A method and system for controlling hydrogen concentration in a hydrogen internal combustion engine crankcase

Abstract

The application discloses a hydrogen internal combustion engine crankcase hydrogen concentration control method, and relates to the technical field of internal combustion engines, and solves the technical problem that the existing crankcase ventilation system does not effectively reduce hydrogen concentration. The method is to obtain real-time hydrogen concentration in the crankcase, set multiple hydrogen concentration intervals, and enable a hydrogen concentration control strategy according to the hydrogen concentration interval in which the real-time hydrogen concentration is located, so that the real-time hydrogen concentration is within a normal concentration value. The application also discloses a hydrogen internal combustion engine crankcase hydrogen concentration control system. The application can effectively avoid the situation that the hydrogen concentration in the crankcase is gathered to cause uncontrollable combustion or even explosion, and improve work efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the internal combustion engine technical field, more particularly, it relates to a kind of hydrogen internal combustion engine crankcase hydrogen concentration control method and system. BACKGROUND

[0002] As shown in the prior art diesel engine, natural gas engine crankcase ventilation system, such as Figure 1 The main function of the crankcase ventilation system is to realize oil-gas separation and control the pressure of the crankcase. The crankcase gas generated during engine operation enters the gas-driven oil-gas separator through the engine cylinder cover breathing port and pipeline 1. After separation by the oil-gas separator, the gas enters the air filter after pipeline 2, and then enters the air filter and the compressor inlet pipe, forming a closed crankcase ventilation system. The cooled supercharger gas taken from the intercooler and before the throttle valve enters the gas-driven oil-gas separator through pipeline 3, thereby driving the gas-driven oil-gas separator to work and achieving high separation efficiency. However, to maintain high separation efficiency of the gas-driven oil-gas separator and achieve negative pressure in the cylinder cover (crankcase), the gas introduced by pipeline 3 must 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 pipeline 4), a gas-driven oil-gas separator, or a gas-driven oil-gas separator (without connecting pipeline 4). The crankcase ventilation system of this system fully meets the application of traditional engines, achieving efficient separation of oil and gas and controlling crankcase pollutant emissions.

[0003] However, for traditional reciprocating hydrogen internal combustion engines, the in-cylinder hydrogen fuel mixture may leak into the engine crankcase through the piston ring gap and accumulate at a high position in the engine 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 more than 4%), there is a risk of explosion. SUMMARY

[0004] The present application solves the technical problems of the prior art by providing a hydrogen internal combustion engine crankcase hydrogen concentration control method and system, which solves the technical problem of the existing crankcase ventilation system not having effective measures to reduce hydrogen concentration.

[0005] The hydrogen internal combustion engine crankcase hydrogen concentration control method of the present application is as follows: obtaining the real-time hydrogen concentration in the crankcase, setting multiple hydrogen concentration intervals, and enabling hydrogen concentration control strategies according to the hydrogen real-time concentration in the hydrogen concentration interval to keep the hydrogen real-time concentration within the normal concentration value.

[0006] Further improvements to the hydrogen concentration control strategy are as follows:

[0007] The hydrogen concentration interval includes a first concentration interval, a second concentration interval, a third concentration interval, a fourth concentration interval and a fifth concentration interval;

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

[0009] When the real-time hydrogen concentration is in the second concentration interval, the rotating speed of the oil-gas separator is increased to a preset first rotating speed to extract hydrogen in the crankcase, and air is supplemented into the crankcase to dilute hydrogen in the crankcase to reduce the real-time hydrogen concentration to the first concentration interval;

[0010] When the real-time hydrogen concentration is in the third concentration interval, an air throttle valve is opened to supplement air into the crankcase to dilute hydrogen in the crankcase to reduce the real-time hydrogen concentration to the first concentration interval;

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

[0012] When the real-time hydrogen concentration is in the fifth concentration interval, the fault alarm is started and the engine is stopped.

