Theme of abstract:

«Development of the electronic system of control of motor transport emission»

Important note: At the time of writing this abstract the master work is not finished.Final completion: December 2011. Full text of the work and related materials can be obtained after the date mentioned above.

Topic actuality. Pollution of atmospheric air is one of the most serious environmental problems in many industrial cities. Influence of air pollution on human health becomes apparent through the shortening of average life duration, increase the quantity of untimely deaths, increase of sickness rate and the negative effect on children's development. [1]

One of the sources of the Ukraine nature pollution is the transport – automobile, air, water, railway. The mass concentration of air pollution by the motor transport in all big cities of Ukraine is 70-90% of the total mass of pollution [2].

30% of all emissions in the atmosphere in Donetsk are car exhaust gases.

During the operation of vehicle, usage of different grades of gasoline, change of condition and adjustment of engine the concentration of monoxide carbon increases. Check on the service station occurs once in two years. This does not promote sufficient control and reduction of the harmful substances emissions. In the same time, the introduction of new Euro standards for the concentration of toxic substances in emissions of road transport faces with problem of absence of special equipment. That is why it is proposed to develop the electronic system of operational control of emissions without stopping the vehicle in the control zone (zone of control can be the one-traffic road section). This system would test the CM concentration in emissions for compliance with the accepted standards. Besides that, this system will make it possible to carry out the intermediate control over the quality of exhaust gases and to prevent pollution from mobile sources of emissions.

Another actual problem is decrease of cost of testing the quality of exhaust gases, which are carried out by stationary installations.

To perform its functions the electronic system of operative control should have high speed capability, i.e. high level of throughput. High throughput of motor transport reduces the expenses for car testing by stationary devices of control of the vehicles emissions quality. This factor of the "cost" is the main argument in favor of the widespread use of these devices. [3]

The purpose of the work. The purpose of the Master's work is to substantiate and draw the block diagram of the system of monitoring the concentration of carbon monoxide in emissions of the car without stopping the vehicle.

Tasks. For achievement of this purpose it is necessary to accomplish the next tasks:

To analyze the parameters of environment in which the system will be operate, existing methods of measurement of carbon monoxide concentration, to put requirements and restrictions to system and make the choice of method of measurement and also prove it;
To develop a mathematical model of vehicle emissions in the conditions of inhomogeneous gas environment for subsequent evaluation of indications of electronic system;
To perform the mathematical modeling of optical system for obtaining the signal power at the output of the system;
To estimate the influence of concentration of other gases which are contained in an exhaust and an atmospheric, on accuracy of determination of carbon monoxide concentration;
To estimate the influence of destabilizing factors, such as wind force and wind direction, speed of the car, precipitations, on the precision of electronic system;
To estimate the adequacy of the developed electronic system of operative control.

Scientific novelty. Scientific novelty is in the development of import-substituting system of control of carbon monoxide concentration in the emissions of vehicles with the usage of an optical-absorption method of estimation of quality of exhausts in mobile sources of pollution.

The description of the contollable object

The exhaust gases (burnt gases) - is a heterogeneous mixture of different gaseous substances with different chemical and physical features which consists of products of complete and incomplete combustion of fuel, excess air, aerosols and various micro impurity arrived from the cylinder engines into its exhaust system. They contain about 300 substances, many of which are toxic.

The basic normalized toxic components of exhaust gases of engines are carbon monoxide, nitrogen oxide and hydrocarbons. [4]

In the projected scheme the carbon monoxide in the exhaust gases of petrol engines will be controllable parameter. CO concentration in diesel engines, as a rule, isn't high, so it is not the main parameter in these types of engines.

In the engine combustion chamber carbon monoxide is formed at unsatisfactory atomization of fuel, as a result of cold-reactions, at combustion of fuel with an oxygen deficiency and also owing to the dissociation of carbon dioxide at high temperatures. [5]

The concentration of CO is not only a parameter that is taken into account and analyzed of the proper functioning of the engine, but also a regulated parameter.

In Ukraine there are the standard Euro 3 (CO concentration is not higher than 2.3 g / km). [6]

General requirements for contollable object and performs measurements

According to the description of the controllable object and the environment in which the device will be used, the following basic requirements will be specified for the electronic system:

engine type: petrol;
measuring of CO concentration without stopping the vehicle;
opened optical channel;
speed: no more than 10 ms;
quantity of measurements: not less than 5-6 measurements;
measuring range CO: 0 ... 5 vol. %;
limits of the permissible absolute error for measuring range from 0 to 5 vol. %: : no more than ± 5%;
height of a car exhaust pipe: 25-50 sm;
the measuring part of system must be synchronized with system of video observation of cars;
the information received from a measuring part of system and system of video observation, must be ready to be transferred to a communication channel.

Requirements concerning the limits which should not exceed influencing factors will be established during the modeling based on the errors made by each of them in measurement. These influencing factors will be the following:

heterogeneity of the CO concentration in the exhaust cloud;
vehicle speed;
speed and direction of the wind;
precipitation;
temperature.

According to the above mentioned system requirements, the method of measurement will be chosen. Sufficient operation speed (about 2 ms for one measurement), the necessary accuracy (an error not more ±5 %), measuring without stopping the vehicle can be provided only with an optical absorption method of direct linear absorption.

Structural diagram of system

Structural diagram of system of vehicles emission control is shown in Picture 1.

Structural diagram of system of control of road transport emission

Picture 1 - Structural diagram of system of control of road transport emission

The radiation source is a LED. The wavelength of LED is chosen according to the gas the concentration of which has to be determined. In accordance with the absorption spectrum of CO, the range of infrared radiation must lie in the framework of 4.5-4.9 microns. In order to minimize the influence of other gases which compound an exhaust and the atmosphere, the wavelength of the radiation source is chosen about the maximum of absorption spectrum or is limited by the optical filter around λ =4,67 microns. IK-ray passes through lens L2 intended for focusing, and then the ray gets to the opened optical channel, where the analyzed gas mixture is. The ray reverberates from the optical system of mirrors OZ, gets into the L1 and focuses on the photodiode PD. Reverberation of the ray is necessary to override a certain spatial region, where the vehicles exhaust may be located and where it can be spread. The range of this area depends on the height of the exhaust pipe of the vehicle and is determined during the modeling of system provided the achievement of certain metrological characteristics of the electronic system.

At the output of photo diode the current is formed, and this current magnitude is proportional to capacity of IR radiation that gets to photo detector window.

List of major trends in research

The main research directions are the following:

the accounting of influence of each gas component which are part of the exhaust and the estimation of their influence on the metrological characteristics of electronic system;
the accounting of influence of weather conditions on the system work and the development of optimum requirements to them for ensuring the given accuracy of measurements of electronic system;
searching of adjustable coefficients, which would allow to measure the influence of speed of moving transport on the accuracy of measurement.

List of references

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