JPH0143493Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to an exhaust heat recovery device for an engine used as a drive source for a compressor of an air conditioner.

(b) Prior Art A system that uses an engine to drive the compressor of an air conditioner, recovers exhaust heat from the engine's cooling water, and uses this exhaust heat as a heat source for hot water supply, for example, is disclosed in Utility Model Application No. 57-11475. It is presented in the official bulletin.

As pointed out in this publication, if the cooling water from the engine is always allowed to flow through the heat exchanger for exhaust heat recovery, the engine will not warm up easily when the engine is started, and the temperature will rise in the engine jacket, further increasing the temperature in the muffler. A thermo valve is installed on the outlet side of the engine cooling water that is heated by the exhaust gas heat exchanger inside the engine, and when the engine is started, the cooling water bypasses the exhaust heat recovery heat exchanger and flows until it warms up. Ta.

(c) Problems to be solved by the invention In the thermo control means presented in the above publication, the cooling water bypasses the exhaust heat recovery heat exchanger when the engine is started, but the cooling water bypasses the exhaust gas heat exchanger in the muffler. It takes time for the circulating coolant to warm up because it is returned to the engine jacket by the pump, and when the engine is started, the low-temperature coolant flows through the engine jacket, which cools the engine cylinders and causes condensation. However, this dew water mixes into the lubricating oil, causing the oil sealing effect to deteriorate and the engine to seize up.

The present invention solves the above problems and provides an engine exhaust heat recovery device that recovers engine exhaust heat even during warm-up operation.

(d) Means for solving the problem The proposed device cools the engine jacket, thermo valve, engine exhaust gas heat exchanger, exhaust heat recovery heat exchanger, and circulation pump in order in an annular manner. In addition to being connected by a water pipe, a flow path resistor is provided in a bypass pipe that bypasses the engine jacket and the thermo valve.

(e) Effect In this device, when the engine starts, the thermo valve is closed because the cooling water temperature is low, and the circulation pump circulates the cooling water through the bypass pipe, exhaust gas heat exchanger, and exhaust heat recovery heat exchanger. . At the same time as this startup, the engine's exhaust gas heat exchanger is rapidly heated, causing the temperature of the circulating cooling water to rise, which releases heat in the exhaust heat recovery heat exchanger and heats the engine jacket, which is contained in a thermovalve. The temperature of the cooling water inside the unit rises in a short period of time. When the temperature of the cooling water in the engine jacket reaches the set temperature of the thermovalve, the thermovalve opens, and the circulation pump causes the cooling water to flow parallel to the engine jacket and the bypass pipe, joining together, and flowing into the exhaust gas heat exchanger. It is returned to the circulation pump via a heat exchanger for exhaust heat recovery.

(F) Embodiment The drawing is a piping system diagram showing an embodiment of the present device, in which 1 is a gas engine that is driven by sucking fuel gas from a supply port 2, and 3 is an engine gear that cools the cylinder part of this engine. 4 is an exhaust manifold in which the exhaust gas from the engine 1 is precooled by a precooling heat exchanger 5; 6 is an exhaust gas heat exchanger housed in the muffler 7 and exchanges heat with the exhaust gas from the exhaust manifold 4; 8; is an expansion tank, 9 is a heat exchanger for exhaust heat recovery installed outdoors, 10 is a circulation pump, and 11 opens when the inlet cooling water temperature reaches 60℃, and closes when it is lower than 60℃ (cooling water temperature It is a thermo valve (open just enough to allow a slight flow of cooling water to detect this).

These engine jacket 3, thermovalve 11, precooling heat exchanger 5, exhaust gas heat exchanger 6, exhaust heat recovery heat exchanger 9, and circulation pump 10 are sequentially connected in an annular manner through a cooling water pipe 12. , a bypass pipe line 1 bypassing the series circuit of the engine jacket 3, thermovalve 11, and precooling heat exchanger 5;
3 is provided with a flow path resistor 14 formed of a capillary tube, an orifice, or the tube path 13 itself formed of a thin tube.

