JPH08177626A - Exhaust heat recovery system - Google Patents

Abstract

PURPOSE: To make unstabilization avoidable in control due to an installation part of an inlet temperature sensor, by giving a delay of time corresponding to a deviation between an actual installation part of the inlet temperature sensor and an optimum installation part where arrival time of cooling water agrees with operating time of necessary heat radiation. CONSTITUTION: In the first comparator means 19 of a microcomputer 17, a measured temperature by a cooling water temperature sensor 15 is compared with the first present temperature, to output a drive signal to a driver 18 through a control regulating means 24. In a change factor arithmetic means 25, a measured temperature by an inlet temperature sensor 16 of cooling water is input, to calculate this change factor. Further in the third comparator means 21, the change factor is compared with a preset value, to calculate an opening of a three-way valve 12. On the other hand, in the second comparator means 20, a measured temperature by the inlet temperature sensor 16 is compared with the second preset temperature, to output a priority signal to the control regulating means 24 through a time delay means 23. In the time delay means 23, the drive signal is output with a delay by the delay time set in a delay time setter 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an engine cooling section such as a cooling jacket for a gas engine or a diesel engine, for use in a cogeneration system or the like.
While connecting the exhaust heat recovery part of the hot water absorption refrigerator, hot water supply equipment, heating device, etc. via piping, connect the three-way valve and the bypass pipe to the cooling water supply side piping from the exhaust heat recovery part to the engine cooling part. Is provided with a heat exchanger for exhaust heat having a cooling amount changing means, and the temperature of the cooling water is between the exhaust heat recovery part of the pipe for supplying cooling water and the heat exchanger for exhaust heat. The present invention relates to an exhaust heat recovery system provided with an inlet temperature sensor for measuring, and a cooling amount control means for operating a cooling amount changing means based on the temperature of cooling water measured by the inlet temperature sensor.

[0002]

2. Description of the Related Art In an exhaust heat recovery system, a cooling water temperature sensor for measuring the temperature of cooling water to be supplied to an engine cooling section is usually provided downstream of a bypass pipe of a cooling water supply side pipe, and the cooling water is also provided. A cooling amount control unit that operates the cooling amount changing unit so that the temperature of the cooling water measured by the temperature sensor becomes the set temperature is provided, so that the temperature of the cooling water supplied to the engine cooling unit becomes the set temperature. The amount of cooling water distributed to the heat exchanger for exhaust heat is controlled. As a result, the temperature of the cooling water in the cooling jacket rises too much, the engine protection circuit operates, and the so-called engine trip, which automatically stops the engine, can be avoided.

[0003]

However, in the conventional example, when the exhaust heat demand suddenly decreases, such as when the hot water absorption refrigerator suddenly stops, for example, a three-way valve is used in the wake. Even if an exhaust heat heat exchanger is installed to lower the water temperature, the exhaust heat heat exchanger does not fully absorb heat due to control delays when the water temperature rises rapidly, and the temperature of the cooling water exceeds the set temperature. A shot is made and hot cooling water returns to the engine, causing the engine to trip.

Therefore, the set temperature is lowered in anticipation of the maximum temperature due to overshoot. However, there is a drawback that the temperature of the cooling water taken out from the engine cooling section becomes low during normal times, and the exhaust heat recovery efficiency decreases.

Therefore, as described at the beginning, the temperature of the cooling water discharged from the exhaust heat recovery unit is measured by the inlet temperature sensor, and the feed for operating the cooling amount changing means such as the three-way valve based on the measured temperature. It has been proposed to perform forward control and activate the cooling amount changing means at an early stage to prevent overshoot.

However, in the case of performing the feedforward control, even if the inlet temperature sensor detects the temperature rise of the cooling water, the cooling water which is the basis of the detection reaches the heat exchanger for exhaust heat and is supplied. There is a time lag between. On the other hand, with a cooling amount changing means such as a three-way valve, the exhaust heat demand suddenly decreases, such as when the hot water absorption refrigerator suddenly stops, and the entire amount of engine exhaust heat is transferred to the exhaust heat exchanger. When it is necessary to radiate heat, it takes time to obtain the required opening to radiate all the exhaust heat of the engine. It takes time.

