Showing papers on "Spark-ignition engine published in 2010"

Combustion and Emissions of 2,5-Dimethylfuran in a Direct-Injection Spark-Ignition Engine

Abstract: Biomass has the potential to become an important source of energy for future automotive fuels. Recent biological and chemical improvements to the conversion of biomass-derived carbohydrates have produced high yields of liquid 2,5-dimethylfuran (DMF). This discovery has made DMF a possible substitute for petroleum-based gasoline, because they share very similar physicochemical properties, which are superior to those of ethanol. In the present study, experiments have been carried out on a single-cylinder gasoline direct-injection (GDI) research engine to study the performance of DMF benchmarked against gasoline and what is considered to be the current biofuel leader, ethanol. Initial results are very promising for DMF as a new biofuel; not only is the combustion performance similar to commercial gasoline, but the regulated emissions are also comparable.

Evaluation of Butanol–Gasoline Blends in a Port Fuel-injection, Spark-Ignition Engine

Abstract: This paper assesses different butanol–gasoline blends used in a port fuel-injection, spark-ignition engine to quantify the influence of butanol addition on the emission of unburned hydrocarbons, carbon monoxide, and nitrogen oxide. Furthermore, in-cylinder pressure was measured to quantify combustion stability and to compare the ignition delay and fully developed turbulent combustion phases as given by 0%–10% and 10%–90% Mass Fraction Burned (MFB). The main findings are: 1) a 40% butanol/60% gasoline blend by volume (B40) minimizes HC emissions; 2) no significant change in NOx emissions were observed, with the exception of the 80% butanol/20% gasoline blend; 3) the addition of butanol improves combustion stability as measured by the COV of IMEP; 4) butanol added to gasoline reduces ignition delay (0%–10% MFB); and 5) the specific fuel consumption of B40 blend is within 10% of that of pure gasoline for stoichiometric mixture.

Irregular combustion in supercharged spark ignition engines – pre-ignition and other phenomena:

Abstract: Downsizing is one of the most promising concepts to reduce fuel consumption of gasoline engines. However, it is currently limited by the occurrence of irregular combustion phenomena at high...

Automotive model predictive control : models, methods and applications

Abstract: Chances and Challenges in Automotive Predictive Control.- Chances and Challenges in Automotive Predictive Control.- I: Models.- On Board NOx Prediction in Diesel Engines: A Physical Approach.- Mean Value Engine Models Applied to Control System Design and Validation.- Physical Modeling of Turbocharged Engines and Parameter Identification.- Dynamic Engine Emission Models.- Modeling and Model-based Control of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics.- II: Methods.- An Overview of Nonlinear Model Predictive Control.- Optimal Control Using Pontryagin's Maximum Principle and Dynamic Programming.- On the Use of Parameterized NMPC in Real-time Automotive Control.- III: Applications.- An Application of MPC Starting Automotive Spark Ignition Engine in SICE Benchmark Problem.- Model Predictive Control of Partially Premixed Combustion.- Model Predictive Powertrain Control: An Application to Idle Speed Regulation.- On Low Complexity Predictive Approaches to Control of Autonomous Vehicles.- Toward a Systematic Design for Turbocharged Engine Control.- An Integrated LTV-MPC Lateral Vehicle Dynamics Control: Simulation Results.- MIMO Model Predictive Control for Integral Gas Engines.- A Model Predictive Control Approach to Design a Parameterized Adaptive Cruise Control.

Investigations of the Formation and Oxidation of Soot Inside a Direct Injection Spark Ignition Engine Using Advanced Laser-Techniques

Abstract: In this work the formation and oxidation of soot inside a direct injection spark ignition engine at different injection and ignition timing was investigated. In order to get two-dimensional data during the expansion stroke, the RAYLIX-technique was applied in the combustion chamber of an optical accessible single cylinder engine. This technique is based on the quasi-simultaneous detection of Rayleigh-scattering, laser-induced incandescence (LII) and extinction which enables simultaneous measurements of temporally and spatially resolved soot concentrations, mean particle radii and number densities. These investigations show that in our test engine the most important source for soot formation during combustion are pool fires, i.e. liquid fuel burning on the top of the piston. These pool fires were observed under almost all experimental conditions.

Acetone laser-induced fluorescence behavior for the simultaneous quantification of temperature and residual gas distribution in fired spark-ignition engines.

Abstract: Although the fluorescence behavior of acetone has already been examined widely, the amount of data is still not sufficient for the quantification of signals over the parameter field relevant for combustion engines. This leads to large uncertainties when new excitation wavelengths are applied or in cases where temperature and pressure and bath gas composition dependences of the fluorescence yield must be extrapolated from models. This work presents calibration results of the fluorescence signal intensities in nitrogen, air, and an exhaust-gas-air mixture in the wide range from 298 to 748 K and from 0.2 bar (0.02 MPa) to 20 bars for the two important excitation wavelengths 308 and 248 nm. Based on this data, measurements of temperature and exhaust gas concentrations in a fired spark ignition engine were performed with high accuracy in single-shot images also.

