, TP = 2%) as a lower coefficient of variation of engine speed (COVrpm) and coefficient of variation indicated mean effective pressure (COVimep) were recorded. Increased intake velocity and swirl flow in the VDA strategy creates more turbulence intensity causing higher heat release rate and faster combustion. However, there is no significant difference in the pumping work during the intake cycle but there is extra pumping work recorded towards the end of expansion stroke due to the very early end of combustion. Therefore, valve deactivation strategy provides limited positive improvement to the idling performance in PFI engine.

To overcome the difficulty of cold start of a spark-ignition (SI) engine fueled with aviation kerosene, a series of experimental investigations were carried out on a port fuel injection (PF...

In this study, the optimum advances for parameters such as specific fuel consumption, emissions were investigated in ignition advances below 100 EA and above 100 EA. Cylinder pressure was measured for calculating the heat release rate. 13B MSP (Multi Side Port) single rotor and port fuel injection Wankel engine was used in the experiments. In this context, single rotor Wankel test engine was operated at 2000, 3000 and 4000 rpm engine speed, part loads and λ = 1 condition. The optimum ignition advance is based on the value at which the maximum torque is obtained. Thus, the effect of ignition advance was investigated on Wankel engine. As a result, it is observed that ignition advance has a significant effect on emissions, in-cylinder pressure and fuel consumption in Wankel engine. Bu çalışmada, optimum avans, 10 derece EMA altı ve 10 derece EMA üstü avanslarda özgül yakıt tüketimi, emisyonlar, silindir içi basınç ve ısı salımı oranları gibi parametreler incelenmiştir. Motor olarak deneyde 13B-MSP tek rotorlu ve manifolda püskürtmeli bir Wankel motor kullanılmıştır. Bu kapsamda, tek rotorlu Wankel deney motoru 2000, 3000 ve 4000 dev/dak motor hızında, kısmi yüklerde ve λ=1 koşulunda çalıştırılmıştır. Optimum ateşleme avansı maksimum momentin elde edildiği değer baz alınmıştır. Böylece, ateşleme avansının Wankel motordaki etkisi incelenmiştir. Sonuç olarak ateşleme avansının Wankel motorda emisyonlar, silindir içi basınç ve yakıt tüketimi üzerinde büyük bir etkiye sahip olduğu gözlenmiştir.

The percentage of HC emission before catalyst light-off is beyond 90% in WLTC driving cycle. It is a big challenge to reduce the HC emission during cold start phase due to poor mixture preparation from port injection spark ignition engines. This study focuses on cold start period to investigate HC emissions based on cycle-by-cycle method, using fast FID HC analyzer (HFR500) and cylinder pressure indicating system. The results have been compared with two different types of fuel injectors installed on a 1.5-L port-fuel-injection gasoline engine. The transient HC emission of first 10 cycles has been analyzed. The test results also show that HC emissions of the type B injector (8-hole) are 11% lower than that of the type A injector (6-hole) under same fuel injection strategy.

This study examines the effects of ethanol and gasoline injection mode on the combustion performance and exhaust emissions of a twin cylinder port fuel injection (PFI) spark ignition (SI) engine. Generally, when using gasoline&ndash, ethanol blends, alcohol and gasoline are externally mixed with a specified blending ratio. In this activity, ethanol and gasoline were supplied into the intake manifold into two different ways: through two separated low pressure fuel injection systems (Dual-Fuel, DF) and in a blend (mix). The ratio between ethanol and gasoline was fixed at 0.85 by volume (E85). The initial reference conditions were set running the engine with full gasoline at the knock limited spark advance boundary, according to the standard engine calibration. Then E85 was injected and a spark timing sweep was carried out at rich, stoichiometric, and lean conditions. Engine performance and gaseous and particle exhaust emissions were measured. Adding ethanol could remove over-fueling with an increase in thermal efficiency without engine load penalties. Both ethanol and charge leaning resulted in a lowering of CO, HC, and PN emissions. DF injection promoted a faster evaporation of gasoline than in blend, shortening the combustion duration with a slight increase in THC and PN emissions compared to the mix mode.