For this reason, when the arrival time of the cooling water to the heat exchanger for exhaust heat is longer than the operation time required to obtain the required heat radiation state in the cooling amount changing means, the cooling is not raised. Water is also supplied to the heat exchanger for exhaust heat, and the temperature of the cooling water returned to the engine cooling section is lowered to an unnecessarily high level.
The control becomes unstable and hunting occurs due to the continuous influence, and the cooling amount changing means such as the three-way valve is operated more than necessary, causing early mechanical wear and the like and the durability decreases. However, for safety reasons, the set temperature must be lowered a little, and the temperature of the cooling water returned to the engine cooling section becomes low, which causes a problem of reduced exhaust heat recovery efficiency, and there is still room for improvement. It was Further, in order to avoid such a problem, it is sufficient to install the inlet temperature sensor at the optimum position where the arrival time and the required operation time are equal, but it is necessary to install various devices and installation locations of pipes. At present, it is difficult to install the inlet temperature sensor at a desired position.

The present invention has been made in view of such circumstances, and in the exhaust heat recovery system of the invention according to claim 1, the inlet temperature sensor can be installed at an arbitrary position deviated from the optimum installation location. However, the purpose is to prevent the control from becoming unstable due to its installation position, and the exhaust heat recovery system of the invention according to claim 2 is
The purpose is to prevent the control from becoming unstable due to the waste time of the inlet temperature sensor itself, and the exhaust heat recovery system of the invention according to claim 3 does not cause an engine trip. Another object of the present invention is to make the temperature of the cooling water supplied to the engine cooling section as high as possible to further improve the exhaust heat recovery efficiency.

[0009]

The invention according to claim 1 is
In order to achieve the above-mentioned object, the engine cooling unit and the exhaust heat recovery unit are connected via a pipe, and a cooling amount changing unit is provided in a cooling water supply side pipe from the exhaust heat recovery unit to the engine cooling unit. Is provided with an exhaust heat exchanger, and an inlet temperature sensor for measuring the temperature of the cooling water is provided between the exhaust heat recovery part of the cooling water supply side pipe and the exhaust heat exchanger, and its inlet In an exhaust heat recovery system provided with a cooling amount control means for operating a cooling amount changing means based on the temperature of cooling water measured by a temperature sensor, during temperature measurement by an inlet temperature sensor and during control operation by a cooling amount control means. During the period, from the time required for the cooling water measured by the inlet temperature sensor to reach the location controlled by the cooling amount changing means, no cooling water is supplied to the exhaust heat exchanger in the cooling amount changing means. Securing the required heat radiation amount from the state Constitute by interposing a time delay means to provide the delay time by subtracting the time required for changing to reach the amount of cooling water required for that.

As the exhaust heat recovery unit, a hot water absorption refrigerator, a hot water supply facility, a heating device or the like is used.

The exhaust heat recovery system of the invention according to claim 2 is the same as that of claim 1 in order to achieve the above object.
The time delay means in the exhaust heat recovery system of the invention according to claim 1 subtracts the difference from the actual temperature change of the cooling water until the inlet temperature sensor starts to sense the temperature change as a measured value from the time delay. Configure.

The exhaust heat recovery system of the invention according to claim 3 is the same as that of claim 1 in order to achieve the above-mentioned object.
Alternatively, in the exhaust heat recovery system of the invention according to claim 2, a cooling water temperature sensor for measuring the temperature of the cooling water supplied to the engine cooling unit on the downstream side of the exhaust heat heat exchanger of the cooling water supply side pipe is provided. First cooling means for activating the cooling amount changing means so that the temperature of the cooling water measured by the cooling water temperature sensor reaches the set temperature, and the cooling amount control means is prioritized over the first controlling means. And a second control means for operating the cooling amount changing means, and the second control means includes a change rate calculating means for calculating a change rate of the temperature of the cooling water measured by the inlet temperature sensor, and a change rate. A cooling amount calculation means for calculating a cooling amount according to the change rate calculated by the rate calculation means,
Only when the rate of change calculated by the rate-of-change calculating means exceeds the set value, the cooling-amount changing means is operated and controlled so as to reach the cooling amount calculated by the cooling-amount calculating means.

