Fuel Injection Control Research Articles

Investigation of HCCI Combustion in a DI Diesel Engine for Various Injection Timings – A CFD Study

Homogeneous charge compression ignition engines have the potential for low emissions and better efficiency. This benefit is due to its low temperature constant volume combustion where the diesel cycle moves closer to Otto cycle for the same compression ratio. Numerical investigations are carried out on a direct injection diesel engine for different HCCI modes and the results are compared with the engine operating on standard mode. Since control of fuel injection is one of the methods of obtaining controlled auto ignition, three injection modes viz., very early injection (during the start of compression) late injection (middle of compression) and injection just before the end of the compression (conventional injection) are investigated. The earliest injection timing of SOI during the start of compression stroke produced lowest levels of pollutants. But it suffers from poor evaporation of injected fuel and lowest pressure rise and hence poor fuel economy. The injection during the middle of compression stroke produced steep rise in pressure coupled with highest NOx emission level. This indicates that this timing more or less is a typical diesel combustion. The conventional injection timing of SOI 20° bTDC produced pressures which are comparable with experimental data and highest soot emission. Hence it is concluded that injection timing control alone is not sufficient to produce a reliable HCCI combustion.

Design and Validation of a Model‐Based Starting Speed Control Scheme for Spark Ignition Engines

AbstractThe main objective of this paper is to present the design and experimental validations of a model‐based control scheme, which aims at smooth and fast response for spark ignition (SI) engines during the starting phase. The control scheme consists of the fuel injection control loop and the speed regulation loop. As far as the fuel control is concerned, an observer‐based estimation scheme is designed which includes the air charge estimation for each cylinder: this estimation is needed to generate the individual injection command by inverting the dynamical model of fuel path. The speed regulation is achieved by an event‐based coordinated feedback control of spark advance (SA) and throttle opening: the convergence analysis is shown by using the Lyapunov–Krasovskiii stability theorem for time‐delay systems. The control scheme proposed formerly by the authors, which was only tested by simulations, is redesigned and recalibrated to meet the robustness specifications which were violated in experiments. The redesigned controller is found to be satisfactory in extensive experimental tests.

Progress in electronic fuel injection control systems for automotive diesel engines

The fuel injection timing and the fuel quantity are two of the major parameters to be precisely controlled to optimise diesel engine. This paper presents a new electronic injection timing control based on direct sensing of the start of combustion. Although the injection timing is usually optimised against engine rpm and load, it is also affected by the atmospheric pressure, coolant temperature, fuel properties and injection rate deterioration. By using a start–of–combustion sensor the influence of these parameters on injection timing can be compensated for and the engine performance can be recovered. A new fuel quantity control has been also developed. Instead of 'spill ring' control, an electronic magnetic valve with fast response has been adopted, which enables more precise control of the amount of fuel injected.

Fuel injection and EGR control strategy on smooth switching of CI/HCCI mode in a diesel engine

Homogeneous charge compression ignition(HCCI) combustion has been demonstrated abilities to lower engine emissions due to its nature of even mixture and low temperature combustion. This combustion mode is only applicable in part load and low speed area so far. This range limitation results in frequently combustion mode switching from CI mode to HCCI mode(CI–HCCI) and HCCI mode to CI mode(HCCI–CI) in real applications. Large variation of IMEP and combustion phase occurs during mode switching process. This is unfavorable to the performance of engine. In the research, diesel HCCI realized by early injection with negative valve overlap(NVO) is investigated.Fuel injection control strategy is studied to improve the smoothness of IMEP during mode switching firstly. Based on the concluded fuel injection control strategy, EGR strategy is studied to improve the smoothness of CA50 during mode switching. In the analysis, fuel compensation coefficient(η) and dimensionless cycle number(σ) are defined. Results of this study show fuel compensation of transition cycle is necessary in CI–HCCI mode switching, but direct mode switching is adequate in HCCI–CI mode switching. The optimum fuel compensation coefficient for CI–HCCI mode switching is at about 1.06, and the COVIMEP is about 5.6. Too late and early switching of EGR are both unfavorable to the smoothness of CA50 during mode switching. The optimum dimensionless cycle number of CI–HCCI and HCCI–CI mode switching are 4.8 and 0.6 respectively.

