A method for detecting crankcase pressure in a diesel engine

Abstract

This invention relates to a method for detecting crankcase pressure in a diesel engine. The method involves creating a through-hole in the crankcase, with a pressure detection mechanism installed at the through-hole. The crankcase pressure is converted into the physical displacement of internal components within the pressure detection mechanism. When the crankcase pressure exceeds a set value, an emergency stop mechanism on the pressure detection mechanism is triggered, causing the diesel engine to stop running. This invention presents changes in the internal pressure of the crankcase as the lateral movement of a piston within the piston cylinder, replacing the traditional method of directly using electronic instruments. This allows for timely and accurate detection of crankcase pressure even in cold conditions, ensuring the normal operation of the diesel engine.

Description

Technical Field

[0001] This invention belongs to the field of pressure detection technology, specifically relating to a method for detecting the pressure of a diesel engine crankcase. Background Technology

[0002] When a diesel engine is running normally, the crankcase pressure remains stable. However, if the piston seal is poor, air leakage can occur, causing the air-fuel mixture to leak into the crankcase. This can lead to excessive gas in the crankcase and increased pressure. Alternatively, during engine operation, the high-pressure combustible mixture and burned gas from the combustion chamber can leak into the crankcase through the gap between the piston assembly and the cylinder, causing blow-by. This can lead to a sudden increase in crankcase pressure. If the diesel engine continues to run under these conditions, the excessive combustion gas entering the crankcase can easily ignite the crankshaft oil mist, causing an explosion of the air-fuel mixture in the crankcase, endangering personnel and other equipment.

[0003] Typically, a crankcase pressure sensor is installed inside the crankcase. The function of the crankcase pressure sensor is to transmit the pressure inside the crankcase to the electronic control unit in the form of an electrical signal to detect the working status of the crankcase forced ventilation system. However, when the diesel engine is operating in extremely cold environments, the crankcase pressure sensor often freezes due to the low temperature. After the diesel engine is started, the frozen material on the sensor cannot melt in time, and the crankcase pressure sensor cannot collect the true crankcase pressure, causing the crankcase pressure sensor to report false crankcase pressure detection results. This greatly affects the safety of diesel engine operation. Summary of the Invention

[0004] The purpose of this invention is to provide a method for detecting crankcase pressure in a diesel engine in order to solve the problems mentioned in the background art.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] A method for detecting crankcase pressure in a diesel engine, comprising: opening a through hole in the crankcase, and installing a pressure detection mechanism at the through hole; converting the pressure in the crankcase into the physical displacement of the internal parts of the pressure detection mechanism; and triggering an emergency stop mechanism on the pressure detection mechanism when the pressure in the crankcase exceeds a set value, thereby stopping the diesel engine.

[0007] The pressure detection mechanism includes a piston cylinder located at the crankcase through hole and a movable piston located inside the piston cylinder. The end of the piston cylinder away from the crankcase is closed and the end close to the crankcase is open. The pressure in the sealed space formed by the movable piston and the piston cylinder is equal to the pressure in the crankcase.

[0008] Preferably, the emergency stop mechanism includes a trigger switch on the piston cylinder, a pressing member on the piston cylinder, and an extending member on the piston cylinder. The piston cylinder is provided with an air passage filled with honey. The pressing member is used to drive the extending member to move.

[0009] Preferably, the frictional force between the piston cylinder and the moving piston gradually increases in the direction away from the crankcase.

[0010] Preferably, the cross-section of the press-in member is trapezoidal.

[0011] Preferably, the movable piston includes a main body and a movable intermediate body. The intermediate body is provided with a pull rope on the side near the trigger switch. The piston cylinder is provided with two or more cavities. Each cavity is provided with two or more levers along its length. Each lever is provided with a magnetic ball. The end of the pull rope away from the intermediate body is divided into two or more forked ropes. The end of each forked rope away from the intermediate body is provided with two or more magnetic blocks and connected to an elastic rope. The elastic rope is provided on the piston cylinder.