[0013] Further, the intelligent cylinder stopping strategy is,

[0014] The number of cylinders in the hydrogen internal combustion engine is I;

[0015] The hydrogen injection of the i-th cylinder is sequentially stopped, 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 the first concentration interval, the hydrogen injection of the i-th cylinder is stopped to make the engine continue to run in a cylinder-lacking limp mode;

[0016] After the hydrogen injection of the i-th cylinder is sequentially stopped, when the hydrogen concentration after the hydrogen injection of the i-th cylinder is stopped is still not in 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 hydrogen injection are obtained, the hydrogen injection of the two cylinders is stopped, and the hydrogen concentration after the hydrogen injection of the two cylinders is obtained;

[0017] When the hydrogen concentration after the hydrogen injection of the two cylinders is stopped is in the first concentration interval, the hydrogen injection of the two cylinders is stopped to make the engine continue to run in a cylinder-lacking limp mode. When the hydrogen concentration after the hydrogen injection of the two cylinders is stopped is still not in the first concentration interval, the engine is stopped;

[0018] Wherein, i=1~I.

[0019] Further, when the engine is in the process of stopping, the rotating speed of the oil-gas separator is kept working according to a preset delay time to make the hydrogen in the engine exhaust.

[0020] Further, the hydrogen concentration interval includes a first concentration interval, a second concentration interval, a third concentration interval, a fourth concentration interval and a fifth concentration interval.

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

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

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

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

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

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

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

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

[0029] An air throttle valve installed on a fourth pipeline connected between the engine cylinder head cover and an air filter, used to supplement air in the crankcase to dilute the hydrogen in the crankcase;

[0030] An ECU used to receive the hydrogen concentration signal;

[0031] The ECU enables the hydrogen concentration control strategy according to the above hydrogen internal combustion engine crankcase hydrogen concentration control method through the hydrogen concentration signal to make the real-time hydrogen concentration be in the normal concentration value.

[0032] Further improvement, the air throttle valve is a crankcase air supplement electric control cut-off valve or a mechanical one-way pressure difference valve.

[0033] Advantages

[0034] The advantages of the present application are:

[0035] The present application can effectively avoid the situation of uncontrolled combustion or even explosion caused by the accumulation of hydrogen concentration in the crankcase by obtaining the real-time hydrogen concentration in the crankcase, setting multiple hydrogen concentration intervals, and enabling the hydrogen concentration control strategy according to the real-time hydrogen concentration in the hydrogen concentration interval to make the real-time hydrogen concentration in the concentration normal value, thereby improving the work efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure of the existing traditional diesel engine, natural gas engine crankcase ventilation system;

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

[0038] Figure 3 It is a flow chart of the hydrogen internal combustion engine crankcase hydrogen concentration control method of the present application with a crankcase air supply electric control cut-off valve;

[0039] Figure 4 It is a flow chart of the hydrogen internal combustion engine crankcase hydrogen concentration control method of the present application with a mechanical one-way pressure difference valve.

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

[0041] The present application will be further described below in conjunction with examples, but does not constitute any limitation on the present application, and any limited number of modifications made by anyone within the scope of the claims of the present application is still within the scope of the claims of the present application.

[0042] Reference Figures 2-4 The present application provides a hydrogen internal combustion engine crankcase hydrogen concentration control method, which is started by electricity on the engine, controls the crankcase ventilation system to run according to the traditional default mode, synchronously obtains the real-time hydrogen concentration in the crankcase, sets multiple hydrogen concentration intervals, and enables the hydrogen concentration control strategy according to the real-time hydrogen concentration in the hydrogen concentration interval to make the real-time hydrogen concentration in the concentration normal value.

[0043] According to the type of the installed air throttle valve 11, the present application provides two different embodiments of hydrogen concentration control strategy.

[0044] As Figure 3As shown in Example 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 as follows:

[0045] The hydrogen concentration range includes the first concentration range, the second concentration range, the third concentration range, the fourth concentration range, and the fifth concentration range.

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

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

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

[0049] The hydrogen concentration in the fourth concentration range is greater than the third hydrogen concentration threshold but less than the preset fourth hydrogen concentration threshold.

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

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

[0052] When the real-time hydrogen concentration is within the first concentration range, the real-time hydrogen concentration is the normal concentration value.

