Paper 7: Accuracy of and Representative Results Obtained with an Infra-Red Pyrometer Measuring Compression Temperatures

Author(s):  
P. S. Myers ◽  
O. A. Uyehara

In a spark-ignited internal combustion engine there are two zones of interest ( a) the burnt mixture and ( b) the unburnt mixture. Of interest to the authors and to many of their colleagues are the pre-reactions which occur in the unburnt zone. To follow the extent of these pre-reactions both the pressure and the temperature of the unburnt mixture are required. Pressure transducers can be obtained from many commercial establishments, but a temperature pyrometer that can follow the temperature of the unburnt mixture is not commercially available. The current technique uses the absorption, emission characteristic of the water vapour in the cylinder. The use of water vapour as the sensing element is desirable since water vapour is normally in the air which the internal combustion (i.c.) engine breathes. Radiation of a known intensity (known black-body temperature) is passed through the engine, through a band pass filter (H2O water vapour band at 2.6 μ) to an infra-red detector. The output from the detector, after amplification, is fed to a cathode-ray oscilloscope. By suitable means, it is possible to compare the undisturbed radiation from the black body with the black-body radiation after it has experienced absorption emission events during the compression process. The reversal point can be visually observed on the oscillogram. At this reversal point the temperature of the gas and the black body are equal and the crank angle at which this occurs can be determined. Other temperatures and crank angles at which reversal occurs can be observed to obtain the unburnt mixture temperature versus crank angle curve. The authors' experiences with different infra-red detectors and other temperature-measuring techniques, as well as comparison between the velocity of sound method and the infra-red technique, are discussed. Data obtained with the instrument are presented.

2016 ◽  
Vol 852 ◽  
pp. 719-723
Author(s):  
Sunil S. Hebbalkar ◽  
Kaushik Kumar

An internal combustion engine with opposed piston engine (OPE) develops higher power density than any other conventional internal combustion engine by virtue of its design. A Two stroke OPE gives two power stroke within 3600 of crank revolution which indicates the higher power density. But this extra power also results in large amount of forces gets transmitted to both the crankshaft amounting to large unbalance in the engine. Hence for a smoother and noise free performance, engine should be dynamically balanced. So balancing is one of the main criteria for better performance. In this paper the dynamic analysis was performed by varying the linkage dimensions of OPE for balance OPE. The analytical calculation of inertia forces and dimensions for linkages has been compared with software based results, depending on pressure crank angle plot for two stroke engine.


2018 ◽  
Vol 20 (7) ◽  
pp. 718-725 ◽  
Author(s):  
Masayasu Shimura ◽  
Shingo Yoshida ◽  
Kosuke Osawa ◽  
Yuki Minamoto ◽  
Takeshi Yokomori ◽  
...  

A micro particle image velocimetry has been performed to investigate tumble enhanced flow characteristics near piston top surface of a motored internal combustion engine for three inlet valve open timing (−30, −15, 0 crank angle degrees). Particle image velocimetry was conducted at 340, 350 and 360 crank angle degrees of the end of the compression stroke at the constant motored speed of 2000 r/min. The measurement region was 3.2 mm × 1.5 mm on the piston top including central axis of the cylinder. The spatial resolution of particle image velocimetry in the wall-normal direction was 75 µm and the vector spacing was 37.5 µm. The first velocity vector is located about 60 µm from the piston top surface. The micro particle image velocimetry measurements revealed that the ensemble-averaged flow near the piston top is not close to the turbulent boundary layer and rather has tendency of the Blasius theorem, whereas fluctuation root-mean-square velocity near the wall is not low. This result shows that revision of a wall heat transfer model based on an assumption of the proper characteristics of flow field near the piston top is required for more accurate prediction of heat flux in gasoline engines.


Author(s):  
В. В. Руденко ◽  
И. В. Калужинов ◽  
Н. А. Андрущенко

The presence in operation of many prototypes of UAVs with propeller propellers, the use of such devices at relatively low altitudes and flight speeds makes the problem of noise reduction from UAVs urgent both from the point of view of acoustic imperceptibility and ecology.The aim of the work is to determine a set of methods that help to reduce the visibility of UAVs in the acoustic range. It is shown that the main source of noise from the UAV on the ground is the power plant, which includes the engine and the propeller. The parameters of the power plants influencing the processes that determine the acoustic signature of the UAV were investigated. A comprehensive analysis of the factors affecting visibility was carried out. The power plants include two-stroke and four-stroke engines, internal combustion and two-blade propellers. The use of silencers on the exhaust of the internal combustion engine was considered. The spectral characteristics of the acoustic fields of the propeller-driven power plants for the operating sample of the UAV "Eco" were obtained. The measurements were carried out in one-third octave and 1/48 octave frequency bands under static conditions. The venue is the KhAI airfield. Note that the propellers that were part of the power plants operated at Reynolds numbers (Re0,75<2*105), which can significantly affect its aerodynamic and acoustic characteristics. It is shown that when choosing a UAV control system, one should take into account the fact that two-stroke piston engines are the dominant source in the noise of propeller-driven control systems in the absence of a hood and mufflers in the intake and exhaust tracts. The use of a four-stroke internal combustion engine significantly reduces the noise of the control system. In the general case, the position of the boundaries of the zone of acoustic visibility of a UAV at the location of the observer is determined by the ratio between the intensity of acoustic radiation perceived by the observer from the UAV and the intensity of sound corresponding to the natural acoustic background and depends on the degree of manifestation of acoustic effects accompanying the propagation of sound in a turbulent atmosphere - the refraction of sound waves. Absorption and dissipation of acoustic energy. The calculation and comparison of the UAV detection range was carried out taking into account the existing natural maskers.The results of experimental studies are presented that allow assessing the degree of acoustic signature of the UAV. A set of measures aimed at reducing the intensity of the acoustic signature of the UAV in various regions of the radiation spectrum has been determined.


Author(s):  
Oleksandr Gryshchuk ◽  
Volodymyr Hladchenko ◽  
Uriy Overchenko

This article looks at some comparative statistics on the development and use of electric vehicles (hereinafter referred to as EM) as an example of sales and future sales forecasts for EM in countries that focus on environmental conservation. Examples of financial investments already underway and to be made in the near future by the largest automakers in the development and distribution of EM in the world are given. Steps are taken to improve the environmental situation in countries (for example, the prohibition of entry into the city center), the scientific and applied problem of improving the energy efficiency and environmental safety of the operation of wheeled vehicles (hereinafter referred to as the CTE). The basic and more widespread schemes of conversion of the internal combustion engine car (hereinafter -ICE) to the electric motor car (by replacing the gasoline or diesel electric motor), as well as the main requirements that must be observed for the safe use and operation of the electric vehicle. The problem is solved by justifying the feasibility of re-equipment of the KTZ by replacing the internal combustion engine with an electric motor. On the basis of the statistics collected by the State Automobile Transit Research Institute on the number of issued conclusions of scientific and technical expertise regarding the approval of the possibility of conversion of a car with an internal combustion engine (gasoline or diesel) to a car with an electric motor (electric vehicle), the conclusions on the feasibility of such conclusion were made. Keywords: electricvehicles, ecological safety, electricmotor, statistics provided, car, vehicle by replacing.


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