Review on Plasma-Assisted Ignition Systems for Internal Combustion Engine Application

Purpose. It is to determine the functions of the temperature of the coolant on the time of heating of the cooling system of the small internal combustion engine in two variants – with a coolant pump with a constant mechanical drive, and with an electrical driven pump. Research methods. Methods of analysis of scientific literature and theoretical generalization, methods of statistical analysis, synthesis, observation, method of project development have been used. The graphs were treated with the least squares with the finding a polynomial function of temperature from time. The accuracy of the results is evaluated by the correlation index R2. Results. Modern internal combustion engines cooling systems, including the direct driven coolant pump, are considered. The dependence of the engine heating temperature on the time of its operation with a mechanical drive of the pump and a drive from the electric motor was found. Analysis of cooling systems of the modern internal combustion engine with a direct drive of the coolant pump and with a controlled electric drive was carried out. Scientific novelty. Analysis of the cooling system of the car gasoline engine showed their dependence on the time of heating of the engine during cold start. It is established that engine with electrical driven pump has been found to reduce the heating time, compared to the engine with a mechanical drive of the pump, for one and a half minutes. This provides fuel savings 3 %, at the temperature of the pump motor switching on 130 °C. It is established that the use of the electric driven pump reduces its operation time by almost 50 %. Practical value. The functions of the coolant temperature dependence on the time of heating of the gasoline engine with the direct driven coolant pump and with the electrical driven pump are determined. This makes it possible to modernize the cooling system of small internal combustion engines.

The article discusses the need to solve the problem of increasing the temperature limits of the operation of the cooling system of the internal combustion engine (ICE) of the helicopter. This issue arose from the fact that during the operation of the helicopter on the territory of African countries with a hot climate, the engine overheated. The use of helicopters in these conditions was due to the demand in the aviation market. To solve the problem, new elements of the cooling system were selected, i.e. radiator and two types of fans. The research was aimed at increasing the heat transfer from the radiators of the cooling system by increasing the size of the radiator and increasing the air flow rate through the radiator. 3D modeling, design of a new cooling system (CO), and then design of CO in two versions with TEMIC and SPAL fans were done. First, ground and flight tests for two prototypes in a temperate climate were done, as a result of which a prototype with the best performance parameters was determined. During the tests the equipment and measuring instruments were used: voltmeter, ammeter, voltmeter; shunt; motor tester with the ability to transfer data via Bluetooth; smartphone with OpenDiag software installed, which is included and connected to the motor tester via Bluetooth, helicopter objective control system, flight data registration system, equipment and devices normally installed on the helicopter. For flight tests in hot climates, a new cooling system with a SPAL fan was used, these tests lasted three days. This article describes the final stage of a series of tests for the effectiveness of the cooling system of a helicopter and an analysis of the results obtained with confirmation of the final achievement of the set goals, i.e. raising the upper temperature limit of the outside air for the safe operation of the helicopter.

Almost 70% of heat power produced by pistons in internal combustion engines is lost due to exhaust and cooling. In the course of the heating process, 25% of useful energy transfers to the exit shaft. There have been a lot of studies on recycling waste heat of internal combustion engines, especially on cooling and exhaust systems. A thermoelectric generator is an important way to recycle waste energy in exhaust systems of internal combustion engines. In this study, an air-cooled thermoelectric generator was designed to recycle waste heat energy in exhaust systems of internal combustion engines and its performance was tested. Waste heat recycling tests were conducted by measuring voltage, current, and power values under different thermal conditions depending on the change in load resistance. The results obtained were compared with the results of analyses and experiments. Maximum voltage value at RI = 45Ω load resistance was obtained as 11.03 V (experiment) and 11.22 V (analysis), and maximum current value at RI = 5Ω load resistance as 0.42 A (experiment) at Th = 250°C, Δ T = 40°C.

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.

Internal combustion engines inherently demand startup assistance to perform its autonomous functioning. Nevertheless, the common solution over more than one century has been the electric starter motor, for both Otto and diesel cycles. The dynamic coupling system defined herein as the mechanical connection between the internal combustion engine and the starter motor has not evolved considerably since the intermittent pinion–ring gear interface has been adopted. This paper reviews the conceptual design behind the starting systems developed so far, focusing on their functional analysis, and proposes an innovative concept. Preliminary study on dynamic simulation using lumped parameters model, implemented in AMESim, is also discussed as potential aid for the proposed design. Based on decision matrix method, it is possible to evaluate the proposed design against state-of-the-art and promising alternatives to find a real cost-effective alternative to the existing concepts to couple the electric motor and the internal combustion engine. The patented dynamic coupling system proposed herein demonstrates potential to evolve as a cost-effective solution to implement start–stop systems worldwide, contributing to reduction of pollution caused by automotive vehicle emissions.

