Method and system for controlling hydrogen concentration of crankcase of hydrogen internal combustion engine

Abstract

The invention discloses a method for controlling the hydrogen concentration of a crankcase of a hydrogen internal combustion engine, relates to the technical field of internal combustion engines, and solves the technical problem that an existing crankcase ventilation system does not have an effective measure for reducing the hydrogen concentration. The method comprises the steps that the real-time hydrogen concentration in a crankcase is obtained, a plurality of hydrogen concentration intervals are set, and a hydrogen concentration control strategy is started according to the fact that the real-time hydrogen concentration is located in the hydrogen concentration intervals, so that the real-time hydrogen concentration is located at a normal concentration value. The invention further discloses a system for controlling the hydrogen concentration of the crankcase of the hydrogen internal combustion engine. The situation of uncontrollable combustion and even explosion caused by concentration gathering of hydrogen in the crankcase can be effectively avoided, and the working efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of internal combustion engines, and more specifically, to a method and system for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine. Background Art

[0002] Existing conventional diesel and natural gas engine crankcase ventilation systems such as Figure 1 As shown, the main function of the crankcase ventilation system is to achieve oil-gas separation and control the crankcase pressure. The crankcase gas generated by the engine operation enters the air-driven oil-gas separator through the engine cylinder head cover breathing port and pipe 1. The gas separated by the oil-gas separator enters the air filter rear pipe through pipe 2, and then the gas enters the air filter and the compressor inlet pipe, thus forming a closed crankcase ventilation system. The cooled supercharger gas taken from the back of the intercooler and before the throttle enters the air-driven oil-gas separator through pipe 3, thereby driving the air-driven oil-gas separator to work and achieve high separation efficiency. However, the air-driven oil-gas separator maintains a high separation efficiency and realizes negative pressure in the cylinder head cover (crankcase), requiring the gas introduced by pipe 3 to be greater than the set pressure limit value (the set pressure limit value is generally 1.5 bar). The oil-gas separator can be an electric-driven oil-gas separator (without connecting pipe 4), an air-driven oil-gas separator, or an air-driven oil-gas separator (without connecting pipe 4). The system's crankcase ventilation system fully meets the application of traditional engines, achieving efficient oil and gas separation and controlling crankcase pollutant emissions.

[0003] However, for traditional reciprocating hydrogen internal combustion engines, the hydrogen-fuel mixture in the cylinder may leak into the engine's crankcase through the gap between the piston rings and accumulate at a high position in the engine's crankcase ventilation system. The existing crankcase ventilation system does not have effective measures to reduce the hydrogen concentration. When the hydrogen concentration in the crankcase ventilation system exceeds a certain concentration (generally exceeding 4%), there is a risk of explosion. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for controlling hydrogen concentration in the crankcase of a hydrogen internal combustion engine in view of the deficiencies in the prior art, so as to solve the technical problem that the existing crankcase ventilation system has no effective measures to reduce the hydrogen concentration.

[0005] The present invention discloses a method for controlling the hydrogen concentration in the crankcase of a hydrogen internal combustion engine. The method comprises the following steps: obtaining the real-time concentration of hydrogen in the crankcase, setting a plurality of hydrogen concentration intervals, and activating a hydrogen concentration control strategy based on the real-time concentration of hydrogen being in the hydrogen concentration interval so that the real-time concentration of hydrogen is at a normal concentration value.

[0006] As a further improvement, the hydrogen concentration control strategy is:

[0007] The hydrogen concentration intervals include a first concentration interval, a second concentration interval, a third concentration interval and a fourth concentration interval;

[0008] When the real-time concentration of hydrogen is within the first concentration interval, the real-time concentration of hydrogen is a normal concentration value;

[0009] When the real-time concentration of hydrogen is in the second concentration range, the rotation speed of the oil-gas separator is increased to a preset first rotation speed to extract the hydrogen in the crankcase, and at the same time, air is added to the crankcase to dilute the hydrogen in the crankcase so as to reduce the real-time concentration of hydrogen to the first concentration range;

[0010] When the real-time concentration of hydrogen is in the third concentration range, the air throttle valve is opened to add air into the crankcase to dilute the hydrogen in the crankcase so as to reduce the real-time concentration of hydrogen to the first concentration range;

[0011] When the real-time concentration of hydrogen is in the fourth concentration interval, a fault alarm is initiated and an intelligent cylinder deactivation strategy is triggered;

[0012] When the real-time concentration of hydrogen is within the fifth concentration interval, the fault alarm is activated and the engine is shut down.