This article reports on the application of independent component analysis (ICA) to line-of-sight, cycle-resolved images of luminosity during combustion, acquired in an optically accessible engine. The experiments are conducted on a port fuel injection spark ignition (PFI SI) engine. The analysis identifies the independent components related to the underlying phenomena of the combustion process. The components, along with their corresponding time dependent coefficients, are used to characterize the morphological evolution of the luminous combustion during a single cycle and over a number of cycles. When ICA is applied to a single cycle, independent structures are identified, clearly separated in time, and related to the spatial distribution in the high-luminosity zone. The corresponding coefficients correlate well with the integral flame luminosity, and characterize the time evolution of the combustion morphological pattern in the chamber. The analysis over several cycles shows that independent com...

Wall film formation and evaporation were studied on a flat wall inside a constant-volume vessel using a three-dimensional numerical method. The computation was based on the discrete phase model (DPM) of spray dispersion, a spray–wall interaction model coupled with an enhanced wall film evaporation sub-model, in which the operating conditions of cold wall are considered for port fuel injection (PFI) engines. The influence of impacting parameters including injection pressure, the impingement distance from the injector and the impinged wall, injection duration, impingement angle, and wall temperature was discussed.

Gasoline direct injection (GDI) system has been shown to have several advantages over the more conventional Port Fuel Injection system in a SI engine. However, it has also been reported that GDI engines have higher particulate emissions. One of the possible reasons for this higher particulate emission is collapse of the spray emanating from the injector and wetting on the piston head, particularly when the engine is operating under high-load conditions. In this study, a detailed analysis has been performed to understand spray collapse and its effect on in-cylinder combustion for three different fuels: isooctane, n-butanol, and isobutanol. Initially, spray studies in a constant volume chamber were performed. Parameters like liquid and vapor penetration lengths, droplet size, and velocity distribution were estimated from image analysis of high-speed videography and phase Doppler particle analyzer (PDPA). To mimic in-cylinder conditions, the injector body temperature was raised such that injected fuel was also at elevated temperature. Spray collapse was observed at higher fuel temperature conditions, and this resulted in higher axial liquid penetration and finer droplet size distribution. Similar experiments were then performed in an optically accessible engine, and it was observed that spray collapse at higher fuel temperature leads to wetting of the piston wall. It also leads to formation of pool fire over the piston head which may lead to particulate emission. Effect of engine operating conditions like start of injection on wall wetting and formation of pool fire has been quantified using image analysis of high-speed videography.

Particulate Matter (PM) emissions from gasoline direct injection (GDI) engines, particularly Particle Number (PN) emissions, have been studied intensively in both academia and industry because of the adverse effects of ultrafine PM emissions on human health and other environmental concerns. GDI engines are known to emit a higher number of PN emissions (on an engine-out basis) than Port Fuel Injection (PFI) engines, due to the reduced mixture homogeneity in GDI engines. Euro 6 emission standards have been introduced in Europe (and similarly in China) to limit PN emissions from GDI engines. This article summarises the current state of research in GDI PN emissions (engine-out) including a discussion of PN formation, and the characteristics of PN emissions from GDI engines. The effect of key GDI engine operating parameters is analysed, including air-fuel ratio, ignition and injection timing, injection pressure, and EGR; in addition the effect of fuel composition on particulate emissions is explored, including the effect of oxygenate components such as ethanol.