Performance and emissions of a small scale generator powered by a spark ignition engine with adaptive fuel injection control

Distributed generation of electricity is more and more viewed as a solution for reducing transmission losses and provide better catering for the needs of end users. Small-scale generation is therefore likely to increase its share in the energy sector, as it ensures high degree of flexibility, quick start-up and good performance in combination with intermittent power sources such as solar or wind. One drawback of small scale generators driven by internal combustion engines is, however, low fuel conversion efficiency and high specific emissions compared to medium or high scale power units. A new control strategy for fuel injection and emissions reduction is proposed to mitigate both aspects, while ensuring flexibility in the choice of fuels for a spark ignition engine powered generator. Performance and emissions are compared for carburetor and fuel injection combined with the use of a three way catalytic converter, with the latter solution proving to be more efficient and environmentally friendly. Significant improvements in fuel conversion efficiency and reductions of carbon monoxide and unburned hydrocarbons emissions were obtained by employing the proposed setup and control strategy. Flexibility in the use of different fuel types was evaluated by performing measurements with gasoline, iso-butanol and combined use of alcohol and natural gas. Financial aspects are also covered through a brief analysis of initial capital costs and payback time in order to offer a more detailed view of both fuel systems.

10302 高速ディーゼル機関の燃焼に及ぼすエマルション燃料,EGR,燃料噴射制御の効果

The use of emulsified fuel and EGR(Exhaust gas recirculation) system are effective methods to reduce NOx emission from diesel engines. In this paper, the authors studied on combustion and emission characteristics of the high speed, naturally aspirated, 4 stroke cycle diesel engine using emulsified fuel (EF, Gas oil(GS)80% + Water20%) and EGR(30%EGR ratio). And the effect of fuel injection control on combustion was investigated. The findings are the following: (1) Advancing main fuel injection timing at EGR operation using emulsified fuel, NOx, thermal efficiency and smoke are increased but CO is low. (2) Delaying pre-injection timing at EGR operation using emulsified fuel, NOx, thermal efficiency and smoke are low but CO is high.

Switching Fractional-Order Controllers of Common Rail Pressure in Compressed Natural Gas Engines

This paper concerns fuel injection control of compressed natural gas engines. The main operating conditions are considered and for each one a fractional-order PI controller is designed. Then at each sudden change of rail pressure and injection timing, a change of the determined controller gains is scheduled. Switching between controllers is driven by step changes of the reference pressure. Robust stability of the designed closed-loop system is guaranteed by D-decomposition. Detailed simulation verifies both dynamic performance and robustness given by the controllers and stability of the switching.

The Application of a Wave Action Design Technique with Minimal Cost on a Turbocharged Engine Equipped with Water Cooled Charge Air Cooler Aimed for Energy Management

The vast majority of today's cars remain powered by gasoline or Diesel engines. In the European market, Diesel cars accounts for 55% of all new registrations while gasoline cars for 44%. All the other technologies such as hybrids, fully electric or natural gas and ethanol powered cars combine to make up the remaining 1%. Despite the publicity on these highly anticipated alternative technologies, statistics indicate that their usage remains marginal when compared to more ‘traditional’ powertrains. The internal combustion engine remains the principal way of transportation, at least for the foreseeable years. That being said, undesirable emissions (HC, CO, NOx, PM) are today's major concern because of their negative impact on air quality and global warming. The latest Euro 6 standard limits the CO emissions on a gasoline engine to 68% and the PM (particulate matter) on a Diesel engine to 96% lower than those established in 1992. CO2 emissions which are directly proportional to consumption rates are recently added to the list with a target of 95g/Km for 2020.The main trend for solving these issues is through engine downsizing with high rates of turbocharging accompanied by fuel injection control, after-treatment and system integration. Techniques that increment the energy saving costs. The ICCT (International Council on Clean Transportation) estimates that the cost of taking a 4-cylinder 1.5L Diesel engine from no emission controls to the Euro 6 standard is around US$1400. A major technique to gain control of the engine processes and achieve high performance and low emission levels is through air handling depicted by air intake tuning, turbocharging tuning and charge air cooling.This article briefly describes the air intake line of 4-cylinder 1.5L turbocharged Diesel engine and investigates the role of wave action phenomena on its intake line. The goal here is to achieve lower consumption and better performance by finding the optimal intake geometry. The latter comprises of a compressor wheel, a water cooled charge air cooler prototype (WCAC) and connecting pipes. The wave action effects were first explained and highlighted on a dynamic flow bench at “Mann+Hummel” using a frequency modeling approach which enabled to find the optimal length of piping upstream and downstream of the WCAC. Next this length was experimentally verified by mounting the different length on an engine test bench and registering pressure wave amplitudes. Finally the pressure recordings were fed to engine simulation software GT-PowerTM for a transient low speed simulation mimicking urban driving conditions and specific fuel consumption data were recovered.The result is a proposed air intake line for a turbocharged engine with a water cooled charge air cooler design choice. The proposed changes do not add any engine costs, but invests in significant R&D and retooling.

