Engine Start-up Research Articles

Controlling idling: a ready-made solution for reducing exhaust emissions from agricultural tractors

Mechanised agriculture accounts for nearly 70 million tonnes of CO 2 emissions annually. To mitigate these CO 2 emissions, powertrains running on alternative fuels and hybrid powertrains are under development. However, such solutions have not yet reached the technical maturity required for the marketplace. To make significant progress, considering the pressure imposed by the European Commission and others, ready-made solutions must be deployed to achieve rapid and large-scale reductions of greenhouse gas emissions. One such solution is to reduce unnecessary engine idling. This paper presents an investigation of the duration of idling stops, the energy required for starting the engine, and the time at which the engine should be turned off to avoid higher emissions from continued idling. Four tractors with different engine displacements were used in experiments. For the tractors, the energy required for engine start-up was measured and real-world data were collected over several months. From data analysis, it was found that shutting off the engines for idling stops longer than 4.4 s resulted in lower emissions. The four tractors showed different idling patterns; turning off the engine during unnecessary idling stops led to fuel savings of 1.1%–5.1%. Based on these results, 770,000 tonnes of CO 2 annually could be saved by equipping tractors with the proper technology for turning off the engine during unnecessary idling stops. • Engine idling is a common status of tractors and is environmentally detrimental. • Energy for engine start-up was measured on four tractors of different power levels. • Turning off the engine for idling stops longer than 4.4 s leads to fuel saving. • From 1.1% up to 5.1% of the total fuel consumed is caused by unnecessary idling. • Avoiding unnecessary idling may lead to a yearly saving of 770,000 tonnes of CO 2 .

Structured neural-network-based modeling of a hybrid-electric turboshaft engine's startup process

Given its highly nonlinear and multi-physics-coupling nature, modeling the startup process of a turboshaft engine has always been a difficult task, which is further aggravated on a turboshaft engine in a hybrid-electric system. With sufficient data from bench experiments, this article establishes a data-driven numerical model to simulate the startup process of a hybrid-electric turboshaft engine. Neural networks are organized hierarchically to estimate three key parameters of the engine system: engine speed, leftover torque, and exhaust temperature. Specifically, on exhaust temperature, different neural networks were tried and compared. The networks were built, trained, and tested in sections, and then tested as a whole. Compared with the mechanism-based methods, the model proposed in this article has a simple structure and can be built automatically. According to the running tests, the proposed method can give accurate results at a fast speed using small hardware resources, showing great potential as a reference model on real-time control units.

Computer modeling of electromechanical system of two-speed elevator

Today, elevator production in Ukraine needs innovative solutions and changes, because most of the equipment in operation was built and installed in the 70-80s of the last century. Due to the high cost of new frequency-controlled winches and the complexity of maintenance, the search for modernization and improvement of existing elevator winches remains an alternative. No less important stage of operation is diagnostics. Timely detection of damages and forecasting of future failures allow to provide high-quality work during all term of operation, and also to reduce expenses of budgetary funds for difficult repairs. Computer simulation playsan important role in the modern world both during the design of a new elevator and during operation. Thanks to fairly simple and clear programs, it is possible to reproduce not only the standard modes of operation of the mechanisms, but also to perform calculations of future possible faults. The use of visualization facilitates the perception of information for operators, engineers and other users involved. The paper presents a computer model of a two-speed elevator with an induction motor and a reduction winch. The research used Matlab / Simulink software, which is intuitive to use and, in the full sense of the word, informative. The built model of the elevator has feedback on the calculated load of the cabin. The latter is determined by the transients during engine start-up and affects the positioning accuracy at a stop. The dependences of the influence of the degree of cab loading on the positioning accuracy are found. In the second stage, the supply voltage parameter is added. A change in this parameter within ± 10% affected the previous calculations of the loading degree and deteriorated the accuracy by almost three times.At the same time, most indicators (75%) meet the requirements of international standards EN 81-20: 2014 with positioning accuracy in the range of ± 10 mm. In further studies it is planned to use the obtained results to reduce the sensitivity of the algorithm for calculating theloadingdegree of the cabin to change the supply voltage and ensure the required positioning accuracy in the entire load range of the cabin when changing the supply voltage ± 10%.

