JP5409240B2 - Protection device and method for internal combustion engine - Google Patents

Description

  The present invention relates to a protection device and method for an internal combustion engine, and more particularly to a protection device and method for an internal combustion engine that can protect the internal combustion engine and the exhaust system even when there is a sudden rise in exhaust temperature. is there.

  The exhaust gas temperature is known as an index indicating the degree of exhaust gas purification and combustion efficiency of the engine and the state of the engine. An abnormal change in the exhaust temperature during traveling of a vehicle or the like equipped with an engine, particularly an abnormal increase in the exhaust temperature, means an abnormal combustion of the engine or a serious abnormality of the exhaust system. For this reason, an exhaust thermometer is installed in more vehicles than before, and an alarm is issued when the exhaust temperature rises above the specified alarm set value, and when the temperature rises to the specified trip set value, the engine is tripped (engine stoppage) ) To protect the engine and exhaust system.

FIG. 5 is a flowchart of a conventional protection device for an engine using the exhaust temperature.
When the process is started, the exhaust temperature is detected in step S101.
When the exhaust temperature is detected in step S101, it is determined in step S102 whether the exhaust temperature is higher than a specified trip set value. If NO in step S102, that is, if the exhaust gas temperature is lower than the trip set value, the process returns to step S101. If YES in step S102, that is, if the exhaust gas temperature is higher than the trip set value, the process proceeds to step S103.
When the specified delay time has elapsed in step S103, the process proceeds to step S104. In step S104, the exhaust temperature is detected again, and in step S105, it is determined whether the exhaust temperature detected in step S104 is higher than the trip set value.
If NO in step S105, that is, if the exhaust gas temperature is lower than the trip set value, the process returns to step S101. If YES in step S105, that is, if the exhaust gas temperature is higher than the trip set value, the process proceeds to step S106.
In step S106, a trip command is issued and the engine generating exhaust is stopped.
In addition, it changes to step S105 from step S102, it is judged whether the state where exhaust temperature is higher than a trip setting value continues for the fixed time equivalent to the delay time of step S103, and when continuing, it progresses to step S106 If a trip command is issued and the operation is not continued, the flow may return to step S101.

Further, as a technology related to an engine protection device using another exhaust temperature, Patent Document 1 _discloses an exhaust system component according to a rate of change in exhaust temperature when the exhaust temperature reaches a first predetermined temperature _Tmax. A technique is disclosed in which a delay time until (exhaust manifold) reaches a heat-resistant allowable temperature T _em is set and fuel is increased in order to lower the exhaust temperature after the delay time has elapsed.

JP 2008-51092 A

  However, in the conventional engine protection device shown in the flowchart of FIG. 5, the exhaust temperature is higher than a certain trip set value regardless of whether the exhaust temperature rises rapidly or slowly. Only whether it is high or not is used as a criterion for trips. Therefore, when the exhaust temperature rises rapidly, the exhaust temperature reaches the trip set value, and when the trip command is issued, the engine and exhaust system parts such as the exhaust valve seat and exhaust valve rod are damaged. There is a possibility.

Further, the technique disclosed in Patent Document 1 changes a delay time from when the exhaust temperature reaches a predetermined temperature _Tmax until the fuel increase is performed in order to reduce the exhaust temperature, according to the rate of change of the exhaust temperature. However, it does not lead to trips such as an engine that exhausts exhaust. For this reason, when the exhaust gas temperature increases particularly rapidly, the exhaust gas temperature may not be sufficiently lowered only by the fuel increase.

  Accordingly, in view of the problems of the prior art, the present invention provides a protection device and method for an internal combustion engine that can reliably protect the engine and the exhaust system equipment even when the exhaust temperature rises rapidly. With the goal.