20915 高速ディーゼル機関におけるエマルジョン燃料燃焼への燃料噴射制御の効果(GS-19【エンジン(2)】)

20915 高速ディーゼル機関におけるエマルジョン燃料燃焼への燃料噴射制御の効果(GS-19【エンジン(2)】)

Waste Cooking Oil Biodiesel Use in Two Off-Road Diesel Engines

This study examines the composition and combustion performance of biodiesel produced from waste cooking oil. Six fuel batches produced from waste oil used in dining-hall fryers were examined to determine their physical and chemical properties, including their elemental and fatty acid methyl ester composition. Oleic and linoleic methyl esters accounted for more than 70% of the fuel composition, while the oxygen content averaged 10.2% by weight. Exhaust emissions were monitored for 5–100% biodiesel blends using two off-road engines: a 2007 Yanmar diesel generator and a 1993 John Deere front mower. Increasing biodiesel content resulted in reduced emissions of partial combustion products from the diesel generator but a rise in NOx, with the greatest changes occurring between 5 and 20% biodiesel content. For the riding mower, biodiesel content up to 50% had little effect on emissions, while NOx and total hydrocarbon emissions decreased with 100% biodiesel. The difference in NOx emissions is attributed to the two different fuel injection control designs used in the two engines. These results indicate that the effects of biodiesel use on nonroad engine exhaust emissions may be substantially lower in older engines optimized for performance over emissions control.

Crank Event Based Fuel Injection and Spark Ignition Timing Control Strategy for SI Engines

For the controlled gasoline engine MR479Q, the crank speed, camshaft position, fuel injection, spark ignition timing signals and their relationships under control mode of group ignition and fuel sequential injection were deeply analyzed, then an electronic control unit (ECU) hardware platform solution based on Freescale 16-bit microcontroller MC9S12XEP100 was given out. Taking advantages of the hardware platform itself, a crank event based fuel injection and spark ignition timing control strategy was proposed to enhance traditional fuel injection and ignition reliability. Fuel pulse width, ignition coil dwell time and spark advance control under different engine operating conditions were then designed in detail respectively. The bench test results show that, the fuel injection and spark ignition timing control signals of ECU are accurate and stable enough under steady operating conditions, even under transient operating conditions when step disturbance exists in throttle opening, the fuel pulse width, dwell time and spark advance are also delivered correctly and reliably. The strategy is feasible enough to accomplish precise control of fuel injection and spark ignition.

舶用ディーゼル機関における廃食油の燃焼および排気の改善

In this research, used vegetable oil without esterification was used in a medium speed marine diesel engine as an alternative fuel. The effect of fuel properties, such as kinematic viscosity, evaporation characteristics and ignition delay, and fuel injection control, such as fuel injection pressure and fuel injection pattern (Pre-injection and After-injection) on the combustion characteristics and the exhaust emissions were investigated by test bench investigation. Results show that: the evaporation characteristics and ignition delay of the fuel have much effect on combustion characteristics and the exhaust emissions, but kinematic viscosity has hardly such effects; the fuel injection control such as Pre-injection with little injection quantity is effective in reducing smoke, CO, unburned HC and PM at low load operation.

