On December 8, 1946, the first domestic ZiS-154 bus, which had a carriage layout, was tested. And this was not his only feature. The new bus was the first Soviet car with a hybrid powertrain. That is, a sequential circuit was implemented in it. In it, the internal combustion engine was rotated by a generator, from which, in turn, were powered by electric motors that transmit torque to the drive wheels.
Start and prototypes
Work on the project began in early spring of 1946. By May of that year, a specialized bus design bureau was organized at ZiS, which was engaged in the construction of a new car. The bureau was headed by A. I. Skerdzhiev. It is worth noting that the design of the bus was not created from scratch. The prototypes of the new model are the American GMC and Mack. It was these machines that had a carriage layout and a body made of aluminum alloy, which was subsequently used in the design of the ZiS-154 body.
The engine of the new car was also not original. Two-stroke power unit with a capacity of 110 liters. from. (YAZ-204D), in essence, was a "pirated" copy of the American engine from GMC. Moscow buses were supposed to take in their ranks a new car for the 800th anniversary of the capital of the USSR. Therefore, to prevent unforeseen situations during the celebration of the anniversary, on the first issued 45 “model” copies of the ZiS, the domestic power unit was replaced with a GMC-4-71 diesel engine, received during the war years from the Lendlis allies.
Aluminum bus
Since ZiS had never before produced cars with all-metal bearing bodies, it was decided to involve specialists from the Tushino aircraft plant in the design of the bus. As a result of the joint work of two design bureaus, a load-bearing body was created, the design of which was a set of several sections similar to each other, consisting of frames, cast from steel and aluminum profiles. They also decided to unify the ZiS-154 body structure with the bodies of the MTB-82B trolleybus and the MTV-82 tram. The difference was only in the fact that for these types of transport it was made not bearing.
Bus transmission
The power unit was located transversely in the rear overhang of the bus, under a five-seater sofa. The YaAZ-204 D diesel engine was connected to a power generator that supplied direct current to the electric motor, which transmitted rotation through the cardan to the rear drive axle. Changing the direction of movement (back and forth) was carried out using a switch located near the driver's seat. Switching was allowed to be performed only after the bus stopped completely.
The magnitude of the required traction effort was automatically adjusted, which was an undoubted advantage of the electric transmission. In this regard, the driver’s work was much easier. There was no need to shift gears, respectively, and to squeeze the clutch pedal, which was important in urban conditions. However, such convenience required accurate and, most importantly, qualified maintenance of the unit, which, naturally, at that time was a big problem due to the novelty of the system and the lack of specialists who could make repairs.
In addition, the energy transmitted from the internal combustion engine, while reaching the wheels, underwent a double conversion with significant efficiency losses. And this led to high fuel consumption (65 liters per 100 km). Nevertheless, the new ZiS went into the series. By early July, Moscow buses accepted the first 7 cars produced by the plant. And on September 7, the fleet replenished by another 25 units.
To the delight of passengers
The design of the bus in terms of passenger convenience turned out to be quite successful. The salon was designed for 60 seats, including 34 seats. The seats were covered with dermantine or plush. For the winter period, the ZiS-154 was equipped with a good heating system, and for the summer - ventilation. Comfort was also added by the soft suspension. The bus smoothly accelerated, evenly moved, which in comparison with previous models was just an automobile miracle. Nevertheless, during operation, a significant drawback was revealed, which ultimately led to the removal of the machine from production.
The big problem of the new bus
The whole problem of the ZiS-154 was the engine. In addition to high fuel consumption, the YAZ-204D was very noisy. At the same time, he still mercilessly chado black exhaust. But even this was not the worst. From time to time, the diesel of the bus, as they say, "went into the spreader", that is, independently and uncontrollably increased speed. To stop him, the driver needed to shut off the fuel line. And if you remember that the engine was in the rear of the car, then this really was a serious problem.
"Spacing" has become a real scourge ZiS-154. Even in the instructions for safe operation of the bus, the driver was instructed to stop the bus with a hand and foot brake. Then he needed to ask the conductor or one of the passengers to continue braking, and immediately go to the engine compartment and turn off the fuel line, thereby interrupting the supply of fuel to the engine nozzles. They could not eliminate this malfunction at the plant, since they did not exactly know the main cause of the phenomenon.
Therefore, already in 1950, that is, three years after the start of production, the serial production of the ZiS-154 was completely discontinued. Nevertheless, during this time the plant managed to produce 1,165 “miracle buses”, from which bus fleets tried to get rid of by hook or by crook. Of course, the bus, although it was an innovation for its time, was very unsuccessful, and therefore did not receive further development.