RU192388U1 - Vehicle Testing Station - Google Patents

Abstract

The utility model relates to test equipment for determining the performance characteristics of motor vehicles and at temperatures from +50 to -50 ° C. The proposed utility model provides measurements and tests of vehicles in an extended temperature range from +50 to -50 ° C. The technical result is achieved by that in a test station for checking vehicles, including a thermally insulated chamber, refrigeration and heating systems, as well as a set of equipment for measuring and automatically maintaining temperatures ry, the thickness of the thermal insulation of the chamber is increased to 200 mm, two layers of a thermal insulator 100 mm thick are laid on the floor of the chamber with overlapping joints between adjacent plates, and a distributed heat-generating element is placed under the thermal insulation layer, the temperature of which is controlled and automatically maintained at a predetermined level by a separate control system, the operating mode of the existing refrigeration system is changed in such a way that the temperature of its evaporator during operation does not drop to a temperature below +2 ... + 4 ° C, There are two more refrigeration systems: medium temperature, providing operation up to minus 25 ° С, and low temperature, providing operation up to -50 ° С, increase the number of fan heaters up to 6 units and supplement the measurement and automatic temperature control system with equipment capable of operating with an extended temperature range from -50 to + 50 ° С.

Description

The utility model relates to test equipment for determining the performance characteristics of motor vehicles and at temperatures from +50 to -50 ° C.

The test station is designed for measurements in laboratory conditions:

- heat transfer coefficient of isothermal vans in accordance with the requirements of the ATP agreement (measurements are carried out at an air temperature in the measuring chamber of + 7 ° C). Details of the ATP agreement are below;

- measuring the refrigerating capacity of refrigeration units of refrigerated trucks, as well as automobile air conditioners, including those designed to operate in hot and tropical climates (measurements are carried out at air temperature in the measuring chamber from +30 to + 50 ° С);

- tests of the operability of automotive heating equipment (measurements are carried out in the range of air temperature in the measuring chamber from 0 to -50 ° C).

In addition, developers of vehicles designed to work in the Arctic and subarctic regions are interested in checking the performance at low temperatures up to -50 ° C of steering, brakes, hydraulics, PZD (pre-heater for a liquid diesel engine), whether the vehicle’s engine starts warming of the PZD, the condition of the batteries, do the doors and hatches open, do the windshields in the driver’s cabin freeze, do the wiper blades, lighting devices work, radio and navigation equipment, additional equipment installed, for example, in a car laboratory or car workshop and much more.

Very often you have to deal with large-sized vehicles, for example, the length of the semi-trailer of the truck reaches 14 meters, and the width of the heavy tank reaches 3.7 meters.

To test the individual components of vehicles, you can use many types of heat-cold cameras on sale, but their dimensions do not allow you to work with large-sized products of motor vehicles. For example, a large line of heat-cold chambers is known, OOO Mir Oborudovaniya, the leading Russian manufacturer of climate chambers, http://miroborudovaniya.ru/klimaticheskie_kamery_teplo-kholod.

A common drawback of all these cameras and cameras of many other foreign and domestic manufacturers with all their technical advantages are too small dimensions for working with large-sized products of motor vehicles.

A large-sized chamber for temperatures from +50 to -50 ° C for testing vehicles is a piece-wise development that is created for a specific range of tasks. Such measuring chambers intended for testing motor vehicles both at high temperatures up to + 50 ° C and at low temperatures up to minus 50 ° C are units.

As a prototype of the selected "Test station for checking vehicles for compliance with the requirements of the ATP", A.A. Petrov, B.A. Obolensky, M.G. Korchazhkin, Transport Systems, No. 3 (6), 2017, pp. 12-20, located on the territory of NSTU named after R.E. Alekseev in the city of Nizhny Novgorod. See figure 1.

The station is a heat-insulated chamber made of sandwich panels (polyurethane foam 80 mm thick) with heat-insulated double-leaf gates at both ends.

In the side wall of the chamber there is an additional heat-insulated single-leaf door and an entrance to the inspection hole.

In front of FIG. 1, through the open double-leaf insulated gate, the lifting door of the heated room is visible, in which the heat-insulated chamber of the test station is installed.

There are four air vents near the entrance gates with insulated doors each to provide for supply and exhaust ventilation of the chamber. Two of them in figure 1 to the left and right of the gate at the bottom of the end wall, the other two - above the gate in the opposite end wall. To the vents located above the gate, you can climb the stairs. Exhaust fans are installed in these windows. From the sites at the top of the stairs, a survey can be carried out using a thermal imager of vehicle roofs. The thermal insulation of gates, window leaves and side doors is also 80 mm, like the camera itself.

