A Novel Method to Estimate Parameters of the Wall-Wetting Fuel Model in MPFI Engines for Cold Start and Warm Up Conditions

2004 ◽  
Author(s):  
M. Shahbakhti ◽  
M. Ghafuri ◽  
A. R. Aslani ◽  
A. Sahraeian ◽  
S. A. Jazayeri ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Cold Start ◽  
Spark Ignition Engine ◽  
Intake Manifold ◽  
Exhaust Emission ◽  
Model Parameters ◽  
Transfer Model ◽  
Fuel Film ◽  
Warm Up ◽  
Fuel Ratio

In order to fulfill the LEV/ULEV exhaust emission standards, it is necessary to have a precise control of air fuel ratio under transient conditions especially during cold start and warm up periods. The objective in this study was to estimate parameters of a fuel delivery model and use them to provide a correct fuel injection compensation strategy. In this study, fuel transfer characteristics of intake port of a typical fuel-injected spark ignition engine have been determined for engine warm-up conditions following cold starts at temperature down to −15°C and extending to fully-warmed-up conditions, using a method based upon perturbing fuel injection rate and recording AFR (Air Fuel Ratio) response. Since there was no cold chamber available to perform tests in cold start conditions, a new method was utilized to simulate cold start conditions. This method can be used on any PFI engine with closed valve injection strategy. Following the estimation of fuel transfer model parameters, the variation of fuel film deposit factor (X), fuel film evaporation time constant (τf) and transport delay to oxygen sensor (ΔT) parameters over a range of temperatures, engine speeds and intake manifold pressures have been evaluated, providing a good insight to define transient fuel compensation requirements for cold start and warm up conditions.

A Method to Determine Fuel Transport Dynamics Model Parameters in Port Fuel Injected Gasoline Engines During Cold Start and Warm-Up Conditions

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
M. Shahbakhti ◽  
M. Ghafuri ◽  
A. R. Aslani ◽  
A. Sahraeian ◽  
S. A. Jazayeri ◽  
...  
Keyword(s):  
Thermal Conditions ◽  
Cold Start ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
New Method ◽  
Intake Manifold ◽  
Dynamics Model ◽  
Fuel Film ◽  
Warm Up ◽  
Transport Dynamics

In order to meet stringent emission standards, it is essential to have a precise control of air-fuel ratio (AFR) under cold start and warm-up conditions. This requires an understanding of the fuel transport dynamics in the intake system during these conditions. This study centers on estimating the parameters of a fuel transport dynamics model during engine operation at different thermal conditions ranging from cold start to fully warmed-up conditions. A method of system identification based on perturbing fuel injection rate is used to find fuel dynamics parameters in a port fuel injected (PFI) spark ignition engine. Since there was no cold chamber available to prepare cold start conditions, a new method was utilized to simulate cold start conditions. The new method can be applied on PFI engines, which use closed valve injection timing. A four-cylinder PFI engine is tested for different thermal conditions from −15°C to 82°C at a range of engine speeds and intake manifold pressures. A good agreement is observed between simulated and experimental AFR for 52 different transient operating conditions presented in this study. Results indicate that both fuel film deposit factor (X) and fuel film evaporation time constant (τf) decrease with increasing coolant temperature or engine speed. In addition, an increase in the intake manifold pressure results in an increase in X while causes a decrease in τf.

Transient air-fuel ratio control of a multi-point injection engine with an integration-type ultrasonic flowmeter

2001 ◽  
Vol 215 (3) ◽  
pp. 385-391
Author(s):  
J. Kim ◽  
T. Kang ◽  
S. K. Kauh
Keyword(s):  
Fuel Injection ◽  
Spark Ignition Engine ◽  
Ultrasonic Flowmeter ◽  
Intake Manifold ◽  
Air Mass ◽  
Fuel Ratio ◽  
Throttle Valve ◽  
Fuel Model ◽  
Model Control ◽  
Point Injection