Effect of dual fuel homogenous charge diesel combustion for simultaneous reduction of NOx and smoke –an experimental study

The present work focuses on reducing oxides of nitrogen (NOx) and smoke emissions significantly and simultaneously without much compromise in efficiency by involving simple and cost-effective in-cylinder modifications i.e., Homogeneous Charge Diesel Combustion (HCDC) using dual fuels (mixture of gasoline- diesel (G-D) and gasolinesarasol (G-S)). The experiments have been carried out on a single-cylinder, four-stroke, direct injection diesel engine developing 4.4 kW at 1500 rpm. The study had been carried out by fabricating a diesel engine into HCDC mode to install a port fuel injector at intake manifold to create a homogenous charge. The injection timing and duration of the premixed charge was electronically controlled for which electronic fuel injection controller was developed. Gasoline was premixed and port injected before ignition whereas the diesel/sarasol was injected by the conventional injector directly into the cylinder and tested for various premixed percentages, however 10% and 40% was optimized in case of lower and upper limits. It was found that the effect of reduction in NOx and smoke with sarasol in HCDC mode is appreciable than diesel as secondary fuel. With G-S NOx and smoke was reduced by 56.15% and 2.1 BSU respectively whereas with G-D NOx and smoke was reduced by 51.09% and 1.9 BSU respectively. This significant reduction in emissions is due to the thermodynamic physical and chemical properties of sarasol 175/360 apart from HCDC contribution. Keywords: HCDC engine, port injection timing, premixed charge, NOx emissions

Effect of Dual Fuel Homogenous Charge Diesel Combustion for Simultaneous Reduction of NOx and Smoke-an Experimental Study

The present work focuses on reducing oxides of nitrogen (NOx) and smoke emissions significantly and simultaneously without much compromise in efficiency by involving simple and cost-effective in-cylinder modifications i.e., Homogeneous Charge Diesel Combustion (HCDC) using dual fuels (mixture of gasoline- diesel (G-D) and gasolinesarasol (G-S)). The experiments have been carried out on a single-cylinder, four-stroke, direct injection diesel engine developing 4.4 kW at 1500 rpm. The study had been carried out by fabricating a diesel engine into HCDC mode to install a port fuel injector at intake manifold to create a homogenous charge. The injection timing and duration of the premixed charge was electronically controlled for which electronic fuel injection controller was developed. Gasoline was premixed and port injected before ignition whereas the diesel/sarasol was injected by the conventional injector directly into the cylinder and tested for various premixed percentages, however 10% and 40% was optimized in case of lower and upper limits. It was found that the effect of reduction in NOx and smoke with sarasol in HCDC mode is appreciable than diesel as secondary fuel. With G-S NOx and smoke was reduced by 56.15% and 2.1 BSU respectively whereas with G-D NOx and smoke was reduced by 51.09% and 1.9 BSU respectively. This significant reduction in emissions is due to the thermodynamic physical and chemical properties of sarasol 175/360 apart from HCDC contribution.

舶用ディーゼル機関における植物油燃焼への燃料噴射制御の効果

舶用ディーゼル機関における植物油燃焼への燃料噴射制御の効果

高速ディーゼル機関におけるバイオ燃料燃焼への燃料噴射制御の効果

高速ディーゼル機関におけるバイオ燃料燃焼への燃料噴射制御の効果

Modelling and identification of a piezoelectrically driven fuel injection control valve

In this article, the modelling and identification of a piezoelectrically driven control valve of a common-rail diesel fuel injector in an experimental setup is presented. The piezoelectric actuator of the control valve exhibits a strong temperature dependence. Furthermore, an unknown mechanical parameter in the control valve mechanics, the idle stroke value, has to be determined. An optimization-based method is used for temperature adaptation as well as for the identification of the unknown idle stroke value. Both the suppression of the temperature dependence and the exact knowledge of the idle stroke value are essential for the opening width and opening point of time of the control valve and thus for the accuracy of the fuel injection. The identification task becomes even more challenging because only the electrical signals of the actuator, namely voltage and current, are measurable. The method is successfully validated in an experimental setup.

