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Maintenance regimes of Mercedes-Benz buses, used in the conditions of Tashkent city
Section 10. Transport
DOI: http://dx.doi.org/10.20534/ESR-17-3.4-113-114
Musadjanov Makhamadjan Zakirdjanovich, Candidate of technical sciences, Associate Professor E-mail: Musadjanov-37@mail.ru Musaev Doniyor Xabibullaevich Senior teacher of Department of operation of road transport E-mail: doniyor4444@yandex.ru Mahkamov Mirjamol Yulchievich, Scientific researcher, E-mail: mahkamov-my@mail.ru Tashkent institute of design, construction and maintenance of automotive roads
Maintenance regimes of Mercedes-Benz buses, used in the conditions of Tashkent city
Abstract: Buses' reliability operating conditions largely depends on the adopted maintenance regimes. This paper presents the results of research on maintenance regime of buses Mercedes-Benz, used in Tashkent city. Keywords: operating conditions, maintenance, interval, work capacity, list of operations.
On June 4, 1992 by Government of the Republic of Uzbekistan was issued a decree on the establishment of the State Association "Tashgorpasstrans", which identified as key objectives: integration of all types ofurban transport in a single system, improve working and living conditions and wages of the passenger transport workers and upgrade transportation. Over the years, bus fleets operated buses of LAZ, PAZ, LIAZ models, as well as the Hungarian "IKARUS" brand production.
It was decided to acquire modern foreign large class buses of Mercedes-Benz to serve a large population of Tashkent city.
Delivery of modern city buses Mercedes-Benz has begun since 1995. Buses were distributed based on population areas in Tashkent in 9 bus parks. In order to maintain the technical condition of buses on a high level of the bus Service Center was established.
In 2015, the number of buses in Tashkent was over 1450 units, while passenger traffic reached - 268,7 million passengers.
Nowadays in Tashkent successfully operated more than 700 units of buses Mercedes-Benz O 405, O 345, Sitaro and Conecto Low floor.
Buses' operation conditions in Tashkent:
- Climate - extremely continental;
- Temperature - maximum + 44 °C, minimum - 29 °C, the average + 14,8 °C.
- Humidity - during the hottest time of - 21%, cold weather -55%. The annual precipitation is about 429 mm.
- Barometric pressure - 1 bar.
- Average annual wind speed - 1,4 m/s.
- Solar radiation - 1.52. (Cal/cm 2 min).
Air pollution (number of dust particles in the air 1 sm 3) is - 137 (in summer) and 77 (in winter).
Tashkent city belongs to the third category of operating conditions: - road surface: cement concrete, asphalt, paving stones, mosaic. Type of relief - plain (altitude is about 200).
Buses of city transport of Tashkent are used very intensively. The average mileage is - 269,3 km per day and annual average -
96.9 thousand km. In two-shift operation, the average duration of a bus operation of Mercedes-Benz is 12,70 hours. Operating speed -
21.10 km/h, the technical readiness coefficient - 0,923, buses graduation rate on the line - 0,919.
The distance between the stops is 800-1000 meters, between traffic lights - 300-500 meters.
Under the scheme of bus routes number of turns is about 1015 units.
The operating speed varies within 10,8-14,0 km/h in different routes. Solutions of coordination of optimum engine operation regimes with moving conditions of the vehicle are reflected in scientific works [7, 5-213].
Production and technical base provides timely technical maintenance ofbuses. It consists of three sections which run on the territory of the bus fleet, which are equipped with modern technological equipment in the areas of service and repair.
Reliability of the vehicle is put in the design, obtained in manufacturing and is realized in operation.
Reliability of buses for specific operating conditions largely depends on the accepted regimes of maintenance and repair in the automotive companies.
Development of maintenance regimes of buses performed by the usual method taking into account the specific conditions of operation and features of the bus structure.
Maintenance regime is corrected considering certain operating conditions.
There are resource and operational corrections.
The essence of the resource correction is that the regulations of car operation vary with respect to the reference is corrected using the correction factors for these conditions [2, 139-149].
Section 10. Transport
At resource correcting the maintenance interval is based on regulations, set in "Regulations on maintenance and repair of the vehicles" and "Operation manual of Mercedes-Benz cars O 405" [3; 4; 5].
At operational correcting by considering results of the resource correcting of buses' maintenance, as well as at the joint analysis of the experience of the service station, of results of chronometry data and expert evaluating the specialists, the maintenance regimes have been developing for specific conditions of buses operation.
The effectiveness of the maintenance and repair system is characterized by a list of operations, interval, species number and the multiplicity of maintenance [6].
Development of maintenance regime is performed in the following sequence:
1. Resource correcting of bus service interval. Choosing regulations for Mercedes-Benz O 405 from operation manual of buses Mercedes-Benz.
The recommended maintenance interval for buses MercedesBenz O 405 for Europe conditions is 45000 km [2; 3; 4].
2. For real operating conditions of Tashkent city considering the third category of operating conditions, hot climate region, as well as the quality of fuel (sulphur content) recommended maintenance interval is 15 000 km.
According to results of analysis of maintenance interval based on operation experience of service station for buses Mercedes-Benz O 405, the following intervals and types of services are accepted: L15 = 15 000 km, L30 = 30 000 km, L45 = 45 000 km, L90 = 90 000 km.
3. Choosing the list of operations from "Manuals for MercedesBenz buses".
Taking into account the operating experience of service station the list of maintenance operations of buses for the specific conditions will be set.
4. Determining the complexity of the maintenance operation for specific conditions of buses operation by experiment (by timing).
5. To organize the technologic process ofMercedes-Benz buses a flow chart (check lists) of maintenance operation develops by intervals L15 = 15,000 km, L30 = 30 000 km, L45 = 45 000 km, L90 = = 90 000 Ism.
On check lists of maintenance operation a code of operation of maintenance of structural group buses is used.
In carrying out the maintenance L15 = 15000 km, a work is done according to routine of maintenance L15 = 15,000 km.
In carrying out the L30 = 30 000 km, the works of L15 = 15 000 km are done and additional works, which are not included to the list of L15 = 15 000 km are done too;
In carrying out the L45 = 45000 km, the works of L30 = 30 000 km are done and additional works, which are not included to the list of L30 = 30 000 km are done too;
In carrying out the L90 = 90 000 km, the works of L45 = 45 000 km are done and additional works not included to the list of L45 = 45 000 km are done too.
On the base of conducted researches the following complexity of maintenance of buses are set for buses of Mercedes-Benz O 405: t15 = 33,0 person hour. t30 = 33,0 person. hour, t 45 = 50,06 person. hour, t 90 = 68,7 person. hour.
The results of research on the development of maintenance regimes of Mercedes-Benz O 405 buses in actual operating conditions are applied in motor enterprises and service stations in Tashkent, and in educational process [6, 247-260], in preparation of bachelors on a branch 5521200 - "Maintenance and repair of vehicles" and masters on a specialty 5A521205," Automobiles and automotive economy".
References:
1. Mukhitdinov A.A "Selection of control mode of continuously variable transmission of a vehicle": diss... cand. techn. sciences. - M, -1984. - 213 p.
2. Kuznetsov E. S. Technical operation of the vehicle. - M. Science. - 2004-535 p.
3. Mercedes-Benz AG. Service Manual of buses. Volume 1-5 / 95. Stuttgart 1995.
4. Service book of buses O 405, O 405 N, O 405 G. O 405 Mercedes-Benz A.G. - 1995. - 64 p.
5. Operating manual O 405, O 405 G. Mercedes-Benz A.G. - 1995. - 144 p.
6. Mahkamov M. Y., Mahkamova SH. Y. Management of buses Mercedes-Benz operated in Tashkent. Scientific journal: Tashkent State Technical University Bulletin - No. 1 / - 2015. - P. 3-7.
7. Musadjanov M. Z. Designing the enterprises of automotive industry. - Tashkent. Publisher A. Navoi library. - 2013. - 326 p.
