LAZ-695NG

In the early 1970s, the USSR decided that it was necessary to develop work on converting vehicles to compressed natural gas. After 1981, a number of resolutions were adopted aimed at accelerated production of gas-filled motor vehicles, the construction of a network of automobile gas-filling compressor stations and the manufacture of equipment necessary for them ^[4] .

The LAZ-695NG bus was developed in 1984 ^{[5] by a} team of specialists from the All-Union Design and Experimental Institute of Bus Engineering and the Lviv Bus Plant ^[6] under the leadership of the main designer of the All-Russian Higher School of Economics G. Skrechko ^[7] .

Initially, the ZIL-138A engine with a volume of 6000 cm³ was installed on the first prototype of the bus, however, the engine of the ZIL-138 I model was installed on the next two pre-production LAZ-695NG samples and all the following serial buses ^[8] . The use of natural gas as a fuel allowed to reduce the toxicity of exhaust gases by 20-30%, reduce carbon formation by 30-40% and reduce engine wear. In addition, the use of natural gas as a fuel had a positive economic effect (the control fuel consumption of LAZ-695NG per 100 km at a speed of 60 km / h was 0.173 m³ of gas or 35 l of gasoline) ^[2] .

According to the results of the operation of the first buses, the specialists of NITSIAMT and the 3rd bus fleet of Moscow developed a neutralizer-muffler for the LAZ-695NG ^[9] .

On July 19, 1985, the Lviv Bus Plant began mass production of the LAZ-695NG ^[3] .

At the end of 1985, the first 32 LAZ-695NG buses arrived in Tashkent and were sent to convoy No. 2519 of Glavtashpasstrans. During the operation of buses in hot climates, generally positive results were obtained, however, specialists from the Uzavtotranstekhnika Scientific Production Association identified individual failures (mainly, leakages in the high-pressure system and several cases of engine failures) sent to motorcade No. 2519 for technical support of new cars , including those associated with poor build quality), but parts of the high pressure reducer needed to be replaced 92 times. As a result, changes were made to the design of the gearbox ^[10] .

In 1986, the design of the LAZ-695NG was improved - gas cylinders were installed so that their center of gravity was exactly above the axis of the rear axle of the bus, and a new three-stage gas reduction heater was installed in gas equipment ^[8] .

By the beginning of 1987, the operational experience of the LAZ-695NG was assessed as positive and the expansion of their use in the USSR was limited primarily by the lack of infrastructure (lack of gas stations) ^[10] .

On February 7 - 9, 1990, the All-Union Scientific and Practical Meeting on the Use of Alternative Motor Fuels in Automobile Transport was held in Kiev with the participation of 30 organizations (scientific and design institutes, automobile and oil and gas industry enterprises), at which the possibilities of improving the design of gas cylinders used in automobile transport: as a replacement for standard cylinders made of steel sheet, cylinders made of seamless steel pipes and metal were proposed reinforced fiberglass plastic cylinders and cylinders made of aluminum ^[11] .

In 1991, it was decided to continue production of the LAZ-695NG until 1995 ^[12] .

After the independence of Ukraine, the production of the LAZ-695NG was continued, while there were cases of conversion of the previously issued LAZ-695N buses to the LAZ-695NG.

In May 2002, the press service of the Lviv Automobile Plant announced the termination of production of all modifications of the LAZ-695 buses ^[13] and in June 2002 the production of all modifications of the LAZ-695 (including the LAZ-695NG) in Lviv was discontinued ^[14] .

In 2003, the technological equipment necessary for the production of all modifications of the LAZ-695 bus was transferred to the Dnieper Bus Plant , ^{[15] [16]} where the LAZ-695 buses (including the LAZ-695NG ^[17] ) were produced until 2010. ^[1] Dneprodzerzhinsky buses differed from Lviv in the absence of a driver’s door and seamless sides without molding. ^[18]

LAZ-695NG is developed on the basis of the design of the serial LAZ-695N bus and is a mid-size, mid-engine, mid-engine city bus with a rear engine. The main differences from the base model are the power plant (LAZ-695NG is equipped with a ZIL-138I multi-fuel engine with the possibility of using gasoline and compressed natural gas as a fuel, as well as a set of gas equipment manufactured by the Ryazan automobile equipment plant) and a cap over the rear of the roof (under which placed compressed gas cylinders). On the roof they had only one hatch (in front). There was no hatch in the back or in the middle. They also had a gas tank on the right (for convenience), which was also on the LAZ 695 and 699 gas buses, though not all. As a result, in comparison with the LAZ-695N, the height of the LAZ-695NG bus increased from 2950 to 3100 mm, and the weight increased from 6850 to 7525 kg ^[2] .

The machines were equipped with standard 50-liter carbon steel gas cylinders ^[4] . The placement of methane cylinders on the roof of the bus is explained by the requirements for safe operation - in case of depressurization of the system or in an emergency, methane, which is lighter than air, instantly disappears before it has time to make fire or explode.

For the manufacture of facing parts LAZ-965NG began to use steel 08DPR ^[19] .

Since 1991, the LAZ-695N, LAZ-695NG and LAZ-699R began to install generators G-287-K ^[20] .

The main fuel was methane ^[3] high pressure ^[10] (compressed to 200 atmospheres), which from the cylinders through pipelines is fed to a pressure reducing valve. From the gearbox, the gas-air mixture enters the engine.

• A.A. Zubarev, I.P. Plekhanov. Gas balloon cars. M., publishing house DOSAAF USSR, 1984.
• Cand. those. n A. Morev, Ph.D. those. n V. Erokhov. Basic conditions for the safe operation of gas-filled vehicles // Automobile Transport, No. 10, 1986. p. 37-39