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

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

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

[0056] When the real-time hydrogen concentration reaches the fifth concentration range, it indicates a serious hydrogen leak in the engine. The fault alarm will be activated, and the engine will be shut down. The customer is advised that the engine has a serious malfunction and requires temporary removal from the road for repairs, with hydrogen injection to be stopped in all cylinders.

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

[0058] The hydrogen concentration interval includes a first concentration interval, a second concentration interval, a third concentration interval, a fourth concentration interval and a fifth concentration interval.

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

[0060] The hydrogen concentration of 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 of 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 of the fourth concentration interval is greater than or equal to the fourth hydrogen concentration threshold.

[0063] The first hydrogen concentration threshold is 0.75% and the fourth hydrogen concentration threshold is 3%.

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

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

[0066] When the real-time hydrogen concentration is in the third concentration interval, a fault alarm is started and an intelligent cylinder stopping strategy is triggered.

[0067] When the real-time hydrogen concentration is in the fourth concentration interval, it indicates that the engine has a serious hydrogen leak, a fault alarm is started and the engine is stopped for processing. The customer is prompted that the engine has a serious consequence fault and needs to be repaired on the side, and all cylinder hydrogen injection is stopped.

[0068] The intelligent cylinder stopping strategy in the two embodiments is,

[0069] Suppose the number of cylinders in the hydrogen internal combustion engine is I. The hydrogen injection of the i-th cylinder is stopped in turn, and the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is obtained. When the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is in the first concentration interval, the hydrogen injection of the i-th cylinder is stopped to make the engine continue to limp with a missing cylinder.

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

[0071] When the hydrogen concentration after stopping the hydrogen injection of the two cylinders is in the first concentration interval, stopping the hydrogen injection of the two cylinders makes the engine continue to limp operation; when the hydrogen concentration after stopping the hydrogen injection of the two cylinders is still not in the first concentration interval, the engine is stopped.

[0072] When the engine is stopped, the rotating speed of the oil-gas separator 3 is kept working according to the preset delay time to make the hydrogen in the engine exhaust.

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

[0074] A hydrogen concentration sensor 10 is installed on the engine head cover 2 at the position where the hydrogen concentration is the highest or on the second pipeline 18 connected with the oil-gas separator 3 to obtain the real-time hydrogen concentration in the crankcase and output a hydrogen concentration signal.

[0075] When the hydrogen concentration sensor 10 has the anti-oil property, the hydrogen concentration sensor 10 is installed on the engine head cover 2 at the position where the hydrogen concentration is the highest; when the hydrogen concentration sensor 10 cannot resist the oil, the hydrogen concentration sensor 10 is installed on the second pipeline 18 connected with the outlet of the oil-gas separator 3.

[0076] An air throttle valve 11 is installed on the fourth pipeline 20 connected between the engine head cover 2 and the air filter 4 to supplement the air in the crankcase to dilute the hydrogen in the crankcase.

[0077] An ECU 9 is used to receive the hydrogen concentration signal.

[0078] The ECU 9 uses the hydrogen concentration signal to implement the hydrogen concentration control strategy according to the hydrogen internal combustion engine crankcase hydrogen concentration control method to make the real-time hydrogen concentration be in the normal concentration value.

[0079] The oil-gas separator 3 in the embodiment is an electric-driven oil-gas separator without the crankcase negative pressure regulating valve, and the rotating speed of the oil-gas separator 3 can be controlled by the ECU 9. Increasing the rotating speed of the oil-gas separator can realize more suction force to quickly exhaust the hydrogen gathered in the crankcase. At the same time, the fresh air is supplemented to the crankcase through the fourth pipeline 20, the air throttle valve 11 and the fifth pipeline 21 (the fifth pipeline 21 is installed on the engine at the position where the hydrogen is most easily gathered, which is generally confirmed by the test) to dilute the hydrogen concentration in the crankcase and ensure that the pressure in the crankcase is not too high.

[0080] When the air throttle valve 11 is a crankcase air supplement electric control cut-off valve, the ECU 9 monitors that the hydrogen concentration in the crankcase is lower than the threshold value, then controls the electrically driven oil-gas separator 3 to increase the working speed to improve the suction power, and controls the air throttle valve 11 (electric control cut-off valve) to open to supplement air to the crankcase.