Modern engines depend directly on the effectiveness of lubricating systems in terms of reliability and efficiency. An engine lubrication system does have the functions of reducing the friction between the bearing surfaces of moving parts and of heated emission and cleaning up the engine parts with the elimination of carbon and other foreign matter in order to be effectively operational. The lubrication system for these functions is the forced lubrication system in nearly all modern internal combustion engines. Although lubrication systems for internal combustion engines are subject to many variations, their components and operational methods are virtually identical. The lubrication industry strives to create environmentally friendly lubrication options for internal combustion engines, given the continuous environmental legislation. To tackle this challenge, lubricants that comply with environmental standards while maintaining high lubrication performance are required. This paper reviewed the performance of various types of engine oils under different conditions, showing that a great many available references demonstrate that lubricant technologies have a strong potential to develop modern engines. The operational parameters, such as compression ratio, injection pressure and time effects, were reviewed to perform a better comparison to the vegetable oils. In conclusion, current researches on engine oil efficiency still have some problems and challenges to take into account in terms of mechanisms to improve heat transfer, the practical use of engine oil for vehicles and further progress.

We consider the possibilities of combustion and detonation initiation for propane mixtured with air by microwave discharges created by a quasi-optical electromagnetic beam. Comparison of initiation is performed by different types of discharge: spark, streamer, and attached one. The formation theory of streamer discharges is given, the velocity of their propagation and the volume of energy supplies are analyzed. Experiments have been carried out together with calculation of the propane-air mixture ignition by various types of discharges. It is shown that when burning is initiated by a streamer discharge, a multiple increase in the propagation velocity of the flame front and the completeness of the fuel combustion is obtained as compared to a spark discharge with an equal energy contribution. In the prechamber initiation of combustion by igniting a streamer discharge on the inner walls of the quartz tube, a significant acceleration of combustion was obtained up to the rates characteristic for the transition of deflagration to detonation. The results can be applied in the development of multi-volumetric volumetric ignition systems in internal combustion engines, gas turbine engines, low-emission combustion chambers, for combustion in supersonic flow, and in combustion chambers for detonation engines.

This paper presents the modeling of a novel pressure control mechanism for a common rail (CR) fuel injection system of internal combustion engines (ICE). The pressure fluctuations in the common rail caused by multiple injections negatively affect the accuracy of both injected fuel quantities and flow rates. The objective of this work is to design a new control mechanism to suppress the pressure pulsation in the rail. First we develop a one-dimensional distributed model for the common rail by using basic fluid flow equations, which can capture the distributed dynamics of the pressure disturbances in the rail and this result is validated with a physics based simulation model in AMESIM®. The periodic nature of injection event due to stroke by stroke motion of the ICE generates disturbance in the rail which in the rotational angle domain presents a primarily periodic signal. However, the period changes in the time domain due to the variation in engine speed. We then propose the concept of an active fluid storage device like a piezoelectric actuator (PZT) to minimize this pressure fluctuations. The location of the actuator on the common rail has also been evaluated to maximize its effect. Finally a time-varying repetitive controller is designed to compensate for the periodic pressure disturbances in the rotational angle domain.

Li-ion battery safety in electric buses is critically affected by rollover accidents, which can cause severe deformation of the bus superstructure. Such deformation may cause internal short circuits and trigger thermal runaway. In this context, this work investigates how different propulsion modes affect the safety of a bus superstructure under a rollover scenario in accordance with UNECE Regulation No. R66.02. This work studied an internal combustion engine (ICE) and electric propulsion systems, using the ICE chassis as the base for the electric bus. The study defines worst-case scenarios for both vehicle types, determines the center of gravity (CoG), and performs numerical simulations using the finite element method. The ICE and electric buses have CoGs of 5397.5 × 13.0 × 1617.4 and 4474.1 × 20.9 × 1682.2 mm, respectively. The ICE vehicle had a total weight of 15,836 kg and a reference energy of 5.0580 × 10 5 kg·m 2 /s 2 , while the electric vehicle had a total weight of 18,118 kg and a reference energy of 5.1145 × 10 5 kg·m 2 /s. For the rollover simulations, the unstable positions before tilting were set to 33.7° and 35° for the ICE and electric vehicles, respectively, and the models were rotated to ground contact at angular velocities of 1.75 and 1.79 rad/s. The results indicate that the ICE vehicle satisfied the regulatory requirements. However, the electric vehicle exhibited intrusion of up to 32 mm into the residual space when the same ICE structural concept and passenger configuration were applied. Therefore, some modifications were proposed, including capacity adjustments and alternative battery systems, to preserve the residual space during the rollover scenario. These results highlight the need to account for electric bus specific characteristics rather than directly converting ICE chassis designs.