The objective of this study was to compare the injection and spray characteristics of water with n-heptane using a port fuel injection (PFI) system. In this study, the injection pressure was changed to 0.3–0.9 Mpa and the energizing duration was changed to 0.5–4 ms. To investigate spray characteristics, the injection quantities of n-heptane and water were measured. Macroscopic spray characteristics were determined through spray visualization. The Sauter mean diameter (SMD) and velocity of spray droplets were measured with a phase Doppler anemometry (PDA) experiment. Spray tip penetration, spray angle, SMD of droplets, and spray droplet velocity were compared. As the injection pressure increased, the injection quantity and the droplets velocity increased. However, the spray tip penetration, SMD of the droplet, and the spray angle decreased. The increase in energizing duration led to an increase in the injection quantity without affecting other spray characteristics. The higher density of water also increased injection quantity, resulting in a decrease in spray tip penetration and increases of SMD and velocity of spray droplets due to high viscosity and surface tension of water.

To reduce the cyclic variation is an effective way to improve the fuel economy and combustion of spark ignition engines. In this paper, the effect of exhaust gas recirculation (EGR), compression ratio and boost pressure on cyclic variation was investigated by means of both experiments and simulation for a port fuel injection (PFI) engine. The mechanisms of these effects were analyzed by computational fluid dynamics (CFD) tools. A Ricardo E6 PFI engine was used as the experimental prototype. The experiments were performed with six EGR ratios, three compression ratios and two boost pressures for a given equivalence ratios. The experiments were operated with the same parameters as that of the simulation. Results showed that the simulation work agree well with the experiment. Both simulation and experiment results showed that an increase of EGR ratio will increase cyclic variation for its lower laminar flame speed. However, the combination of EGR with either an appropriate compression ratio or boost pressure can achieve a relatively low cyclic variation.

The cycle variation characteristics of a port fuel injection hydrogen internal combustion engine (PFI-HICE) have been extensively investigated. The covariance of indicated mean effective pressure (COV imep ) is the best parameter for evaluating the cycle variations in the PFI-HICE. COV imep decreases as fuel–air ratio increases from 1000 to 5500 rpm, and engine speed minimally affects COV imep . The effect of ignition advance angle on COV imep is determined by fuel–air ratio. The ignition advance angles that correspond to the minimum COV imep of the PFI-HICE decrease as fuel–air ratio increases. The effect of ignition advance angle on COV imep diminishes as fuel–air ratio increases. The COV imep of the PFI-HICE rapidly decreases as throttle increases when the throttle is less than 20%. Injection timing only slightly affects COV imep under high-speed conditions, and COV imep increases when hydrogen is injected in intake periods under low-speed conditions. These results indicate that studying COV imep improves the stability of PFI-HICEs.

[EN] Two-wheeler engines still use carburetor as a fuelling system in many Asian countries, owing to its low cost and less maintenance. The usage of carburetor to handle the upcoming stringent emission norms gets difficult, due to the absence of a closed-loop fuel correction. An electronic fuel injector (EFI), on the other hand, with the help of an electronic control unit (ECU), can correct the fuel quantity and set the air-fuel mixture close to stoichiometric, based on the feedback obtained from the oxygen sensor placed in the exhaust pipe. In this context, an innovative injection system has been developed, that can be applied for such electronic fuel injection in two-wheelers. In this design, the pump and injector are integrated into a single unit, making the system, simple, compact and less expensive. The integrated injector uses a solenoid and spring arrangement, for pressurizing the fuel in a small chamber, and the pressurized fuel is then injected through orifices to produce spray in the intake port. Two-wheeler engines can operate in the order of 10,000 rpm and it poses a big challenge in such injector designs, and therefore the time response of the mechanical and magnetic components of the injector become critical. High-speed back-lit imaging helps in understanding the time response of such injector, by visualizing the spray, while injecting continuously over a period of time. This paper presents the results of high-speed images, obtained from the spray of this new-concept gasoline pump injector (GPI). This exercise, demonstrated that this injector can work at a frequency as high as 83 Hz and also consistently. The spray pattern was found to be very unique and different from the conventional PFI injection sprays.