The camera is assembled inside a heated room and attached to the elements of its structure (figure 2).

The chamber has a system for removing exhaust gases from a working car engine.

On the walls of the chamber are eight axial fans for mixing air in order to ensure uniformity of the temperature field.

The chamber is equipped with refrigeration and heating equipment that automatically maintains the air temperature in the chamber from +30 to minus 10 ° C at any ambient temperature.

The compressor unit of the refrigeration system is located outside the chamber, and is not shown in FIG. 1, as is the condenser unit placed on the outer wall of the room. Their images will be given below.

The air cooler of the refrigeration system is installed above the gate inside the measuring chamber (figure 1).

The refrigeration system provides the possibility of cooling the air in the chamber with an unloaded isothermal van installed in it weighing up to 1000 kg up to a temperature of + 7 ° C for a time of about 3-4 hours. This temperature is necessary to measure the heat transfer coefficient of the isothermal van in accordance with the ATP agreement.

To ensure positive temperatures up to + 30 ° C, four electric fan heaters available there controlled by a temperature control system (not shown in Fig. 1) can be included in the chamber. Fan heaters are installed on the floor, their number and location is determined by the test mode.

An inspection pit is required for thermal imaging inspection of the vehicle from below.

The temperature measurement and maintenance system located outside the chamber provides automatic maintenance of the air temperature in the chamber with the help of cooling and heating systems in the range from +30 to -10 ° С.

This thermally insulated measuring chamber was created to ensure measurements in accordance with the requirements of the ATP agreement - the “Agreement on the International Transport of Perishable Foodstuffs and on Special Vehicles Designed for this Transport”. This agreement is a document of the United Nations Economic Commission for Europe (UNECE). The current version is located at http://www.unece.org/trans/main/wp11/atp.html.

The thermally insulated measuring chamber, selected as a prototype, has all the necessary components to ensure measurements in accordance with the ATP and provides the necessary range of air temperatures in the chamber from + 30 to -10 ° С.

The disadvantage of the prototype is the small operating temperature range.

Recently, there have been many customers to test vehicles in laboratory conditions in an extended temperature range from +50 to -50 ° C. Especially in demand tests at low temperatures. The relevance of such tests is determined by the need to develop hydrocarbon reserves on the shelf of the oceans. A significant part of the Russian shelf is located in the cold Arctic and Far Eastern seas.

The above prototype camera cannot provide the required temperature range.

The technical result is the provision of measurement and testing of vehicles in an extended temperature range from +50 to -50 ° C.

The technical result is achieved by the fact that in a test station for checking vehicles, including a thermally insulated chamber, a refrigeration and heating system, as well as a set of equipment for measuring and automatically maintaining temperature, the thickness of the thermal insulation of the chamber is increased to 200 mm, they are laid on the chamber floor with overlapping joints between adjacent two layers of a heat insulator with a thickness of 100 mm each, and a distributed heat-generating element is located under the heat-insulating layer, the temperature of which is controlled they are controlled and automatically maintained at a predetermined level by a separate control system, the operating mode of the existing refrigeration system is changed in such a way that the temperature of its evaporator during operation does not drop to a temperature below +2 ... + 4 ° C, and two additional refrigeration systems are installed: medium temperature, which ensures operation up to minus 25 ° С, and low-temperature, ensuring operation up to minus 50 ° С, increase the number of fan heaters up to 6 pieces and complement the system for measuring and automatically maintaining the device temperature a tour capable of working with an extended temperature range from -50 to + 50 ° C.

View of the camera after all the modifications in Fig.3, Fig.4, Fig.5, Fig.6 and Fig.7

The essence of the utility model and its operation is illustrated by the example of a real design, shown in Fig.3,4,5 and 6. Schematic diagram in Fig.7.

In a heat-insulated chamber 1 with entrance gates 2 and 3 at opposite ends, the thickness of the heat insulation of all walls, the ceiling, the gate, the side door and the window leaves, which in the prototype chamber was 80 mm, is increased to 200 mm by installing an additional layer of heat insulator. Seals made of elastic material on the perimeters of all gates, doors and windows are replaced with low-temperature ones.