The cooling amount control means in the exhaust heat recovery system of the invention according to claim 1 or 2 is based on the temperature of the cooling water measured by the inlet temperature sensor, and discharges according to the temperature difference from the set temperature. The cooling amount changing means may be operated and controlled so as to obtain the amount of heat (claim 4).

[0014]

According to the configuration of the exhaust heat recovery system of the invention as claimed in claim 1, the installation location of the inlet temperature sensor, the arrival time of the cooling water to the heat exchanger for exhaust heat, and the cooling amount. The time delay means has a time delay corresponding to the deviation from the optimal installation location where the operation time required to obtain the necessary heat radiation state in the changing means matches, and when the exhaust heat demand sharply decreases, After the inlet temperature sensor senses the cooling water whose temperature has risen rapidly, the cooling water reaches the heat exchanger for exhaust heat, and at the same time, secures the necessary amount of heat dissipation in the heat exchanger for exhaust heat. Obtainable.

According to the structure of the exhaust heat recovery system of the second aspect of the invention, even if the inlet temperature sensor has a dead time until it starts to sense the actual temperature change of the cooling water, When the waste water is subtracted by the time delay means and the temperature of the cooling water rises sharply, the rising cooling water reaches the heat exchanger for exhaust heat and at the same time, the amount of heat radiation required by the heat exchanger for exhaust heat. Can be obtained.

According to the structure of the exhaust heat recovery system of the third aspect of the present invention, the exhaust heat recovery system is controlled so that the temperature of the cooling water supplied to the engine cooling section is maintained at the set temperature during normal operation. When the demand amount suddenly decreases or increases, it is judged by the rate of change of the temperature of the cooling water at the inlet side of the heat exchanger for exhaust heat that is equal to or higher than the set value, and a sudden temperature change is detected. When there is, the cooling amount according to the rate of change of temperature is calculated by the cooling amount calculation means, and the cooling amount changing means is immediately activated so that the calculated cooling amount is obtained. It is possible to accurately control the temperature change of the cooling water supplied to the engine cooling unit regardless of the rapid change of the exhaust heat demand amount by controlling the cooling amount of.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of an exhaust heat recovery system according to the present invention, a gas engine 1
Further, a generator 3 is interlocked and coupled via a transmission clutch 2.

A main pipe 5 having a first pump 4 interposed between the outlet and the inlet of the engine cooling portion of the gas engine 1.
Is connected. A hot water absorption refrigerator 6 as an exhaust heat recovery unit and a hot water supply facility 7 are connected to the main pipe 5 in parallel with each other via a feed pipe 8a and a return pipe 8b. Further, a cooling device 11 ... Is connected to the hot water absorption refrigerator 6 via a cooling pipe 10 in which a second pump 9 is interposed, and exhaust heat generated by engine cooling is used as a heat source for cooling or hot water supply. Is configured. The main pipe 5, the feed pipe 8a, and the return pipe 8b are collectively referred to as pipes.

Further, heat exchange for exhaust heat is provided to a cooling water supply side pipe downstream of the connection point of the main pipe 5 with the return pipe 8b via a three-way valve 12 as a cooling amount changing means and a bypass pipe 13. Device 14 is connected. The three-way valve 12 may be provided on the inlet side to the heat exchanger 14 for exhaust heat.

A cooling water temperature sensor 15 for measuring the temperature of the cooling water supplied to the engine cooling section is provided downstream of the connection point of the cooling water supply side pipe with the three-way valve 12. Further, the cooling water supplied to the three-way valve 12, that is, the cooling water on the inlet side to the heat exchanger 14 for exhaust heat, is provided on the upstream side of the upstream connection point of the cooling water supply side pipe with the bypass pipe 13. An inlet temperature sensor 16 is provided to measure the temperature of the.

