Injection Pulse Width Research Articles

Performance study of an innovative dual injection mode injector for marine low-speed dual-fuel engine

Marine low-speed dual-fuel engines typically have two sets of fuel injection system, main-injection and micro-injection. In order to make the fuel injection system of marine low-speed dual-fuel engine compact in structure and flexible in injection control, an innovative dual injection mode injector (DIMI) which can achieve both the functions of main-injection and micro-injection was proposed. The switching between main-injection and micro-injection mode of the injector is achieved through the collaborative control of dual solenoid valves. Based on the constructed AMESim model, the injection quantity characteristic and hydraulic efficiency of the DIMI were investigated under different working conditions and injection modes. The results show that, when the DIMI in main-injection mode achieves injection quantity characteristic similar to those of a traditional electronically controlled injector (TECI), the electromagnetic forces of solenoid valves of the DIMI are less required to 80% of that of the TECI, and the fuel return quantity and hydraulic efficiency of the DIMI are comparable to those of the TECI under the same working conditions. By changing the minimum limit height of the needle of the DIMI under micro-injection mode, different ranges of micro-injection quantity could be designed according to the requirements of the engine, and the control accuracy of injection pulse width (IPW) on micro-injection quantity is higher than on main-injection quantity. Both the hydraulic efficiency of the DIMI under main-injection and micro-injection mode increase with the rail pressure and IPW in the small IPW range, then gradually tend to be saturated with the increase of IPW. As the minimum limit height of the needle increases, the injection quantity and hydraulic efficiency of the DIMI under micro-injection mode increases overall, however, the saturation values of the hydraulic efficiency in micro-injection mode under different needle minimum limit heights are still smaller than those in main-injection mode.

New control scheme for a dynamic voltage restorer based on selective harmonic injection technique with repetitive controller

Repetitive controller and selective harmonic injection technique (SHI) in medium and low voltage distribution networks improve dynamic voltage restorer (DVR) DC bus voltages as well as nullify power quality (PQ) problems. DVRs use sinusoidal pulse width modulation (SPWM) firing control, but DC bus use seems to be limited, affecting density, cost, and power packaging. By adding 1/6th of the 3rd harmonic waveform to the basic waveform, SPWM yields the developed model. According to the findings, 15% of DC bus usage improves and produces high voltage AC. Nevertheless, just control systems perturb PQ. The proposed controller uses feed forward and feedback to enhance transient response and justify stable zero error. 3rd third harmonic injection pulse width modulation (THIPWM) improves total harmonic distortion (THD) in the proposed scheme. Power system computer aided design (PSCAD) simulation produced high accuracy for THIPWM and repetitive controllers.

Investigations on the effects of injection parameters and EGR in a glow plug assisted methanol fueled Hot Surface Ignition (HSI) Engine

Methanol can be produced from renewable sources and is also clean burning. Hence it is an ideal alternative fuel for transportation applications. However, its low cetane number prevents its direct application in compression ignition (CI) engines. One of the promising but not widely explored methods is to use a hot surface for its ignition in CI engines at normal compression ratios. In this work a turbocharged automotive common rail diesel engine was modified to operate in the hot surface ignition (HSI) mode with methanol as the sole fuel with 3% by mass of lubricity and corrosion inhibiting additive. Initially, a single pulse injection (SPI) strategy was employed at different injection timings at a BMEP of 8 bar. Subsequently a double pulse injection (DPI) strategy was employed and the effects of gap between the injection pulses, injection timing and injection pulse width share among the two pulses were studied. The HSI mode of neat methanol performed with comparable brake thermal efficiency (BTE), reduced combustion rates and hence low NOx emission levels with respect to diesel operation when the DPI mode was employed with almost equal pulse width share. Engine performance was better at rail pressures of around 800 bar. Hot EGR of up to 8% was beneficial as it reduced the engine-out NOx without affecting the BTE. The engine was operated at different BMEPs in the range of 4–10 bar and compared with the baseline diesel operation. The BTE was similar to the baseline diesel engine at all loads. Engine-out NOx was lower than diesel operation by 23.6%–61.5% while near zero smoke levels and similar CO and THC emissions (after the DOC) were observed. Though slipped methanol and formaldehyde were the significant unregulated emissions, they were reduced to very low levels after the DOC.