[0013] Furthermore, the intelligent cylinder deactivation strategy is:

[0014] Assume that the number of cylinders in the hydrogen internal combustion engine is 1;

[0015] Stopping the hydrogen injection of the i-th cylinder in sequence and obtaining the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder, when the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is within a first concentration interval, stopping the hydrogen injection of the i-th cylinder to allow the engine to continue to run in a cylinder-missing limp state;

[0016] After the hydrogen injection of the i-th cylinder is stopped in sequence, if the hydrogen concentration after the hydrogen injection of the i-th cylinder is still not within the first concentration interval, the hydrogen concentration after the hydrogen injection of the i-th cylinder is stopped is obtained, the hydrogen concentrations after the hydrogen injection of the i-th cylinder are arranged from small to large, the two cylinders with the lowest hydrogen concentrations after the injection are obtained, and the hydrogen injection of the two cylinders is stopped to obtain the hydrogen concentrations after the hydrogen injection of the two cylinders;

[0017] When the hydrogen concentration after stopping the hydrogen injection of the two cylinders is within the first concentration range, the hydrogen injection of the two cylinders is stopped so that the engine continues to run in a cylinder-missing limp manner; when the hydrogen concentration after stopping the hydrogen injection of the two cylinders is still not within the first concentration range, the engine is shut down;

[0018] Among them, i=1~I.

[0019] Furthermore, after the engine is shut down, the speed of the oil-gas separator keeps working according to a preset delay time to discharge hydrogen in the engine.

[0020] Furthermore, the hydrogen concentration interval includes a first concentration interval, a second concentration interval, a third concentration interval and a fourth concentration interval;

[0021] The hydrogen concentration in the first concentration interval is less than a preset first hydrogen concentration threshold;

[0022] The hydrogen concentration in the second concentration interval is greater than or equal to the first hydrogen concentration threshold and less than or equal to a preset second hydrogen concentration threshold;

[0023] The hydrogen concentration in the third concentration interval is greater than the second hydrogen concentration threshold and less than or equal to a preset third hydrogen concentration threshold;

[0024] The hydrogen concentration in the fourth concentration interval is greater than the third hydrogen concentration threshold and less than a preset fourth hydrogen concentration threshold;

[0025] The hydrogen concentration in the fifth concentration interval is greater than or equal to a fourth hydrogen concentration threshold.

[0026] Furthermore, the first hydrogen concentration threshold is 0.5%-1%, and the fourth hydrogen concentration threshold is 2.5%-3.5%.

[0027] A hydrogen concentration control system for a hydrogen internal combustion engine crankcase, the system comprising:

[0028] A hydrogen concentration sensor is installed on the engine cylinder head cover or on the second pipeline connected to the oil-gas separator, and is used to obtain the real-time concentration of hydrogen in the crankcase and output a hydrogen concentration signal;

[0029] An air throttle valve, mounted on a fourth pipe connected between the engine cylinder head cover and the air filter, for supplementing air into the crankcase to dilute the hydrogen in the crankcase;

[0030] ECU, used for receiving the hydrogen concentration signal;

[0031] The ECU activates a hydrogen concentration control strategy through a hydrogen concentration signal according to the above-mentioned hydrogen concentration control method for a crankcase of a hydrogen internal combustion engine so that the real-time concentration of hydrogen is at a normal concentration value.