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

[0082] The above only describes the preferred embodiments of the present application, it should be noted that for those skilled in the art, without departing from the structure of the present application, a number of variations and improvements can be made, which will not affect the effect of the present application and the practicality of the patent.

Claims

1. A method for controlling hydrogen concentration in the crankcase of a hydrogen internal combustion engine, characterized in that, The method involves obtaining the real-time hydrogen concentration in the crankcase, setting multiple hydrogen concentration ranges, and activating a hydrogen concentration control strategy based on the real-time hydrogen concentration falling within the specified range to ensure that the real-time hydrogen concentration remains within the normal range. The hydrogen concentration control strategy is as follows: The hydrogen concentration range includes a first concentration range, a second concentration range, a third concentration range, a fourth concentration range, and a fifth concentration range; When the real-time concentration of hydrogen is within the first concentration range, the real-time concentration of hydrogen is the normal concentration value. When the real-time hydrogen concentration is in the second concentration range, the rotation speed of the oil-gas separator is increased to the preset first rotation speed to extract the hydrogen from 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 hydrogen concentration to the first concentration range. When the real-time hydrogen concentration is in the third concentration range, the air throttle valve is opened to add air to the crankcase to dilute the hydrogen in the crankcase and reduce the real-time hydrogen concentration to the first concentration range. When the real-time hydrogen concentration is in the fourth concentration range, a fault alarm is activated and an intelligent cylinder shutdown strategy is triggered. When the real-time hydrogen concentration is in the fifth concentration range, the fault alarm is activated and the engine is shut down. The intelligent cylinder shutdown strategy is as follows: Let the number of cylinders in the hydrogen internal combustion engine be I; The hydrogen injection of the i-th cylinder is stopped sequentially and the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is obtained. When the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is within the first concentration range, the hydrogen injection of the i-th cylinder is stopped so that the engine continues to run in a mis-cylinder limp mode. After the hydrogen injection of the i-th cylinder is stopped sequentially, if the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is still not in the first concentration range, the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is obtained, and the hydrogen concentration after stopping the hydrogen injection of the i-th cylinder is arranged from small to large. The two cylinders with the lowest hydrogen concentration after injection are obtained, and the hydrogen injection of the two cylinders is stopped. The hydrogen concentration after stopping the hydrogen injection of the two cylinders is obtained. When the hydrogen concentration after stopping hydrogen injection in two cylinders is within the first concentration range, hydrogen injection in the two cylinders is stopped, causing the engine to continue to operate in a misfired limp-out mode; when the hydrogen concentration after stopping hydrogen injection in two cylinders is still not within the first concentration range, the engine is shut down. Among them, i=1~I.

2. The method for controlling hydrogen concentration in the crankcase of a hydrogen internal combustion engine according to claim 1, characterized in that, After the engine is shut down, the oil-gas separator continues to operate at a speed that is set for a preset delay time to allow hydrogen to be discharged from the engine.

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

4. The method for controlling hydrogen concentration in the crankcase of a hydrogen internal combustion engine according to claim 3, characterized in that, The first hydrogen concentration threshold is 0.5%-1%, and the fourth hydrogen concentration threshold is 2.5%-3.5%.

5. A hydrogen concentration control system for the crankcase of a hydrogen internal combustion engine, characterized in that, The system includes: A hydrogen concentration sensor is installed on the engine cylinder head cover or on a second pipe connected to the oil-gas separator to obtain the real-time hydrogen concentration in the crankcase and output a hydrogen concentration signal. An air throttle valve, installed on the fourth pipe connecting the engine cylinder head cover and the air filter, is used to supply air to the crankcase to dilute the hydrogen in the crankcase. ECU, used to receive the hydrogen concentration signal; The ECU, according to any one of claims 1-4, implements a hydrogen concentration control strategy in the crankcase of a hydrogen internal combustion engine by using a hydrogen concentration signal to reduce the real-time hydrogen concentration to a normal value.

6. A hydrogen concentration control system for a hydrogen internal combustion engine crankcase according to claim 5, characterized in that, The air throttle valve is either a crankcase air supply electrically controlled shut-off valve or a mechanical one-way differential pressure valve.

Images