Saliency-Based Sensorless Control Using Current Derivative in IPMSM Drives With Single DC-Link Current Sensor

In vector-controlled drive systems, a position sensorless drive with a single current sensor (SD-SCS) is an attractive system due to the minimum number of sen- sors. However, when the saliency-based SD-SCS is applied, the position estimation accuracy is deteriorated due to the errors in the injected pulse width modulated voltage and the reconstructed current. This paper proposes a current derivative-based sensorless control using a tri-active vector pulse width modulation (TAVPWM) to enhance the saliency-based SD-SCS. First, the TAVPWM scheme, which eliminates the current reconstruction dead zone in the low-modulation region, is adopted to improve the low- speed drive. Next, the derivatives of the phase currents are utilized and analyzed to minimize the position estimation error in the overall operating regions. Lastly, the transition strategy with respect to the speed is proposed for the full-speed sensorless drive. Owing to the proposed method, the switching frequency increases up to 16 kHz and the audible noise is virtually eliminated in the saliency-based SD-SCS. Furthermore, the enhanced dynamic performance is verified by various experimental results.

Comprehensive comparison of single-stage and novel two-stage hydrogen direct injection strategies on the combustion and thermodynamic performance of X-type rotary engine using gasoline-hydrogen fuel

In this paper, the CFD simulation model of a high-efficiency X-type rotary engine using premixed gasoline and hydrogen direct injection is established. The effect of hydrogen injection timing on combustion, pollutant emissions, and thermodynamic performances is investigated under hydrogen single-stage direct injection (HSDI). Furthermore, a novel hydrogen two-stage direct injection (HTDI) strategy using different first injection mass fractions (FIMF) and the same total injection pulse width of 3.5 °CA is proposed for improving combustion performance in the later phase under HSDI. The results show that the hydrogen injection timing of 290 °CA presents a 6.09% higher indicated thermal efficiency than that of 270 °CA under HSDI. The delay of the hydrogen injection timing leads to a decrease in soot emission. The optimal HTDI strategy is obtained at the FIMF of 60%, which shows a 6.35% higher combustion efficiency and a 0.89% higher indicated thermal efficiency than the optimal HSDI.

Effect research of fuel injection and pressurization pulse width on injection characteristics of ultra high pressure common rail system

Ultra high pressure common rail system can realize adjustable injection rate by controlling the relationship between fuel injection and pressurization timing, and then affect the fuel injection characteristics of diesel engine. In order to ascertain the effect law and its formation mechanism of the fuel injection and pressurization pulse width on the fuel injection characteristics of ultra high pressure common rail system, on the basis of introducing the mathematical model of the system, the simulation model of ultra high pressure common rail system was established, and the accuracy of the model was verified by performance experiment, the effect of fuel injection and pressurization pulse width on the fuel injection characteristics of the system under different common rail pressure were analyzed. The results show that with the increase of fuel injection pulse width, the shape of fuel injection rate curve is similar to saddle shape and the proportion of large fuel injection rate range in the whole injection process increases gradually. At the same time, the fuel injection opening delay remains unchanged, but the fuel injection closing delay increases significantly when the fuel injection pulse width is small (0.6~1 ms), while it remains basically unchanged when the fuel injection pulse width is large (1~1.4 ms). With the increase of pressurization pulse width, the shape of fuel injection rate curve is similar to saddle shape and remains unchanged under the condition of small injection pulse width, while the fuel injection rate curve shape may appear similar to the "inverted saddle-shaped" under the condition of large injection pulse width, this is due to the rapid decrease of pressurization pressure caused by the closing of the solenoid valve control signal in the pressure-amplifier device before the end of fuel injection.