The cooling water temperature sensor 15 and the inlet temperature sensor 16 are connected to a microcomputer 17, and the microcomputer 17 has a driver 18 for the three-way valve 12.
(See FIG. 2) are connected.

As shown in the block diagram of FIG. 2, the microcomputer 17 includes first, second and third comparing means 19, 20, 21, an abnormality detecting means 22, a time delaying means 23 and a control regulating means 24. A change rate calculation means 25 and a cooling amount calculation means 26 are provided.

In the first comparison means 19, the temperature T of the cooling water supplied to the engine cooling section measured by the cooling water temperature sensor 15 is input, and the temperature T and the first set temperature Ta (for example, 83 ° C.). ), The measured temperature T is the first set temperature T
When it is higher than a, an opening signal is output, and the amount of cooling water flowing to the exhaust heat exchanger 14 is increased on the side where the opening is large, and conversely, the measured temperature T is the first set temperature Ta. When it is lower than the above, a closing signal is output, and the drive signal is output to each driver via the control restricting means 24 so that the opening degree becomes smaller, that is, the amount of cooling water flowing to the exhaust heat heat exchanger 14 is decreased. It is designed to output to 18. The cooling water temperature sensor 15 and the first comparing means 19 are referred to as a first controlling means.

The change rate calculating means 25 inputs the inlet temperature T1 of the cooling water measured by the inlet temperature sensor 16 and calculates the change rate dT of the temperature. Then, the calculated change rate dT is input to the third comparison means 21 and compared with the set value K, and when the change rate dT exceeds the set value K, or a value within a certain range is kept for a certain time or longer. When held (when the inlet temperature continues to rise), the cooling amount calculation means 26 calculates the cooling amount according to the change rate dT. That is, the predetermined opening degree of the three-way valve 12 is calculated such that the larger the rate of change dT, the larger the amount of cooling water flowing to the heat exchanger 14 for exhaust heat. A drive signal corresponding to the calculated opening is output to the driver 18 via the time delay means 23 and the control regulation means 24. The inlet temperature sensor 16, the change rate calculating means 25, the third comparing means 21, and the cooling amount calculating means 26 are constituted to be referred to as a second control means. In addition, the above-mentioned first
The control means and the second control means are referred to as a cooling amount control means.

In the second comparing means 20, the inlet temperature T1 of the cooling water measured by the inlet temperature sensor 16 is input to the second comparing means 20.
Compared with the set temperature Tb of No. 2, the priority signal is output to the control restriction unit 24 via the time delay unit 23 only when the inlet temperature T1 exceeds the second set temperature Tb (for example, 83 ° C.),
The second control means is operated to perform control based on the change rate dT.

The abnormality detecting means 22 detects a disconnection to the microcomputer 17 and outputs an abnormality detection signal, and a disconnection detector 27 detects an operation abnormality due to a voltage drop of the microcomputer 17 and detects an abnormality. An abnormality signal is output to the control regulation means 24 in response to the abnormality detection signal from each of the operation abnormality detectors 28 that output detection signals, and the control regulation means 24 responds to the abnormality signal by the second control. The operation of the means is stopped (see FIG. 4).

In the time delay means 23, when the exhaust heat demand suddenly decreases, the inlet temperature sensor 16 senses the cooling water whose temperature has risen sharply, and then the cooling water is used for exhaust heat. At the same time as reaching the heat exchanger 14, a delay time sufficient to obtain a state in which a necessary heat radiation amount is secured in the exhaust heat heat exchanger 14 is input from a delay time setter 29 capable of changing a set value. The drive signal is output to the driver 18 via the control restricting means 24 after being delayed by the set delay time. As this delay time, a flow velocity sensor is provided at a position downstream of the connection point with the most downstream return pipe 8b of the main pipe 5, calculated based on the flow velocity of the cooling water, and the calculated time is input. You may

