JPS621848B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vehicle cooling device.

As shown in FIG. 3, on the frame 1 are refrigerant system components such as a sub-engine 2, which is a drive source dedicated to the cooling system, a compressor 3, a condenser 4, a liquid receiver (not shown), an evaporator 6, etc. An integrated cooler unit A is constructed by installing the blower fan 7, suction duct 8 containing an evaporator, blower duct 9, and other blower system components, and this cooler unit A is mounted under the floor of the vehicle body. Cooling devices have been commonly used as bus cooling devices. Note that 10 is a radiator for cooling the sub-engine 2 with cooling water.

In such an integrated cooling system, the sub-engine 2 operates at a substantially constant rotation speed, and the compressor 3, blower fan 7, etc. rotate at a constant rotation speed, regardless of fluctuations in the rotation speed of the bus's running engine. Usually, it is designed to be driven.

However, although the amount of air blown changes in proportion to the rotation speed of the blower fan 7, the cooling capacity is not proportional to the rotation speed of the compressor 3, and has the characteristics shown by the thick line Q in FIG. compressor 3 as described above.
In the conventional device in which the fan 7 and the blower fan 7 are both driven by the sub-engine 2 at a constant rotation speed, as shown in FIG. If W _{is set to W 1 to} adapt to the cooling capacity Q ₁ of the compressor 3 at rotation n 1 (low cooling), the output will be adjusted to the cooling capacity Q ₂ at high rotation n ₂ (strong cooling). The air volume becomes significantly large, such as W ₂ , resulting in inconveniences such as increased power consumption and increased noise. Furthermore, if the air flow rate from the blower fan 7 is set as W ₂ ' to match the cooling capacity Q ₂ at high speed rotation n ₂ of the sub-engine 2, then at low speed rotation n ₁ the air flow rate will _be If the air flow rate becomes too small as W ₁ ', the cooling capacity per unit air flow rate becomes large.

The amount of cooling heat is air volume x air specific heat x temperature difference (in the case of dry air), and since air specific heat is constant, the temperature difference increases as the cooling capacity per unit air flow rate increases. The experimental results show that when n ₂ is 1800 rpm, the air volume W ₂ ' is 3000 m ³ /H and the temperature difference is 14°C, but when n ₁ is 1000 rpm, the air volume W ₁ ' is 1670 m ³ /H, and the temperature difference is 19 ~ When the indoor air temperature, that is, the inlet air temperature of the evaporator, becomes 24 to 25 degrees Celsius, the evaporator outlet air temperature becomes 4 to 5 degrees Celsius, and the temperature of the refrigerant flowing inside the evaporator is -3 to -6 degrees Celsius. A problem occurs in which frost begins to form when the temperature reaches .

The present invention aims to solve the various problems of the conventional integrated cooling device as described above, and the present invention will be explained below with reference to the embodiments shown in FIGS. 1 and 2.

In the present invention, as shown in FIGS. 1 and 2,
On the frame 1, there is a sub-engine 2, which is a power source dedicated to the cooling system, refrigerant system components such as a compressor 3, a condenser 4, a liquid receiver 5, an evaporator 6, and a blower fan 7.
A suction duct 8 containing an evaporator, blower system components such as a blower duct 9, and a radiator 10 for cooling the cooling water of the sub-engine 2 are installed to form an integrated cooler unit A. In an integrated vehicle cooling system that is removably installed under the floor of a bus or the like, the compressor 3 is configured to be directly connected and driven by the output shaft 11 of the sub-engine 2 as before, and the air blower fan 7 is connected from the sub-engine 2 to the compressor 3.
A transmission mechanism B is provided in the power transmission system leading to the sub-engine 2, and the transmission mechanism B is switched automatically or manually by switching between low speed rotation (weak cooling) and high speed rotation (strong cooling) of the sub-engine 2, and the blower fan is operated. The rotational speed of the air conditioner 7 is variably controlled, thereby making it possible to always obtain an amount of air blown that matches the cooling capacity Q.

That is, as shown in FIGS. 1 and 2, the intermediate shaft 12 is rotated from the output shaft 11 of the sub-engine 2 via a pulley and a V-belt hooked thereto, and the intermediate shaft 12 is rotated from the output shaft 11 of the sub-engine 2 via a universal joint shaft 13. Blow fan 7
In the power transmission mechanism for the blower fan, the pulleys provided on the output shaft 11 and the intermediate shaft 12 of the sub-engine 2 are replaced with two sets of pulleys 14 and 14' having different ratios of pulley diameters. 15,1
5' are provided for the pulleys 14, 14' and 15, 1.
V-belts 14'' and 15'' are hung on the V-belts 14'' and 15'', respectively, and an electromagnetic clutch 16 is provided to switch between the two sets of pulleys, and a transmission mechanism is constructed by the two sets of pulleys and the electromagnetic clutch 16 that switches between them. are doing.

First pulley set 1 of the above two sets of pulleys
The second pulley set 15, 15' and the V-belt 15'' hooked thereon are for low rotation.

Note that 12' indicates a bearing portion that supports the intermediate shaft 12.