Modelling and design of grid voltage oriented vector control scheme for DC railway recuperating system

The braking energy harvested by a railway vehicle can be restored to the utility grid with a power recuperating system. A grid connected voltage source inverter (VSI) is commonly used as a grid-feeding converter in the recuperating system. This paper proposes to integrate grid voltage oriented vector control (GVOVC) and third harmonic voltage injection pulse width modulation (THVI-PWM) technique for the VSI to ensure grid voltage and frequency synchronization. A simulation study is carried out to evaluate the feasibility of the proposed control and modulation schemes using MATLAB/Simulink. The results show that the proposed controller may reach steady-state operating mode within 7 ms by producing good quality AC voltages and currents waveforms. With the independent control of voltage quantities in dq reference frame, the regulation of active and reactive power could be realized.

Experimental study of the effect of structural differences in the composition of kerosene-like blended fuels on low-temperature autoignition in a constant volume combustion chamber

The cold start performance of compression ignition engines at high altitudes is expected to be improved by means of fuel design involving kerosene-like blended fuels. In this study, the autoignition characteristics of ten blended fuels with different chemical compositions and physical properties were investigated in a constant volume combustion chamber. Steady-state conditions in a low thermal atmosphere are considered at varying temperatures (723, 773, 823 K), pressures (2.2, 2.8, 4 MPa), injection pressures (40, 60, 80 MPa), and injection pulse widths (1.5, 2.5, 5 ms). The relative importance and relevance of the physical and chemical properties of the fuel to the ignition delay were evaluated based on characteristic parameters e.g. total ignition delay, physical delay, chemical delay, combustion delay, pressure and heat release rate evolution. It was found that adding ether-oxygenated component content to kerosene-like significantly shortened the ignition delay, followed by chain alkanes, naphthenes, and aromatics, in that order. The effect of oxidation chemistry changes on the ignition performance of fuels in low-temperature-pressure environments is more significant than physical properties. As the thermal atmosphere or fuel activity intensifies, the percentage of physical delay in the total ignition delay gradually exceeds that of chemical delay as the main part, and the variability in the ignition qualities of fuels with different physicochemical properties diminishes. There is a good linear correlation between ignition delay and cetane number (ranging from 44 to 60), density, viscosity, and recovery temperature, whilst the role of cetane number and density is more prominent.

Experimental Study on the Impact of Hydrogen Injection Strategy on Combustion Performance in Internal Combustion Engines.

Hydrogen is an ideal alternative fuel for internal combustion engines due to its fast combustion rate and near-zero carbon emissions. To further investigate the impact of the injection strategy on combustion performance under various excess air coefficients and loads, experimental methods were employed to systematically study injection timing, injection pressure, and dual injection. The results demonstrate that appropriately delaying hydrogen injection timing can improve the thermal efficiency by up to 2.6% and reduce NOx emissions of equivalent combustion by nearly 88%. While increasing the hydrogen pressure to 8 MPa does not directly enhance the thermal efficiency and emissions, it can reduce the injection pulse width by approximately 75%, allowing for more flexibility in delaying the injection timing. Delaying the secondary end of injection (SEOI) leads to a reduction of over 47% in NOx emissions for λ (excess air coefficient) values of 1.5 and 1.0. The combustion duration and ignition delay initially increase and then decrease with the delay in SEOI, depending on the movement state of the fuel jet. With the increase in secondary injection proportion (SIP), brake thermal efficiency increases by no more than 1%, but NOx is reduced by more than 43% for λ values of 1.5 and 1.0. In the case of ultralean conditions (λ = 2.3), increasing the SIP from 0 to 30% results in a nearly 14% increase in the peak heat release rate (HRR) and a 19% reduction in combustion duration.

Experimental observation of the TJI-initiated HPDI gas combustion: Vertically crossed flame jet and methane jet

In the field of natural gas marine engines, the high-pressure direct injection (HPDI) technology is widely used to achieve emission reduction while maintaining equivalent thermal efficiency and power output compared to diesel engines. In these engines, the in-cylinder combustion is primarily initiated by the diesel spray flame near the top dead center (TDC). In the present work, pre-chamber turbulent jet ignition (TJI) is employed to substitute diesel injection to initiate the combustion of HPDI methane jets. The optical experiments of ignition and flame development in the TJI-HPDI system with various injector configurations and injection/ignition control parameters are conducted in a constant-volume combustion chamber (CVCC). It is revealed that with the increase of injection-ignition delay(ti), three ignition modes are observed sequentially: methane jet suppresses ignition, methane jet first suppresses ignition then promotes flame propagation, and direct ignition and promoted flame propagation. The effect of various injection-ignition delays and injection pulse width were explored. The injection-ignition delay significantly influences the combustion characteristics such as heat release rate, while the injection pulse width influences the duration of the lifted jet flame. The flame lift-off length first decreases and then increases due to variations in thermodynamic conditions and oxygen concentration. With a larger-nozzle injector, the critical injection-ignition delay to initiate the main chamber combustion is significantly reduced. Moreover, the use of different nozzle diameters leads to varying levels of turbulent intensity in the methane jet, which in turn affects the combustion behavior.

