Unitsky String Technologies

3 September 2019

A new algorithm of unicont cooling system operation

Looking at a truck, a freight train or a multi-ton barge with containers, we do not even think about the aesthetics or environmental friendliness of this type of transport. Perhaps, some people will recall the logistical advantages in each of them. And, accordingly, the cost of cargo transportation. But few people will think about how it operates.

Unicont is not like any of the above analogues. This type of freight transport deserves attention at least because it is more attractive, efficient and environmentally friendly. However, a lot of parts, worthy of admiration, are hidden under its outer casing. We will tell about one of them today.
 

What is a cooling system and why is it needed?

As in a car, the cooling system in unicont is needed to remove heat from the elements heated as a result of its operation: motors, inverters, energy storage, charger and DC/DC converter.

Each of them has its own maximum permissible temperature for operation, at which the element overheats and ceases to function. But there’s also the outside temperature. 25°С is considered “comfortable” for unicont. Although, in general, it can “tolerate” even 60°С.

In order to avoid overheating, the new system provides 3 circuits through which heat exchange proceeds. One big circle or three small ones. Uninterrupted operation is ensured with 2 pumps: main and auxiliary.

What does the new cooling system provide?

The new three-circuit cooling system is adapted to unicont’s technical features that are radically different from the needs of passenger transport.

As a reminder, unicont is a mounted self-propelled double-rail vehicle of SkyWay transport system, designed to transport sea containers with a nominal length of 20 and 40 feet. Unicont consists of two traction modules connected to each other with a rigid telescopic coupling of centre girder type, which also serves as a cargo support platform. Its maximum speed is up to 80 km/h.

The new system allows to fully ensure the performance of the traction drive. Moreover, the cooling system algorithm provides a set of solutions in case of failure of various elements. Unicont will be able to receive them on its own thanks to an intelligent control system.

How does the new cooling system work?

As we said, the system is equipped with a large number of “smart” sensors. They constantly check the temperature in the main units. Based on this information, the intelligent control system (ICS) isolates or integrates circuits, turns on or off the air conditioner and auxiliary pump.

All actions are automated and spelled out in the program. If the system generates an error, it is assigned a code and a hazard level. Based on this level, IСS decides whether to transfer this particular unicont in the protective mode for the dispatcher to monitor it, or to eliminate the fault independently.

If failures are detected in the elements of the system, can they be fixed remotely?

The professionals of SkyWay Technologies Co. have conducted DFMEA analysis. It allowed to find out possible ways to detect failures of the main elements in this cooling system. Design Failure Mode and Effects Analysis is a method of identifying the most critical steps of production processes required for product quality management. While conducting it, they analyze potential inconsistencies of the structure, the effects of these inconsistencies and their reasons.

Based on this analysis, a number of recommendations were drawn up on what to do in case of various errors in the system. The keynote of solving problematic situations was the delivery of cargo “at whatever the cost”. Engineers say already now that this can be achieved almost always by reducing energy consumption regardless of the situation. However, there are other options of solutions that unicont will be able to make on its own.

In the event of a fault that ICS could not solve, unicont reduces speed and heads to the depot. Technical maintenance is conducted there based on the error codes and recommendations for their fixing. The main thing is not to slow down the movement on the line by no means.

Еhe cooling system is capable to come out of operation completely only in one case — violation of its integrity. And this is possible only when exposed to the outside. That is, before unicont starts to move. If the tightness of the system is affected, the coolant level will drop, which means that the sensors will be activated. Such a vehicle will not be allowed to operate.

If there is a wire break or a failure of any sensor in the system, the vehicle will not be released to the line thanks to the controller function “breakage control”.

What distance can unicont pass using only the onboard energy storage?

Unicont is designed for a contact network. However, in case of loss of power from it, it will reduce speed and switch over to operation from the onboard energy storage. Driving distance in this case will be 60 km (with straight line motion).

A large number of sensors are installed in the entire system, which ensures the performance capacity of transport. They allow to self-diagnose the problem, determine its level of danger. They determine it not only while loosing communication with some element, but also by additional features. In order to understand exactly whether this failure affects the performance capacity of unicont.

At what stage of development is unicont now?

Unicont is now in the active work phase, 95% of documentation on it is passed over to the production facility and its main units are already being manufactured. Start-up and commissioning work and bench tests in the workshop will be conducted before the end of the year.

When will we see unicont?

Unicont can be demonstrated on the readiness of the 6-th line in EcoTechnoPark, which is being built specifically for freight transportation. Then unicont will be put on rails and tested under field conditions.

As early as at the design stage, high level of safety and all possible ways to reduce risks for customers are laid down in SkyWay cargo transport. Despite all the technologically complex "stuffing" of unicont, its operation should not cause difficulties, because the design of the vehicle provides ease of maintenance, repair and storage.

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