That is, first, as shown in the schematic diagram of FIG. 3, the operating time (used) which the three-way valve 12 receives from the drive signal and is operated from the fully closed state to the opening for obtaining the required heat radiation state is used. Based on the optimum installation location I that is automatically specified according to the three-way valve) and the actual installation location A of the inlet temperature sensor 16, the distance difference L between the locations I and A and the main pipe 5
The delay time Td1 is obtained from the flow velocity V of the cooling water flowing inside. Next, the waste time Td2, which is the difference between the actual temperature change of the cooling water identified from the characteristics of the inlet temperature sensor 16 and the time when the inlet temperature sensor 16 starts to sense the temperature change as a measured value, is considered. This wasteful time T
The set delay time Td (= Td1−Td2) is obtained by subtracting d2 from the delay time Td1 described above.

For example, in the three-way valve 12, the operating time required to operate from a standby state in which cooling water is not supplied to the exhaust heat heat exchanger 14 to an opening for obtaining a required heat radiation state.
If the cooling water flow velocity V is 2 m / sec for 10 seconds, the optimum installation location I is 20 m upstream of the three-way valve 12. On the other hand, if the actual installation location A is 40 m upstream of the three-way valve 12, the delay time Td1 = (40−20) / 2 = 10
Seconds. Then, the dead time Td of the inlet temperature sensor 16
If 2 is 2 seconds, the set delay time Td = 10-2
= 8 seconds.

Next, the control operation according to the above configuration will be described with reference to the flowchart of FIG. First, it is determined whether there is an abnormal signal (S1), and if there is no abnormal signal, the inlet temperature T1 measured by the inlet temperature sensor 16 is input (S1).
2) Compare with the second set temperature Tb (S3). here,
When the inlet temperature T1 exceeds the second set temperature Tb,
The rate of change dT is calculated (S4), and then it is determined whether the rate of change dT is greater than the set value K or whether the rate of increase dT continues for a certain period of time (S5).

When the rate of change dT is larger than the set value K, the cooling amount computing means 26 computes the cooling amount corresponding to the rate of change dT (S6), the process proceeds to step S7, and the set delay time Td elapses. Then, the drive signal of the opening degree corresponding to the calculated cooling amount is output (S8), and the inlet temperature exceeds the set temperature due to the rapid decrease of the exhaust heat demand amount such as the rapid decrease of the cooling load. When the cooling water to be controlled reaches the exhaust heat exchanger 14 when the temperature rapidly rises, the three-way valve 1
2 is immediately controlled to increase the amount of cooling water flowing through the exhaust heat heat exchanger 14. The control of steps S4, S5, S6, S7 and S8 corresponds to the second control means.

When it is determined in step S1 that there is an abnormal signal, and in step S3, the inlet temperature T
When it is determined that 1 exceeds the second set temperature Tb, and when it is determined in step S5 that the rate of change dT is not larger than the set value K, both are set in step S9.
The temperature T of the cooling water supplied to the engine cooling unit is input, and the temperature T of the cooling water is compared with the first set temperature Ta (S10).

Here, the cooling water temperature T is the first set temperature T
When the temperature exceeds a, a closing signal is output (S11), the flow rate of the cooling water flowing to the exhaust heat heat exchanger 14 side is increased, and the cooling water temperature T becomes the first set temperature Ta. Adjust the opening of 12. On the other hand, when the cooling water temperature T is lower than the first set temperature Ta, an opening signal is output (S
12), the flow rate of the cooling water flowing to the exhaust heat heat exchanger 14 side is reduced, and the opening degree of the three-way valve 12 is adjusted so that the cooling water temperature T reaches the first set temperature Ta.