[0032] As a further improvement, the air throttle valve is an electrically controlled crankcase air supply cut-off valve or a mechanical one-way pressure differential valve.

[0033] Beneficial Effects

[0034] The advantages of the present invention are:

[0035] The present invention obtains the real-time hydrogen concentration in the crankcase, sets a plurality of hydrogen concentration intervals, and activates a hydrogen concentration control strategy according to the real-time hydrogen concentration being in the hydrogen concentration interval to make the real-time hydrogen concentration at a normal concentration value, thereby effectively avoiding the accumulation of hydrogen concentration in the crankcase to cause uncontrollable combustion or even explosion, thereby improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the structure of the crankcase ventilation system of existing traditional diesel engines, natural gas engines, etc.

[0037] Figure 2 It is a schematic structural diagram of a hydrogen concentration control system for a hydrogen internal combustion engine crankcase of the present invention;

[0038] Figure 3 It is a flow chart of a method for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine with an electrically controlled shut-off valve for filling a crankcase with gas of the present invention;

[0039] Figure 4 The present invention is a flow chart of a method for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine with a mechanical one-way pressure differential valve.

[0040] Among them: 1-hydrogen internal combustion engine, 2-cylinder head cover of the engine, 3-oil-gas separator, 4-air filter, 5-supercharger compressor, 6-intercooler, 7-throttle, 8-cylinder body, 9-ECU, 10-hydrogen concentration sensor, 11-air throttle, 12-crankcase pressure difference sensor, 13-pipeline one, 14-pipeline two, 15-pipeline three, 16-pipeline four, 17-first pipeline, 18-second pipeline, 19-third pipeline, 20-fourth pipeline, 21-fifth pipeline. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0042] See also Figure 2-Figure 4 The present invention provides a method for controlling the hydrogen concentration in the crankcase of a hydrogen internal combustion engine. The method comprises the following steps: powering on the engine, controlling the crankcase ventilation system to operate according to a conventional default mode, and synchronously acquiring the real-time concentration of hydrogen in the crankcase, setting a plurality of hydrogen concentration intervals, and activating a hydrogen concentration control strategy when the real-time concentration of hydrogen is in the hydrogen concentration interval so that the real-time concentration of hydrogen is at a normal concentration value.

[0043] According to different types of installed air throttle valves 11 , the present invention provides two different embodiments of hydrogen concentration control strategies.

[0044] like Figure 3As shown, in Embodiment 1, when the installed air throttle valve 11 is a crankcase air supply electronically controlled shut-off valve, the first hydrogen concentration control strategy is:

[0045] The hydrogen concentration intervals include a first concentration interval, a second concentration interval, a third concentration interval, a fourth concentration interval, and a fifth concentration interval.

[0046] The hydrogen concentration in the first concentration interval is less than a preset first hydrogen concentration threshold.

[0047] The hydrogen concentration in the second concentration interval is greater than or equal to the first hydrogen concentration threshold and less than or equal to a preset second hydrogen concentration threshold.

[0048] The hydrogen concentration in the third concentration interval is greater than the second hydrogen concentration threshold and less than or equal to a preset third hydrogen concentration threshold.

[0049] The hydrogen concentration in the fourth concentration interval is greater than the third hydrogen concentration threshold and less than a preset fourth hydrogen concentration threshold.

[0050] The hydrogen concentration in the fifth concentration interval is greater than or equal to the fourth hydrogen concentration threshold.

[0051] Among them, the first hydrogen concentration threshold is 0.75%, and the fourth hydrogen concentration threshold is 3%.

[0052] When the real-time concentration of hydrogen is in the first concentration interval, the real-time concentration of hydrogen is a normal concentration value.

[0053] When the real-time concentration of hydrogen is in the second concentration range, the speed of the oil-gas separator 3 is increased to the preset first speed to extract the hydrogen in the crankcase, and air is added to the crankcase to dilute the hydrogen in the crankcase to reduce the real-time concentration of hydrogen to the first concentration range.