A numerical study is conducted in a port fuel-injection, spark-ignition engine fuelled with 1-butanol at different fuel/air equivalence ratios and inlet air temperatures. The effect of fuel/air equivalence ratio and inlet air temperature on the engine performance and emission characteristics is analyzed. The modeling results show that the incylinder pressure and temperature increases with the increase of fuel/air equivalence ratio. The slightly lean mixtures offer the maximum level of NOX emissions. In addition, preheating the inlet air can increase the incylinder pressure peak value and NOX emissions.

As an internal combustion engine fuel, hydrogen had been acknowledged by international auto industry to be a possible practical and economical fuel for automobile in the future. Port fuel injection is currently considered as the easiest way for hydrogen-powered vehicle application. As the key component of hydrogen system, the performance of hydrogen injector significantly influences the characteristic of the mixture before injection into the cylinder. However, current hydrogen injector system using one injector per cylinder is not capable of meeting the flow demand. To investigate the injector's flow characteristics and find a method of improving the injector's flux, a calibration test stand was designed for gas injectors that can exactly calibrate the injector's flow characteristics under injection pressure from 0.2 MPa to 0.45 MPa and injection duration from 1 ms to 10 ms. The minimum injection duration that enables the injector to work steadily was found to increase from 1.8 ms to 2.1 ms, which must be considered in idling speed. In addition, a hydrogen injector model was established using a one-dimensional simulation software. The effect of the structure parameters of the hydrogen injector on the flow characteristics was studied after verification and validation of the model with test data. By comparing the test and the calculation results, the flow area between the armature and the seal was established to have the largest effect on the injector's flow characteristics, and larger flux can be achieved by optimizing the related parameters of the injector. Therefore, the current paper can provide guidance to the technological research on hydrogen injectors in hydrogen internal combustion engine.

The trend towards vehicle powertrains that are ever more frugal is increasingly leading to the use of three-cylinder engines. This is because the concept makes it possible to save fuel with a turbocharged three-cylinder engine compared to a four-cylinder engine of the same power. Volkswagen is a pioneer in this powertrain concept and, at the request of MTZ, presents this overview of current developments.

This work investigates the potential of stratified charge compression ignition (SCCI) to extend the high-load limits of homogeneous charge compression ignition (HCCI) engine. Engine experiments were conducted on a single-cylinder diesel engine equipped with an electrical port fuel injection system. When the n-heptane fuel amount of port injection and in-cylinder direct injection was calibrated, partial fuel stratification was created and three different combustion modes as SCCI, HCCI, and direct injection compression ignition (DICI) were achieved. The premixed ratio (rp) was used to indicate the partial fuel stratification, and the effects of premixed ratio on SCCI combustion were examined. It was found that SCCI could achieve a staged combustion event of reduced pressure-rise rates, thus offering good potential to expand the operating range of the HCCI engine. Also, the engine performance and emission characteristics of SCCI were evaluated, focusing on the comparison with the HCCI and conventional DICI c...

This report describes the experimental evaluation of a prototype free piston engine - linear alternator (FPLA) system developed at Sandia National Laboratories. The opposed piston design wa developed to investigate its potential for use in hybrid electric vehicles (HEVs). The system is mechanically simple with two - stroke uniflow scavenging for gas exchange and timed port fuel injection for fuel delivery, i.e. no complex valving. Electrical power is extracted from piston motion through linear alternators wh ich also provide a means for passive piston synchronization through electromagnetic coupling. In an HEV application, this electrical power would be used to charge the batteries. The engine - alternator system was designed, assembled and operated over a 2 - year period at Sandia National Laboratories in Livermore, CA. This report primarily contains a description of the as - built system, modifications to the system to enable better performance, and experimental results from start - up, motoring, and hydrogen combus tion tests.

2.2-litre Ecotec engine with port fuel injection (PFI) was successfully introduced in 1999. In 2003, a new 2.2-litre Direct Ecotec with gasoline direct injection (GDI) is being introduced into the market. The 2.2-litre Direct Ecotec is the first GDI engine from Fiat-GM Powertrain to be developed for Opel. In this article, the new engine is described and compared to the PFI version.