Control technique for power quality improvement of isolated wind power generation system

Power quality (PQ) problems for renewable energy system (RES) is major challenge for using these systems. Amplitude, frequency, and waveform is important PQ parameters especially for standalone or isolated systems. In this paper we propose RES with wind turbine (WT) and permanent magnet synchronous generator (PMSG) to feed different loads (liner, non-liner) through AC-DC-AC converter. The PMSG operate with fuzzy logic inertia controller, to convert turbine torque form PU to Nm. The inverter stage in the converter operate according to proportional integral derivative (PID) controller with 3rd harmonic injection pulse width modulation (PWM) to regulate the AC voltage in load side. For the same case study and operating condition, we compared the result for system parameters when using ordinary PWM and using PID with 3rd harmonic injection. Voltages total harmonics distortion (THD) was less than 2% with liner loads, and 3.5% with non-liner load and the same was for current load, the voltage amplitude was between (1-1.03) PU under different wind speed by using the proposed controller.

Control technique for power quality improvement of isolated wind power generation system

Power quality (PQ) problems for renewable energy system (RES) is major challenge for using these systems. Amplitude, frequency, and waveform is important PQ parameters especially for standalone or isolated systems. In this paper we propose RES with wind turbine (WT) and permanent magnet synchronous generator (PMSG) to feed different loads (liner, non-liner) through AC-DC-AC converter. The PMSG operate with fuzzy logic inertia controller, to convert turbine torque form PU to Nm. The inverter stage in the converter operate according to proportional integral derivative (PID) controller with 3rd harmonic injection pulse width modulation (PWM) to regulate the AC voltage in load side. For the same case study and operating condition, we compared the result for system parameters when using ordinary PWM and using PID with 3rd harmonic injection. Voltages total harmonics distortion (THD) was less than 2% with liner loads, and 3.5% with non-liner load and the same was for current load, the voltage amplitude was between (1-1.03) PU under different wind speed by using the proposed controller.

Effects of injection parameters and intake air temperature on acetone-butanol-ethanol (ABE) blend HCCI-DI engine

Homogeneous charge compression ignition-direct injection (HCCI-DI) approach was reported to effectively eliminating the problems associated with HCCI engine while promoting HCCI combustion. Acetone-butanol-ethanol (ABE) fuel has been studied previously to replace butanol due to its lower production cost and time. This paper aims to extend the potentials of ABE fuel in HCCI-DI engine with other parameters such as intake air temperature, port injection timing and port injection pulse width also investigated. Diesel, ABE5 (5 % ABE and 95 % diesel by vol.) and ABE10 (10 % ABE and 90 % diesel by vol.) were used with different engine loads (1 Nm, 2 Nm, 3 Nm, 4 Nm and 5 Nm). Further experiments were carried out using ABE10 with different intake temperatures (60 °C, 80 °C, 100 °C, 120 °C and 140 °C), port injection timings (230 °CA BTDC, 250 °CABTDC, 270 °CA BTDC, 290 °CA BTDC and 310 °CA BTDC) and port injection pulse widths (3 ms, 4 ms and 5 ms). It was found that increasing ABE ratio reduces the brake specific fuel consumption (BSFC) and increases the brake thermal efficiency (BTE) of the HCCI-DI engine. Up to 13.55 % and 23.8 % BTE improvement when ABE5 and ABE10 were used compared to diesel respectively. Furthermore, increasing the port injection pulse width increased the BSFC and reduced the BTE significantly by 10 % on average. Compared to diesel, ABE5 reduced the NOx emission by 20.2 % on average while NOx reduced by 24.8 % when ABE10 was used. Increasing the intake air temperature more than 100 °C significantly increased NOx by 54.1 % while HC decreased up to 23.2 % with 140 °C intake air temperature. Advanced port injection timing reduced the NOx emission by up to 24.7 %. NOx emission was reduced by 12.5 % as the pulse width increased from 3 ms to 5 ms due to higher premixed ratio combustion leading to lower combustion temperature. The combustion phasing of the engine was sensitive to the variation of intake temperature resulting in advanced start of combustion as the intake temperature increased. Besides, the combustion phasing reported to be steadily advanced as the pulse width increased which is showing its sensitivity towards the amount of port fuel injected. In conclusion, it was shown that ABE fuel is not only renewable but also capable of reducing emission without compromising the engine performance of HCCI-DI engine.