An integration-type flowmeter, composed of an ultrasonic flowmeter and an integration circuit, is used to measure the air mass for transient air-fuel ratio (AFR) control of a port fuel injection (PFI) spark ignition engine. Also, the air mass and required fuel mass in the cylinder are accurately calculated for precise AFR control. The proposed method can significantly improve the accuracy of measuring air mass inducted through a throttle valve. Air mass passing into a cylinder is estimated using the measured air mass at the throttle valve and intake manifold pressure. A simple two-constant fuel model is used for a dynamic fuel model. Control parameters from the air and fuel dynamics are applied to minimize AFR excursions, and a four-cylinder, 1.51 PFI engine was used to demonstrate this AFR control strategy. Results show that the AFR followed a command value with a peak error of 4 per cent during throttle transients at various operating points.

Effects of injection parameters on the amount of wall-wet fuel in a port-fuel-injected spark-ignition engine during cold start

2019 ◽  
Vol 22 (1) ◽  
pp. 184-198
Author(s):  
Mikiya Araki ◽  
Katsuya Sakairi ◽  
Takashi Kuribara ◽  
Juan C González Palencia ◽  
Seiichi Shiga ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Fuel Injection ◽  
Cold Start ◽  
Spark Ignition ◽  
Stokes Number ◽  
Liquid Films ◽  
Spark Ignition Engine ◽  
Spray Angle ◽  
Short Period ◽  
Two Parameters

In a four-stroke cycle port-fuel-injected spark-ignition engine, a significant portion of unburned hydrocarbons is exhausted during the short period of cold start. The aim of this study is to investigate the physics behind the wall-wet phenomena and its determining parameter as simply as possible even though qualitative to some extent. The test engine is driven at a constant speed of 350 r/min. The fuel injection starts at a certain cycle, and the cycles required for the first ignition is counted. Three gasoline injectors having different atomization characteristics are used for port fuel injection, and the droplet size, the spray angle and the spray velocity are varied independently. The fuel transport phenomena from the injector to the cylinder are characterized by only two parameters, α and β, the mass fraction of the fuel without wall-wet and the mass fraction of the evaporated fuel from liquid films on walls. They are determined so that all the first ignition cycles observed experimentally are consistently reproduced by the model. The value of α is successfully determined for every single injector, and it increases monotonously with the decrease in the Stokes number.

Engine Friction Characteristics Under Cold Start Conditions

2001 ◽  
Author(s):  
Paul J. Shayler ◽  
John A. Burrows ◽  
Clive R. Tindle ◽  
Michael Murphy
Keyword(s):  
Fuel Injection ◽  
Cold Start ◽  
Operating Conditions ◽  
Valve Train ◽  
Bulk Temperature ◽  
Oil Viscosity ◽  
Engine Operation ◽  
Warm Up ◽  
Injection Pump ◽  
Engine Friction

Abstract Most studies of engine friction have been carried out at fully-warm operating conditions. Relatively little attention has been given to frictional losses when the engine is running cold, although these can be considerably higher and have a strong influence both on cold-start characteristics and fuel consumption during warm-up. The losses which effect the indicated load on the engine are rubbing losses and loads associated with driving auxiliaries. The equivalent frictional mean effective pressures (fmep) are generally highest during the first seconds of engine operation. These decay rapidly onto a characteristic variation which depends upon oil viscosity, and which fmep follows throughout the warm-up period. The oil viscosity can be evaluated at the bulk temperature of oil in the sump or main gallery. Breakdown motoring tests have been carried out on a series of diesel engines to examine how the friction contribution of various sub-assemblies in the engine contribute to the total and how this varies with temperature and speed. Tests were carried out using a compact cold cell and engine motoring facility. The engine was cold soaked to a target test temperature and then motored to a target speed and the variation of motoring torque recorded. Sets of tests were carried out at several stages of breaking the engine down. This enables the contributions due to the valve train, piston and big end assembly, crankshaft, fuel injection pump, and auxiliary load to be determined.

scholarly journals Individual Cylinder Combustion Optimization to Improve Performance and Fuel Consumption of a Small Turbocharged SI Engine