Spray stability of outwards opening pintle injectors for stratified direct injection spark ignition engine operation

Abstract: The spray characteristics and spray stability from three prototype piezoelectric pintle-type injectors were investigated under different operating conditions in an optical direct injection engine designed for stratified combustion. The pintle-type outwards opening injector has the potential to address and overcome many of the typical problems related to close-spacing, spray-guided configurations owing to its hollow cone spray, exhibiting better air utilization than multihole sprays, with good penetration during early injection, and a spray angle almost independent of cylinder backpressure. The three prototype injectors have different nozzle exit geometries for optimization of spray stability under all engine operating conditions. The emerging fuel sprays for both single- and double-injection operation were visualized using Mie scattering and a high-speed CCD camera. The performance of the injectors was assessed by constructing mean and RMS images at different operating conditions of injection pressure, backpressure, injector needle lift, and engine speed. From these images, a spray angle analysis was performed by comparing the mean, standard deviation, maximum, and minimum cone angle under different operating conditions; the spray stability was quantified by analysing the mean and RMS images and the mean and RMS spray cone angles. Evaluation of the three prototypes has revealed that the positive-step inward seal band design produces the most robust spray angle ideally suited for stratified fuel/air mixture formation and combustion in spray-guided direct injection spark ignition (DISI) gasoline engines.

The Influence of Ethanol–Gasoline Blends on Spark Ignition Engine Vibration Characteristics and Noise Emissions

Abstract: Engine vibration characteristics and noise emission of a two stroke spark ignition engine were investigated by using blends of ethanol–gasoline–oil (25% E–70% G–5% O and 50% E–45% G–5% O) and pure gasoline. Engine test conditions were 0.86 kW (5.5 Nm) at 1,500 rpm, 1.25 kW (6.0 Nm) at 2,000 rpm, and 1.83 kW (7.0 Nm) at 2,500 rpm. A high sensitivity electronic vibration analysis system was used for measurement of frequency spectrum of the spark ignition engine vibration. Higher octane number, lower sulphur content, and higher oxygen content were important advantages of blend fuels. Experiment results indicated that when the blend fuels were used, vibration characteristics of the engine changed significantly at 1,500 and 2,500 rpm. In general, in comparison with gasoline, vibration amplitudes and noise emission of the engine with the blend fuels showed a trend of increasing. These results are probably due to oxygen content and higher latent heat of evaporation of ethanol, in which the increasing ra...

Emissions of Formaldehyde and Unburned Methanol from a Spark-Ignition Methanol Engine during Cold Start

Abstract: The effects of the methanol injection quantity per cycle, the ignition timing, the methanol injection timing, the additional liquefied petroleum gas (LPG) injected into the inlet port, and the LPG ...

Spark Advance Real-Time Optimization Based on Combustion Analysis

Abstract: Future emission regulations could force manufacturers to install in-cylinder pressure sensors on production engines. The availability of such a signal opens a new scenario in terms of combustion control: many settings that previously were optimized off-line, can now be monitored and calibrated in realtime. One of the most effective factors influencing performance and efficiency is the combustion phasing: in gasoline engines Electronic Control Units (ECU) manage the Spark Advance (SA) in order to set the optimal combustion phase. SA optimal values are usually determined by means of calibration procedures carried out on the test bench by changing the ignition angle while monitoring Brake and Indicated Mean Effective Pressure (BMEP, IMEP) and Brake Specific Fuel Consumption (BSFC). The optimization process relates BMEP, IMEP and BSFC mean values with the control setting (SA). However, the effect of SA on combustion is not deterministic, due to the cycle-to-cycle variation: the analysis of mean values requires many engine cycles to be significant of the performance obtained with the given control setting. This paper presents a novel approach to SA optimization, with the objective of improving the performance analysis robustness, while reducing the test time. The approach can be either used in the calibration phase or in on-board applications, if the in-cylinder pressure signal is available: this would allow maintaining the optimization active throughout the entire engine life. The methodology is based on the observation that, for a given running condition, IMEP can be considered a function of a single combustion parameter, represented by the 50% Mass Fraction Burned (50%MFB). Due to cycle-to-cycle variation, many different MFB50 and IMEP values are obtained during a steady state test carried out with constant SA, but these values are related by means of a unique relationship. The distribution on the plane IMEP-MFB50 forms a parabola, therefore the optimization could be carried out by choosing SA values maintaining the scatter around the vertex. Unfortunately the distribution shape is slightly influenced by heat losses (i.e., by SA): this effect must be taken into account in order to avoid over-advanced calibrations. SA is then controlled by means of a PID (Proportional Integer Derivative) controller, fed by an error that is defined based on the previous considerations: a contribution is related to the MFB50-IMEP distribution, and a second contribution is related to the net Cumulative Heat Release (CHRNET )-IMEP distribution. The latter is able to take into account for heat losses. Firstly, the methodology has been tested on in-cylinder pressure data, collected from different SI engines; then, it has been implemented in real-time, by means of a programmable combustion analyzer: the system performs a cycle-to-cycle combustion analysis, evaluating the combustion parameters necessary to calculate the target SA, which is then actuated by the ECU. The approach proved to be efficient, reducing the number of engine cycles necessary for the calibration to less than 1000 per operating condition.Copyright © 2010 by ASME

Burn angles and form factors for Wiebe function fits to mass fraction burned curves of a spark ignition engine with variable valve timing

Abstract: The charge burn characteristics of a port-injected spark ignition engine with a pent-roof combustion chamber and variable valve timing have been investigated experimentally. The engine was ...

Comparison of Waste Heat Recovery from the Exhaust of a Spark Ignition and a Diesel Engine

Abstract: We present herein a design for and performance measurements of a prototype thermoelectric generator (TEG) mounted on both a spark ignition engine (0.9 dm 3 ) and a self-ignition engine (1.3 dm 3 ). Using the prototype TEG as a tool, benchmark studies were performed in order to compare its parameters in terms of heat recovery from exhaust gases of both engine types. The test bed study was performed with an Automex AMX-210/100 eddy-current brake dynamometer. To provide a comprehensive overview of the TEG operating conditions, characterization of its parameters such as temperature distribution, heat flux density, and efficiency was done at engine speeds and loads similar to those within the range of operation of real road conditions.