Implementation of a comprehensive reduced order methodology for transient analysis of nuclear thermal propulsion engines

Nuclear thermal propulsion offers high thrust and specific impulse engine capabilities for future manned missions to Mars and beyond. Legacy nuclear engine designs developed and experimented with highly enriched uranium engine systems. Currently, extensive research is performed to analyze the behavior of low enriched uranium reactors to meet the current regulation limits. Most of these analyses are focused on complicated multiphysics steady-state calculations to determine key engine performance parameters. Often time these computational frameworks decouple various engine components in the calculation phase, resulting in uncertainties of the engine’s performance. The challenges and limiting factors associated with transient operations in low enriched uranium reactors, such as engine startups and shutdowns, must be well understood. The objective of this paper is to present a reduced-order computational transient framework that examines a system-wide low enriched uranium nuclear thermal engine. The framework includes a steady-state solver used to converge on pumping requirements and conserve enthalpy prior to the start of a transient. The novel approach here relies on the steady-state component within the framework to generate operational maps. The latter indicate the feasibility of control based on nozzle chamber conditions for a given engine design in lieu of publicly unavailable pump curves. The framework is applied to investigate uprate in power maneuvers in conjunction with sensitivity studies to show the feasibility of an engine startup.

Development of a Ceramic EHC

<div class="section abstract"><div class="htmlview paragraph">In recent years, electrically heated catalysts (EHCs) have been developed to achieve lower emissions. In several EHC heating methods, the direct heating method, which an electric current is applied directly to the catalyst substrate, can easily activate the catalyst before engine start-up. The research results reported on the use of the direct heating EHC to achieve significant exhaust gas purification during cold start-up [<span class="xref">1</span>]. From the perspective of catalyst loading, ceramics is considered to be a better material for the substrate than metal due to the difference in coefficient of thermal expansion between the catalyst and the substrate, but the EHC made of ceramics has difficulties such as controllability of the current distribution, durability and reliability of the connection between the substrate and the electrodes. This paper reports about the hardware configuration of the direct heating EHC made of ceramics, including the catalytic substrate as an electric circuit, its electrode, and the insulation structure between pipe and them, which can solve these difficulties.</div></div>

Пуск дизельного двигателя 1Ч9,5/8,0 путем принудительной подачи предварительно разогретого воздушного заряда

The use of small-sized air-cooled diesel engines as part of mobile units for operation in the harsh climatic conditions of the Arctic is a rather difficult task. As the ambient temperature decreases, the temperature at the compression stroke end, which is necessary for the appearance of the first flashes in the diesel cylinder, decreases significantly. At the ambient temperature of minus 60°C, start of a diesel engine becomes impossible. The stage of the appearance of the first flashes is very important for the subsequent spin-up of the crankshaft and the onset of a diesel engine independent operation on fuel without the involvement of auxiliary starting devices. The article proposes a method and device for increasing the temperature in the combustion chamber at the compression stroke end. The results of a diesel engine start at various negative ambient temperatures are given. The regularities of the dynamics of starting a diesel engine 1Ch9.5/8.0 and the dependence of the crankshaft speed during start-up on the ambient temperature is established. The rational range of intake air temperature required for the diesel engine start-up by the proposed method at an ambient temperature from minus 50 to minus 60°C is determined. The proposed method and device can be applied in similar diesel engines with a smaller working volume.

Start and stop systems on agricultural tractors as solution for saving fuel and emissions

Agricultural tractors may idle from 10 to 43% of their entire operating life and this inoperative time must be minimised because it is detrimental to the environment, public health, fuel economy, and engine lifespan ( Perozzi et al., 2016 ). On passenger cars, start and stop (SS) systems have been extensively used, but they are not currently installed in any commercial tractor. Studies show that for very short idling stops SS systems might be ineffective for the additional energy required for re-starting the engine. This study aims to investigate the potential advantages of SS systems on agricultural tractors. To this aim, the energy required for engine start-up and the subsequent emissions were measured and then compared with the energy and the emissions during idling. Moreover, a predefined control strategy of the SS system was developed, and its potential fuel and emission savings were estimated using real-world data. In terms of fuel consumption and CO emission, turning off the engine is recommended for stops longer than 4 s and 134 s, respectively. From the collected real-world data, the tractor was run on idle for 21.7% of the entire operating duration. The results obtained with the SS control strategy developed in this paper applied to the US area, where there are 1.2 million tractors of the same power level of the tractor used in this study with a yearly usage up to 850 h, would permit to save 285.6 million litres of fuel, and, respectively of 16.5 and 754 tons of CO and CO 2. • Turning off the engine for idling stops longer than 4 s leads to fuel savings. • Turning off the engine for idling stops longer than 134 s leads to CO savings. • 45% of idling time could be avoided by farmers. • Start and Stop systems are an effective way for saving fuel and emissions.

