Diagnostic device and protection method for preventing tempering of hydrogen engine

Abstract

The invention discloses a diagnostic device for preventing backfire of a hydrogen engine. The diagnostic device comprises the hydrogen engine, the hydrogen engine is provided with an air cylinder, a front air inlet pipe connected with the air cylinder, a throttle valve and a hydrogen injection valve which are arranged on the front air inlet pipe, an exhaust pipe connected with the air cylinder, and a turbocharger arranged on the exhaust pipe; and a throttle valve front pressure sensor and a throttle valve rear pressure sensor are respectively arranged in front of and behind the throttle valve. According to the diagnosis device and the protection method for preventing backfire of the hydrogen engine, the throttle valve front pressure sensor and the throttle valve rear pressure sensor are arranged in front of and behind the throttle valve respectively, the gas pressure difference value in front of and behind the throttle valve is monitored so as to diagnose backfire of the hydrogen engine, and the risk of backfire is judged; and after diagnosis is completed, corresponding tempering protection modes are adopted according to different triggering conditions, the gas pressure difference between the front portion and the rear portion of the throttle valve is adjusted, the tempering risk is reduced, and protection for preventing tempering of the hydrogen engine is provided.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen engines, and in particular to a diagnostic device and a protection method for preventing backfire of a hydrogen engine. Background Art

[0002] Hydrogen engines, as an engine that uses hydrogen as internal combustion fuel, work in a similar way to traditional gasoline or diesel engines, where a mixture of fuel and air is burned in the cylinder to generate power, push the piston to move, and then drive the vehicle or mechanical equipment. Hydrogen only produces water after combustion, and does not emit carbon dioxide or other harmful gases, so it is considered an ideal clean energy source. This helps reduce greenhouse gas emissions and improve air quality. Hydrogen has high combustion efficiency: hydrogen has a high combustion calorific value, and the energy released by the combustion of the same mass of hydrogen is almost three times that of gasoline. This makes hydrogen engines theoretically have a higher thermal efficiency.

[0003] However, hydrogen is an extremely flammable and explosive gas. Due to the rapid diffusion speed of hydrogen flames and the excessively fast combustion process, backfire may occur. Backfire may not only damage engine components, but may also cause fires or explosions. When the concentration of the hydrogen mixture in the intake duct is too high at the beginning of intake, it is easy to be ignited when encountering the high-temperature exhaust gas that flows back or the hot spots near the intake valve (such as spark plugs, exhaust valve heads, etc.), resulting in backfire. Especially under high load or high speed conditions, in order to increase power output, the amount of hydrogen injection is increased, which can easily lead to an overly rich mixture. Factors such as air flow velocity and pressure fluctuations in the intake duct may affect the uniform distribution of the mixture, causing the concentration of the mixture in local areas to be too high, increasing the risk of backfire. Therefore, it is necessary to develop a backfire diagnosis device and control method for hydrogen engines to solve the risk of backfire during engine operation. Summary of the invention

[0004] The purpose of the present invention is to provide a diagnostic device and a protection method for preventing backfire of a hydrogen engine in order to solve the risk of backfire occurring during the operation of the engine in view of the above-mentioned problem.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A diagnostic device for preventing backfire of a hydrogen engine comprises a hydrogen engine, wherein the hydrogen engine is provided with a cylinder, a front intake pipe connected to the cylinder, a throttle valve and a hydrogen injection valve arranged on the front intake pipe, an exhaust pipe connected to the cylinder and a turbocharger arranged on the exhaust pipe; a throttle valve front pressure sensor and a throttle valve rear pressure sensor are respectively arranged before and after the throttle valve.

[0007] Preferably, an intake manifold temperature sensor is provided on the front intake pipe.

[0008] Preferably, the turbocharger is provided with an air release valve.

[0009] Preferably, the exhaust pipe is divided into two parts: a pre-turbine exhaust pipe and a post-turbine exhaust pipe. The pre-turbine exhaust pipe is connected to the cylinder and the turbocharger, the post-turbine exhaust pipe is connected to the exhaust port of the turbocharger, and a post-turbine temperature sensor is provided on the post-turbine exhaust pipe.

