JPS60148715A - Heater of vehicle - Google Patents

Abstract

PURPOSE:To improve the setting up characteristics of a heater after an engine is started by providing both a main hot water circuit in which cooling water runs from the engine through both a preheater and a main heat-exchanger to the engine and a sub hot water circuit in which cooling water runs from the engine through a sub heat- exchanger to the engine. CONSTITUTION:In a heater of a bus or like, the cooling water outlet part of an engine 1 is connected to a radiator 2 via a thermostat 3. A main hot water circuit 10 in which cooling water (or hot water) is sent by the operation of a heating water pump 6 from a shut-off valve 5 to pass through a burning type preheater 7 and a main heat- exchanger 8 and then fed to a hot water return port 9 which is disposed at the cooling water inlet part of the engine 1 is connected to the heating hot water take-out port 4 disposed at said outlet part. And a sub hot water circuit 12 which is separated from the main circuit 10 at the upstream side point of the preheater 7 thereof, passes through a sub heat-exchanger 11 and then is combined with the main hot water circuit 10 at the lower current side of the main heat-exchanger 8 is connected the main hot water circuit 10. The temperature of hot water at the inlet of the main heat-exchanger 8 is controlled to maintained equally or higher than the temperature of hot water at the inlet of the sub heat-exchanger 11.

Description

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

Conventionally, hot water heating systems that use the cooling water of the driving engine have been used as heating systems for buses, etc., and usually the cooling water (hot water) that has removed the heat from the driving engine is used as a heating water pump. The heat is then led to a preheater, where it is further heated, and then flows into a heating heat exchanger, where it radiates heat to the indoor air, and then flows back into the driving engine.
For example, see FIG. 1 of Japanese Utility Model Application Publication No. 48-42244).

In the conventional device described above, when the engine cooling water temperature is low, for example, immediately after starting the driving engine, the preheater operates to heat the cooling water and raise the temperature of the inlet water to the heating heat exchanger. However, the preheater has the disadvantage that the hot water heating effect is not sufficiently exerted and the rise characteristic of the indoor air temperature after the engine starts is particularly poor.

That is, the flow rate of cooling water to the heating circuit by the heating water pump is usually about 30 to 40 J/-, and in this state, the flow rate of cooling water to the heating circuit is about 10.
Assuming that a preheating machine with a heating capacity of 000 Kcal/H is operated, the rising water temperature Δt in the preheating machine is q IQ, 000 Δ""wcp 40X60X1ζ4℃... (1
). Here, W is the cooling water flow rate and cp is the specific heat.

q indicates hot plaster.

Therefore, for example, if the outside air temperature is 3°C and the engine cooling water temperature before the engine starts is about 3°C, the outlet water temperature of the preheater immediately after the engine starts will be 6°C + 4°C = 7°C, which is inappropriate as a heat source for heating. It is.

After that, the cooling water temperature gradually rises to 80-90℃.
Once the temperature reaches that point, it becomes possible to heat the room without using a preheater, but since the water temperature rises with the preheater only by 4°C, the rise characteristics of the indoor air temperature are extremely poor and it takes a long time to warm up the engine. , and the energy loss is extremely large.

In general, it goes without saying that the higher the water temperature at the inlet of the heat exchanger, the higher the amount of water delivered to the joists, the higher the heating capacity. Since it is inversely proportional, increasing the capacity of the heating water pump and increasing the amount of water sent to the heat exchanger will reduce the amount of temperature rise in the preheater. For example, as shown in equation (1) above, when the temperature rise is 4℃ at 4011/sleeve water flow, 60v
- If the amount of water fed increases, the temperature rise in the preheater will be 2.8°C. In this case, assuming that the engine coolant temperature is 70°C and the indoor temperature is 15°C, let Q and Q' be the amount of heat released from the heating heat exchanger when the preheater is not operating and when the preheater is operating, respectively. , and the increase in heat radiation due to the operation of the preheater is only 0.05, or 5%, so Q = 20.000KCα
If it is a l/H heat exchanger, the preheater will be 10,000 K.
C (Even if Ll/H is added, 20.000X0.05=1,0
00 KC (tl/H, 10.000-1.00
0=9,000 Kcal/H is not radiated indoors but is used to heat the engine for driving, and is eventually radiated into the outside air from the radiator of the engine, resulting in a very large energy loss.

The present invention provides a heating device for a vehicle that can solve all the problems of the conventional devices as described above, and the present invention will be explained below with reference to the accompanying drawings.

