LAZ-4202

The development of a promising medium-sized city bus designed to replace obsolete 695 cars began in the first half of the 1960s. First of all, the task was set to create a fundamentally new body with wide doors. The prototypes of the medium bus (LAZ-698) and large capacity (LAZ-696) were built in 1966. However, for a number of reasons, they were not launched into mass production. From the "big" model 696 subsequently completely abandoned. Model 698 has undergone improvements.

In the 1970s, after the cessation of the creation of the LAZ-698 bus with a ZIL-375 gasoline engine, the GSKB for medium and high-capacity city buses (since 1975 - the All-Union Design and Experimental Institute of Bus Engineering ) began work on the creation of a new diesel bus KAMAZ-7401 engine ^{[3] [4]} . The bus was originally developed as part of a new unified family of buses (which included the average city bus LAZ-4202, suburban bus LAZ-42021, large city buses LiAZ-5256 and LiAZ-5256M and tourist buses LAZ-5255 ) ^[5] .

The new promising bus retained in some way the body of the previous experimental model 698 of the early 70s, however, since its engine was located at the rear, the interior layout was redesigned for greater convenience. There were still two doors to the passenger compartment, but now the second one was not in the rear overhang, but in the base, almost in the middle of the body in front of the rear axle, like many urban European buses.

In 1976-1978, the forces of the experimental workshop produced several pre-production samples of the bus, which passed state tests. In 1978, the 25-seater LAZ-4202 was recommended for production as a basic model of a middle-class bus for urban transportation ^[6] for the period until 1990 ^[7] .

The official release of the bus began in November 1978 ^[8] . However, due to delays in the supply of components, that year only 2 samples were collected, the next 11 copies, and in 1980 15 copies. After that, the release of the bus was temporarily suspended until 1982 by the Lviv Center for Metrology and Standardization due to the insecurity of buses of this model by extension valves for the pumping pad of the internal wheels of the rear axle.

The first few LAZ-4202 were tested in the 5th bus fleet of Moscow ^[9] .

The experience of operating the first buses in the country's car fleets by the beginning of 1981 revealed design flaws: low reliability of the new three-speed hydromechanical gearbox GM-3-80 and increased fuel consumption by the engine in the winter in urban areas ^[10] . The base KamAZ-740 engine was not quite suitable for operation in urban conditions, and since 1981, the demanded KamAZ-740 engines began to be put on buses. In addition, it was recommended to send diesel LAZ-4202 to fleets, technical personnel and drivers of which are already familiar with the peculiarities of operation of Ikarus diesel buses. Separate emphasis was placed on the inadmissibility of replacing the recommended all-weather grade A oil grade TU 38 101179-11 recommended for lubrication of a hydromechanical gearbox by any other oils ^[2] .

In 1982, the Lviv Automobile Plant resumed serial production of the city bus LAZ-4202 with a new three-speed gearbox ^[11] .

During operation, insufficient structural strength of the supporting body was revealed - it quickly loosened, and the service life of the first LAZ-4202 was approximately three years ^[12] .

In 1984, at the Avtoprom-84 exhibition, the plant introduced a new modification of the LAZ-4202 - a 35-seater local bus LAZ-42021 ^[8] . The LAZ-42021 resource was increased to 900 thousand kilometers (for a new bus, the resource before the first overhaul was 500 thousand km, the repair provided an overhaul life of another 400 thousand km) ^[13] .

Also in 1984, a pilot batch of LAZ-42021 buses was released, which were soon to be replaced by the 4202 model on the LAZ conveyor. At the same time, the production of LAZ-4202 lasted until October 1985, until it was finally replaced by the 42021 model. A total of 1,542 units of the 4202 model were built.

Until April 1984, the Sirocco liquid fuel heater manufactured by the German Democratic Republic was installed on the buses (subsequently, they began to install the model 148106 heater); since July 1984, the buses stopped installing a separate fuel tank for the heating system (the main fuel tank was the source of fuel) ^{[ 14]} .

In 1985, the specialists of NAMI and the Lviv Automobile Plant manufactured two LAZ-4202 operating on compressed natural gas and diesel fuel - gas equipment manufactured by the Ryazan Automobile Equipment Plant from LAZ-695NG was installed on them ^[15] .

Since 1991, instead of the generator of the G289 model, the generators of the 65.3701 model ^[16] began to be installed on the LAZ-42021.

In mid-1991, the VKEI of bus engineering proposed to start production of the LAZ-4206 at the Lviv Automobile Plant to replace the LAZ-695N and LAZ-42021 ^[17] .

After the fire on April 14, 1993, at the KamAZ engine factory in 1993, all modifications of the LAZ-42021 were discontinued (although the Cabinet of Ministers of Ukraine in January 1994 considered the possibility of continuing the production of city buses LAZ-42021 to meet the needs of the Ministry of Transport of Ukraine) ^[18] .

For several years, until 1995 inclusive, the bus under the name "42021" continued to be produced in small batches at the Konotop Aircraft Repair Plant . ^{[19] [20]}

LAZ-4202 received a 180-horsepower KamAZ-7401 diesel engine, a 2.2 kW G289 generator, four 6ST-90EMS ^[1] rechargeable batteries and 24 V electrical equipment, which reduced the degree of unification of electric equipment LAZ-4202 with other Soviet buses production up to 57% - only 70 of 165 products of electrical equipment and devices were interchangeable (while at LAZ-695N the degree of unification was 95%) ^[21] . When creating the LAZ-4202, new technical solutions were used ^[22] (in particular, an automatic transmission and power steering) ^[6] and progressive materials (noise-absorbing material like “Antiphon”; self-adhesive heat-insulating material developed by NPO “Cell”; new adhesives and other) ^[23] .

The front axle assembly with brakes and the steering trapezoid was unified with the LiAZ-677 bus, the power steering was unified with the Ural-375 ^[1] .

The driver's seat was developed by specialists of the Kama Automobile Plant ^[2] .

The all-metal body of the carriage layout had a base in the form of a frame made of large closed profilesPS-232 and PS-233 connected by electric arc welding ^[1] . Due to the size of the engine, the traditional layout of the city bus has changed - the LAZ-4202 four-wing doors were not located in the overhangs, but in the front overhang and in the base ^[22] .

The floor of the bus was made of 12 mm thick bakelized plywood , between which a sound-absorbing layer of sheet rubber 1.5 mm thick was laid underneath the steel frame of the body, and the top floor was covered with 6 mm thick corrugated polyvinyl chloride sheet linoleum ^[1] .

To improve ride smoothness, the bus was equipped with a spring-air suspension with a telescopic shock absorber and three body position regulators ^[22] . The cruising range of the bus on paved roads was 600 km ^[2] .

LAZ-4202 is equipped with a liquid heating system that provides the possibility of operating the bus at temperatures from −40 to +40 ° C ^[1] .

• LAZ-4202 - basic version, 25-seater city bus ^{[6] [17]}
• LAZ-42021 - Suburban 35-seater bus ^[8]
• LAZ-4204 - a standardized version of a 25-seater city bus with a modified heating system and some other design changes ^[14]
• LAZ-420212 is an intercity bus based on the LAZ-42021, which was produced at the Konotop Aircraft Repair Plant in the early 1990s. In this version, both automatic doors were replaced by manual ones. For this reason, the doorways became narrower, and between the doors there were not two windows, like the standard LAZ-42021, but three windows ^[20]
• LAZ-420217 - self-propelled chassis ^[17]
• LAZ-4969 - a mobile dining room based on the LAZ-4202 ^[17]

Further development of the design of the LAZ-4202 steel model LAZ-4206 and LAZ-4207 .

LAZ-4202, 42021 and their modifications were, of course, a big step forward in the Soviet bus industry. In particular, compared with the previous LAZ-695 model, the new buses had a much more spacious interior with greater capacity, wide doors, a diesel engine, in fact, for the first time in almost two decades (since the ZiS-127 was taken out of production in 1961 ) At the same time, the bus was created for a long time and launched into the series painfully difficult. It is officially accepted that this happened in 1978, but in fact, in 1985, it was possible to create a rhythmic release and overcome all the “diseases” of the machine.

• Shugurov L.M. , Shirshov V.P. Automobiles of the country of the Soviets. - M .: DOSAAF, 1980 .-- 105 p.
• LAZ-4202 // Brief automobile reference book of NIIAT. 10th ed., Trans. and add. M., "Transport", 1983. p. 51-52
• Shugurov L. M. Cars of Russia and the USSR. In three parts. Club fans of technology. - M .: ILBI, Prostrex, 1993.

• Bus photobank [1] , [2] , [3]
• Cars in pictures