[0010] Preferably, the air inlet of the compressor of the turbocharger is connected to the front air intake pipe of the turbine, the front air intake pipe of the turbine is provided with an intake temperature sensor, the exhaust port of the compressor is connected to the rear air intake pipe of the turbine, and the rear air intake pipe of the turbine is connected to the front air intake pipe.

[0011] Preferably, an intercooler is provided on the rear intake pipe of the turbine.

[0012] A protection method for preventing backfire of a hydrogen engine. The present invention provides a front-throttle pressure sensor and a rear-throttle pressure sensor before and after the throttle respectively, monitors the gas pressure difference before and after the throttle to perform backfire diagnosis of the hydrogen engine, determines the risk of backfire, and adopts corresponding backfire protection modes according to different trigger conditions after diagnosis. The present invention provides three protection modes.

[0013] After the engine completes the hot start, the engine outlet water temperature exceeds the outlet water temperature limit (60°C). If it is diagnosed that the difference between the pre-throttle pressure measured by the pre-throttle pressure sensor and the post-throttle pressure measured by the post-throttle pressure sensor is less than the pressure difference limit 1 (20kpa), and the engine throttle change rate exceeds the throttle change rate limit (10% / s), and there is a demand for load increase, the intake volume change rate exceeds the intake volume change rate limit (100kg / min), the hydrogen engine's backfire protection mode 1 is triggered.

[0014] Tempering protection mode 1 includes the following steps:

[0015] S1, monitoring the pressure difference measured by the throttle pre-pressure sensor and the throttle post-pressure sensor;

[0016] S2. When the pressure difference measured in step S1 is less than the set value or the pressure after the throttle is higher than the pressure before the throttle, the hydrogen engine backfire protection mode is triggered, the engine combustion parameters are adjusted, the ignition advance angle is delayed or the injection pressure is reduced; the main purpose is to increase the exhaust temperature of the engine, thereby improving the efficiency of the turbocharger, increasing the intake volume and pressure, and increasing the pressure difference before and after the throttle.

[0017] S3. Determine whether the pressure difference is still lower than the set value. If so, continue the backfire protection mode; otherwise, exit the backfire protection mode.

[0018] If it is diagnosed that the difference between the pre-throttle pressure measured by the pre-throttle pressure sensor and the post-throttle pressure measured by the post-throttle pressure sensor is less than the pressure difference limit 2 (10kpa), and the engine throttle change rate exceeds the throttle change rate limit (10% / s), the engine power percentage exceeds the engine load limit (60%), and there is a demand for load increase, the intake volume change rate exceeds the intake volume change rate limit (100kg / min), which means that the engine has a higher power demand, triggering the backfire protection mode 2 of the hydrogen engine.

[0019] Backfire protection mode 2 is based on backfire protection mode 1, forcibly closing the turbocharger's bleed valve, which includes the following steps:

[0020] S1, monitoring the pressure difference measured by the throttle pre-pressure sensor and the throttle post-pressure sensor;

[0021] S2. When the pressure difference measured in step S1 is less than the set value or the pressure after the throttle is higher than the pressure before the throttle, the hydrogen engine backfire protection mode is triggered, the engine combustion parameters are adjusted, the ignition advance angle is delayed or the injection pressure is reduced, and the exhaust valve is forcibly closed; so that all the high-temperature exhaust gas of the engine drives the turbocharger to work, increase the intake volume and intake pressure, and increase the pressure difference before and after the throttle.

[0022] S3. Determine whether the pressure difference is still lower than the set value. If so, continue the backfire protection mode; otherwise, exit the backfire protection mode.