In FIG. 1, 1 is the running engine of the bus, 2 is its radiator, and 3 is a thermostat installed in the cooling water outlet side waterway of the engine 1.The thermostat 3 indicates the amount of cooling water flowing from the engine 1 to the radiator 2. is adjusted according to the cooling water temperature to set the engine cooling water temperature to a predetermined temperature (for example, 7
(approximately 5℃). A bypass passage 3' is provided to bypass the cooling water from the upstream side of the thermostat 3 to the downstream side of the radiator, and the cooling water that does not flow to the radiator 2 passes through the bypass passage 3' and flows into the cooling water inlet of the engine 1. It is configured like this.

A heating hot water J outlet 4 is provided at the cooling water outlet of the engine 1, and the steam cooling water (hot water) that cools the engine by the operation of the heating water pump 6 is passed from the heating hot water outlet 4 to the shut-off pulp. 5, for example, a combustion type preheater T.
A main hot water circuit 10 is provided in which the hot water is further heated, passes through a main heat exchanger 8, and returns to a hot water return port 9 provided at the cooling water inlet of the engine 1.

Further, a side hot water circuit 12 is provided which branches from the upstream side of the preheater 7 of the main hot water circuit 10, passes through a side heat exchanger 11, and joins the main hot water circuit 10 downstream of the main heat exchanger 8. .

Reference numeral 13 denotes a flow rate control valve, which controls the distribution ratio between the flow rate of hot water flowing into the preheater T and main heat exchanger 8 and the flow rate of hot water flowing into the side hot water circuit 12; An example is shown in which the flow rate control valve 13 variably controls the flow rate of hot water flowing into the preheater I and the main heat exchanger 8 based on the output of the control device 15 based on the temperature signal of the temperature sensor 14 which detects and operates. It shows.

As shown in FIG. 2, the main and sub heat exchangers 8 and 11 are arranged in series such that the side heat exchanger 11 is on the upstream side with respect to the ventilation direction 1γ by the heating fan 16. The air heat-exchanged in the vessel 11 flows into the main heat exchanger 8 for further heat exchange.

In the above configuration, the outlet water temperature of the preheater 1 is 80 to 90.
By setting the control 1f11 so that the temperature is ℃, when the cooling water temperature is low immediately after starting the engine 1, the flow rate control valve 13 throttles the flow rate of hot water flowing into the preheater 7, and the hot water flowing into the side hot water circuit 12 is Increase flow rate. Then,
Since the flow rate of hot water flowing through the preheater T becomes considerably small, from the above equation (1), the heating temperature Δt of the hot water in the preheater 7 increases significantly, and the outlet water temperature of the preheater T quickly increases to 80 to 90.
Increase temperature to ℃. As time passes, the temperature of the cooling water produced by the engine 1 rises, and accordingly, the opening of the flow control valve 13 is gradually increased, and the water temperature at the end of the preheater T is always maintained at 80 to 90°C. The temperature characteristics are as shown in A in the figure.

A thermoswitch (not shown) is installed at the inlet of the preheater T, and when the artificial water temperature reaches a preset temperature, the thermoswitch is activated and automatically stops the operation of the preheater T, controlling the flow rate. Valve 13 is fully opened.

On the other hand, since engine cooling water directly flows through the auxiliary hot water circuit 12 side, the temperature characteristics of the hot water flowing through the side heat exchanger 11 are as shown in B in FIG. 4, but the flow rate of hot water flowing through the side heat exchanger 11 is
Due to the operation of the flow control valve 13, the flow rate of the hot water flowing through the side heat exchanger 11 is often reduced when the hot water temperature is low and the flow rate on the side of the preheater 7 is greatly reduced, and as the opening degree of the flow rate control valve 130 increases, the flow rate of hot water flowing through the side heat exchanger 11 is gradually reduced. It becomes less.

According to the present invention configured as described above, even when the engine cooling water temperature is low immediately after the engine starts, the hot water temperature at the inlet of the main heat exchanger 80 can be maintained at a high temperature of 80 to 90°C, and the temperature is equal to the guide air temperature. Since the temperature difference becomes extremely large, the amount of heat exchange increases compared to the conventional method, and the flow rate of hot water flowing through the side heat exchanger 11 increases significantly, increasing the amount of heat radiation.
As shown in FIG. 5, compared to the conventional one with solid line water, the one of the present invention has much better room temperature rise characteristics as shown in dotted line water, and the warm-up time of the engine is also shortened.