Dynamic Modelling and Control of Semifree-Piston Motion in a Rotary Diesel Generator Concept

A new semifree-piston rotary generator concept is modelled dynamically and reduced to a single equation for piston stroke motion. This new concept comprises a toroidal-segment piston and cylinder, which orbit on separate generator disks, coupled by a pair of torsion springs to form a balanced mass-elastic system capable of spin. Conventional cyclic combustion takes place in the cylinder causing resonant motion of the disks. A two-part control strategy is proposed and tested by simulation to address the multi-objectives of maximum mechanical power transfer, minimum peak generator torque, and accurate piston top dead center (TDC) position control. A Part I strategy initially assumes that the combustion gas pressure is a function of time only. This produces torque control that follows a stroke velocity feedback law, which maximizes power transfer and implicitly minimizes generator torque, at the same time as power generation. When stroke-dependent gas pressure is introduced, however, the Part I strategy creates an unstable self-excited nonlinear system. The Part II strategy is designed to control piston TDC position and stabilize the response. This uses proportional control of gas pressure rise, assumed possible through fuel injection control and in-cylinder pressure sensing. An ideal-air-standard-dual-combustion two-stroke cycle is then adopted for nonstochastic simulation purposes, excluding the effect of delays and coupled system dynamics. A study is undertaken of a nominal 1.42 l, 200 mm orbit-radius, constant-pressure-scavenged diesel design with three different spring stiffness values. By focusing near the minimum compression ratio for diesel, to give a lower bound on the possible ideal output power, control gains are found that produce stable motion with piston TDC position errors of less than 1%. The power range is from 16 kW to 336 kW, depending mainly on spring stiffness. Since the concept can also store significant kinetic energy, it is potentially attractive as a range-extender for electric vehicles.

Detecting Solenoid Valve Deterioration in In-Use Electronic Diesel Fuel Injection Control Systems

The diesel engine is the main power source for most agricultural vehicles. The control of diesel engine emissions is an important global issue. Fuel injection control systems directly affect fuel efficiency and emissions of diesel engines. Deterioration faults, such as rack deformation, solenoid valve failure, and rack-travel sensor malfunction, are possibly in the fuel injection module of electronic diesel control (EDC) systems. Among these faults, solenoid valve failure is most likely to occur for in-use diesel engines. According to the previous studies, this failure is a result of the wear of the plunger and sleeve, based on a long period of usage, lubricant degradation, or engine overheating. Due to the difficulty in identifying solenoid valve deterioration, this study focuses on developing a sensor identification algorithm that can clearly classify the usability of the solenoid valve, without disassembling the fuel pump of an EDC system for in-use agricultural vehicles. A diagnostic algorithm is proposed, including a feedback controller, a parameter identifier, a linear variable differential transformer (LVDT) sensor, and a neural network classifier. Experimental results show that the proposed algorithm can accurately identify the usability of solenoid valves.

Experimental Investigation of a Control Method for SI-HCCI-SI Transition in a Multi-Cylinder Gasoline Engine

Air/Fuel Ratio (AFR) and Residual Gas Fraction (RGF) are difficult to control during the SI-HCCISI transition, and this may result in incomplete combustion and/or knocking. As a result, engine load may fluctuate, as indicated by the Net Indicated Mean Effective Pressure (NIMEP). The objectives of this work are to further understand this process and develop control methods to minimize the engine load fluctuation. This paper presents instantaneous AFR and RGF measurements, both taken by novel experimental techniques. The data provides an insight into the cyclic AFR and RGF fluctuations during the switch. The results suggest that the relatively slow change in the intake Manifold Air Pressure (MAP) and actuation time of the Variable Valve Timing (VVT) are the main causes of undesired AFR and RGF fluctuation, and hence unacceptable NIMEP fluctuation. We also found large cylinder-to-cylinder AFR variation in the transition. Therefore, besides throttle opening control and VVT shifting, cyclic and individual cylinder fuel injection control is necessary to achieve a smooth transition. The control method was developed and implemented in the test engine, and resulted in much reduced NIMEP fluctuations during the switch. The instantaneous AFR and RGF measurements could be adopted to develop more sophisticated control methods for SI-HCCI-SI transition.