System interrelations of thermomegments

9 октября, 2021 от arto Выкл

The average owner of a modern passenger car is likely to have absolutely no idea about

Temperature control

The value of the vehicle temperature control system is difficult to overestimate. It consists in increasing the thermal efficiency of the car, as well as in ensuring the comfort of passengers and the long-term reliability of the components. Therefore, more and more automakers are implementing advanced approaches to the temperature control of vehicles.

After all, see what is happening. Relationships here are the most direct. By increasing the effectiveness of the temperature control systems of the vehicle, the thermal efficiency of the vehicle increases. This in turn leads to a higher savings of vehicle fuel with an internal combustion engine or an increase in the mileage on one charging of electric vehicles. That is, the optimized temperature control system of the vehicle is crucial for both MOX cars and electric vehicles.

There is also an obvious difference between temperature regime management solutions for cars and electric vehicles, which exists in the energy source, power transmission and HVAC system (Heating, Ventilation and Air-Condition System — heating, ventilation, air conditioning). Motion energy in ICA is created by burning fossil fuels. In electric vehicles, it is produced by batteries.

Typical DVS produces sufficient excess mechanical power to drive a water pump, compressor and other heat sink components to monitor the temperature of the engine and the cab. In contrast, the batteries are the main source of energy for electric vehicles; Therefore, the thermal control of batteries in electric vehicles is of particular importance. Moreover, although the components of electricity can achieve higher energy efficiency at a relatively lower heat generation rate, high temperature sensitivity and low range of operating temperatures of these components require the temperature control system to have a quick reaction in real time for the conditions of vehicle movement. The engine, power modules and transmission are three main components that need to be cooled or heated using a thermostat system in an electrified transmission.

Therefore, when controlling the temperature on the electric car, cooling should be taken into account for each component, as well as the distribution of cooling circuits to achieve the best thermal characteristics with minimal power and maintain the temperature of each component at the optimal level.

Innovative development

Thus, the role of thermomeagement in vehicles equipped with any of the existing types of actuators in the foreseeable future will only increase. Returning to what we talked a little higher: the efficiency of the internal combustion engine, as everyone knows, for example, modern diesel engine, is only about 40%. That is, only 40% turns into the useful energy of motor vehicles. The remaining 60% of the energy released from the combustion of the fuel-air mixture, move along with heat, with the pressure of the exhaust gases into the atmosphere and are not used in any way.

In the electric transport, we yourself such a luxury — freely dispose of heat — we can not allow, because instead of the OI, we have a traction rechargeable battery with a specific capacity, with a certain charge, and every joule, which is formed in the process of energy transformation in traction batteries, should be extremely useful .

In order to maximize the efficiency of engines, manufacturers offer various solutions. For example, Mahle is currently developing a new type of electric motor without magnets for which rare-earth elements are not required. This not only makes production more environmentally compatible, but also provides advantages in terms of costs and safety of resources. The main feature of the new engine is inductive and, therefore, contactless power transmission — this allows the engine to work without wear and is particularly efficient at high speeds. Efficiency above 95% in almost all working points — the level that was previously achieved only by racing cars of Formula E. Thus, Mahle managed to combine the strengths of various concepts of electric motors in one product.

Technical coach, Mahle, Ilya Gusev:

One of the main goals of MAHLE — CO2 neutral transport. Motor transport using fossil energy is the main source of greenhouse effect, MAHLE offers other solutions, developing alternative power plants, not limited to one type of internal combustion engine technologies.

Therefore, the company adopted a dual development strategy — strengthening existing positions in the market, for example, a further increase in the efficiency of internal combustion engines and the development of future technologies in the changing world of mobility.

When it comes to the further development of the internal combustion engine — thermostat is in the first place, because the optimal temperature of the unit is the determining factor in its effective work.

In this regard, the role

Here, the air conditioning system is already connected directly to the regulation. Elements appear as a chieler, in which the refrigerant evaporates is evaporated, but it is already cooled not the air entering the interior of the car, and the coolant of this low-temperature contour responsible for the thermostat of the batteries.

Mahle has developed and now many autocontracens put a special ITS (Integrated Thermal System), which accumulates both warm and cold in them. The unit is assembled based on the E-Compressor Electric Compressor, represented by Mahle several years ago. It allows you to save up to 20% of electricity by car.

If you translate it into applied numbers, useless without additional clarifications, the use of this unit on an electric car with a maximum mileage on one charging 100 km without changing the characteristics of the traction battery and other elements gives a plus another 20 km.

Another new technology that MAHLE introduced last year is 3D printing technology. The fact is that on a 3D printer, not only parts made of polymeric materials can be printed, but even from metal. In fact, the same aluminum-based material is used as with the traditional production of pistons or heat exchangers used in the cooling system — MAHLE has applied 3D printing technology for the first time in the world for the manufacture of these parts. You ask why?

In order to increase the efficiency of manufactured items. For example, if we talk about the heat exchanger, then thanks to 3D printing the wall thickness, between which heat exchange occurs, is reduced to 0.2 mm. It is practically like foil from chocolate candy. Well, maybe a little thicker.

If we produce such partitions with conventional methods, which are now widely used, then so thin walls in principle cannot be performed — many unreserved problems will immediately arise with the compound of the heat exchanger components made from so thin materials. With 3D printing such problems completely disappear.

In addition, Mahle is one of the partners of the Nikola project — this is an American project of a commercial car on fuel cells — in which it is fully responsible for the development and delivery of thermomeagement systems on the conveyor. The main complexity that occurs when designing systems is an ultra-high operating pressure of the gas — in the tanks hydrogen is stored under pressure about 700 bar! At the same time, the hydrogen itself has the largest specific heat of combustion among well-known fuels, respectively, more heat is released than in the internal combustion engine and which must be used to effectively use, for example, to heat the gas before serving into a catalyst using a special heat exchanger.

In the KVS systems, the struggle besides Jouley goes also for grams — for the reduction of gramms of harmful emissions. One of the latest company innovations

Questions of the system and solutions

In hybrid cars, it is also not to do without thermomeagement. But in view of the fact that in such systems we have internal combustion engine, and the traction electrical battery, it is undoubted, much more complex. Even despite the fact that getting energy here is easier than in a battery electric car or electric vehicle with hydrogen fuel cells, because there is an internal combustion engine that gives heat. Accordingly, the question from which it does not occur to heat for heating the salon and the traction battery in winter — we take heat from the engine through the thermostat system and connecting hoses. Conversely — when we need to cool anything, we can connect the air conditioning system.

And in electric cars, whatever the source of energy, the complexity is that the heat ishing is nowhere. Essentially in electric car to get
Heat, you need to use the same battery, which is still cold after the parking lot and did not reach the optimal temperature mode. That is, in this regard, the task is much tougher than in a hybrid.

You will ask why? Because at the same time the temperature in the cabin, the outdoor temperature, the temperature of the electrical power plant, the temperature of the aggregates and all this is interconnected. If the battery is heated strong, then heat from it can be transmitted to heating the cabin. Thus, as we have already spoken, every joele of energy becomes useful and not lost. After all, the battery charge is very limited, now it increases, but nevertheless charging electric vehicles is not fast, so engineers make every effort to make a more efficient battery consumption.

If you contact machines on hydrogen fuel cells, then there is a situation even more interesting. The fact is that it is still necessary to warm up and hydrogen in the cylinders under the colossal pressure of several hundred bar and very cooling during evaporation. Therefore, it is necessary to heat this gas — it is impossible to be supplied to the fuel cell reactor in such a low temperature, where it must enter into a further reaction. That is, in cars on fuel cells even more complex systems

Challenges for after-sales service

Fortunately, any new faults in the cooling and air conditioning system did not appear in connection with its complication. As noted

A.A. Rybkin:

A fundamentally design of the air conditioning system has not changed, therefore the recommendations voiced above are equally relevant for both modern and older cars. It can be noted that modern cars, as a rule, have a more dense layout of the engine compartment, so for them the purity of the radiator is especially important.

If not to talk about full failure of the system due to damage to the main components (compressor, condenser), which happens relatively rarely, the car owners may encounter two problems — an unpleasant odor when the air conditioner is turned on and reduced the efficiency of its operation.

A.A. Rybkin:

An unpleasant smell occurs due to the contamination of the evaporator. So that he does not appear, you need to not forget to regularly change the cabin filter. By the way, in the Delphi assortment there are not only standard, but also coal filters that clean the air more efficiently. It also makes sense to periodically clean the system with special cleaners with antiseptics.

One of the main reasons for reducing the effectiveness of the climatic system is the refrigerant leakage, as a rule, through rubber seals, with time losing elasticity. In such cases, the system is refueling with a special refrigerant with a dye that allows you to localize the leakage place for subsequent elimination.

But the emergence of new components of the system definitely complicates the tasks facing the staff of the service station and presents additional requirements.

After all, see, we have already mentioned Chiler, which is responsible for cooling the low-temperature cooling circuit. You can also meet an integrated intercooler with a separate liquid contour, for example, on the «charged» cars of the Mercedes series, BMW. Therefore, the mechanics need to have broader competencies in service, at least, understanding how it is in principle, and why the system is so organized; As a maximum — easy to understand the nuances of the service.

I. Gusev:

Today, there are many different hybrid cars: «soft», plug-in, full, «micro» and so on., The proper functioning of which is largely due to the health of the air conditioning system. You will not believe, but, for example, one of the most common cars in this segment — Toyota Prius, when the air conditioner compressor malfunction simply does not start. Why? Because the drive is carried out by means of high voltage, that is, this is not a low voltage, as on many other hybrids, here the voltage is calculated by hundreds of volts, and accordingly, the high-voltage network in terms of the air conditioning system malfunction can output other electrical components of the car. Therefore, if the control unit sees the presence of any problems with the compressor, it simply will not give the machine until these problems are eliminated.

The mechanic unfamiliar with such nuances can be very surprised that the cause of difficulties with the launch of the vehicle is a malfunction of one of the components of the air conditioning system.

Increased personnel requirements

Naturally technological development of the system improves the qualifications and competence of staff staff.

I. Gusev:

We always speak the services that you should not wait for the moment when the high-tech vehicles of the future will begin massively come to the service. Employee training must be carried out in advance! It is very important.

Our company offers all existing opportunities for this. We have instructions, trainings, including practical — we leave for enterprises and demonstrate on real examples. Features of replacement of various elements of systems — DVS parts, filters, cooling and air conditioning system, oil change in automatic transmission, mechanical engineers — starters, generators, and Various service equipment. Accordingly, now we can present comprehensive materials on the replacement of compressors on hybrid cars. We already have certain materials, brochures, and so on. And we are ready to conduct trainings of this kind.

Not so long ago, a new web application was launched from Mahle — TechTool specialists. It contains basic technical information on temperature control, a detailed description of technical processes, actively troubleshooting and general information online.

A.A. Rybkin:

Our company conducts technical training both in offline and in online format on various product groups of our range, including through air conditioning systems. We not only tell about the peculiarities and benefits of our products, but also pay attention to practical aspects — nuances of the design, installation and subsequent maintenance, so that store employees and a hundred could answer almost any customer question.

As an example — the situation with the «conditionally new» freon R-1234YF and the traditional R-134: need new equipment and need special gas and, of course, special competences to understand how it is all
works.

Every year cars are technologically in due to the large number of innovation. At the same time, it is extremely important to clearly realize — due to such improvements, the car does not become less reliable. It is becoming more and more difficult due to increasing demands not only to the environmental friendliness, but also comfort, safety, dynamics, and so on. And, of course, the more systems and elements are added to the vehicle, the probability of breakage becomes higher.

What’s next

Absolutely naturally with the development of mobility technologies, in what direction they went, as already mentioned, the value of the thermomeagement system will increase and stronger and stronger. New elements appear, for example, an electrical compressor.

The advantage is that this compressor can be used in a wide range of applications — from light passenger to severe commercial vehicles. Only the actuator changes — the electric part of the control, and the mechanical remains the same.

The big plus is that this compressor can work incl. During charging, which is very important, since the presence of additional cooling allows you to charge the electric vehicle faster and more efficient. Development has already been marked by the European Association of Automotive Suppliers with a prestigious reward Clepa Innovation Awards 2019.

Undoubtedly, a certain development will continue in terms of chemistry. For example, new types of refrigerants allow you to increase the stroke of the electric vehicle.