As an apparatus invention for solving the above-described problems, an exhaust temperature of an internal combustion engine is detected in an internal combustion engine protection device that detects an abnormality based on an exhaust temperature and protects the internal combustion engine whose output shaft is connected to a generator. An exhaust temperature detecting means, a change rate calculating means for calculating a change rate of the exhaust temperature in a predetermined time unit based on a moving average of the exhaust temperature detected by the exhaust temperature detecting means, and corresponding to the change rate, A trip value setting means for setting a trip value lower as the rate of change is larger, and a stop means for stopping fuel supply when the exhaust temperature is higher than a trip value set by a trip value setting means , The internal combustion engine is a multi-cylinder engine, and the exhaust temperature detection means is provided in each of the multi-cylinders and detects the exhaust temperature for each cylinder, and the trip value The determining means sets a trip value corresponding to the rate of change for each cylinder, and the stopping means stops only the cylinder that detects an exhaust temperature higher than the trip value, and supplies fuel to the cylinder. It is characterized by stopping .
Further, as a method invention for solving the above-mentioned problems, in the protection method for an internal combustion engine that detects an abnormality based on the exhaust temperature and protects the internal combustion engine whose output shaft is connected to the generator , the internal combustion engine is a multi-cylinder. The engine is calculated based on the moving average of the exhaust temperature, and the rate of change of the exhaust temperature for each cylinder of the internal combustion engine in a predetermined time unit is calculated, and the rate of change is larger as the rate of change corresponds to the rate of change for each cylinder. A low trip value is set, and when the exhaust temperature is higher than the trip value, only a cylinder that detects an exhaust temperature higher than the trip value is deactivated , and fuel supply to the cylinder is stopped. .
Here, the trip value refers to a boundary temperature at which fuel supply is stopped to protect the internal combustion engine. That is, when the exhaust temperature exceeds the trip value, the fuel supply is stopped to protect the internal combustion engine.

  According to the device invention and the method invention described above, the trip value is set so that the trip value decreases as the change rate increases, so that the exhaust temperature change rate increases and the exhaust temperature increases. When it rises rapidly, the fuel supply is stopped at a low temperature, that is, at an early stage. Therefore, even when the exhaust temperature rises rapidly, the fuel supply is stopped early, so that the engine and the exhaust system can be reliably protected.

In the present invention, it is preferable that the internal combustion engine is a multi-cylinder engine, and the exhaust temperature detecting means is provided in each of the multi-cylinders to detect an exhaust temperature for each cylinder, and the trip value The setting means sets a trip value corresponding to the rate of change for each cylinder, and the stop means pauses only a cylinder that detects an exhaust temperature higher than the trip value, and supplies fuel to the cylinder. It is good to stop.
In the method invention, the internal combustion engine is a multi-cylinder engine, the rate of change of the exhaust temperature in a predetermined time unit is calculated for each cylinder, a trip value is set in correspondence with the rate of change for each cylinder, When the exhaust temperature is higher than the trip value, it is preferable to stop only the cylinder that detects the exhaust temperature higher than the trip value and stop the fuel supply to the cylinder.

  In particular, when the engine itself cannot be stopped during operation such as a marine engine, it is possible to protect the engine and the exhaust system by stopping only the cylinder that detects the exhaust temperature higher than the trip value. In this case, the control system is complicated, but there is an advantage that the operation can be continued even if there is a cylinder that detects an exhaust temperature higher than the trip value.

Further, the internal combustion engine is a single cylinder or a multi-cylinder engine, the exhaust temperature detection means is provided for each cylinder, and detects the exhaust temperature for each cylinder, and the trip value setting means includes: The trip value is set corresponding to the rate of change for each cylinder, and the stop means stops the engine when there is a cylinder that has detected an exhaust temperature higher than the trip value. It is good to stop the fuel supply to
In the method invention, the internal combustion engine is a single-cylinder or multi-cylinder engine, and based on the moving average of the exhaust temperature, a rate of change of the exhaust temperature in a predetermined time unit is calculated for each cylinder, and the When a trip value is set corresponding to the rate of change, and there is a cylinder in which the exhaust temperature is higher than the trip value, the engine is stopped and fuel supply to the cylinder is stopped. Good.

  For example, when the engine itself can be stopped during operation, such as a vehicle engine, the engine and the exhaust system are protected by stopping the engine when there is a cylinder that detects an exhaust temperature higher than the trip value. Is possible. In this case, if there is a cylinder that detects an exhaust temperature higher than the trip value, operation cannot be continued, but the engine and exhaust system are protected more reliably, and the control system is simple. There is.

  As described above, according to the present invention, it is possible to provide an exhaust control method and apparatus for an internal combustion engine that can reliably protect the engine and the equipment of the exhaust system even when the exhaust temperature rises rapidly. .