In addition, in conventional systems, when the capacity of the heating water pump is increased to increase the flow rate of hot water, the effect of the preheater decreases as shown in equation (2) above, which not only results in wasted energy, but also in some cases reduces heat exchange. However, it was not possible to increase the flow rate of hot water because the amount of heat exchanged in the heat exchanger would be less than the amount of heat added by the preheater, and the excess heat would be released to the outside by the radiator of the driving engine, resulting in wasted energy. In the invention, even if the capacity of the pump is increased and the flow rate of hot water is increased, the flow rate of hot water passing through the preheater is throttled by the flow control valve, so the preheating effect in the preheater never decreases, and the amount of heat added by the preheater is reduced. is all consumed in the main heat exchanger to heat the indoor air, and all remaining hot water is radiated into the indoor air in the side heat exchanger, so no matter how much you increase the hot water flow rate, there will be no loss of heat from the preheater. The amount of heat dissipated can be greatly increased by increasing the amount of hot water as necessary.

Furthermore, as shown in the second figure, the side heat exchanger 11 is connected to the main heat exchanger 8.
By providing the air adjacent to the upstream side (with respect to the air flow), the air is once warmed by the side heat exchanger 11 and then has a temperature higher than the hot water flowing through the side heat exchanger 11 (the above-mentioned implementation). Since the hot water (maintained at 80 to 90 degrees Celsius in this example) is further heated by the main heat exchanger 8, it is possible to supply air at a higher temperature than conventional systems into the room, and the defroster is also more effective. It can melt frost and ice adhering to the outer surface of window glass in a short period of time.

The side heat exchanger 11 and the main heat exchanger 8 may be integrally configured by providing a partition 19 within one heat exchanger 1B, as shown in FIG.

In the above embodiment, the flow control valve 13 is provided between the preheater T and the main heat exchanger 8, but the flow control valve 1
3 may be provided anywhere in the main hot water circuit 10 or in the side hot water circuit 12 between the branch point of the side hot water circuit 120 and the confluence point of the side hot water circuit 120. It is more preferable to provide it on the downstream side of the main heat exchanger 8 because the water pressure in the main heat exchanger 8 increases and the boiling point of hot water increases.

In the illustrated embodiment, the flow rate control valve 13 is automatically operated based on the signal from the temperature sensor 14 to variably control the flow rate, but the flow rate control valve 13 is automatically operated based on the signal from the temperature sensor 14 to variably control the flow rate. The flow control valve 1 is activated by a signal, etc.
3 may be operated, and furthermore, the flow control valve 13 may be operated.
The preheater T should be a fixed type such as an orifice.
Even if the flow distribution ratio between the side and the side hot water circuit 12 side is set to a constant value, the above-mentioned effects such as improving the rise characteristics of the indoor air temperature, improving the heating effect, and preventing loss of thermal energy can be achieved. Obtainable.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a heating water circuit showing one embodiment of the present invention, Fig. 2 is an enlarged explanatory diagram of the heat exchanger section of Fig. 1, and Fig. 6 is another embodiment of the heat exchanger. FIG. 4 is a diagram showing the temperature rise characteristics of hot water flowing through the main heat exchanger and side heat exchanger immediately after the engine starts in the device shown in FIG. 1, and FIG. FIG. 3 is a diagram showing characteristics in comparison with a conventional device. 1...Travelling engine, 6...Heating water pump, 1
... Preheater, 8... Main heat exchanger, 10... Main hot water circuit, 11... Side heat exchanger, 12... Side hot water circuit,
13...Flow rate control valve. Upper beak 3 flash 2

Claims (4)

[Claims] (1) In addition to using the engine cooling water after cooling the engine as a heat source, a preheater is installed to heat the engine cooling water, and the heat of the engine cooling water is radiated to the indoor air using a heat exchanger. In a hot water heating system for a vehicle, there is a main hot water circuit in which engine cooling water passes from the engine through a preheater, passes through a main heat exchanger, and returns to the engine, and a main hot water circuit in which engine cooling water returns from the engine to the engine through a side heat exchanger. 1. A heating system for a vehicle, characterized in that a sub hot water circuit is provided, and the inlet hot water temperature of the main heat exchanger is maintained at a temperature equal to or higher than the artificial hot water temperature of the side heat exchanger. (2) The side heat exchanger, in the heating air circulation direction,
The vehicle according to claim 1, characterized in that the vehicle is disposed upstream of the main heat exchanger, and the temperature at which the air that has passed through the side heat exchanger comes to flow through the main heat exchanger is ℃. heating equipment. (3) The hot water flow rate of each of the main hot water circuit and the sub hot water circuit is controlled at a certain set distribution ratio or variably by a flow control valve provided in either or both of the raw hot water circuit and the sub hot water circuit. The vehicle heating device according to claim 1 or 2, characterized in that the vehicle heating device is adapted to be heated. (4) The flow control valve is actuated by a signal from a temperature sensor that detects the hot water temperature at the inlet or outlet of the preheater to change the opening degree. The vehicle heating device described in .