FIG. 5 is a block diagram showing a second embodiment of the exhaust heat recovery system according to the present invention. The difference from the first embodiment is as follows. That is, the cooling water temperature sensor 15 in the first embodiment is eliminated, and the cooling water supplied to the three-way valve 12, that is, the heat exchange for exhaust heat, is provided upstream of the three-way valve 12 in the cooling water supply side pipe. Inlet temperature sensor 30 for measuring the temperature of cooling water on the inlet side to the vessel 14
The inlet temperature sensor 30 is connected to the microcomputer 31, and the driver 18 of the three-way valve 12 (see FIG. 6) is connected to the microcomputer 31.

In the microcomputer 31, as shown in the block diagram of FIG. 6, the comparison means 32 and the time delay means 3 are provided.
3 and 3 are provided. In the comparison means 32, the inlet temperature T1 of the cooling water measured by the inlet temperature sensor 30 is input,
The temperature T1 is compared with the set temperature Tc, and based on the temperature difference between the measured temperature T1 and the set temperature Tc, the larger the temperature difference is, the larger the opening degree is, that is, the amount of cooling water flowing to the exhaust heat heat exchanger 14. On the contrary, the driving signal is output to the time delay means 33 so that the opening degree becomes smaller as the temperature difference becomes smaller, that is, the cooling water amount flowing to the exhaust heat heat exchanger 14 decreases. Has become. The time delay unit 33 delays the set delay time Td input from the delay time setting unit 34 before outputting the drive signal to the driver 18, as in the first embodiment.

Further, in order to change the flow rate of the cooling water flowing to the heat exchanger 14 for exhaust heat, instead of the three-way valve 12, for example, the flow rate is individually supplied to the cooling water supply side pipe of the main pipe 5 and the bypass pipe 13, respectively. An adjusting valve may be provided and both flow rate adjusting valves may be interlocked with each other to change the flow rate of the cooling water flowing to the heat exchanger 14 for exhaust heat.

In the above embodiment, the dead time Td2 of the inlet temperature sensor 16 is also taken into consideration as the delay time. However, in the case of the inlet temperature sensor 16 used, the dead time is negligible. You do not have to consider it.

[0039]

As is apparent from the above description, according to the exhaust heat recovery system of the first aspect of the present invention, the location where the inlet temperature sensor is installed is such that the cooling water flows from the location where the inlet temperature sensor is installed to exhaust heat. The inlet temperature sensor is installed at a position that is different from the optimum installation location where the arrival time to reach the exchanger and the operation time of the cooling amount changing means required to obtain the required heat radiation state for the exhaust heat heat exchanger are the same. However, the delay caused by the deviation is compensated by the time delay means. When the exhaust heat demand sharply decreases, the cooling water whose temperature rises sharply due to it is detected by the inlet temperature sensor, and then the cooling water reaches the exhaust heat exchanger and at the same time the exhaust heat Since the exchanger can secure the required amount of heat radiation, the inlet temperature sensor can be installed at an arbitrary position deviating from the optimum installation location, but the control becomes unstable due to the installation location. It is possible to improve the workability for installing the inlet temperature sensor, improve the durability by eliminating unnecessary operation of the cooling amount changing means such as the three-way valve, and improve the exhaust heat recovery efficiency. You can now avoid lowering.

Further, according to the exhaust heat recovery system of the second aspect of the present invention, when the inlet temperature sensor starts to sense the actual temperature change of the cooling water of the inlet temperature sensor unit, there is a waste time. The waste time is further subtracted from the time delay according to claim 1, and when the temperature of the cooling water rises sharply, the rising cooling water reaches the heat exchanger for exhaust heat and, at the same time, the exhaust heat is exhausted. Since it is possible to obtain a state in which the required heat release amount is secured by the heat exchanger for use, it is possible to avoid a decrease in durability and exhaust heat recovery efficiency due to the waste time of the inlet temperature sensor itself, so that it can be more preferably implemented. became.