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5548
Author(s):  
Luca Marchitto ◽  
Cinzia Tornatore ◽  
Luigi Teodosio
Keyword(s):  
Fuel Consumption ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Exhaust Emission ◽  
Cycle Variation ◽  
Spark Timing ◽  
Experimental Findings

Stringent exhaust emission and fuel consumption regulations impose the need for new solutions for further development of internal combustion engines. With this in mind, a refined control of the combustion process in each cylinder can represent a useful and affordable way to limit cycle-to-cycle and cylinder-to-cylinder variation reducing CO2 emission. In this paper, a twin-cylinder turbocharged Port Fuel Injection–Spark Ignition engine is experimentally and numerically characterized under different operating conditions in order to investigate the influence of cycle-to-cycle variation and cylinder-to-cylinder variability on the combustion and performance. Significant differences in the combustion behavior between cylinders were found, mainly due to a non-uniform effective in-cylinder air/fuel (A/F) ratio. For each cylinder, the coefficients of variation (CoVs) of selected combustion parameters are used to quantify the cyclic dispersion. Experimental-derived CoV correlations representative of the engine behavior are developed, validated against the measurements in various speed/load points and then coupled to an advanced 1D model of the whole engine. The latter is employed to reproduce the experimental findings, taking into account the effects of cycle-to-cycle variation. Once validated, the whole model is applied to optimize single cylinder operation, mainly acting on the spark timing and fuel injection, with the aim to reduce the specific fuel consumption and cyclic dispersion.

Measurements of in-cylinder mixture strength and fuel accumulation in the inlet port of a gasoline - injected engine during very rapid throttle openings

1998 ◽  
Vol 212 (2) ◽  
pp. 103-118 ◽  
Author(s):  
N Ladommatos ◽  
D Rose
Keyword(s):  
Engine Speed ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Spark Ignition Engine ◽  
Fuel Injectors ◽  
Inlet Port ◽  
Fuel Ratio ◽  
Fuel Accumulation ◽  
Engine Coolant ◽  
Three Way Catalyst

The mixture strength in a cylinder of a port-injected gasoline engine was monitored continuously during very rapid throttle openings. The data on mixture strength were combined with other engine data collected in order to obtain for each successive engine cycle: the air—fuel ratio within the cylinder and the change in the fuel mass accumulating on the inlet port of the cylinder being monitored. The four-cylinder spark-ignition engine used had a displacement of 1.6 litre, four valves per cylinder and multipoint sequential fuel injection controlled by an electronic management system programmed for three - way catalyst operation. All tests were conducted with the engine coolant at the temperature of 90°C and at a constant engine speed of 2000 r/min. The engine transient involved very rapid throttle openings which were completed within about 15 ms. Small and large throttle openings were investigated along with the effect of altering the type and condition of the fuel injectors. The engine response to the fast throttle opening comprised a sharp rise in the air—fuel ratio (maximum gravimetric air—fuel ratio of around 25:1) which lasted for only a single cycle, followed by a drop in the air-fuel ratio (minimum air—fuel ratio of about 10:1) and, subsequently, a gradual rise towards a stoichiometric air—fuel ratio within about 10 engine cycles.

scholarly journals Effect of Water Vapor Injection on the Performance and Emissions Characteristics of a Spark-Ignition Engine

2021 ◽  
Vol 13 (16) ◽  
pp. 9229
Author(s):  
Ming-Hsien Hsueh ◽  
Chao-Jung Lai ◽  
Meng-Chang Hsieh ◽  
Shi-Hao Wang ◽  
Chia-Hsin Hsieh ◽  
...  
Keyword(s):  
Air Pollution ◽  
Water Vapor ◽  
Internal Combustion Engines ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Injection System ◽  
Intake Manifold ◽  
Exhaust Emission ◽  
Engine Torque ◽  
Vapor Injection