Performance and emission of a converted bio-fuel motorcycle engine in cold condition: A case study

ABSTRACT This paper presents a study on the performance and emission characteristics of a currently used motorcycle fueled with either gasoline or ethanol at cold starting and idling condition. The engine’s fuel system was modified by extending the injection pulse width to allow it to operate with pure ethanol or gasoline. The ethanol-fueled engine required three to four cranking times to achieve success starting at an ambient temperature between 15°C and 20°C. In cold idling conditions, the ethanol-fueled engine operated at a high coefficient of variation of speed (COVspeed) of 1.20% to 2.49% at an ambient temperature of 17°C, while a COV speed of 0.92% of the gasoline-fueled engine was observed. However, with the aid of the electric-based heating system (EHS), the ethanol-fueled engine performance was enhanced significantly as the COV speed was 0.95% at 15°C, 0.85% at 17°C, and 0.73% at 20°C in idling condition and achieved successful starting at the first time of cranking after 30 s of pre-heating. During the warm-up stage, a significant fluctuation of emission was observed with different test cases. However, with the heating system, the engine enhanced completed combustion quicker as incomplete combustion products of HC and CO were reduced rapidly in idling compared to gasoline and ethanol-fueled engine. NOx emissions increased with the aid of the heating system but were still lower compared to the gasoline-fueled engine during idling condition.

A Study of the Pulse Cleaning Process for Metal Fiber Filter Bags Based on a Discrete Phase Particle Deposition Model

Emissions of airborne particulate matter are a major cause of air pollution. A numerical approach was used to establish a single-filter-bag cleaning model based on the discrete phase particle deposition distribution law to study the effect of pulse backflushing operation parameters on the cleaning performance of the specific structure of the dust collector. It was found that increasing the pulse blowing pressure (0.2 MPa to 0.6 MPa) and extending the pulse width (0.02 s to 0.1 s) resulted in an increase in the side wall pressure of the filter bag and, thus, improved its cleaning effect. The influence of the injection pressure on the side wall pressure peak of the filter bag was more obvious than that of the pulse width. However, it cannot be concluded that the greater the injection pressure and pulse width, the better the cleaning effect. Therefore, in the actual production application, the operating cost of the equipment needs to be taken into account, as well as the amount of dust on the surface of the filter bag.

Open problem: WTHD reduction understanding for a synchronous saw-tooth injection PWM control

Third harmonic injection pulse width modulation (PWM) is a well known inverter control method improving the harmonics quality. Nevertheless this field of research is not closed and recent researches showed that a wide spread of third harmonics injection inside the zero sequence component of a synchronous carrier based PWM improves the voltage harmonics at the output of a three phases two-level inverter.Furthermore, for some specific parameters, this new zero sequence component modulation (ZSCM) seems to converge to a saw-tooth shape. The presented research is the direct continuity of the previous paper on ZSCM [Bourgeade et al. (2021a)].The following work is attached to show a description and advantages of the saw-tooth injection PWM (STIPWM). As STIPWM is very singular in the literature, a mathematical understanding is judged necessary in order to find new PWM properties to stimulate power electronics control research.Then, this paper present to the community the STIPWM problem and an incomplete demonstration which leads to establish a conjecture, following a stimulating explanation will be found.