The energy transition from hydrocarbon-based energy sources to renewable and carbon-free energy sources such as wind, solar and hydrogen is facing increasing demands. The decarbonization of global transportation could come true via applying carbon-free fuel such as ammonia, especially for internal combustion engines (ICEs). Although ammonia has advantages of high hydrogen content, high octane number and safety in storage, it is uninflammable with low laminar burning velocity, thus limiting its direct usage in ICEs. The purpose of this review paper is to provide previous studies and current research on the current technical advances emerging in assisted combustion of ammonia. The limitation of ammonia utilization in ICEs, such as large minimum ignition energy, lower flame speed and more NOx emission with unburned NH3, could be solved by oxygen-enriched combustion, ammonia–hydrogen mixed combustion and plasma-assisted combustion (PAC). In dual-fuel or oxygen-enriched NH3 combustion, accelerated flame propagation speeds are driven by abundant radicals such as H and OH; however, NOx emission should be paid special attention. Furthermore, dissociating NH3 in situ hydrogen by non-noble metal catalysts or plasma has the potential to replace dual-fuel systems. PAC is able to change classical ignition and extinction S-curves to monotonic stretching, which makes low-temperature ignition possible while leading moderate NOx emissions. In this review, the underlying fundamental mechanism under these technologies are introduced in detail, providing new insight into overcoming the bottleneck of applying ammonia in ICEs. Finally, the feasibility of ammonia processing as an ICE power source for transport and usage highlights it as an appealing choice for the link between carbon-free energy and power demand.

Diagnosis of a turbocharging system of 1 MW internal combustion engine

Electric vehicles (EVs) represent a new paradigm for a sustainable transportation future with the potential to offer unparalleled energy security, environmental cleanliness, and economic prosperity for all humanity. However, rapid development and adaptation of this new transportation approach depend on addressing multiple challenges, including the development of new materials and coatings that can meet the more stringent thermal, electrical, and tribological requirements of EV drivetrains. Specifically, the operating conditions of moving mechanical assemblies (i.e., bearings, gears, among others) in EVs differ radically from those found in conventional internal combustion (IC) engines—thus giving rise to notable reliability issues. In particular, as the function of bearings and gear systems shift from mostly load-carrying (in IC engines) to the torque-transferring mode in EVs, durability concerns of these assemblies due to severe deformation, wear, micro-pitting, fatigue, and scuffing may worsen—as electric motors can generate maximum torque at near zero speeds but maximum efficiency at around 90% speed (this is opposite of conventional IC engines, which generate high torques at high speeds). These conflicting requirements require a different set of lubricant-material combinations to circumvent such problems under high loads and low-speed conditions of EVs. Therefore, new materials, coatings, and lubrication strategies need to be developed and implemented for future EVs to become tribologically viable and reliable. Accordingly, EV drivetrains can potentially benefit from advanced functional coatings that have already significantly improved the functionality of moving components of IC engines. The main objective of this article is to draw attention to some of the tribological issues in EVs and how advanced functional coatings can help resolve these issues due to their unique thermal, electrical, mechanical, and tribological properties, ultimately making EVs more durable and reliable.

An efficient combustion depends on many factors, such as injection, turbulence and ignition characteristics. With the improvement of internal combustion engines the turbulence intensity and internal pressure have risen, demanding more efficient and powerful ignition systems. In direct injection engines, the stratified charge resultant from the wall/air-guided or spray-guided system requires even more energy. The Paschen’s law shows that spark plug gap and mixture density are proportional to the dielectric rupture voltage. It is known that larger spark gaps promote higher efficiency in the internal combustion engines, since the mixture reaction rate rises proportionally. However, the ignition system must be adequate to the imposed gap, not only on energy, but also on voltage and spark duration. For the reported study in this work two test benches were built: a standard inductive ignition system and a capacitive discharge high energy ignition system, with variable voltage and capacitance. The influence of the important parameters energy and ignition voltage on the spark duration, as well as the electrode gap and shape were analyzed. It was also investigated the utilization of a coil with lower resistance and inductance values, as well as spark plugs with and without internal resistances.