On a concrete floor, which was not thermally insulated in the prototype chamber, two layers of heat insulator 4, 100 mm thick each (extruded polystyrene foam of 1200x600x100 mm in size) are laid in a checkerboard pattern with overlapping joints. In the schematic representation of Fig 7. the thickness of the insulation 4 on the floor is exaggerated and it is emphasized by shading that it consists of individual plates. The inspection hole is completely blocked.

To protect the concrete floor 5 when testing at a negative temperature (from 0 to -50 ° C) from cracking and to prevent freezing of the soil under the floor, a distributed fuel element 6 (heating cable from the Heat-insulated floor kit) is laid directly on the concrete floor under a double layer of heat insulator ), the temperature of which (+2 ... + 3⁰С) is controlled and automatically maintained at a predetermined level by the control system 7.

Before installing the vehicle 8 in the measuring chamber, the area from the entrance gate to the location of the vehicle is freed from the heat insulator, while the heat insulating plates are placed along the chamber walls, as can be seen in Fig. 4 and Fig. 5. It is to facilitate this procedure that the floor insulation is made of separate lightweight plates of the heat insulator. Fuel elements are pushed to the side to prevent damage to the wheels of the vehicle.

After installing the car in a measuring chamber, the initial air temperature in which is +20 ... + 25 ° С, since the measuring chamber itself is mounted in a heated room, it is often necessary to dry a car that has been in the rain or in snow. A large amount of moisture in the closed volume of the measuring chamber excessively increases the humidity of the air, which is deposited on the heat exchangers of the air coolers in the form of a layer of frost, reducing their cooling capacity, and forcing the refrigeration systems to excessively frequent automatic stops for defrosting the heat exchangers, which lengthens the already lengthy measurement process. Moreover, until we remove water from the car and snow falling from the wheel arches of the car with anti-icing reagents from the floor, we cannot start laying the heat insulator on the floor, which was previously set aside, and which, in conditions of excessive humidity and draining water from the car will quickly lose its heat-insulating properties. In addition, the remaining water on the roof of the test vehicle for determining the heat transfer coefficient of the insulated van in accordance with the ATP agreement distorts the obtained value of the heat transfer coefficient.

Most of the water from the concrete floor and the roof of the van is removed by traditional means - rags, vacuum cleaners, compressed air, and to complete the moisture removal process, a reconstructed refrigeration system 9 and an air cooler 9 are used as a dehumidifier.

As mentioned above, the refrigeration unit 9, initially present in the prototype chamber, originally capable of cooling the air in the prototype chamber to minus 10 ° С, which initially included the air cooler 10, was reconstructed so that, firstly, its powerful three-fan air cooler 10 is replaced by a less powerful two-fan heat exchanger 9, which, secondly, after reconfiguring the control unit of the refrigeration system, never cools to negative temperatures, but cools only to +2 ... + 4 ° С.

Before such a readjustment, the heat exchanger quickly cooled to negative temperatures, condensed excess moisture on itself in the form of hoarfrost, was forced by the readings of its sensors to automatically periodically stop working on cooling the chamber to defrost the heat exchanger, and therefore increased the duration of the cooling process of the chamber.

Passing repeatedly through a heat exchanger cooled to a temperature above the freezing point of water for several hours, moisture from the air of the measuring chamber does not condense on the ribs of the evaporator in the form of hoarfrost, but flows into a tray and is removed outside the chamber through a drain. The refrigeration unit 9 in this mode does not stop according to the readings of its sensors for defrosting the heat exchanger. At the same time, the refrigerating capacity of this reconstructed refrigeration system is sufficient to obtain and automatically maintain in the measuring chamber an air temperature of + 7 ° С, necessary, for example, for measuring the heat transfer coefficient of insulated vans in accordance with the requirements of the ATP agreement.

Only after the car and concrete floor have been completely dried for 3-4 hours, if necessary, heating cables and heat insulating plates are again laid under the car. (Sometimes you have to climb into the inspection hole for this!) Near the wheels, a rigid heat insulator does not allow you to close the remaining slots tightly, therefore, a soft polyurethane foam (foam rubber) is used near the wheels.

Rubber wheels themselves are a good enough heat insulator, but sometimes, for the convenience of laying heat insulator plates near the wheels and always when testing tracked vehicles, they are driven (or even installed with jacks) onto heat-insulating linings (high density foam and multi-layer plywood on top), the correct geometry of which simplifies laying of heat-insulating plates. The use of a soft heat insulator is, however, also necessary.

