JP7690197B2 - Cooling water control device and method for marine internal combustion engine - Google Patents

Description

The present invention relates to a cooling water control device and method for a marine internal combustion engine.

In the cooling water circulation path for cooling internal combustion engines such as marine diesel engines, in addition to a cooler that cools the jacket cooling water, exhaust heat utilization equipment such as a freshwater generator that utilizes the exhaust heat of the internal combustion engine is generally provided, and the ship's crew adjusts the flow rate to the freshwater generator etc. while monitoring the temperature of the jacket cooling water.

However, in recent years, due to the trend towards reducing manpower in the engine room and declining skills of the crew, there has been an increase in operational errors, such as poor flow rate adjustment to the freshwater production system or failure to produce the required amount of freshwater, and so there is a growing need to automate the control of jacket cooling water.

As an apparatus for automating the control of jacket cooling water in the cooling system of an internal combustion engine, for example, the exhaust heat recovery and utilization system disclosed in Patent Document 1 is known. As shown in FIG. 4, the exhaust heat recovery and utilization system 100 is provided with a jacket cooler 103, a power generation means 104 that recovers heat from the jacket cooling water to generate power, and a water production means 105 that recovers heat from the jacket cooling water to produce water, in a jacket cooling water circulation path 102 that circulates the jacket cooling water of a diesel engine 101.

In this exhaust heat recovery and utilization system 100, the temperature of the jacket cooling water before being supplied to the diesel engine 101 is measured by a first temperature measurement means 106, and if this measured temperature is lower than a set temperature, the jacket cooling water passes through a bypass flow path 108 by controlling the operation of a first three-way valve 107. In addition, the temperature of the jacket cooling water after heat recovery by the power generation means 104 is measured by a second temperature measurement means 109, and the amount of heat recovered from the jacket cooling water by the power generation means 104 is adjusted by controlling the opening and closing of an opening/closing valve 110 based on this measured temperature.

JP 2013-160132 A

In the above-mentioned exhaust heat recovery and utilization system 100, the control of bypassing the jacket cooling water for the jacket cooler 103 and the power generation means 104 is performed based on the measured temperature of the jacket cooling water. However, the first temperature measurement means 106 and the second temperature measurement means 109 that measure the temperatures of the jacket cooling water flowing through different devices (i.e., the diesel engine 101 and the power generation means 104), so there was a risk that it would be difficult to maintain the temperature of the jacket cooling water supplied to the diesel engine 101 within the desired range when the load on the diesel engine 101 fluctuated, etc.

The present invention aims to provide a cooling water control device and method for a marine internal combustion engine that can accurately control the jacket cooling water in the cooling system of the marine internal combustion engine.

The object of the present invention is achieved by a cooling water control device for an internal combustion engine for a marine vessel, which controls jacket cooling water of a cooling system having a cooler and exhaust heat utilization equipment in a cooling water circulation path of the internal combustion engine for a marine vessel, the cooling water control device comprising: temperature detection means for detecting a temperature of the jacket cooling water passing through the internal combustion engine for a marine vessel; first bypass means for adjusting a bypass flow rate for bypassing the cooler; second bypass means for adjusting a bypass flow rate for bypassing the exhaust heat utilization equipment; and control means for controlling operation of the first bypass means and the second bypass means based on detection by the temperature detection means, wherein a plurality of the exhaust heat utilization equipment are provided, and the second bypass means is provided for each of the exhaust heat utilization equipment, and the control means controls operation of the second bypass means individually based on a priority order preset for the plurality of the exhaust heat utilization equipment.

In this cooling water control device for a marine internal combustion engine, the temperature detection means can be arranged to detect the temperature of the jacket cooling water before it is supplied to the marine internal combustion engine, and the control means can control the operation of the first bypass means and the second bypass means so that the temperature detected by the temperature detection means is within a preset temperature range.

The cooling system may further include a heating means for heating the jacket cooling water flowing through the cooling water circulation path, and the control means can control the operation of the heating means based on detection by the temperature detection means.

At least one of the above waste heat utilization devices can be a water generator that produces fresh water by evaporating seawater using jacket cooling water as a heat source.