[ES] En los últimos años, la investigación en motores se ha centrado principalmente en la reducción de emisiones contaminantes y en el aumento de la eficiencia. Muchos de los esfuerzos de investigación actuales en este campo están dirigidos a mejorar y desarrollar nuevas estrategias activas para la reducción de emisiones, en particular centradas en los nuevos conceptos de combustión y en la obtención de un mejor control sobre ella. Su desarrollo requiere la aplicación de nuevas herramientas experimentales y teóricas. Estas herramientas deberían permitir tanto la aplicación de nuevas estrategias activas de control de contaminantes como ampliar el conocimiento básico de los fundamentos de los procesos involucrados. En este contexto es donde se encuadra el objetivo de esta Tesis: el desarrollo y optimización de un nuevo sistema de encendido no intrusivo y modulable, que permitirá el control sobre el tiempo y la ubicación del punto de encendido. Dicho sistema se aplicará para el encendido de chorros Diesel de inyección directa. En particular, se pretende evidenciar cómo las condiciones locales al encendido pueden afectar al desarrollo de la combustión posterior. Para lograr este objetivo, el trabajo de investigación se ha dividido en dos bloques principales. El primero se centra en el desarrollo y la optimización del sistema de encendido. Aprovechando las posibilidades que ofrece el proceso de inducción de plasma con láser y, una vez seleccionado el mejor método de inducción para su aplicación en un entorno especifico como el de un motor, se ha llevado a cabo un proceso de optimización y validación del sistema. Tal proceso resulta de importancia básica en el desarrollo de esta investigación, ya que la aplicación de un sistema de encendido totalmente fiable resulta ser fundamental, tanto en términos de su posible aplicación para control de combustión como en términos de las posibilidades de estudios que pueda ofrecer. Al principio, a partir de un extenso estudio de la literatura sobre el proceso de inducción de plasma con láser, se han obtenido los parámetros fundamentales a tener en cuenta para la aplicación del sistema al encendido de chorros de combustible de inyección directa. A partir de estos parámetros, se ha diseñado un primer sistema de encendido. Luego su fiabilidad en la inducción de plasma ha sido estudiada experimentalmente en condiciones ambientales y de motor, aplicando una metodología de optimización desarrollada en este mismo trabajo experimental. Como resultado principal de este primer bloque de trabajo, se ha podido obtener un sistema de encendido por plasma inducido con láser completamente optimizado y fiable, así como un método novedoso para su validación y optimización. El segundo bloque de trabajo corresponde a la aplicación del sistema al encendido de un chorro Diesel de inyección directa en condiciones reales del motor. El objetivo de este bloque era lograr dos hitos principales: la determinación de las capacidades y los límites del sistema en su aplicación, y el desarrollo de un primer estudio experimental sobre la influencia de las condiciones locales de la zona de encendido sobre una combustión Diesel. Para lograrlo, primero se ha validado la capacidad de encendido del sistema bajo un conjunto adecuado de condiciones termodinámicas, previamente seleccionadas para mantener la máxima efectividad. Los resultados de este estudio, en comparación con los típicos parámetros de autoencendido en las mismas condiciones, han permitido demostrar la capacidad de encendido del sistema. Posteriormente, se ha llevado a cabo una variación paramétrica de tiempos y posiciones en las que inducir el plasma, con el fin de determinar el efecto de las condiciones locales sobre el desarrollo de la combustión Diesel. En este caso, al comparar los resultados obtenidos con los parámetros estándar de autoencendido, se han podido obtener tendencias interesantes, que subra

<div class="section abstract"><div class="htmlview paragraph">The “Water Spider Geometry” (WSG) configuration, representing a newly developed reference test sample designed to suitably investigate the flow and heat transfer processes relevant to cooling systems of internal combustion engines, was computationally investigated by applying a recently proposed Reynolds Stress model called the “Elliptic-Blending Model” (EBM). The WSG configuration resembles a specifically configured pipe geometry that appropriately mimics the flow phenomena encountered in cooling channels of realistic internal combustion engine, such as flow impingement and bifurcation, multiple deflections and flow confluence. The reference database, consisting of mean flow and turbulence fields, was provided by a Large-Eddy Simulation. The EBM formulation has been intensively validated by calculating numerous isothermal wall-bounded flows. The present work focuses on testing the EBM predictive performances under the conditions of non-isothermal flow scenarios. Before proceeding to the WSG configuration, the EBM is pre-validated by computing a jet discharging from a channel-like nozzle and impinging perpendicularly onto a heated wall. The results obtained follow closely the data of the reference Direct Numerical Simulation, also with respect to the predicted second peak at the Nusselt number distribution in terms of different nozzle-to-wall spacing. The EBM-predicted mean velocity field and associated global flow characteristics within the WSG configuration agree well with the results of the reference Large-Eddy Simulation, in contrast to those obtained by the widely used <i>k</i> − <i>ω</i>-SST model, which has been applied in addition. Different treatments of the near-wall region were also used, including integration to the wall and the universal wall-functions. The computationally obtained temperature field evaluated at the WSG walls reveals the hot spot location within a straight pipe segment situated between two deflections, closer to the upstream one, coinciding with the experimentally detected region of most severe degradation caused by intense heating.</div></div>