The procedure for laying a heat insulator under a car is quite laborious, therefore, a heat insulator and heat insulating linings for a car are installed only in the case of tests at low temperatures. The refrigeration system will not provide either -25 ° C or -50 ° C if the concrete floor with heating cables turned on is not insulated from the chamber volume.

If the test temperature is above zero degrees, for example + 7 ° С, which is required to measure the heat transfer coefficient of refrigerated vans in accordance with the ATP, the cooling capacity even of the reconstructed and reconfigured high-temperature refrigeration system 9 allows you to get the desired temperature of type + 7⁰С without thermal insulation of the floor, and the heating a system in the form of several fan heaters placed on the floor around the perimeter of the camera allows you to heat the camera to + 50 ° C. In this case, the vehicle without any heat-insulating linings on the floor is installed directly on the concrete floor.

Only after complete thermal insulation of the floor under the test vehicle at low temperatures installed on the heat-insulating linings does the refrigeration system and the automatic heating system for the concrete floor surface be included. Depending on the required test temperature, either a medium temperature refrigeration system 10 (for operation up to -25 ° C) or a low temperature system 11 (during operation up to -50 ° C) is selected. They always strive to use a refrigeration system, the energy consumption of which is less.

Suffice it to say that the rating power consumed from the 380V network of two compressor units of the low-temperature refrigeration system, providing -50 ° C, is 32 kW versus 9.7 kW for medium temperature and 5 kW for high temperature. Plus 2-10 kW for fans of condenser systems and air coolers.

For all three refrigeration systems, Bitzer compressors and components of leading world companies were used.

The total duration of the tests, including drying a wet vehicle and the floor, cooling the chamber and the vehicle itself to low temperatures, performing all measurement procedures and subsequent heating of the vehicle, can reach 3 days.

At the end of low-temperature measurements, the vehicle is heated directly in a closed measuring chamber to at least + 10 ° C, otherwise, especially in the summer, when the humidity is very high, the vehicle, if it is driven out of the camera to the street or even simply opened the measuring chamber gate is covered with a thick layer of frost, which, when melted, can damage the car’s electronics.

To heat the air in the chamber, the number of fan heaters (12 in Fig. 7) is increased to 6 pcs. (against 4 pcs. of the prototype) with a total power of 18 kW (against 12 kW of the prototype). Heaters, as a rule, are distributed around the perimeter of the chambers, in some cases some of them are installed even in the inspection pit.

The control unit using the temperature controller allows you to heat and automatically maintain, with an accuracy of ± 0.5 ° C, the set air temperature in the chamber with in the range from room to + 50 ° C. The control unit is outside the measuring chamber.

High temperatures in the measuring chamber are necessary (to simulate a hot summer) when measuring cooling capacity or checking the operability of refrigeration units of refrigerated trucks, as well as automobile air conditioners, including those designed to operate in hot and tropical climates (measurements are carried out at an air temperature in the measuring chamber of +30 up to + 50 ° C).

We add that gas discharge lamps illuminating the space of the measuring chamber of the prototype, at a temperature below minus 40 ° C, light up, so they are replaced with LED lamps. In Fig. 4, on the left wall there are LED lamps, and on the right there are also discharge lamps.

Temperature measurement in the measuring chamber after its reconstruction is carried out by two multi-channel (12 measuring channels each) TM-12 thermometers, which cover our entire extended range from -50 to + 50 ° С. Thermometers are also placed outside the measuring chamber.

All controls for the electrical equipment of the camera, measuring instruments and other electronic equipment involved in the measurements (their composition depends on the type of measurement) are concentrated in one zone - measurement zone 13, located outside the measuring chamber, where, like in the whole room in which a measuring chamber is installed, maintain room temperature.

Given the significant dimensions of the measuring chamber, elongated cables are used to transmit the signal from the measuring sensors to the measuring equipment, which is taken into account when calibrating the measuring devices.

We give an example of testing a car on a fragment from a real test report.

This test was supposed to simulate the following situation: the ambulance was on the street for a long time at an ambient temperature of -25 ° С. Inside the car, with the car engine running, using its standard heating equipment (antifreeze heater), the air temperature was maintained at + 20 ° С. The car stalls, the heat output of the antifreeze heater drops to 0. By how many degrees will the air inside the car cool down in 30 minutes at several given points? The rate of fall in air temperature in such a situation is regulated by the relevant documents and is one of the criteria for acceptance of a vehicle by the customer.

PROTOCOL No. 294 / З-25 dated August 10, 2018

thermal insulation estimates for a van.