Internal Combustion Engine Starting and Torque Boosting Control System Design with Vibration Active Damping Features for a P0 Mild Hybrid Vehicle Configuration

In order to meet the increasingly stricter emissions’ regulations, road vehicles require additional technologies aimed at the reduction of emissions from the internal combustion engine (ICE). A favorable solution from the standpoint of costs and simplicity of integration is a 48-V electrical architecture utilizing a low-voltage/high-power induction machine, which operates as the so-called engine belt starter generator (BSG) coupled via a timing belt with the ICE crankshaft within a P0 mild hybrid power train and used for starting up and boosting of the ICE power output, as well as for recuperating kinetic energy during vehicle deceleration. The aim of this work was to design a vibration damping system for the belt transmission within the so-called front end accessory drive (FEAD), which couples the BSG with the ICE crankshaft and to test the control system by means of simulations for realistic operating regimes of the P0 mild hybrid power train in order to show the functionality of the proposed approach in terms of mild hybrid vehicle performance improvement. Simulation results have pointed out effective attenuation of belt compliance-related vibrations using the proposed active damping control, with vibration magnitude reduced between three and five times compared to the default case during engine start-up phase. They have indicated the realistic belt slippage effects during engine start-up phase and have illustrated the effectiveness of the FEAD torque boosting capability with 30% gain in acceleration during vehicle launch.

Research on the potential of advanced engine loading strategy in meeting Beijing VI regulatory for a range-extended hybrid gas vehicle

Although the transient NOx emissions produced from a typical range-extended hybrid vehicle can meet the requirements of the China VI emissions regulations, it is rather difficult to comply with Beijing VI emissions regulations. This is due to the fact that the sharp fluctuation in air-fuel ratio control during engine start-up period resulting in lower conversion efficiency for the three-way catalyst (TWC). In response to these issues, the potentials of different loading strategies in meeting Beijing VI were explored on a light-duty natural gas (NG) engine for range-extended hybrid application. The experiments were performed on the basis of typical Chinese City Bus Cycle (CCBC). This paper analyzed the operation characteristics of the typical range-extended hybrid NG vehicle and investigated the impacts of engine loading strategy on the vehicle’s performance and emissions during the start-up phase. Results showed that the transient NOx emissions of 30 s-averaged decreased from 786 to 504 ppm when extending the loading time from 3 to 40 s in a typical loading path (i.e. engine speed and load increased linearly). The transient NOx emissions could meet the Beijing VI NOx limit but with little margin. Research also investigated the use of a new designed engine loading strategy (i.e. engine speed and load with time-separated control manner). Results revealed that this method effectively curbed the transient NOx emissions, reducing the maximum transient NOx emissions of 30 s-averaged from 504 to 271 ppm. In comparison, this low NOx level was better to meet the Beijing VI with sufficient margin.

Rheological Properties of Engine Oil with Nano-Additives Based on MoS2 Materials.

To enhance oil’s tribological and rheological properties, various nano-additives are used. An example of such a nano-additive is nanosized molybdenum disulfide (MoS2). Due to its unique properties, MoS2-based materials used as lubricants have attracted significant attention. In our previous work, we developed a novel, scalable, and low-cost method for MoS2-based materials production using an impinging jet reactor. Hybrid nanostructures based on MoS2 and carbon nanomaterials (MoS2/CNMs) decreased the friction factor of the base oil. In the present study, a mathematical model that accounts for the viscous heating effects in rheograms was formulated. The model was used to interpret the results of rheological measurements conducted for the base oil 10W40 and its mixtures with different nanosized lubricant additives. The model of the non-isothermal Couette flow allowed us to correct the rheograms of the engine oils in the region of high shear rates where viscous heating effects become significant. The temperature correlations for the consistency and flow behavior indexes were proposed. The nanohybrid suspensions of MoS2 in the base oil were found to have the lowest apparent viscosity at low temperatures, typical for the cold engine startup.

Effect of compression ignition engine preheating on its performance under cold start conditions

This paper examines the effect of an external preheating system for an internal combustion engine on fuel consumption, CO2 emissions, and cabin temperature of a Euro4 vehicle. A 1 kW electric system powered by 220 V was installed in series in the cooling system of a vehicle with a compression-ignition engine of 2.5 dm3 capacity. The tests were carried out in simulated urban driving conditions (distance of 4.2 km), extra-urban driving conditions (distance of 17 km), and during idling at cold-start temperatures ranging from -10 oC to 2 oC. Preheating the engine under simulated city conditions reduces fuel consumption by 2.64 dm3/100 km and increases the supply air temperature immediately after engine start-up. Due to the preheater being powered from an external power grid, the cost per trip and total CO2 emissions are increased. Assuming renewable energy sources, CO2 emissions would be reduced the most for the stationary tests after engine preheating. In contrast, emissions would be reduced the least for extra-urban driving.

The model for cylinder charge parameters during engine starting

The process of cylinder charge – air sucked into the cylinder – transformation during engine start-up phase is characterized. Heat exchange and air flow through piston-cylinder group leakage processes are described as factors influencing the gas thermodynamic parameters. The Woschni formula based on similarity theory was finally used as equation describing heat transfer in combustion engines cylinder. The computational model for cylinder charge parameters in the whole engine cycle during its starting at low temperature is presented. Some taken assumptions and characteristics of partial processes resulting from the computations are shown. There are indicated the possibilities of using the model at internal combustion engine diagnostic process.

Automatic imaging system mounted on boom sprayer for crop scouting using an off-the-shelf RGB camera

This article describes an imaging system mounted on the boom of a self-propelled sprayer, which was developed to automatically capture and store high-definition video images, while handling agrochemical spray and machine vibration. This was accomplished using an off-the-shelf camera (DSC-RX0M2, Sony) and two single board computers. To enable automatic operation, the system was designed to start and terminate along with the engine. All components were powered successfully except for the camera which runs only on its own battery. This was overcome by delaying powering certain hardware and software components of the system for different periods to allow consistent initialization of the entire system. Accordingly, the current version of the system starts imaging 15 min after engine start-up and guarantees performance for 3 h of consecutive video capturing. After several field trials, the imaging system became able to save images with the required quality. The developed software is able to handle images at a rate of 30 frames per second without delay. In order to handle dynamic light conditions, the camera shooting mode was set to manual at a very high shutter speed. This provided detailed images at both sunny and cloudy conditions. While the current captured images proved to be adequate to start machine vision system development, there is a setback when trying to get images at early morning or evening as they tend to be too dark. This will be handled while upgrading the system towards a machine vision for the purpose of automatic scouting.

Numerical simulation of filling process of cryogenic propellants with inert gas purge

The cryogenic filling process is a complex phenomenon with a combination of thermal and flow transients, especially in the case of inert gas purge during the start-up of liquid rocket engines. A 7-Equation two-fluid model is proposed in this work by adding an extra mass conservation equation for the purging gas compared with the conventional 6-Equation model. And the conservation equations for mass and energy are in the differential form, while the momentum equations are given in quasi-steady state. The model is programmed in Modelica language based on the idea of modular modeling. A two-step rising pressure in the supply system of a real engine shown by the experimental data is also predicted by the model. Then the reason for the pressure surge is analyzed by the numerical results. Finally, the numerical study is carried out to examine the effect of inlet pressure and purging pressure on filling characteristics in the supply system. The results show that within the range of parameter considered, the magnitude of pressure surge in the oxygen dome increases with increase in inlet pressure and purging pressure. The filling rate of liquid oxygen in the dome changes in a positive way with inlet pressure while in a negative way with purging pressure.

A study on diesel engine crankshaft bearing failure analysis with consideration of bearing lubrication

PurposeThe edge of diesel engine crankshaft main bearing is more likely to fail in its real working condition. This paper aims to study the bearing failure mechanism by finding the relationship between bearing lubrication characteristics and its working condition.Design/methodology/approachThis work builds the mixed lubrication model of crankshaft bearing to analyze the cause of bearing abnormal wear, and the finite difference method was used to solving the average Reynolds equation. During the analysis, journal misaligned angle, external load and roughness are considered.FindingsThe result shows that the wear of the diesel engine crankshaft bearing happens in engine startup phase and the bottom of the bearing are more prone to be excessively worn. Under the influence of journal misalignment, bearing asperity contact load and speed range of mixed lubrication will increase markedly. The edge of the bearing will be excessively worn. The effect of misalignment on bearing lubrication performance varies under different shaft rotation speed.Originality/valueThe former research studies on crankshaft bearing either just focused on its lubrication characteristics or interested in its failure types (wear, adhere, cavitation). This paper studies the relationship between bearing failure mechanism and lubrication performance.

Evolution of Electric Traction Vehicle Design Based on the Example of Škoda Locomotives

The article describes the evolution of Škoda electric locomotives, starting with vehicles supplied with 3 kV DC and 25 kV 50 Hz, initially featuring a resistor start-up (for DC supply), optionally high-voltage voltage regulation (for AC supply), and later with a pulse (thyristor) start-up. The railway network in Czechoslovakia was initially electrified with direct volt-age (including the Prague junction); however, learning the advantages of the 25 kV 50 Hz voltage developed in Germany led to some new sections of the ČSD network being electrified with alternating current. At the same time, Czechoslova-kia’s national manufacturer Škoda developed vehicles (locomotives, EMUs) suitable for DC and AC operation. Initially, these were single-system vehicles, as the development of multi-system ones was technically complicated at the time (only short-series production was practiced). The advent of pulse-starting traction motors not only provided more economical and simpler traction motor control but also simplified the construction of multi-system vehicles. The article discusses the specifics of both engine start-up systems and the evolution of DC and AC vehicle design and operation.

SYSTEMATIC APPROACH TO THE DEVELOPMENT OF GENERAL REQUIREMENTS FOR GROUND HANDLING FACILITIES

The topical issue of providing aircraft with ground handling equipment of flights that would meet modern requirements of functional and quality indicators, international standards and prospects for the development of aircraft in the context of cooperation with NATO countries is considered.
 The results of the analysis of open literature sources on the possibilities of manufacturing means of ground maintenance of aircraft by the military-industrial complex of Ukraine are presented. The methodology of the system approach is aimed at the development of general requirements for ground-based power supply and start-up of aircraft engines. Analysis of trends in domestic and foreign models of ground handling equipment has determined that the problem of ensuring a given military-technical level of the fleet of military aircraft and helicopters is becoming more relevant every year, and work to create products and their components requires a comprehensive system approach.
 Methodical approaches to the development of general requirements for ground-based means of power supply of aircraft are presented. The practical significance of the obtained results lies in the possibility of their use to justify the decision to supply these samples of special-purpose ground handling equipment to the Armed Forces of Ukraine. In this regard, the main task of the military-industrial sector of Ukraine is to prepare the production of analogues of electric and gas equipment for ground handling of aircraft and helicopters and their harmonization with NATO standards.