1 is an overall configuration diagram of a gas engine system in which an exhaust control device for an internal combustion engine of the present invention is used. It is a flowchart of the control routine which protects the engine and exhaust system using the exhaust temperature in an Example. It is the graph which showed roughly the time change of the exhaust temperature in an Example. It is the graph which showed roughly the time change of the exhaust gas temperature in a comparative example. It is a flowchart of the protection apparatus of the engine using the conventional exhaust temperature.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

FIG. 1 is an overall configuration diagram of a gas engine system in which an exhaust control device for an internal combustion engine according to the present embodiment is used.
With reference to FIG. 1, the whole structure of the gas engine system which concerns on a present Example is demonstrated.
In FIG. 1, 1 is an engine (gas engine), 4 is a cylinder head of the engine 1, 13 is a generator directly connected to the engine 1, and 14 is a flywheel. An exhaust pipe 5 is connected to the exhaust outlet of each cylinder head 4, and each exhaust pipe 5 is connected to an exhaust collecting pipe 6. Each exhaust pipe 5 is provided with an exhaust pipe temperature sensor 51 for detecting the exhaust temperature in each exhaust pipe, and the detected value of the exhaust pipe temperature sensor 51 is input to the control device 52.

  7 is a supercharger comprising an exhaust turbine 7a and a compressor 7b. Reference numeral 3 denotes an air supply branch pipe connected to the air supply inlet of each cylinder head 4. The air supply outlet of the compressor 7 b and each air supply branch pipe 3 are connected by the air supply pipe 2. An air supply cooler 9 for cooling the air supplied through the air supply pipe 2 is provided above. Further, the exhaust turbine 7a is provided with an exhaust outlet pipe 110 for discharging exhaust gas from the exhaust gas outlet.

An exhaust bypass pipe 11 is branched from the exhaust turbine 7a inlet side of the exhaust collecting pipe 6, bypasses the exhaust turbine 7a, and is connected to the exhaust outlet pipe 110 on the outlet side of the exhaust turbine 7a. The exhaust bypass pipe 11 is provided with an exhaust bypass valve 12 that changes the passage area.
10a is a supercharger inlet air passage for introducing air from the outside to the compressor 7b of the supercharger 7, and 10 is a mixer installed in the supercharger inlet air passage 10a.

Reference numeral 21 denotes a gas supply pipe into which fuel gas is introduced from a fuel gas tank (not shown) that stores fuel gas. A supercharger side gas supply pipe 211 and a cylinder side gas supply pipe 212 are branched from the gas supply pipe 21. Yes.
The supercharger side gas supply pipe 211 is connected to the mixer 10 installed in the supercharger inlet air passage 10a, and controls the ON / OFF of the fuel gas flow rate to the supercharger side gas supply pipe 211. A gas amount adjusting valve (gas supply valve) 19 is provided.
The cylinder-side gas supply pipe 212 is branched for each cylinder on the way and becomes a gas supply branch pipe 213 connected to each supply branch pipe 3. The cylinder side gas supply pipe 212 is provided with a gas compressor 18 for compressing flowing fuel gas, and each supply branch pipe 213 is provided with a cylinder side gas amount adjusting valve (fuel) for controlling a passage area, that is, a fuel gas flow rate. A flow control valve) 20 is provided.

During operation of the gas engine, the fuel gas from the gas supply pipe 21 is branched in the middle of the gas supply pipe 21. Then, one of the branched fuel gases is introduced into the mixer 10 through the supercharger-side gas supply pipe 211 and mixed with the air from the supercharger air inlet passage 10a in the mixer 10, and this mixture is supercharged by the supercharger 7. The compressor 7b is introduced. The air-fuel mixture pressurized to a high temperature and high pressure by the compressor 7b is cooled by the air supply cooler 9 and cooled down, and flows into the air supply branch pipe 3 of each cylinder through the air supply pipe 2.
The other of the branched fuel gas enters the cylinder side gas supply pipe 212, is compressed by the gas compressor 18, passes through the gas supply branch pipes 213 of each cylinder, enters the supply air branch pipes 3, and supplies the air. It is mixed into the air-fuel mixture in the branch pipe 3 and sent into each cylinder.

The exhaust gases from the cylinders of the engine 1 are merged in the exhaust collecting pipe 6 through the exhaust pipe 5 and supplied to the exhaust turbine 7a of the supercharger 7 to drive the exhaust turbine 7a, and then the exhaust outlet pipe 110. It is discharged to the outside through.
When the exhaust bypass valve 12 is opened, a part of the exhaust gas in the exhaust collecting pipe 6 bypasses the exhaust turbine 7a and is discharged to the exhaust outlet pipe 110.

The protection of the engine and the exhaust system using the exhaust temperature in the gas engine system configured as described above will be described with reference to FIGS.
FIG. 2 is a flowchart of the engine protection apparatus using the exhaust temperature in the embodiment.

  When the process is started, the exhaust temperature is detected over time in step S1. The detection of the exhaust temperature in step S1 is performed by each exhaust pipe temperature sensor 51 provided for each exhaust pipe 5. That is, the exhaust pipe temperature is detected individually for each exhaust pipe.