Further, according to the configuration of the exhaust heat recovery system of the invention as claimed in claim 3, the deviation of the installation location of the inlet temperature sensor and the dead time of the inlet temperature sensor are taken into consideration, and the exhaust heat demand is rapidly increased. The cooling amount changing means is activated immediately in response to a rapid temperature rise of the cooling water at the inlet side of the exhaust heat heat exchanger to increase the cooling amount in the exhaust heat exchanger. Since the temperature change of the cooling water supplied to the engine cooling unit is accurately suppressed regardless of the rapid change in the exhaust heat demand, the cooling supplied to the engine cooling unit can be performed without causing an engine trip. It has become possible to raise the temperature of water as much as possible to further improve the efficiency of exhaust heat recovery.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an exhaust heat recovery system according to the present invention.

FIG. 2 is a block diagram showing a configuration of a microcomputer.

FIG. 3 is a schematic diagram related to setting a delay time.

FIG. 4 is a flowchart.

FIG. 5 is a block diagram showing a second embodiment of the exhaust heat recovery system according to the present invention.

FIG. 6 is a block diagram showing a configuration of a microcomputer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas engine 5 ... Main piping 6 ... Hot water absorption refrigerator 7 ... Hot water supply equipment 8a ... Feed piping 8b ... Return piping 12 ... Three-way valve 13 ... Bypass piping 14, 14a ... Heat exhaust heat exchanger 15 ... Cooling water temperature Sensor 16 ... Inlet temperature sensor 17 ... Microcomputer 23, 35 ... Time delay means 25 ... Change rate calculation means 26 ... Cooling amount calculation means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shojiro Matsumura 4-1-2, Hiranocho, Chuo-ku, Osaka City Osaka Gas Co., Ltd.

Claims (4)

[Claims] 1. An exhaust heat which connects an engine cooling part and an exhaust heat recovery part through a pipe, and has a cooling amount changing means in a cooling water supply side pipe from the exhaust heat recovery part to the engine cooling part. And an inlet temperature sensor for measuring the temperature of cooling water between the exhaust heat recovery section of the cooling water supply side pipe and the exhaust heat heat exchanger, and the inlet temperature sensor In the exhaust heat recovery system including the cooling amount control means for operating the cooling amount changing means based on the temperature of the cooling water measured in step 1, when the temperature is measured by the inlet temperature sensor and the control operation by the cooling amount control means is performed. In the meantime, from the time required for the cooling water measured by the inlet temperature sensor to reach the location controlled by the cooling amount changing means, the cooling water is cooled to the exhaust heat heat exchanger in the cooling amount changing means. No water supply Exhaust heat recovery system which is characterized in that by interposing a time delay means to provide the delay time by subtracting the time required for changing to reach the amount of cooling water required to ensure the required dissipation from. 2. The time delay means according to claim 1, the difference between the actual temperature change of the cooling water of the inlet temperature sensor unit and the time from when the inlet temperature sensor starts to sense the temperature change as a measured value. An exhaust heat recovery system which is obtained by further deducting from the time delay according to claim 1. 3. The exhaust heat recovery system according to claim 1 or 2, wherein the temperature of the cooling water supplied to the engine cooling part is provided downstream of the exhaust heat heat exchanger of the cooling water supply side pipe. A cooling water temperature sensor for measuring is provided, and a cooling amount control means is provided to operate the cooling amount changing means so that the temperature of the cooling water measured by the cooling water temperature sensor becomes a set temperature.
Control means and second control means for operating the cooling amount changing means in preference to the first control means, wherein the second control means controls the cooling water measured by the inlet temperature sensor. A change rate calculating means for calculating a temperature change rate and a cooling amount calculating means for calculating a cooling amount according to the change rate calculated by the change rate calculating means are provided, and the change calculated by the change rate calculating means. An exhaust heat recovery system for controlling the operation of the cooling amount changing means so that the cooling amount is calculated by the cooling amount calculating means only when the rate exceeds a set value. 4. The exhaust heat recovery system according to claim 1 or 2, wherein the cooling amount control means responds to a temperature difference from a set temperature based on the temperature of the cooling water measured by the inlet temperature sensor. An exhaust heat recovery system that controls the operation of the cooling amount changing means so that the amount of heat radiation can be obtained.