1. The subject of the test

To assess the thermal insulation, 2 cars No. 1 and No. 2 were provided - an ambulance based on an UAZ chassis, fully equipped with the necessary equipment, state number - without a number, manufactured in 2018 by Avtodom LLC.

2. Measurement conditions, method and means of measurement

The measurements were carried out from 11:00 a.m. August 9 to 15:00 a.m. August 10, 2018.

Place of measurement: NSTU testing station, N. Novgorod, Kazan highway, 12.

3. Instruments and measuring instruments

Name of measuring instruments
Measuring range
Date of last verification / verification interval
Error
Thermometer TM-12.3
(-50 ... + 200) ° С
February 2018/12 months
± 0.05 ° C
Temperature regulator "Metacon-513"
(0.1 - 12) kW
February 2018/24 months
0.5%

4. Test modes:

- automatically maintained temperature in the measuring chamber -25 ° С;

- automatically maintained temperature in the cabin + 20 ° С.

An electric heater with a fan is installed in the van, automatically using the Metacon-513 temperature regulator the air temperature in the ambulance is maintained at + 20 ° С during the entire cooling cycle of the measuring chamber to -25 ° С.

After cooling the air in the measuring chamber to -25 ° C, automatically maintained air temperature in the passenger compartment + 20 ° C and holding it at these temperatures for 6 hours, the heater and fan in the passenger compartment are turned off and within 30 minutes they record a decrease in air temperature in in the following 4 locations:

 1 - above the center of the front seat at a height of 100 mm;

 2 - above the center of the second seat at a height of 100 mm;

 3 - above the center of the stretcher at a height of 100 mm;

 4 - above the midpoint on the passenger compartment floor at a height of 100 mm

5. The measurement results within 30 minutes after turning off the heater for vans No. 1 and 2 are shown in tables 1 and 2.

 Table 1. Temperature, ° C at four measurement points, van No. 1 (white)

Time min Sensor number / temperature, ⁰С one 2 3 four 0 21.59 19.76 21.2 18.9 5 21.51 19.69 07/21 18.97 10 19.91 18.62 19.25 15.91 fifteen 17.86 16.31 16.55 07/13 twenty 15.54 14.66 01/15 11.73 25 13.82 13.3 13.76 10.54 thirty 12.42 12.08 12.5 9.66
ΔТ = Т (0) -Т (30) 9.17 7.68 8.7 9.24

Table 2. Temperature, ° С at four measuring points, van No. 2 (yellow)

Time min Sensor number / temperature, ⁰С one 2 3 four 0 20.52 18.76 20.14 17.93 5 20.44 18.69 02.20 6 p.m. 10 18.90 17.67 18.27 06/15 fifteen 16.94 15.45 15.68 12.34 twenty 14.71 13.86 14.20 11.05 25 06/13 12.56 13.00 9.91 thirty 11.71 11.39 11.79 9.06
ΔТ = Т (0) -Т (30) 8.80 7.37 8.35 8.87

Based on these measurements, the customers concluded that the design of both ambulances based on the UAZ chassis was insufficiently insulated, because in accordance with their regulatory documents, the temperature drop at these points should not exceed 5 ° С.

Work with the reconstructed measuring station, which the authors team claims to be a utility model, began from the end of July 2018. No real tests have been carried out at minus 50 ° С, cooling of the measuring chamber to minus 50 ° С and even to -55 ° С was carried out so far in test mode: the floor in the chamber is completely insulated, there is no test vehicle in the chamber.

Claims (1)

A vehicle inspection test station, including a thermally insulated chamber, refrigeration and heating systems, as well as a set of equipment for measuring and automatically maintaining the temperature, characterized in that the thickness of the thermal insulation of the chamber is increased to 200 mm due to an additional layer of thermal insulation, placed on the floor of the camera in a checkerboard pattern with overlapping joints between adjacent plates, two layers of a heat insulator with a thickness of 100 mm each, and a distributed heat source is located under a layer of a heat insulator the second element, the temperature of which is controlled and automatically maintained at a predetermined level by a separate control system, the operating mode of the existing refrigeration system is changed so that the temperature of the heat exchanger of its air cooler during operation does not drop to a temperature below +2 ... + 4 ° С, two additional refrigeration systems: medium temperature, providing operation up to -25 ° С, and low temperature, providing operation up to -50 ° С, increase the number of heating systems to 6 pieces and complement the appa set ratios for measuring and automatically maintaining temperature by equipment capable of operating with an extended range from -50 to + 50 ° С.

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