  When the exhaust temperature is detected in step S1, a moving average of the exhaust temperature input to the control device 52 is calculated in step S2. The moving average is calculated individually for each exhaust pipe. The moving average value only needs to be a value that can be smoothed to such an extent that the influence of an instantaneous change in the exhaust temperature is almost eliminated, and a moving average between about 500 msec to 1 sec may be obtained.

  When the moving average value of the exhaust temperature of each exhaust pipe is obtained in step S2, the process proceeds to step S3 and step S4.

  In step S3, a moving average value 10 seconds before is extracted from the accumulated data.

  In step S4, the difference between the moving average value in step S2 and the moving average value in step S3 is obtained. Since the moving average value in step S2 is the latest moving average value, and the moving average value in step S3 is the latest moving average value 10 seconds before, the difference between the moving average value in step S2 and the moving average value in step S3 is That is, the difference between the latest temperature moving average value of exhaust gas and the moving average value of exhaust temperature 10 seconds ago. When the difference is obtained, the rate of increase in exhaust gas temperature in 10 seconds (° C./10 seconds) is obtained using the difference.

When the increase rate of the exhaust temperature is obtained in step S4, the process proceeds to step S5.
In step S5, it is determined whether the increase rate is greater than 200 ° C./10 seconds. If Yes in step S5, the trip set value is set to 550 ° C. in step S6. If No in step S5, the process proceeds to step S7.

  In step S7, it is determined whether or not the rate of increase is greater than 100 ° C./10 seconds. If Yes in step S7, the trip set value is set to 560 ° C. in step S8. If No in step S7, the process proceeds to step S9.

  In step S9, it is determined whether or not the rate of increase is greater than 50 ° C./10 seconds. If Yes in step S9, the trip set value is set to 570 ° C. in step S10. If No in step S9, the trip set value is set to 580 ° C. in step S11.

  That is, in step S5 to step S11, a trip set value is determined according to the increase rate, and the trip set value is set lower as the increase rate is larger.

  When the trip set value is determined in any of step S6, step S8, step S10, or step S11, the process proceeds to step S12.

  In step S12, it is determined whether the exhaust temperature is higher than the trip set value determined in any of steps S6, S8, S10, or S11. Here, the exhaust gas temperature used for the determination in step S12 is the latest moving average data, that is, the moving average value in step S2.

  If NO in step S12, that is, if the exhaust gas temperature is lower than the trip set value, the process returns to step S1. If YES in step S12, that is, if the exhaust gas temperature is higher than the trip set value, the process proceeds to step S13.

When the specified delay time has elapsed in step S13, the process proceeds to step S14. In step S14, the exhaust gas temperature is detected again, and in step S15, it is determined whether the exhaust gas temperature detected in step S14 is higher than the trip set value.
If NO in step S15, that is, if the exhaust gas temperature is lower than the trip set value, the process returns to step S1. If YES in step S15, that is, if the exhaust gas temperature is higher than the trip set value, the process proceeds to step S16.

In step S16, a trip command is issued, and the engine 1 generating exhaust is stopped.
Instead of steps S12 to S15, it is determined whether or not the state where the exhaust gas temperature is higher than the trip set value continues for a certain time corresponding to the delay time of step S13. If not continued, the flow may return to step S11.

FIG. 3 is a graph schematically showing a time change of the exhaust temperature in the first embodiment. The vertical axis in FIG. 3 represents the exhaust temperature, and the horizontal axis represents time.
The graph shown on the left side in FIG. 3 shows the time change of the exhaust temperature when the rate of increase of the exhaust temperature is 50 ° C./10 seconds or less. That is, in the flowchart shown in FIG. 2, the exhaust gas temperature changes with time when the process proceeds from step S4 → step S5 → step S7 → step S9 → step S11 → step S12.
In this case, the trip set value is set to 580 ° C. in step S11 of the flowchart of FIG. 2, and the engine 1 stops due to a trip at the exhaust temperature 580 ° C., and the exhaust temperature decreases.

In addition, the graph shown on the right side in FIG. 3 shows the time variation of the exhaust temperature when the exhaust gas temperature increase rate I is larger than 200 ° C./10 seconds. That is, in the flowchart shown in FIG. 2, the exhaust gas temperature changes with time when the process proceeds from step S4 → step S5 → step S6 → step S12.
In this case, the trip set value is set to 550 ° C. in step S6 of the flowchart of FIG. 2, and the engine 1 stops due to a trip at the exhaust temperature 550 ° C., and the exhaust temperature decreases.