[0023] If it is diagnosed that the difference between the pre-throttle pressure measured by the pre-throttle pressure sensor and the post-throttle pressure measured by the post-throttle pressure sensor is less than the pressure difference limit 3 (5kpa), and the engine throttle change rate exceeds the throttle change rate limit (10% / s), the engine power percentage exceeds the engine load limit (60%), and there is a demand for load increase, the intake volume change rate exceeds the intake volume change rate limit (100kg / min), which means that the engine has a higher power demand, triggering the backfire protection mode 3 of the hydrogen engine.

[0024] Backfire protection mode three is based on backfire protection mode two. In step S2, the throttle opening is reduced at the same time to force the pressure of the gas flowing after the throttle to decrease, so that the pressure value after the throttle is much lower than the pressure value before the throttle, thereby increasing the pressure difference before and after the throttle.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention proposes a diagnostic device and a protection method for preventing backfire of a hydrogen engine. A pre-throttle pressure sensor and a post-throttle pressure sensor are respectively arranged before and after a throttle to monitor the gas pressure difference before and after the throttle to diagnose the backfire of the hydrogen engine, judge the risk of backfire, and adopt a corresponding backfire protection mode according to different triggering conditions after the diagnosis is completed. By adjusting the engine combustion parameters, forcibly closing the bleed valve of the turbocharger and reducing the opening of the throttle, the gas pressure difference before and after the throttle is adjusted, the backfire risk is reduced, and protection against backfire of the hydrogen engine is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A diagnostic device for preventing backfire of a hydrogen engine and a working principle diagram of a hydrogen engine.

[0029] Description of reference numerals:

[0030] 1. Throttle valve; 11. Pressure sensor before throttle valve; 12. Pressure sensor after throttle valve;

[0031] 2. Front intake pipe; 21. Intake manifold temperature sensor;

[0032] 3. Hydrogen injection valve;

[0033] 4. Cylinder;

[0034] 5. Exhaust pipe before turbine;

[0035] 6. Turbocharger; 61. Compressor; 62. Air release valve;

[0036] 7. Turbine front intake pipe; 71. Intake air temperature sensor;

[0037] 8. Turbine rear intake pipe; 81. Intercooler;

[0038] 9. Exhaust pipe after turbine; 91. Temperature sensor after turbine. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1As shown, a diagnostic device for preventing backfire of a hydrogen engine comprises a hydrogen engine, wherein the hydrogen engine is provided with a cylinder 4, a front intake pipe 2 connected to the cylinder 4, a throttle 1 and a hydrogen injection valve 3 arranged on the front intake pipe 2, an exhaust pipe connected to the cylinder 4 and a turbocharger 6 arranged on the exhaust pipe; a throttle pre-pressure sensor 11 and a throttle post-pressure sensor 12 are respectively arranged before and after the throttle 1. An intake manifold temperature sensor 21 is arranged on the front intake pipe 2. An air release valve 62 is arranged on the turbocharger 6. The exhaust pipe is divided into a turbine pre-exhaust pipe 5 and a turbine post-exhaust pipe 9, wherein the turbine pre-exhaust pipe 5 connects the cylinder 4 and the turbocharger 6, the turbine post-exhaust pipe 9 connects the exhaust port of the turbocharger 6, and the turbine post-exhaust pipe 9 is provided with a turbine post-temperature sensor 91. The air inlet of the compressor 61 of the turbocharger 6 is connected to the turbine front air intake pipe 7, and the turbine front air intake pipe 7 is provided with an air intake temperature sensor 71. The exhaust port of the compressor 61 is connected to the turbine rear air intake pipe 8, and the turbine rear air intake pipe 8 is connected to the front air intake pipe 2. The turbine rear air intake pipe 8 is provided with an intercooler 81.

[0041] A protection method for preventing backfire of a hydrogen engine. The present invention provides a front-throttle pressure sensor 11 and a rear-throttle pressure sensor 12 before and after a throttle 1, respectively, to monitor the gas pressure difference before and after the throttle 1 to perform backfire diagnosis of the hydrogen engine, determine the risk of backfire, and adopt corresponding backfire protection modes according to different triggering conditions after the diagnosis is completed. The present invention provides three protection modes.