15 is a compressor driven by gas engine 1;
It is connected to an indoor heat exchanger 17, a refrigerant pressure reducer 18, and an outdoor heat exchanger 19 via a four-way valve 16 for switching between cooling and heating, and this outdoor heat exchanger 19 is a heat exchanger for exhaust heat recovery. It is arranged on the leeward side of the vessel 9 in a heat exchange relationship.

Next, to explain the operation, when the engine 1 is started, the thermovalve 11 is closed because the cooling water temperature is low, and the cooling water is transferred by the circulation pump 10 to the bypass pipe 13 - exhaust gas heat exchanger 6 - exhaust heat recovery. The exhaust gas from the engine 1 is circulated through the exhaust manifold 4 and the muffler 7.
is discharged from the exhaust port 20 of.

At the same time as this startup, the temperature inside the muffler 7 rises rapidly due to the exhaust gas, the cooling water flowing through the exhaust gas heat exchanger 6 is heated, and the heat is released in the heat exchanger 9 for exhaust heat recovery and is contained in the thermovalve 11. The coolant temperature within the engine jacket 3 increases within a short time. This rising time is several minutes, and there is no risk that the cylinders of the engine 1 will be cooled and condensed.

On the other hand, the compressor 15 is driven at the same time as the engine 1 is started, and in the winter, the discharged refrigerant is
9-Four-way valve 16-An indoor heat exchanger 17 which circulates with the compressor 15 and acts as a condenser to heat the room, and an outdoor heat exchanger 1 which acts as an evaporator.
At 9, a heat source is drawn from outside air heated by a heat exchanger 9 for exhaust heat recovery.

When the temperature of the cooling water in the engine jacket 3 reaches the set temperature of the thermo valve 11 of 60°C, this valve opens, and the cooling water sent out from the circulation pump 10 flows between the engine jacket 3 and the bypass pipe 1.
The current flows parallel to 3. At this time, cooling water is supplied to the bypass pipe 13 between the engine jacket 3 and the precooling heat exchanger 5.
In consideration of the pressure loss that occurs when the cooling water flows between The cooling water flowing through the passage 13 joins the cooling water heated by the engine jacket 3 and the precooling heat exchanger 5, and then is further heated by the exhaust gas heat exchanger 6. Heat is released from the heated cooling water in the exhaust heat recovery heat exchanger 9, and this exhaust heat constantly heats the outdoor heat exchanger 19 during heating operation, so even if the outside air temperature drops extremely, the outdoor heat exchanger 19 is constantly heated. No dew forms on the heat exchanger 19, and the heating operation continues.

In the above embodiment, the exhaust manifold 4 is used to pre-cool the exhaust gas, since if the exhaust gas from the engine 1 directly enters the muffler 7, the exhaust gas heat exchanger 6 may not be able to withstand high temperatures and may be damaged. Exhaust gas heat exchanger 6
The exhaust manifold 4 may be removed if it can withstand high temperatures.

(g) Effects of the invention According to the device of the present invention, when the engine is started, the cooling water is circulated without passing through the engine jacket, and this cooling water is heated by the exhaust gas heat exchanger, which raises the temperature at the same time as the engine starts. As a result, the exhaust heat can be recovered and used in the exhaust heat recovery heat exchanger from the time the engine is started, and the temperature of the cooling water sealed in the engine jacket rises in a short time, significantly shortening the warm-up time compared to conventional equipment. can do.

Moreover, since cooling water does not circulate inside the engine jacket when the engine is started, there is no risk of the engine cylinder being cooled and condensing, and the engine can be prevented from seizing up.

[Brief explanation of the drawing]

The drawing is a piping system diagram showing an embodiment of the present device. 1...Engine, 3...Engine jacket,
6...Exhaust gas heat exchanger, 9...Exhaust heat recovery heat exchanger, 10...Circulation pump, 11...Thermo valve, 12...Cooling water pipe line, 13...Bypass pipe line, 14...Flow road resistor.

Claims (1)

[Scope of utility model registration request] The engine jacket, the thermo valve, the engine exhaust gas heat exchanger, the heat exchanger for exhaust heat recovery, and the circulation pump are sequentially connected in an annular manner through a cooling water pipe, and the engine jacket and the thermo valve are connected in sequence. An exhaust heat recovery device for an engine, characterized in that a flow path resistor is provided in a bypass pipe line.