Testing the cooling system of the helicopter internal combustion engine in hot climates

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.

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.

A Model Predictive Controller for the Cooling System of Internal Combustion 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.

<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>

Due to the depletion of conventional petroleum-based fuels and increasing environmental concerns, industries have been developing new combustion technologies with acceptable cost ranges and minimum system modifications for consumers. Among many approaches, the utilization of plasma ignition systems is considered as a promising pathway to achieve greener transportation while maintaining conventional internal combustion engine systems. Plasma contains highly reactive radicals, and those have a great potential of enhancing chemical reactions that are beneficial for reducing carbon emissions. The primary objective of this paper is to provide an overview of currently available plasma-assisted combustion systems including recent achievements in research and development, and technical challenges for successfully implementing a new ignition system. This review will introduce various plasma-assisted combustion approaches from worldwide projects, covering non-thermal and thermal plasma systems in internal combustion engines.

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.

Diagnosis of a turbocharging system of 1 MW internal combustion engine

Perspectives of usage natural gas in feeding systems of internal combustion engines and development of electronic control systems have resulted in survived interest in dual fuel system of engine feeding. Compression ignition, dual fuel engine enables to preserve majority of positive features of compression ignition engine and shows many advantageous features comparing with gaseous engine with spark ignition system. The paper shows an impact of gaseous mixture composition on operational parameters of the engine, with special consideration of combustion parameters and toxicity of exhaust gases. It has been confirmed that in range of gaseous mixture composition change in scope of λo = 1.4–6.0 worsening of combustion parameters is negligible and can be accepted for medium size traditional engines. Simultaneously, in spite of implementation of traditional injection system, leaning of the mixture up to λo < 6.0 enables significant change of engine load. Limitation of leaning of the mixture up to λo < 4.5, restricts harmful phenomena connected with combustion of lean gaseous mixtures. It requires, however, fuel injection electronic systems such as common rail. Results presented in the paper can be useful in adaptations of compression ignition engine to gaseous feeding and in stage of development of control systems to such engines.

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.

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.

Most boosting systems in internal combustion engines utilize “pulse turbocharging” to maximize the energy extraction by the turbine. An internal combustion engine with more than four cylinders has a significant overlap between the exhaust pulses which, unless isolated, can decrease the overall pulse energy and increase the engine pumping loss. Thus, it is advantageous to isolate a set of cylinders and introduce the exhaust gases into two or more turbine entries separately. There are two main types of multiple entry turbines depending on the method of flow division: the twin-entry and the double-entry turbine. In the twin-entry design, each inlet feeds the entire circumference of the rotor leading edge regardless of inlet conditions. In contrast, the double-entry design introduces the flow from each gas inlet into the rotor leading edge through two distinct sectors of the nozzle. This paper compares the performance of a twin and double-entry mixed flow turbine. The turbines were tested at Imperial College for a range of steady-state flow conditions under equal and unequal admission conditions. The performance of the turbines was then evaluated and compared to one another. Based on experimental data, a method to calculate the mass flow under unequal admission from the full admission maps was also developed and validated against the test results.

A computational analysis of the impact of bore-to-stroke ratio on emissions and efficiency of a HSDI engine

<div class="htmlview paragraph">One of the methods of representing a turbocharger-turbine in the exhaust system of internal combustion engines is by assuming quasi-steady flow at turbine boundaries, while taking into account the generation of pressure waves both upstream and downstream of the turbine due to non-steady flow conditions.</div> <div class="htmlview paragraph">This method relies substantially on steady flow turbine characteristics for the generation of boundary conditions. A method is presented to allow for wave action both upstream and downstream of a twin-entry radial inflow turbine. The method also allows for different flow rates in each entry to simulate the partial admission condition. Comparison is made between experimental results and theoretical analysis.</div>