[0042] After the engine completes the hot start, the engine outlet water temperature exceeds the outlet water temperature limit (60°C). If it is diagnosed that the difference between the pre-throttle pressure measured by the pre-throttle pressure sensor 11 and the post-throttle pressure measured by the post-throttle pressure sensor 12 is less than the pressure difference limit 1 (20kpa), and the engine throttle change rate exceeds the throttle change rate limit (10% / s), and there is a demand for load increase, the intake volume change rate exceeds the intake volume change rate limit (100kg / min), the hydrogen engine's backfire protection mode 1 is triggered.

[0043] Tempering protection mode 1 includes the following steps:

[0044] S1, monitoring the pressure difference measured by the pre-throttle pressure sensor 11 and the post-throttle pressure sensor 12;

[0045] S2. When the pressure difference measured in step S1 is less than the set value or the pressure after the throttle is higher than the pressure before the throttle, the hydrogen engine backfire protection mode is triggered, the engine combustion parameters are adjusted, the ignition advance angle is delayed or the injection pressure is reduced; the main purpose is to increase the exhaust temperature of the engine, thereby improving the efficiency of the turbocharger 6, increasing the intake volume and pressure, and increasing the pressure difference before and after the throttle 1.

[0046] S3. Determine whether the pressure difference is still lower than the set value. If so, continue the backfire protection mode; otherwise, exit the backfire protection mode.

[0047] If it is diagnosed that the difference between the pre-throttle pressure measured by the pre-throttle pressure sensor 11 and the post-throttle pressure measured by the post-throttle pressure sensor 12 is less than the pressure difference limit 2 (10kpa), and the engine throttle change rate exceeds the throttle change rate limit (10% / s), the engine power percentage exceeds the engine load limit (60%), and when there is a demand for load increase, the intake volume change rate exceeds the intake volume change rate limit (100kg / min), it means that the engine has a higher power demand, triggering the backfire protection mode 2 of the hydrogen engine.

[0048] The second backfire protection mode is based on the first backfire protection mode, and the exhaust valve 62 of the turbocharger 6 is forcibly closed, that is, it includes the following steps:

[0049] S1, monitoring the pressure difference measured by the pre-throttle pressure sensor 11 and the post-throttle pressure sensor 12;

[0050] S2. When the pressure difference measured in step S1 is less than the set value or the pressure after the throttle is higher than the pressure before the throttle, the hydrogen engine backfire protection mode is triggered, the engine combustion parameters are adjusted, the ignition advance angle is delayed or the injection pressure is reduced, and the exhaust valve 62 is forcibly closed; so that all the high-temperature exhaust gas of the engine drives the turbocharger 6 to work, increase the intake volume and intake pressure, and increase the pressure difference before and after the throttle 1.

[0051] S3. Determine whether the pressure difference is still lower than the set value. If so, continue the backfire protection mode; otherwise, exit the backfire protection mode.

[0052] If it is diagnosed that the difference between the pre-throttle pressure measured by the pre-throttle pressure sensor 11 and the post-throttle pressure measured by the post-throttle pressure sensor 12 is less than the pressure difference limit 3 (5kpa), and the engine throttle change rate exceeds the throttle change rate limit (10% / s), the engine power percentage exceeds the engine load limit (60%), and when there is a demand for load increase, the intake volume change rate exceeds the intake volume change rate limit (100kg / min), it means that the engine has a higher power demand, triggering the backfire protection mode three of the hydrogen engine.

[0053] Backfire protection mode three is based on backfire protection mode two. In step S2, the opening of the throttle valve 1 is reduced at the same time, forcing the pressure of the gas flowing after the throttle valve 1 to be reduced, so that the pressure value after the throttle valve is much lower than the pressure value before the throttle valve, thereby increasing the pressure difference before and after the throttle valve 1.