The object of the present invention is also achieved by a method for controlling jacket cooling water of a cooling system having a cooler and exhaust heat utilization equipment in a cooling water circulation path of an internal combustion engine for a marine vessel, the cooling system being provided with temperature detection means for detecting a temperature of the jacket cooling water passing through the internal combustion engine for a marine vessel, first bypass means for adjusting a bypass flow rate for bypassing the cooler , second bypass means for adjusting a bypass flow rate for bypassing the exhaust heat utilization equipment, and control means for controlling operation of the first bypass means and the second bypass means based on detection by the temperature detection means, a plurality of the exhaust heat utilization equipment are provided, and the second bypass means is provided for each of the exhaust heat utilization equipment, the control means controls operation of the first bypass means and the second bypass means based on detection by the temperature detection means, and individually controls operation of the second bypass means based on a priority order preset for the plurality of the exhaust heat utilization equipment.

The present invention provides a cooling water control device and method for a marine internal combustion engine that can accurately control the jacket cooling water in the cooling system of the marine internal combustion engine.

1 is a schematic configuration diagram of a cooling water control device for a marine internal combustion engine according to an embodiment of the present invention; FIG. 11 is a schematic configuration diagram of a cooling water control device for a marine internal combustion engine according to another embodiment of the present invention. FIG. 13 is a schematic configuration diagram of a cooling water control device for a marine internal combustion engine according to still another embodiment of the present invention. FIG. 1 is a schematic diagram of a conventional exhaust heat recovery and utilization system.

An embodiment of the present invention will be described below with reference to the attached drawings. FIG. 1 is a schematic diagram of a cooling water control device for an internal combustion engine for a ship according to an embodiment of the present invention. The cooling water control device for an internal combustion engine for a ship (hereinafter simply referred to as a "cooling water control device") 1 shown in FIG. 1 controls the jacket cooling water flowing through a cooling water circulation path 52 in a cooling system 50 equipped with a cooler 53 and exhaust heat utilization equipment 54 in a cooling water circulation path 52 of an internal combustion engine for a ship 51 such as a diesel engine, which is the main engine of the ship.

The waste heat utilization equipment 54 is, for example, a fresh water production system that produces fresh water by evaporating seawater using the jacket cooling water as a heat source. The waste heat utilization equipment 54 is not particularly limited as long as it is a system that recovers and utilizes the waste heat of the jacket cooling water, and examples of the waste heat utilization equipment include a water production system, a heating system, a power generation system, a hot water supply system, and a power recovery system.

The cooling water control device 1 includes two temperature detection units 2a, 2b that detect the temperature of the jacket cooling water passing through the marine internal combustion engine 51, a first bypass unit 3 that adjusts the bypass flow rate that bypasses the cooler 53, a second bypass unit 4 that adjusts the bypass flow rate that bypasses the exhaust heat utilization equipment 54, and a control unit 10 that controls the operation of the first bypass unit 3 and the second bypass unit 4.

The two temperature detection units 2a, 2b are, for example, temperature sensors, and one of the temperature detection units 2a is arranged to detect the temperature of the jacket cooling water before it is supplied to the marine internal combustion engine 51, and the other temperature detection unit 2b is arranged to detect the temperature of the jacket cooling water after it is supplied to the marine internal combustion engine 51.

The first bypass section 3 includes a bypass flow path 3a that bypasses the cooler 53, and a three-way valve 3b that switches the flow path of the jacket cooling water that flows through the cooling water circulation path 52 toward the cooler 53 to the bypass flow path 3a. The flow rate of the jacket cooling water that flows through the bypass flow path 3a can be adjusted by adjusting the opening degree of the three-way valve 3b.

The second bypass section 4 includes a bypass flow path 4a that bypasses the exhaust heat utilization equipment 54, and a three-way valve 4b that switches the flow path of the jacket cooling water flowing through the cooling water circulation path 52 toward the exhaust heat utilization equipment 54 to the bypass flow path 4a. By adjusting the opening of the three-way valve 4b, the flow rate of the jacket cooling water flowing through the bypass flow path 4a can be adjusted.

The second bypass section 4 also includes an auxiliary bypass flow path 4c, a flow control valve 4d that adjusts the opening degree of the auxiliary bypass flow path 4c, and flow control valves 4e and 4f that are provided on the inlet side and outlet side of the exhaust heat utilization device 54 between the exhaust heat utilization device 54 and the auxiliary bypass flow path 4c, respectively, in order to manually adjust the bypass flow rate of the exhaust heat utilization device 54.

The control unit 10 adjusts the opening of the three-way valve 3b of the first bypass section 3 and the three-way valve 4b of the second bypass section 4 based on the detection by the temperature detection units 2a and 2b, and automatically controls the bypass flow rate of the cooler 53 and the exhaust heat utilization device 54.