The exhaust emissions from Internal Combustion Engines (ICE) are currently one of the main sources of air pollution. This research presented a method for improving the exhaust gases and the performance of a Spark-Ignition (SI) engine using a water vapor injection system and a Non-Thermal Plasma (NTP) system. These two systems were installed on the intake manifold to investigate their effects on the engine’s performance and the characteristics of exhaust emission using different air/fuel (A/F) ratios and engine speeds. The temperatures of the injected water were adjusted to 5 and 25 °C, using a thermoelectric cooler (TEC) temperature control device. The total hydrocarbons (HC), nitrogen oxide (NOx), and engine torque were measured at different A/F ratios and engine speeds. The results indicated that the adaptation of the water vapor injection system and NTP system increased the content of the combustibles and combustion-supporting substances while achieving better emissions and torque. According to the test results, while the engine torque under 25 °C water+NTP was raised to 7.29%, the HC under 25 °C water+NTP and the NOx under 25 °C water were reduced to 16.31% and 11.88%, respectively. In conclusion, the water vapor injection and the NTP systems installed on the intake manifold could significantly reduce air pollution and improve engine performance for a more sustainable environment.

Liquid Film Atomization on Wall Edges—Separation Criterion and Droplets Formation Model

2002 ◽  
Vol 124 (3) ◽  
pp. 565-575 ◽  
Author(s):  
F. Maroteaux ◽  
D. Llory ◽  
J-F. Le Coz ◽  
C. Habchi
Keyword(s):  
Liquid Film ◽  
Fuel Injection ◽  
Liquid Sheet ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Physical Parameters ◽  
Lagrangian Description ◽  
Fuel Film ◽  
Separation Criterion ◽  
Film Separation

In order to predict the fuel mixture preparation inside the cylinder of port fuel injection engines, a model for the aerodynamic stripping of the fuel film deposited on the manifold walls is discussed, and a model for the fuel film separation and atomization near the sharp edges is developed. A separation criterion is set up using an analogy with Rayleigh-Taylor instabilities driven by the inertial forces of the liquid film. To determine the physical parameters of the resulting droplets, a liquid sheet atomization scheme is used. The critical value for the separation criterion is adjusted using experimental data obtained in 2D wind tunnel equipped with different steps shaped as a valve seat, and reproducing the main characteristics of the intake of spark ignition engine. CFD simulations are performed using the KMB code, a modified version of KIVA-2 already including a stochastic Lagrangian description of the spray, and an Eulerian liquid film model. Computations results for different operating conditions are in good agreement with the images of film separation and measured droplet size distributions.

Combustion and Emission Characterization of n-Butanol Fueled HCCI Engine

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Rakesh Kumar Maurya ◽  
Avinash Kumar Agarwal
Keyword(s):  
Fuel Injection ◽  
Combustion Efficiency ◽  
Intake Manifold ◽  
Exhaust Emission ◽  
Injection Technique ◽  
Transportation Fuels ◽  
Hcci Engine ◽  
Auto Ignition ◽  
Hcci Engines ◽  
Homogeneous Charge

Biofuels are attracting global attention as alternate transportation fuels due to advantages of their being produced from locally available renewable resources, lower pollution potential, and biodegradable nature. Butanol is fast emerging as one of the competitive biofuels for use in transportation engines. Homogeneous charge compression ignition (HCCI) engines have shown great potential for higher engine efficiency and ultralow NOx and particulate matter (PM) emissions. This experimental study is therefore carried out to combine the advantages of biofuels and HCCI engines, both. Detailed performance, combustion, and emission characteristics of n-butanol fueled HCCI engine are investigated experimentally. The study is conducted on a four cylinder diesel engine, whose one cylinder was modified to operate in HCCI combustion mode. Port fuel injection technique was used for homogeneous charge preparation in the intake manifold. Auto-ignition of fuel in the engine cylinder was achieved by intake air preheating. In-cylinder pressure-crank angle data acquisition with subsequent heat release analyses and exhaust emission measurements were done for combustion and emission characterization. In this paper, the effect of intake air temperature and air–fuel ratio on the combustion parameters, thermal and combustion efficiency, ringing intensity (RI), and emissions from n-butanol fueled HCCI engine were analyzed and discussed comprehensively. Empirical correlations were derived to fit the experimental data for various combustion parameters.

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