[0054] The above embodiments of the present invention are described in detail through examples, but the contents described are only exemplary embodiments of the embodiments of the present invention and cannot be considered to limit the scope of implementation of the embodiments of the present invention. The protection scope of the embodiments of the present invention is defined by the claims. Anyone who utilizes the technical solutions described in the embodiments of the present invention, or who, inspired by the technical solutions of the embodiments of the present invention, designs similar technical solutions within the essence and protection scope of the embodiments of the present invention to achieve the above technical effects, or who makes equal changes and improvements to the scope of application, shall still fall within the scope of protection covered by the patent of the embodiments of the present invention.

Claims

1. A diagnostic device for preventing hydrogen engine backfire, characterized in that: The invention comprises a hydrogen engine, wherein the hydrogen engine is provided with a cylinder (4), a front intake pipe (2) connected to the cylinder (4), a throttle valve (1) and a hydrogen injection valve (3) arranged on the front intake pipe (2), an exhaust pipe connected to the cylinder (4) and a turbocharger (6) arranged on the exhaust pipe; a throttle valve front pressure sensor (11) and a throttle valve rear pressure sensor (12) are respectively arranged before and after the throttle valve (1).

2. The diagnostic device for preventing hydrogen engine backfire according to claim 1, characterized in that: An intake manifold temperature sensor (21) is provided on the front intake pipe (2).

3. The diagnostic device for preventing hydrogen engine backfire according to claim 1, characterized in that: The turbocharger (6) is provided with an air release valve (62).

4. The diagnostic device for preventing hydrogen engine backfire according to claim 3, characterized in that: The exhaust pipe is divided into two parts: a turbine front exhaust pipe (5) and a turbine rear exhaust pipe (9); the turbine front exhaust pipe (5) is connected to the cylinder (4) and the turbocharger (6); the turbine rear exhaust pipe (9) is connected to the exhaust port of the turbocharger (6); and a turbine rear temperature sensor (91) is provided on the turbine rear exhaust pipe (9).

5. The diagnostic device for preventing hydrogen engine backfire according to claim 4, characterized in that: The air inlet of the compressor (61) of the turbocharger (6) is connected to the turbine front air intake pipe (7), and the turbine front air intake pipe (7) is provided with an air intake temperature sensor (71); the exhaust port of the compressor (61) is connected to the turbine rear air intake pipe (8), and the turbine rear air intake pipe (8) is connected to the front air intake pipe (2).

6. The diagnostic device for preventing backfire of a hydrogen engine according to claim 5, characterized in that: An intercooler (81) is provided on the turbine rear air intake pipe (8).

7. A method for protecting a hydrogen engine from backfire according to a diagnostic device for preventing backfire of a hydrogen engine according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, monitoring the pressure difference measured by the throttle pre-pressure sensor (11) and the throttle post-pressure sensor (12); S2. When the pressure difference measured in step S1 is less than the set value or the pressure after the throttle is higher than the pressure before the throttle, the hydrogen engine backfire protection mode is triggered to adjust the engine combustion parameters, delay the ignition advance angle or reduce the injection pressure; S3. Determine whether the pressure difference is still lower than the set value. If so, continue the backfire protection mode; otherwise, exit the backfire protection mode.

8. A method for protecting a hydrogen engine from backfire according to a diagnostic device for preventing backfire of a hydrogen engine according to any one of claims 3 to 6, characterized in that: The following steps are involved: S1, monitoring the pressure difference measured by the throttle pre-pressure sensor (11) and the throttle post-pressure sensor (12); S2. When the pressure difference measured in step S1 is less than a set value or the pressure after the throttle is higher than the pressure before the throttle, the hydrogen engine backfire protection mode is triggered, the engine combustion parameters are adjusted, the ignition advance angle is delayed or the injection pressure is reduced, and the purge valve (62) is forcibly closed; S3. Determine whether the pressure difference is still lower than the set value. If so, continue the backfire protection mode; otherwise, exit the backfire protection mode.

9. The protection method according to claim 8, characterized in that: In step S2, the opening of the throttle valve (1) is reduced at the same time, forcing the pressure of the gas flowing through the throttle valve (1) to decrease.

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