[0054] When the real-time concentration of hydrogen is in the third concentration range, the air throttle valve 11 is opened to add air into the crankcase to dilute the hydrogen in the crankcase so as to reduce the real-time concentration of hydrogen to the first concentration range.

[0055] When the real-time hydrogen concentration is in the fourth concentration range, the fault alarm is activated and the intelligent cylinder deactivation strategy is triggered.

[0056] When the real-time hydrogen concentration is in the fifth concentration range, it indicates that there is a serious hydrogen leak in the engine, and the fault alarm is activated and the engine is shut down. It reminds the customer that the engine has a serious consequence failure and needs to be pulled aside for maintenance, and hydrogen injection in all cylinders is stopped.

[0057] like Figure 4 As shown, in Embodiment 2: when the installed air throttle valve 11 is a mechanical one-way pressure differential valve, the second hydrogen concentration control strategy is:

[0058] The hydrogen concentration intervals include a first concentration interval, a second concentration interval, a third concentration interval, and a fourth concentration interval.

[0059] The hydrogen concentration in the first concentration interval is less than a preset first hydrogen concentration threshold.

[0060] The hydrogen concentration in the second concentration interval is greater than or equal to the first hydrogen concentration threshold and less than or equal to a preset second hydrogen concentration threshold.

[0061] The hydrogen concentration in the third concentration interval is greater than the second hydrogen concentration threshold and less than or equal to a preset fourth hydrogen concentration threshold.

[0062] The hydrogen concentration in the fourth concentration interval is greater than or equal to a fourth hydrogen concentration threshold.

[0063] Among them, the first hydrogen concentration threshold is 0.75%, and the fourth hydrogen concentration threshold is 3%.

[0064] When the real-time concentration of hydrogen is in the first concentration interval, the real-time concentration of hydrogen is a normal concentration value.

[0065] When the real-time concentration of hydrogen is in the second concentration range, the speed of the oil-gas separator 3 is increased to the preset first speed to extract the hydrogen in the crankcase, and air is added to the crankcase to dilute the hydrogen in the crankcase to reduce the real-time concentration of hydrogen to the first concentration range.

[0066] When the real-time hydrogen concentration is in the third concentration range, the fault alarm is activated and the intelligent cylinder deactivation strategy is triggered.

[0067] When the real-time hydrogen concentration is in the fourth concentration range, it indicates that there is a serious hydrogen leak in the engine, and the fault alarm is activated and the engine is shut down. The customer is reminded that the engine has a serious consequence fault and needs to be pulled aside for maintenance, and hydrogen injection in all cylinders is stopped.

[0068] The intelligent cylinder deactivation strategies in the two embodiments are:

[0069] Assume that the number of cylinders in the hydrogen internal combustion engine is 1. The hydrogen injection of the i-th cylinder is stopped in sequence and the hydrogen concentration after the hydrogen injection of the i-th cylinder is stopped is obtained. When the hydrogen concentration after the hydrogen injection of the i-th cylinder is stopped is in a first concentration interval, the hydrogen injection of the i-th cylinder is stopped so that the engine continues to run in a cylinder-missing limp manner.

[0070] After stopping the hydrogen injection of the i-th cylinder in sequence, if the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is still not within the first concentration interval, the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is obtained, the hydrogen concentrations after stopping the hydrogen injection of the i-th cylinder are arranged from small to large, the two cylinders with the lowest hydrogen concentrations after injection are obtained, and the hydrogen injection of the two cylinders is stopped to obtain the hydrogen concentrations after stopping the hydrogen injection of the two cylinders.

[0071] When the hydrogen concentration after stopping the hydrogen injection of the two cylinders is within the first concentration range, the hydrogen injection of the two cylinders is stopped to allow the engine to continue to run in cylinder-missing limp mode; when the hydrogen concentration after stopping the hydrogen injection of the two cylinders is still not within the first concentration range, the engine is shut down, where i=1~I.

[0072] After the engine is shut down, the speed of the oil-gas separator 3 is kept working according to the preset delay time to discharge the hydrogen in the engine.