In the above configuration, when the sub-engine 2 rotates at low speed, the electromagnetic clutch 16 is operated to the left in the figure automatically or by manual switch operation to engage the first set of pulleys for high rotation. Then, the rotation speed of the blower fan 7 increases with respect to the rotation speed n ₁ of the sub-engine 2, and in FIG. 4, the cooling capacity Q ₁ at n ₁
Air flow rate W ₁ or greater than W ₁
This is the number of rotations to obtain W ₁ ″.

When the sub-engine 2 is switched to high-speed rotation _n2 , the electromagnetic clutch 16 operates to the right in the figure to disconnect the first pulley set and connect the second pulley set for low rotation. Then, the rotation speed of sub engine 2
The rotational speed of the fan 7 becomes lower relative to n ₂ , and the air flow rate W ₂ matches the cooling capacity Q ₂ at that time.
Or, it is the rotation speed at which the air blow amount W ₂ ″ should be smaller than W ₂ .

In the above, when the sub-engine 2 rotates _at low speed, that is, in the weak cooling state, the indoor air temperature _is relatively low. Even if the cooling capacity per flow rate is small and the temperature difference between the inlet air temperature and the outlet air temperature of the evaporator is small, there is no problem in terms of cooling effect, and problems such as frost formation are completely prevented. From this point of view, it is rather like Figure 4.
It is preferable to set the air flow rate to be larger than the standard value, such as W ₁ ″.

In addition, when the sub-engine 2 rotates at high speed, that is, in a strong cooling state, it is generally used when the outside air temperature is high at 30°C or higher and the indoor temperature is from 45 to 50°C to 28 to 30°C due to sunlight etc. Since the inlet air temperature of the evaporator is naturally high, the air flow rate is set lower than the value W ₂ ′ that matches the cooling capacity Q ₂ to increase the cooling capacity per unit air flow rate. Even if the temperature difference between the inlet air temperature and the outlet air temperature is increased, the outlet air temperature will not drop to the temperature at which frost formation should occur, and in fact, from the perspective of improving the indoor cooling effect, the temperature difference shown in Figure 4 W ₂ It is preferable to set the air flow rate to be smaller than the standard value, such as ``.If you do this, the power to drive the blower fan 7 will be reduced, resulting in a reduction in fuel consumption and a reduction in the blower fan and This can bring about many advantages, such as extending the life of bearings, etc., and significantly reducing indoor noise.

Furthermore, in the device of the present invention, the power transmission system from the sub-engine 2 to the blower fan 7 is controlled by placing the electromagnetic clutch 16 in the neutral position as shown in the first and second figures, and by disengaging both the first and second pulley sets. It can be completely shut off, for example, by installing another power source such as an electric motor on the frame 1, and when cooling is not required, the sub engine remains stopped and only the blower fan 7 is rotated by the other power source. It is also possible to circulate indoor air or introduce outside air (ventilation), which is very convenient.

As described above, according to the present invention, in an integrated cooling system using a sub-engine as a power source, a speed change mechanism is provided in the power transmission system from the sub-engine to the blower fan, and changes in the rotational speed of the sub-engine, that is, in the cooling state, are provided. By activating the transmission mechanism and changing the transmission ratio according to the change, it is possible to completely prevent frost formation on the evaporator and obtain an accurate cooling effect, as well as reduce the required power and It is possible to reduce fuel consumption, extend the life of each component, reduce indoor noise, etc., and can bring about great practical effects.

[Brief explanation of the drawing]

Figures 1 and 2 are an explanatory plan view and an explanatory front view showing an embodiment of the present invention, Figure 3 is an explanatory front view showing a conventional example, and Figure 4 is an illustration of cooling capacity and air flow rate with respect to the rotational speed of the sub-engine. FIG. 1...Frame, 2...Sub engine, 3...
Compressor, 4...Condenser, 5...Liquid receiver, 6...Evaporator, 7...Blower fan, 8...Suction duct, 9
...Blower duct, 14, 14', 15, 15'...
Pulley, 14'', 15''... V-belt, 16... Electromagnetic clutch, A... Cooler unit, B... Speed change mechanism.

Claims (1)

[Claims] 1. On the frame, a sub-engine as a power source,
An integrated cooler unit is constructed by installing refrigerant system components such as a compressor, condenser, liquid receiver, and evaporator, as well as blower system components such as a blower fan and various ducts, and the cooler unit is installed under the floor of the vehicle body. What is claimed is: 1. A vehicle integrated cooling system, characterized in that a power transmission system that transmits power from a sub-engine to a blower fan is provided with a transmission mechanism that can variably control a gear ratio. 2. The transmission mechanism includes two pulley sets, a first and a second pulley set, which are provided between the output shaft of the sub-engine and an intermediate shaft connected to the blower fan, and which have different ratios of pulley diameters. 2. The vehicle cooling system according to claim 1, further comprising an electromagnetic clutch that switches and controls the engagement and disengagement of the pulley set. 3. The transmission mechanism is controlled so that the rotation speed of the fan is increased during weak cooling when the sub-engine rotation speed is low, and the rotation speed of the ventilation fan is lowered during strong cooling when the sub-engine rotation speed is high. The vehicle cooling device according to claim 1 or 2, characterized in that: