JPS635108A - Cooling fluid temperature control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent low temperature corrosion, by calculating control deviation value of the temperature of cooling water, through comparing the temperature of a combustion chamber and the set degree of temperature of the cooling fluid, and regulating the flow of the cooling fluid according to this control deviation value, for keeping the temperature of the combustion chamber at the fixed degree over the whole of load range. CONSTITUTION:A temperature detecting element 11 is set on an internal combustion engine 6, for detecting the temperature of a combustion chamber, and a detected value is input into a comparison setting element 12. Proper degree of temperature of cooling fluid, which is correspondent with the temperature of the combustion chamber, at every load of the engine 6, is set in the comparison setting element 12, and control deviation value of the temperature of the cooling water is output, according to the deviation value between the set degree of temperature of the cooling fluid, and the input detected value sent from the temperature detecting element 11. A frequency converter 13 varies the rotating speed of a motor 2 which drives a cooling fluid pump 3, for a quantity of variation which corresponds with said control deviation value.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a cooling fluid temperature control device for an internal combustion engine.

[Conventional technology]

An example of a cooling fluid system diagram of a conventional marine internal combustion engine is shown in FIG. In the figure, fluid pressurized by a cooling fluid pump 3 driven by a motor 2 from an expansion tank 1 passes through a temperature control valve 4 and a cooler 5 and reaches an engine 6. Return to

In the closed cycle cooling system described above, the temperature regulating valve 4 is controlled so that the engine outlet fluid temperature is constant, and if the engine outlet temperature is below a specified value, the temperature control valve 4 passes through the bypass passage 7 without passing through the cooler 5. 6.

[Problem that the invention seeks to solve]

However, in the above conventional system, the motor 2 rotates at a constant rotation speed regardless of the state of the engine 6, so the discharge amount of the pump 3 is constant, and when the engine is under low load, the flow rate in the bypass path 7 is relatively low. It will only increase. As shown in FIG. 2, the power consumption of the pump 3 is always constant.

On the other hand, the combustion chamber temperature tw in this case becomes lower at low load as shown in FIG. A problem arises in that low-temperature corrosion occurs due to condensation of sulfuric acid in the fuel.

The present invention has been made in view of the above, and aims to save energy by reducing the flow rate of cooling fluid at partial loads, thereby reducing the drive power of the cooling fluid pump, and at the same time, maintains the humidity of the combustion chamber at a high temperature at partial loads. An object of the present invention is to provide an internal combustion engine in which low-temperature corrosion of combustion chamber members such as cylinder liners due to condensation of sulfuric acid is prevented.

[Means for Solving the Problems 2] In order to solve the above problems, the present invention detects the temperature of the combustion chamber and changes the rotation speed of the synchronous motor to a frequency converter according to the difference between this temperature and the set temperature. The cooling fluid pump is characterized in that it is configured to change the discharge amount of the cooling fluid pump by controlling the cooling fluid pump through the control or the like.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 3. In the figures, 1 is an expansion tank, 2 is a synchronous motor, 3 is a cooling fluid bottle driven by the motor 2; 4 is a temperature control valve, 5 is a cooler, 6 is an internal combustion engine, and 7 is a fuel passage.

11 is a temperature detector for detecting the temperature of the combustion chamber of the engine 6;
Reference numeral 2 indicates a comparison setting device, and reference numeral 13 indicates a frequency converter, and the output of the frequency converter 13 is input to the synchronous motor 2.

The comparison setting device 12 and frequency converter 13 constitute a temperature control device.

In the above device, the cooling fluid in the expansion tank 1 is pressurized by the pump 3, passes through the cooler 5, and cools the engine 6.
Return to the suction side of pump 3.

The temperature regulating valve 4 operates so that the cooling fluid bypasses the cooler 5 and flows through the bypass pipe 7 depending on the load in order to keep the temperature of the cooling fluid at the engine outlet constant.

The combustion chamber temperature detected by the temperature detector 11 is input to a comparison setting device 12. An appropriate cooling fluid temperature corresponding to the combustion chamber temperature for each load of the engine 6 is set in the comparison setting device 12, and when the combustion chamber temperature is input, cooling is performed based on the relationship with the corresponding cooling fluid temperature. Outputs the water temperature control deviation.

The frequency converter 13 changes the rotation speed of the motor 2 by an amount corresponding to the temperature control deviation. This adjusts the flow rate of the cooling fluid pump 3. Incidentally, instead of controlling the rotational speed of the motor 2, the pump 3 may be provided with a flow rate regulating valve, and its opening may be adjusted based on a detection signal of the combustion chamber temperature. That is, as shown in Fig. 3, by changing the flow rate Q of the cooling fluid, the flow velocity ■ changes, and the heat transfer coefficient αC of the cooling surface changes accordingly, making it possible to maintain the combustion chamber temperature tW constant. can.

There is the following relationship between them.

Voc Q= αC匡v0・8 Regarding the relationship between αC and tw, as is clear from Figure 3, it is possible to maintain the tw at high loads by reducing αC at low loads. becomes.

〔Effect of the invention〕

The present invention is configured as described above, and according to the present invention,
By controlling the flow rate Q of the cooling fluid, the temperature of the combustion chamber can be maintained at V-constant throughout the entire load, and low-temperature corrosion of combustion chamber parts such as the cylinder liner can be prevented. In addition, as the flow rate of the cooling fluid decreases, the fluid discharge pressure P also decreases due to the relationship between the driving power LidL''Q-P of the 91 pump, so energy savings can be achieved by reducing the power consumption. .

[Brief explanation of the drawing]

1 to 3 show a working example of the present invention, FIG. 1 is a system diagram thereof, and FIGS. 2 and 3 are diagrams showing the operation. FIG. 4 is a system diagram showing a conventional example. 2... Motor, 3... Cooling fluid pump, 4... Temperature adjustment valve, 5... Cooler, 6... Internal combustion engine, 11...
...Temperature detector, 12... Comparison setting device, 13... Frequency change @ Load □: Based on the skin g1 1111: Main fluorescence Σ Ac I 2 Sentence 9 ~ Closed room part o Oo double pE input; ・
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Claims (1)

[Claims] A temperature detector that detects the combustion chamber temperature of the internal combustion engine calculates a control deviation of the cooling water temperature by comparing the detected value of the combustion chamber temperature and the set value of the cooling fluid temperature, and calculates a control deviation of the cooling water temperature. 1. A cooling fluid temperature control device for an internal combustion engine, comprising: a temperature control device that adjusts the flow rate of cooling fluid fed to the engine.