[0073] A hydrogen concentration control system for a hydrogen internal combustion engine crankcase, the system comprising:

[0074] The hydrogen concentration sensor 10 is installed at the position where the hydrogen concentration is most concentrated on the engine cylinder head cover 2 or on the second pipe 18 connected to the oil-gas separator 3, and is used to obtain the real-time concentration of hydrogen in the crankcase and output a hydrogen concentration signal.

[0075] When the hydrogen concentration sensor 10 has the property of being resistant to engine oil, the hydrogen concentration sensor 10 is installed at the position of the highest concentration on the engine cylinder head cover 2. When the hydrogen concentration sensor 10 is not resistant to engine oil, it is installed on the second pipe 18 connected to the outlet of the oil-gas separator 3.

[0076] The air throttle valve 11 is installed on the fourth pipe 20 connected between the engine cylinder head cover 2 and the air filter 4, and is used to supplement air into the crankcase to dilute the hydrogen in the crankcase.

[0077] ECU9 is used to receive the hydrogen concentration signal.

[0078] According to the above-mentioned method for controlling hydrogen concentration in the crankcase of a hydrogen internal combustion engine, ECU9 activates the hydrogen concentration control strategy through the hydrogen concentration signal to make the real-time hydrogen concentration at a normal concentration value.

[0079] The oil-gas separator 3 in this embodiment is an electric-driven oil-gas separator without a crankcase negative pressure regulating valve, and the rotation speed of the oil-gas separator 3 can be controlled by the ECU 9. Increasing the rotation speed of the oil-gas separator can achieve more suction force, thereby quickly extracting the accumulated hydrogen in the crankcase. At the same time, fresh air is added to the crankcase through the fourth pipeline 20, the air throttle valve 11 and the fifth pipeline 21 (the fifth pipeline 21 is installed at the point where hydrogen is most likely to accumulate on the engine, generally confirmed by experiments) to dilute the crankcase hydrogen concentration and ensure that the crankcase pressure is not too high.

[0080] When the air throttle valve 11 is an electrically controlled shut-off valve for replenishing air in the crankcase, the ECU 9 detects that the hydrogen concentration in the crankcase is lower than the threshold value, and controls the electrically driven oil-gas separator 3 to increase the operating speed to increase the suction force, and at the same time controls the air throttle valve 11 (electrically controlled shut-off valve) to open to replenish air in the crankcase.

[0081] When the air throttle valve 11 is a mechanical one-way pressure differential valve, the air throttle valve 11 is a one-way valve with an initial pressure differential. When the pressure in the crankcase and the pressure differential downstream of the air filter are lower than the set threshold of the one-way valve, the one-way valve opens under the action of the gas pressure differential, and air is added to the crankcase to dilute the hydrogen concentration in the crankcase.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine, characterized in that: The method comprises obtaining the real-time concentration of hydrogen in the crankcase, setting a plurality of hydrogen concentration intervals, and activating a hydrogen concentration control strategy according to the real-time concentration of hydrogen being in the hydrogen concentration interval so that the real-time concentration of hydrogen is at a normal concentration value.

2. A method for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine according to claim 1, characterized in that: The hydrogen concentration control strategy is: The hydrogen concentration intervals include a first concentration interval, a second concentration interval, a third concentration interval and a fourth concentration interval; When the real-time concentration of hydrogen is within the first concentration interval, the real-time concentration of hydrogen is a normal concentration value; When the real-time concentration of hydrogen is in the second concentration range, the rotation speed of the oil-gas separator is increased to a preset first rotation speed to extract the hydrogen in the crankcase, and at the same time, air is added to the crankcase to dilute the hydrogen in the crankcase so as to reduce the real-time concentration of hydrogen to the first concentration range; When the real-time concentration of hydrogen is in the third concentration range, the air throttle valve is opened to add air into the crankcase to dilute the hydrogen in the crankcase so as to reduce the real-time concentration of hydrogen to the first concentration range; When the real-time concentration of hydrogen is in the fourth concentration interval, a fault alarm is initiated and an intelligent cylinder deactivation strategy is triggered; When the real-time concentration of hydrogen is within the fifth concentration interval, the fault alarm is activated and the engine is shut down.