Next, the operation of the cooling water control device 1 having the above configuration will be described. During operation of the cooling system 50, the control unit 10 controls the opening degree of the three-way valve 3b of the first bypass unit 3 so that the outlet temperature of the marine internal combustion engine 51 detected by the temperature detection unit 2b becomes the preset outlet set temperature Tout. The control unit 10 also compares the inlet temperature Tin of the marine internal combustion engine 51 detected by the temperature detection unit 2a with the preset lower limit value TinL (e.g., 72°C) and upper limit value TinH (e.g., 78°C) of the inlet set temperature, and performs the following control. In the initial state, the flow rate control valve 4d is fully closed, and the flow rate control valves 4e and 4f are fully open.

When the inlet temperature Tin is lower than the lower limit value TinL of the inlet set temperature (case 1: TinL>Tin), the control unit 10 controls the three-way valve 4b of the second bypass unit 4 to bypass the entire amount of jacket cooling water to the exhaust heat utilization equipment 54 (i.e., to prevent the jacket cooling water from flowing to the exhaust heat utilization equipment 54).

When the inlet temperature Tin is equal to or higher than the lower limit TinL of the inlet set temperature and lower than the upper limit TinH (case 2: TinL≦Tin<TinH), the control unit 10 controls the three-way valve 4b of the second bypass unit 4 so that the entire amount of jacket cooling water is supplied to the exhaust heat utilization equipment 54 (i.e., the jacket cooling water does not flow through the bypass flow path 4a). This allows the flow rate of the jacket cooling water supplied to the exhaust heat utilization equipment 54 to be adjusted by manually adjusting the opening of the flow rate adjustment valves 4d, 4e, and 4f.

In the above case 2, the control unit 10 can also automatically adjust the flow rate of the jacket cooling water supplied to the exhaust heat utilization device 54 by adjusting the opening degree of the three-way valve 4. In this case, the condition is that the inlet temperature Tin does not become lower than the lower limit value TinL of the inlet set temperature.

During normal operation, the inlet temperature Tin is lower than the upper limit TinH of the inlet set temperature. However, for example, when the jacket cooling water is bypassed by controlling the second bypass unit 4 from a state in which the jacket cooling water is supplied to the exhaust heat utilization equipment 54 and heat recovery is being performed, the inlet temperature Tin may become equal to or higher than the upper limit TinH of the inlet set temperature because the cooling of the jacket cooling water by the cooler 53 cannot keep up (case 3: Tin≧TinH). In this case, the control unit 10 controls the second bypass unit 4 to supply the jacket cooling water in the bypass state to the exhaust heat utilization equipment 54 again. Note that when the supply of jacket cooling water to the exhaust heat utilization equipment 54 is switched to bypass, if the time change of the inlet temperature Tin rises rapidly beyond the set value, the control unit 10 may control the jacket cooling water to be supplied to the exhaust heat utilization equipment 54 again even if the inlet temperature Tin has not reached the upper limit TinH.

In this way, the cooling water control device 1 of this embodiment is configured to automatically control the bypass flow rate that bypasses the cooler 53 and the exhaust heat utilization equipment 54 by controlling the operation of the first bypass section 3 and the second bypass section 4 based on the temperature detection of the jacket cooling water passing through the marine internal combustion engine 51. This allows the exhaust heat of the jacket cooling water to be efficiently utilized in the exhaust heat utilization equipment 54 while prioritizing the maintenance of an appropriate temperature of the marine internal combustion engine 51.

The cooling water control device 1 shown in FIG. 1 detects the temperature of the jacket cooling water passing through the marine internal combustion engine 51 by two temperature detection units 2a, 2b arranged at the inlet and outlet of the marine internal combustion engine 51, respectively, and thus the output fluctuation of the marine internal combustion engine 51 can be measured in real time by the temperature detection unit 2b, and load following control can be easily performed. However, as shown in FIG. 2, it is also possible to control the operation of the first bypass unit 3 and the second bypass unit 4 only by the detection of the temperature detection unit 2a arranged at the inlet of the marine internal combustion engine 51, which allows for a simple configuration that is low cost, easy to control, and has a low failure rate. Note that in FIG. 2, the same components as those in FIG. 1 are given the same reference numerals.

In the cooling water control device 1' shown in FIG. 2, similar to the cooling water control device 1 shown in FIG. 1, the control unit 10 compares the inlet temperature Tin of the marine internal combustion engine 51 detected by the temperature detection unit 2a with a lower limit value TinL (e.g., 72°C) and upper limit value TinH (e.g., 78°C) of the inlet set temperature that are preset, and performs the same control as described above.