[0012] The beneficial effects of this invention are as follows:

[0013] This invention presents the internal pressure changes of the crankcase as the lateral movement of a moving piston within the piston cylinder, replacing the direct use of electronic instruments for detection. This allows for timely and accurate detection of the crankcase pressure even in cold conditions, ensuring the normal operation of the diesel engine. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the pressure detection mechanism in this invention;

[0015] Figure 2 This is a schematic diagram showing the positional relationship between the movable piston and the piston cylinder in this invention;

[0016] Figure 3 This is a schematic diagram showing the positional relationship between the press-in component and the protruding component in this invention.

[0017] In the diagram: 1. Crankcase; 2. Piston cylinder; 4. Trigger switch; 5. Press-in part; 6. Extender part; 7. Air passage; 8. Honey; 9. Main body; 10. Intermediate body; 11. Pull rope; 12. Cavity; 13. Lever; 14. Magnetic ball; 15. Fork rope; 16. Magnetic block. Detailed Implementation

[0018] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0019] Example 1

[0020] like Figure 1-3 As shown, a method for detecting crankcase pressure in a diesel engine is described. The method involves: opening a through hole in the crankcase 1, and installing a pressure detection mechanism at the through hole. The pressure in the crankcase 1 is converted into the physical displacement of the internal parts of the pressure detection mechanism. When the pressure in the crankcase 1 exceeds a set value, an emergency stop mechanism on the pressure detection mechanism is triggered, causing the diesel engine to stop running.

[0021] The pressure detection mechanism includes a piston cylinder 2 located at the through hole of the crankcase 1 and a movable piston located inside the piston cylinder 2. The end of the piston cylinder 2 away from the crankcase 1 is closed and the end close to the crankcase 1 is open. The pressure of the sealed space formed by the movable piston and the piston cylinder 2 is equal to the pressure of the crankcase 1.

[0022] In the above embodiment, when the internal pressure of the crankcase 1 is normal, the moving piston in the piston cylinder 2 is in a safe position. Indicator scales can be marked on the outer wall of the piston cylinder 2, and the piston cylinder 2 is made of transparent material. When the pressure inside the crankcase 1 increases, the pressure on the side of the moving piston closest to the crankcase 1 increases. When the pressure difference between the two sides of the moving piston exceeds the frictional force between the moving piston and the piston cylinder 2, the moving piston moves. By observing the position of the moving piston, the pressure inside the crankcase 1 can be determined. When the pressure inside the crankcase 1 decreases, the moving piston can move towards the crankcase 1, indicating that the pressure in the crankcase 1 is too low. When the pressure inside the crankcase 1 increases excessively, the emergency stop mechanism is triggered, allowing the emergency stop mechanism to stop the diesel engine from running, thus protecting the diesel engine.

[0023] As a further embodiment of the present invention, the emergency stop mechanism includes a trigger switch 4 disposed on the piston cylinder 2, a pressing member 5 disposed on the piston cylinder 2, and an extending member 6 disposed on the piston cylinder 2. The piston cylinder 2 is provided with an air passage 7, which is filled with honey 8. The pressing member 5 is used to drive the extending member 6 to move.

[0024] As a further embodiment of the present invention, the cross-section of the press-in member 5 is trapezoidal.

[0025] In the above embodiment, a short-term increase in pressure in the crankcase 1 will not affect the operation of the diesel engine. Directly stopping the diesel engine could result in economic losses. By providing the press-in component 5, when the moving piston reaches the press-in component 5, it presses the component into the air passage 7 on the inner wall of the piston cylinder 2, causing the honey 8 in the air passage 7 to be compressed and slowly move towards the protrusion 6. If the pressure increase is short-lived, the honey 8 will stop moving before reaching the protrusion 6. If the pressure increase is prolonged, the honey 8 will slowly move towards the protrusion 6 under the pressure, causing the protrusion 6 to move upwards and press against the trigger switch 4, thus activating the trigger switch 4 and stopping the diesel engine.

[0026] The trapezoidal shape of the insert 5 ensures that the moving piston can gradually press the insert 5 into the air passage 7 during its movement, while avoiding significant obstruction to the movement of the moving piston.

[0027] As a further aspect of the present invention, the frictional force between the piston cylinder 2 and the moving piston gradually increases in the direction away from the crankcase 1.