3. A method for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine according to claim 2, characterized in that: The intelligent cylinder deactivation strategy is: Assume that the number of cylinders in the hydrogen internal combustion engine is 1; Stopping the hydrogen injection of the i-th cylinder in sequence and obtaining the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder, when the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is within a first concentration interval, stopping the hydrogen injection of the i-th cylinder to allow the engine to continue to run in a cylinder-missing limp state; After the hydrogen injection of the i-th cylinder is stopped in sequence, if the hydrogen concentration after the hydrogen injection of the i-th cylinder is still not within the first concentration interval, the hydrogen concentration after the hydrogen injection of the i-th cylinder is stopped is obtained, the hydrogen concentrations after the hydrogen injection of the i-th cylinder are arranged from small to large, the two cylinders with the lowest hydrogen concentrations after the injection are obtained, and the hydrogen injection of the two cylinders is stopped to obtain the hydrogen concentrations after the hydrogen injection of the two cylinders; When the hydrogen concentration after stopping the hydrogen injection of the two cylinders is within the first concentration range, the hydrogen injection of the two cylinders is stopped so that the engine continues to run in a cylinder-missing limp manner; when the hydrogen concentration after stopping the hydrogen injection of the two cylinders is still not within the first concentration range, the engine is shut down; Among them, i=1~I.

4. A method for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine according to claim 3, characterized in that: When the engine is shut down, the speed of the oil-gas separator keeps working according to a preset delay time to discharge hydrogen in the engine.

5. The method for controlling the hydrogen concentration in the crankcase of a hydrogen internal combustion engine according to claim 1, characterized in that: The hydrogen concentration intervals include a first concentration interval, a second concentration interval, a third concentration interval and a fourth concentration interval; The hydrogen concentration in the first concentration interval is less than a preset first hydrogen concentration threshold; The hydrogen concentration in the second concentration interval is greater than or equal to the first hydrogen concentration threshold and less than or equal to a preset second hydrogen concentration threshold; The hydrogen concentration in the third concentration interval is greater than the second hydrogen concentration threshold and less than or equal to a preset third hydrogen concentration threshold; The hydrogen concentration in the fourth concentration interval is greater than the third hydrogen concentration threshold and less than a preset fourth hydrogen concentration threshold; The hydrogen concentration in the fifth concentration interval is greater than or equal to a fourth hydrogen concentration threshold.

6. A method for controlling hydrogen concentration in a crankcase of a hydrogen internal combustion engine according to claim 5, characterized in that: The first hydrogen concentration threshold is 0.5%-1%, and the fourth hydrogen concentration threshold is 2.5%-3.5%.

7. A hydrogen concentration control system for a hydrogen internal combustion engine crankcase, characterized in that: The system includes: A hydrogen concentration sensor is installed on the engine cylinder head cover or on the second pipeline connected to the oil-gas separator, and is used to obtain the real-time concentration of hydrogen in the crankcase and output a hydrogen concentration signal; An air throttle valve, mounted on a fourth pipe connected between the engine cylinder head cover and the air filter, for supplementing air into the crankcase to dilute the hydrogen in the crankcase; ECU, used for receiving the hydrogen concentration signal; The ECU activates a hydrogen concentration control strategy through a hydrogen concentration signal according to a hydrogen internal combustion engine crankcase hydrogen concentration control method as described in any one of claims 1 to 6 above, so as to reduce the real-time hydrogen concentration to a normal concentration value.

8. A hydrogen concentration control system for a hydrogen internal combustion engine crankcase according to claim 7, characterized in that: The air throttle valve is an electrically controlled crankcase air supply cut-off valve or a mechanical one-way pressure differential valve.

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