The heat release characteristics in terms of the maximum pressure rise rate (MPRR) and combustion phasing in a partially premixed compression ignition (PPCI) engine are studied using a calibration gasoline. Early port fuel injection provides a nearly homogeneous charge, into which a secondary fuel pulse is added via direct injection (DI) to provide stratification which is affected by the timing of the start of injection (SOI). As the SOI the DI fuel is retarded from early compression, MPRR first decreases, then increases substantially, and decreases again. The MPRR correlates mostly with the combustion phasing. The SOI timing plays an indirect role. The observation is explained by a bulk heat release process of which the rate increases with temperature rather than by a sequential ignition process. Observations from compression ignition of representative homogeneous charges in a Rapid Compression Machine support this explanation.

A Large-Eddy Simulation of several cycles of a spark-ignition engine with port fuel injection has been performed. The investigated engine is a modified Rotax-engine with one cylinder and four valves, built and measured (Heidenreich, Private communication) by the Institute of Reciprocating Engines of the University of Karlsruhe (IFKM). A recently modified (Magagnato et al., 2008) progress variable combustion model of Schmid et al., 1998 has been used in this computation. A subgrid-scale model for the LES recently proposed by Stolz (Stolz et al., 2003) called High-pass filtered Eddy-Viscosity model has been employed, which appears to be ideal for moving meshes. In order to predict cyclic variations of the combustion process, an additional transport equation for the mixing of the fuel to air ratio inside the combustion chamber is proposed and investigated in this paper. The predicted cylinder pressure vs. crank angle is then compared to measured results (Heidenreich, Private communication).

In the present work, detailed laser-based diagnostic experiments were conducted to characterise the spray from low pressure 2-hole and 4-hole Port Fuel Injection (PFI) injectors. The main objective of the work included obtaining quantitative information of the spatio-temporal spray structure of such low-pressure gasoline sprays. A novel approach involving a combination of techniques such as Mie scattering, Granulometry, and Laser Sheet Dropsizing (LSD) was used to study the spray structure. The droplet sizes, distributions with time, Sauter Mean Diameters (SMD), droplet velocities, cone angles and spray tip penetrations of the sprays from the injectors were determined. The spray from these injectors is found to be ‘pencil like’ and not dispersed as in high pressure sprays. The application of the above mentioned techniques provides two-dimensional SMD contours of the entire spray at different instants of time, with reasonable accuracy.

The short time available for injection and mixing in high-speed engines requires an accurate modeling of the fuel related processes to obtain a valuable in-cylinder charge description, and then a good combustion performance prediction. An advanced version of the KMB code of IFP has been used to compute a racing engine. It includes a fitted on experiments spray model, a comprehensive wall-film model, the AKTIM ignition and ECFM combustion models. A major difficulty was the necessity to compute numerous cycles before reaching a cycle-independent solution. A procedure has been defined to minimize calculation time. Another difficulty was the high concentration of liquid in some zones, which requested a careful meshing. Effects such as the influence of the strong acoustic waves on the spray dynamic, the wall wetting effects on the engine time response, injector position on fuel distribution in the cylinder, charge homogeneity on the combustion process have been investigated. The obtained trends are discussed qualitatively.

Computational Fluid Dynamics simulations are performed to study mixture preparation in the intake manifold of a small engine with Port Fuel Injection. Data from laser-based experiments on two injectors are used as inputs to the spray sub-model. The results reveal improved in-cylinder fuel distribution when the spray is directed onto the intake valve. The Sauter Mean Diameter of the spray is observed to have an insignificant effect during open valve injection, while the targeting is found to have a large influence. The methodology developed as part of this work can be used to further optimize injection parameters in such engines.

Statistically designed experiments with a port fuel injected, single-cylinder engine were run to determine the effects of injector-, engine-, and fuel-related variables on exhaust smoke and hydrocarbon (HC) emissions. Among injector-related variables, targeting the fuel spray at the inlet valve centerline toward the valve head resulted in low smoke and HC emissions