[0028] In the above embodiment, because the piston cylinder 2 is relatively short and has a small diameter, the pressure changes within the crankcase 1 make it easy for the moving piston to move too much, which could easily lead to the moving piston accidentally triggering the emergency stop mechanism. By gradually increasing the friction between the moving piston and the piston cylinder 2, the movement of the moving piston within the piston cylinder 2 becomes increasingly difficult, thus limiting the range of movement of the moving piston. Even if the pressure within the crankcase 1 increases significantly, as long as the pressure in the crankcase 1 does not reach the set value, the normal movement of the moving piston within the piston cylinder 2 can be guaranteed.

[0029] As a further embodiment of the present invention, the movable piston includes a main body 9 and a movable intermediate body 10. The intermediate body 10 is provided with a pull rope 11 on the side near the trigger switch 4. The piston cylinder 2 is provided with two or more cavities 12. Each cavity 12 is provided with two or more levers 13 along its length. The levers 13 are provided with magnetic balls 14. The end of the pull rope 11 away from the intermediate body 10 is divided into two or more forked ropes 15. The end of the forked rope 15 away from the intermediate body 10 is provided with two or more magnetic blocks 16 and connected to an elastic rope. The elastic rope is provided on the piston cylinder 2.

[0030] In the above embodiment, if the moving piston freezes and cannot move in a low-temperature environment, and the pressure in the crankcase 1 decreases, the intermediate body 10 of the moving piston is pressed towards the crankcase 1. At this time, the intermediate body 10 pulls the pull rope 11, causing the pull rope 11 to pull the magnetic block 16. During its movement, the magnetic block 16 attracts the magnetic ball 14, causing the magnetic ball 14 to move towards the magnetic block 16. When the magnetic block 16 moves out of the magnetic range of the magnetic ball 14, the magnetic ball 14 returns to its initial position under the elastic force of the lever 13, thus contacting the piston cylinder 2. During the contact between the magnetic ball 14 and the piston cylinder 2, the magnetic ball 14 impacts the piston cylinder 2, causing it to vibrate. This strong vibration can knock off the ice frozen on the surface of the piston cylinder 2, ensuring that the normal movement of the moving piston is not affected. The elastic rope straightens the pull rope 11 when the moving piston returns to its initial position, preventing the pull rope 11 from becoming loose and allowing it to be used for the next de-icing operation. The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for detecting crankcase pressure in a diesel engine, characterized in that, The method is as follows: a through hole is opened on the crankcase (1), and a pressure detection mechanism is provided at the through hole. The pressure of the crankcase (1) is converted into the physical displacement of the internal parts of the pressure detection mechanism. When the pressure on the crankcase (1) exceeds the set value, the emergency stop mechanism on the pressure detection mechanism is triggered, so that the diesel engine stops running. The pressure detection mechanism includes a piston cylinder (2) located at the through hole of the crankcase (1) and a movable piston located inside the piston cylinder (2). The piston cylinder (2) is closed at one end away from the crankcase (1) and open at the other end near the crankcase (1). The pressure of the sealed space formed by the movable piston and the piston cylinder (2) is equal to the pressure of the crankcase (1). The emergency stop mechanism includes a trigger switch (4) on the piston cylinder (2), a push-in member (5) on the piston cylinder (2), and a protruding member (6) on the piston cylinder (2). The piston cylinder (2) is provided with an air passage (7), which is filled with honey (8). The push-in member (5) is used to drive the protruding member (6) to move. The cross-section of the press-in part (5) is trapezoidal; The movable piston includes a main body (9) and a movable intermediate body (10). The intermediate body (10) has a pull rope (11) on the side near the trigger switch (4). The piston cylinder (2) has two or more cavities (12). Each cavity (12) has two or more levers (13) along its length. Each lever (13) has a magnetic ball (14). The pull rope (11) is divided into two or more forked ropes (15) at the end away from the intermediate body (10). Each forked rope (15) has two or more magnetic blocks (16) at the end away from the intermediate body (10) and is connected to an elastic rope. The elastic rope is located on the piston cylinder (2).

2. The method for detecting crankcase pressure in a diesel engine according to claim 1, characterized in that: The frictional force between the piston cylinder (2) and the moving piston gradually increases in the direction away from the crankcase (1).

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