Meanwhile, unlike the cooling water control device 1 shown in FIG. 1, the control unit 10 of the cooling water control device 1' controls the opening degree of the three-way valve 3b of the first bypass section 3 so that the inlet temperature Tin becomes a preset temperature Tinset (e.g., 75°C) between the lower limit value TinL and the upper limit value TinH of the inlet set temperature. The temperature detection of the jacket cooling water passing through the marine internal combustion engine 51 can also be performed only by the temperature detection unit 2b arranged at the outlet of the marine internal combustion engine 51, and the control unit 10 can control the operation of the first bypass section 3 and the second bypass section 4 based on the detected temperature of the temperature detection unit 2b.

The cooling system 50 shown in Figures 1 and 2 has one waste heat utilization device 54 in the cooling water circulation path 52, but as shown in Figure 3, the present invention can also be applied to a cooling system 50 having multiple waste heat utilization devices 54, 55 in the cooling water circulation path 52 by providing second bypass sections 4, 5 for each waste heat utilization device 54, 55.

The control unit 10 of the cooling water control device 1'' shown in FIG. 3 controls the opening degree of the three-way valve 3b of the first bypass section 3 so that the inlet temperature of the marine internal combustion engine 51 detected by the temperature detection unit 2a becomes a preset temperature, similar to the cooling water control device 1' shown in FIG. 2. The control of the first bypass section 3 may be performed based on the outlet temperature of the marine internal combustion engine 51 detected by the temperature detection unit 2b, similar to the cooling water control device 1 shown in FIG. 1. In this way, even when multiple exhaust heat utilization devices 54, 55 are provided, the marine internal combustion engine 51 by the cooler 53 has the highest priority, and the first bypass section 3 is controlled independently of the bypass control of the exhaust heat utilization devices 54, 55.

The bypass control of the second bypass sections 4, 5 for each of the exhaust heat utilization devices 54, 55 is basically performed in the same manner as the cooling water control device 1 shown in FIG. 1, but in a situation where the temperature of the jacket cooling water supplied to the marine internal combustion engine 51 is higher than the set lower limit value and the jacket cooling water can be supplied to the exhaust heat utilization devices 54, 55, the second bypass sections 4, 5 are individually bypass controlled based on the priority order preset for each of the exhaust heat utilization devices 54, 55. For example, when the priority order of the exhaust heat utilization device 54 consisting of a water production device is higher than the priority order of the exhaust heat utilization device 55 consisting of a heating device, the supply of the jacket cooling water to the exhaust heat utilization device 54 is given priority, and when there is a surplus of heat in the jacket cooling water, the jacket cooling water is supplied to the exhaust heat utilization device 55 as well as the exhaust heat utilization device 54. In this way, the exhaust heat of the jacket cooling water can be efficiently distributed according to the priority order of each of the exhaust heat utilization devices 54, 55.

When there is a risk of a temporary shortage of heat in the jacket cooling water due to the provision of multiple exhaust heat utilization devices 54, 55, a heating unit 20 may be provided to heat the jacket cooling water flowing through the cooling water circulation path 52, as shown in FIG. 3. The heating unit 20 is configured to heat the jacket cooling water by heat exchange between steam and the jacket cooling water, and the opening and closing of the steam valve 21 is controlled by the control unit 10. When the heat of the jacket cooling water is insufficient while the jacket cooling water is being supplied to both exhaust heat utilization devices 54, 55, the control unit 10 can continue to supply the jacket cooling water to the exhaust heat utilization devices 54, 55 by operating the heating unit 20 instead of performing bypass control on one of the exhaust heat utilization devices 55.

In this way, by providing a heating section 20 that heats the jacket cooling water, the control section 10 can more flexibly control the operation of the second bypass sections 4 and 5 while considering the balance between the heat input and output of the jacket cooling water and the priority order of each of the exhaust heat utilization devices 54 and 55.

Temperature detectors 4g and 4h are disposed at the inlet and outlet of the exhaust heat utilization device 54, and temperature detectors 5c and 5d are disposed at the inlet and outlet of the exhaust heat utilization device 55. For the cooler 53 and the heater 20, temperature detectors 3c and 3d are disposed at the inlet and outlet of the cooler 53, and temperature detectors 6a and 6b are disposed at the inlet and outlet of the heater 20. The detection signals of the temperature detectors 3c, 3d, 4g, 4h, 5c, 5d, 6a, and 6b are input to the control unit 10 in the same manner as the detection signals of the temperature detectors 2a and 2b corresponding to the marine internal combustion engine 51.