  According to the present invention, the trip temperature is changed depending on the rate of increase in the exhaust temperature. For example, when the rate of increase in the exhaust temperature is large as shown in FIG. Close. Therefore, even if the exhaust temperature rises rapidly, the engine and the exhaust system can be reliably protected because the engine is stopped by a trip at an early stage.

  In this embodiment, the gas engine has been described as an example. However, the present invention is not limited to a gas engine as long as it is an internal combustion engine that discharges exhaust gas. For example, the technology of the present invention can also be applied to a diesel engine. it can.

  In this embodiment, the engine is stopped by tripping at the trip set value. However, for example, in a multi-cylinder engine, control can be performed so that only the cylinder whose exhaust temperature reaches the trip set value is stopped. In particular, in an engine such as a marine engine where the engine cannot be stopped by a trip, it is necessary to perform control so that only the cylinder whose exhaust temperature reaches the trip set value is stopped.

(Comparative example)
FIG. 4 is a graph schematically showing the time change of the exhaust temperature in the comparative example. The vertical axis in FIG. 3 represents the exhaust temperature, and the horizontal axis represents time.
FIG. 4 is a graph schematically showing a time change of the exhaust temperature when the exhaust temperature is controlled according to the conventional flowchart in FIG.
The graph shown on the left side in FIG. 4 is a graph showing the time change of the exhaust temperature when the exhaust temperature increase rate is 50 ° C./10 seconds or less, that is, when the temperature increase is gradual. The graph shown on the right side is a graph showing the time change of the exhaust temperature when the exhaust temperature increase rate is larger than 200 ° C./10 seconds, that is, when the temperature increase is rapid.
In either case, the engine 1 stops due to a trip at a specified trip temperature (for example, 580 ° C.), and the exhaust temperature decreases.

  In this case, whether or not the exhaust gas temperature rises suddenly or slowly increases, the only criterion for trip determination is whether or not the exhaust gas temperature is higher than a certain trip set value. Therefore, in the case where the exhaust temperature suddenly rises as shown in the graph on the right side of FIG. 4, when the exhaust temperature reaches the trip set value and a trip command is issued, the engine or the exhaust valve seat, for example, And exhaust parts such as exhaust valve rods may be damaged.

  Even when the exhaust gas temperature rises rapidly, it can be used as a protection method and apparatus for an internal combustion engine that can reliably protect the engine and exhaust system equipment.

DESCRIPTION OF SYMBOLS 1 Gas engine 2 Supply pipe 3 Supply air branch pipe 6 Exhaust collecting pipe 7 Supercharger 7a Exhaust turbine 7b Compressor 10a Supercharger inlet air passage 13 Generator 15 Rotational speed sensor 18 Gas compressor 19 Supercharger side gas amount adjustment valve 20 Cylinder side gas amount adjusting valve 21 Gas supply pipe 51 Exhaust pipe temperature sensor 52 Control device

Claims (2)

In the internal combustion engine protection device for detecting an abnormality based on the exhaust temperature and protecting the internal combustion engine whose output shaft is connected to the generator ,
Exhaust temperature detecting means for detecting the exhaust temperature of the internal combustion engine;
A rate of change calculating means for calculating a rate of change of the exhaust temperature in a predetermined time unit based on a moving average of the exhaust temperature detected by the exhaust temperature detecting means;
Trip value setting means for setting the trip value to be lower as the change rate is larger, corresponding to the change rate,
Stop means for stopping fuel supply when the exhaust temperature is higher than the trip value set by the trip value setting means;
Equipped with a,
The internal combustion engine is a multi-cylinder engine;
The exhaust temperature detection means is provided for each of the multiple cylinders and detects the exhaust temperature for each cylinder.
The trip value setting means sets a trip value corresponding to the change rate for each cylinder.
The internal combustion engine protection device , wherein the stop means stops only the cylinder that detects an exhaust temperature higher than the trip value, and stops the fuel supply to the cylinder . In the internal combustion engine protection method for detecting an abnormality based on the exhaust temperature and protecting the internal combustion engine whose output shaft is connected to the generator ,
The internal combustion engine is a multi-cylinder engine;
Based on the moving average of the exhaust temperature, the rate of change of the exhaust temperature for each cylinder of the internal combustion engine in a predetermined time unit is calculated,
Corresponding to the rate of change for each cylinder, the larger the rate of change, the lower the trip value,
When the exhaust temperature is higher than the trip value, only the cylinder that detects the exhaust temperature higher than the trip value is deactivated, and the fuel supply to the cylinder is stopped.

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