Pulse-Width Modulation Technique With Harmonic Injection in the Modulating Wave and Discontinuous Frequency Modulation for the Carrier Wave for Multilevel Inverters: An Application to the Reduction of Acoustic Noise in Induction Motors

An implementation of a harmonic injection pulse width modulation frequency-modulated triangular carrier (HIPWM-FMTC) control strategy applied to a multilevel power inverter feeding an asynchronous motor is presented. The aim was to justify the reduction in acoustic noise emitted by the machine compared with other strategies in the technical literature. In addition, we checked how the THD at the inverter output was reduced compared to the other control techniques used as a reference. The proposed strategy is based on frequency modulation of the triangular carrier. The main advantage of the proposed method is that only one control parameter is required for modifying the electrical spectrum. Therefore, the mechanical natural frequencies and spatial harmonics of the machine can be avoided, and acoustic noise can be reduced. The effectiveness of the technique was demonstrated after laboratory validation by comparing the acoustic results for a 1 kW motor. The results obtained from the laboratory tests are presented and compared with those of other acoustic measurements using different PWM strategies.

Comparison of Control Techniques & Modeling of 15-level cross H Bridge Multilevel Inverter

This paper presents the simulation of a 15-level cross-H bridge multilevel inverter using control techniques like sinusoidal pulse width modulation and third harmonic injection pulse width modulation. This paper aims to enhance output voltage level using fewer switches and to decrease total harmonic distortion by improving overall efficiency. Compared to other inverter topologies cross H bridge topology uses a lesser number of switches and dc voltages. Analysis and simulation of 15-level cross H bridge MLI are performed and presented.

A Sub-100 fs-Jitter 8.16-GHz Ring-Oscillator-Based Power-Gating Injection-Locked Clock Multiplier With the Multiplication Factor of 68

This work presents an ultralow-jitter ring-oscillator (RO)-based injection-locked clock multiplier (ILCM). Using the power-gating (PG) injection method that can completely remove the accumulated phase error of the RO, the proposed ILCM can achieve a very wide injection bandwidth, and, thus, an ultralow-jitter, even when the multiplication factor, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${N}$ </tex-math></inline-formula> , is increased above 60. To overcome the natural limitation of the PG injection, two digitally controlled oscillators (DCOs) were used to operate in a complementary manner. Since the background multi-functional calibrator (MFC) continuously synchronizes the outputs of the two DCOs, the PG-ILCM can generate a seamless output signal by combining these two signals. The proposed injection pulsewidth controller (IPWC) decreased the required delay of the digital-to-time converter (DTC), further reducing the jitter of the output signal. A phase-rotational divide-by-4 divider (PR-DIV4) also was proposed to reduce the operating frequency and the power consumption of the MFC while maintaining the fine resolution of the output frequency. The PG-ILCM, fabricated in a 65-nm CMOS process, used the power of 14.3 mW and an area of 0.102 mm2. The rms jitter measured at 8.16 GHz ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N = 68$ </tex-math></inline-formula> ) was 97 fs.

Influence of modulator injection width on comprehensive two-dimensional gas chromatography peak dimensions.

This study examines how the height and width of peaks exiting the secondary column of a comprehensive two-dimensional gas chromatography (GC × GC) separation are affected by the width of the pulse introduced to the secondary column. A flow-modulated GC × GC apparatus was assembled that allowed input pulse widths to be controlled precisely over a range of 10 to 70ms. GC × GC chromatograms were obtained using secondary columns containing a polyethylene glycol stationary phase with internal diameters of 0.25 and 0.32mm. The area, height, and width of peaks emerging from the secondary column were found to be accurately modeled by the convolution of a rectangular function with a Gaussian distribution. The rectangular function represents the input pulse, and the Gaussian distribution represents the broadening that occurs in the secondary column. The minimum peak width that could be produced by the secondary column was determined for a wide range of compounds. Injection pulse widths that matched a compound's minimum peak width produced peaks that were 25% wider than the minimum width and had heights that were 76% of the maximum possible peak height. Increasing the injection width significantly above the minimum width yielded substantially broader peaks with only a modest increase (< 25%) in peak height.