Research of the modernized intake system of the gasoline engine

Problem. In recent years, Ukraine has seen a sharp decline in ambient temperature, especially in the winter. Accordingly, this has a negative impact on the performance of car engines (difficult to start and prolonged warm-up), as the lion's share of private sector cars are parked in open areas and are subject to sudden temperature and humidity changes. Therefore, to partially solve this problem, our attention was focused on the air lines of the intake system of the gasoline engine, as this system is easily accessible and does not require significant design changes for its modernization. Goal. The purpose of the work is to ensure the ease of starting the gasoline engine and reduce the time to warm up. Methodology. Operation of the car in the conditions of the lowered temperatures, essentially promotes deterioration of its fuel economy. The basis of such a negative process of fuel consumption is incomplete combustion of the working mixture. And this is the deterioration of spraying and evaporation of fuel and increasing the duration of engine warm-up. At such low ambient temperatures, the effective operation of the car in a garage depends significantly on the method of its preparation (which should at a minimum cost of fuel and energy resources to ensure rapid and reliable engine start and accelerated warm-up). We decided to obtain thermal energy to heat the inlet air at no additional cost. This is the installation of a gasoline engine with a spark ignition of the incandescent coil in the intake air line, which will receive power from the battery. Such modernization of the system does not require major design changes and significant financial investments Unresolved issues remain to assess the effectiveness of the process of heating the air entering the combustion chamber of the engine to create a working mixture. It should be noted that the optimal heating of the engines is most appropriate to carry out (ie heating the coolant and oil in the engine lubrication system) not to the temperature of the operating thermal mode, but to the temperature that ensures its reliable start. Results. The scheme of connection of a heater of intake air in an onboard electric network of the car is presented. The results of the heat balance of the studied gasoline engine (using cold and heated air flow) during its heating are obtained. The optimum temperature of the warmed-up engine at which further economical operation of the car is possible is established. Originality. This spiral heater was first used to heat the intake air charge during the start-up and warm-up of a gasoline engine. Practical value. The developed heating equipment can be used for both gasoline and diesel internal combustion engines. It should be switched on only during engine start-up and warm-up.

Методика визначення впливу внутрішніх та зовнішніх факторів на розкид тяги рідинного ракетного двигуна при його запуску

Despite of the package of measures to adjust a liquid-propellant rocket engine (LPRE) to a specified operating regime, minimum acceptable spreads in the geometrical parameters and operating conditions of its units and assemblies steel remain. These internal factors together with external ones (the pressure and temperature of the propellant components at the engine inlet) govern the engine thrust spread. To provide an acceptable engine thrust spread according to the engine requirements specification, it is important to know the spread value as early as at the stage of off-engine tryout of the engine units and assemblies. The aim of this work is to develop a procedure for calculating the effect of external and internal factors on the LPRE startup thrust spread. This paper presents a procedure for determining the effect of internal and external factors on the LPRE startup thrust spread. The procedure includes the development of a mathematical model of engine startup that accounts for the maximum number of internal factors, the choice of internal factors that produce the maximum effect on the LPRE startup thrust spread, the choice of a method for specifying the external and internal factor spread, engine startup calculations at different combinations of external and internal factor spread values, engine thrust spread determination, determining the statistical and the theoretical distributions of the 90 percent thrust time spread and the steady thrust spread, and assessing their goodness of fit using Pearson’s chi-squared test. The paper gives an example of calculating the effect of the external and internal factor spread on the LPRE startup thrust spread for a staged-combustion oxidizer-rich sustainer LPRE. Using the results of previous calculations, 12 internal factors that produce the maximum effect on the engine startup thrust spread are identified. It is shown that the calculated spread of the 90 percent thrust (combustion chamber pressure) time lies in the range – 0.08220s to +0.07300s about its nominal value, and the calculated steady engine thrust (combustion chamber pressure) spread lies in the range –6.4 percent to +6.6 percent of the nominal thrust. Using Pearson’s chi-squared test, an estimate is obtained for the goodness of fit of the anticipated theoretical distributions of the 90 percent thrust time spread and the steady thrust spread to the obtained statistical ones.

Transient characteristic evaluation and optimization of supercritical CO2 Brayton cycle driven by waste heat of automotive gasoline engine

Under the severe situation of low energy efficiency and strict emission standards, waste heat recovery, is considered to be a feasible technology, to achieve fuel economic in automobile industry. Among them, supercritical CO2 Brayton cycle has become one of the most promising technology owing to its high efficiency and compactness. Besides, the exhaust temperature and flow of automobile engine change dramatically in practice, resulting in a negative impact on the thermodynamic performance of the power cycle. Therefore, this paper develops a dynamic model of waste heat recovery system, carries out operating parameters analysis, transient response characteristics research and performance optimization, and finally proposes an improved method to adjust turbine inlet temperature to obtain higher output power. The change trend displays that the influence of turbine inlet pressure on thermodynamic performance is opposite to the dynamic response characteristics, and similar results also occur under engine start-up conditions. The numerical results indicate that the optimized output power and electric production cost reach 2.97 kW and 0.38 USD/kW·h, compared with the previous method, an improvement of 3.48% and 5.00% are achieved, respectively, reflecting the significance of energy conservation and emission reduction.