The heat balance of the jacket cooling water is expressed as Qme + Qd = Qa + Qb + Qc + Qloss, where the heat inputs at the marine internal combustion engine 51 and the heating unit 20 are Qme and Qd, the heat output at the cooler 53 and the exhaust heat utilization equipment 54, 55 are Qa, Qb, and Qc, and the heat loss is Qloss. Since the heat inputs Qme and Qd and the heat outputs Qa, Qb, and Qc are proportional to the temperature difference between the inlet and outlet temperatures of the jacket cooling water passing through them, the control unit 10 can control the heat balance of the jacket cooling water based on the detected temperatures of the temperature detection units 2a, 2b, 3c, 3d, 4g, 4h, 5c, 5d, 6a, and 6b.

As a specific example, assume that the heat output of the exhaust heat utilization device 54 can be controlled in three stages, QbH, QbM, and QbL, and the heat output of the exhaust heat utilization device 55 can be controlled in three stages, QcH, QcM, and QcL, and that the exhaust heat utilization device 55 has a lower priority than the exhaust heat utilization device 54, but it is desired to ensure at least a heat output of QcM. The control unit 10 calculates the ratio of the heat outputs Qb and Qc of the exhaust heat utilization devices 54 and 55 based on the temperature difference detected by the two temperature detection units 4g and 4h of the exhaust heat utilization device 54 and the temperature difference detected by the two temperature detection units 5c and 5d of the exhaust heat utilization device 55, and controls the heat outputs Qb and Qc of the exhaust heat utilization devices 54 and 55 by performing bypass control of the second bypass units 4 and 5. The heat output [Qb, Qc] of each exhaust heat utilization device 54, 55 is controlled to [QbH, QcH] when there is a margin of heat in the jacket cooling water, and is controlled to change sequentially from [QbH, QcM] → [QbM, QcM] → [QbL, QcM] → [QbL, QcL] as the heat in the cooling water decreases.

Reference Signs List 1 Cooling water control device for marine internal combustion engine 2a, 2b Temperature detection section 3 First bypass section 4, 5 Second bypass section 10 Control section 20 Heating section 50 Cooling system 51 Marine internal combustion engine 52 Cooling water circulation path 53 Coolers 54, 55 Waste heat utilization equipment

Claims (5)

A device for controlling jacket cooling water of a cooling system having a cooler and a waste heat utilization device in a cooling water circulation path of an internal combustion engine for a marine vessel, comprising:
a temperature detection means for detecting a temperature of the jacket cooling water passing through the marine internal combustion engine;
a first bypass means for adjusting a bypass flow rate that bypasses the cooler;
a second bypass means for adjusting a bypass flow rate that bypasses the exhaust heat utilization device;
a control means for controlling the operation of the first bypass means and the second bypass means based on the detection of the temperature detection means ,
a plurality of the exhaust heat utilization devices are provided, and the second bypass means is provided for each of the exhaust heat utilization devices,
The control means controls operation of the second bypass means individually based on a priority order preset for the plurality of exhaust heat utilization devices . The temperature detection means is disposed to detect a temperature of the jacket cooling water before it is supplied to the marine internal combustion engine,
2. The cooling water control device for a marine internal combustion engine according to claim 1, wherein the control means controls the operation of the first bypass means and the second bypass means so that the detected temperature of the temperature detection means is within a preset temperature range. The cooling water circulation path further includes a heating means for heating the jacket cooling water flowing therethrough,
2. The cooling water control device for a marine internal combustion engine according to claim 1 , wherein the control means controls the operation of the heating means based on the detection of the temperature detection means. 4. The cooling water control device for a marine internal combustion engine according to claim 1 , wherein at least one of the exhaust heat utilization devices is a fresh water generator that produces fresh water by evaporating seawater using jacket cooling water as a heat source. A method for controlling jacket cooling water of a cooling system having a cooler and a waste heat utilization device in a cooling water circulation path of an internal combustion engine for a marine vessel, comprising:
the cooling system is provided with a temperature detection means for detecting a temperature of jacket cooling water passing through the marine internal combustion engine, a first bypass means for adjusting a bypass flow rate for bypassing the cooler, a second bypass means for adjusting a bypass flow rate for bypassing the exhaust heat utilization device , and a control means for controlling operation of the first bypass means and the second bypass means based on detection by the temperature detection means ,
a plurality of the exhaust heat utilization devices are provided, and the second bypass means is provided for each of the exhaust heat utilization devices;
a control means for controlling operation of the first bypass means and the second bypass means based on detection by the temperature detection means, and for individually controlling operation of the second bypass means based on a preset priority order for the plurality of exhaust heat utilization devices .

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