A hydrogen engine exhaust gas measurement device, system and calibration method

Abstract

The present application belongs to the technical field of engine manufacturing, and discloses a hydrogen engine exhaust gas measuring device, system and calibration method, which comprises an exhaust gas measuring channel, an electromagnetic valve assembly and a measuring device. The exhaust gas measuring channel is a tubular structure in the shape of U. The electromagnetic valve assembly is fixedly connected to the pipe mouths at both ends of the exhaust gas measuring channel. The measuring device is fixedly connected to the middle part of the exhaust gas measuring channel. The calibration method of the present application can quickly adjust the air-fuel ratio to a predetermined value according to the measurement results of the gas concentration in the exhaust gas, and has the advantages of fast calibration speed, simple calibration principle, simple structure of the measuring device, low cost, discharge of the exhaust gas into the supercharger after measurement to ensure the engine power, and connection of multiple measuring devices to complete other measurements at the same time to save the measurement cost.

Description

Technical Field

[0001] This invention belongs to the field of engine manufacturing technology, and specifically relates to a hydrogen engine exhaust gas measurement device, system, and calibration method. Background Technology

[0002] A hydrogen engine is an internal combustion engine that uses hydrogen as fuel. It possesses unique characteristics and advantages, but also faces several challenges. During the development of hydrogen engines, the issue of knocking or misfires in a single cylinder arises. This necessitates the detection of exhaust components in each cylinder to precisely control the engine and achieve efficient operation. Exhaust gas measurement devices and calibration methods for hydrogen engines play a crucial role in their research, optimization, and quality control. Due to the risk of misfires during hydrogen engine development, using the closed-loop air-fuel ratio control of the oxygen sensor found in natural gas engines is extremely dangerous, as the high-temperature oxygen sensor probe can easily ignite unburned hydrogen, leading to an explosion. Therefore, currently, hydrogen internal combustion engines employ open-loop air-fuel ratio control. However, this can lead to air-fuel ratio deviations, causing misfires, knocking, and excessive exhaust temperatures, among other problems. The only solution is to manually adjust the gas injection quantity in each cylinder using cylinder pressure curves to achieve the desired air-fuel ratio. This adjustment process is cumbersome, typically requiring more than ten adjustments, making rapid adjustments impossible, time-consuming, labor-intensive, and resulting in very slow testing progress. Furthermore, during the test, there was a problem that the exhaust gas was directly released, and without the exhaust gas to drive the turbocharger's turbine, a portion of the boost pressure was lost, resulting in a loss of engine power. Summary of the Invention

[0003] The purpose of this invention is to provide a hydrogen engine exhaust gas measurement device, system, and calibration method. This invention employs a hydrogen engine exhaust gas calibration system. The in-cylinder pressure acquisition system and the ECU send the opening time and duration of the solenoid valve to the control unit to control the opening and closing of the solenoid valve in the hydrogen engine exhaust gas measurement device. This accurately measures the concentration of exhaust gas components. The ECU adjusts the engine air-fuel ratio in real time to achieve a predetermined value. This measurement is repeated multiple times until the engine air-fuel ratio consistently reaches the predetermined value, at which point the calibration is complete. This calibration principle is simple, the results are accurate, and the operation is convenient. The air-fuel ratio can be quickly adjusted, typically requiring only 2-3 adjustments to achieve the desired air-fuel ratio, saving time and effort and accelerating the testing process. The measurement device used has a simple structure, occupies little space, and is low in cost. After measurement and analysis, the exhaust gas re-enters the turbocharger through the outlet pipe connected between the engine exhaust manifold and the turbocharger, ensuring engine power. The measurement chamber has multiple measurement device interfaces for connecting different measurement devices, enabling other exhaust gas measurements to be performed simultaneously with gas component concentration calibration, saving measurement costs.

[0004] The specific details of the plan are as follows:

[0005] A hydrogen engine exhaust gas measuring device includes an exhaust gas measuring channel, a solenoid valve assembly, and a measuring device. The exhaust gas measuring channel is an approximately U-shaped tubular structure. The solenoid valve assembly is fixedly connected to the pipe openings at both ends of the exhaust gas measuring channel, and the measuring device is fixedly connected to the middle of the exhaust gas measuring channel.

[0006] During the development of hydrogen engines, issues such as knocking or misfires in certain cylinders arise, necessitating the detection of exhaust gas components in each cylinder to precisely control the air-fuel ratio and achieve efficient engine operation. This invention employs a calibration method for a hydrogen engine exhaust gas calibration system. This method precisely measures the concentration of the target component in the exhaust gas at any given time. Based on the detection results, the engine ECU (Electronic Control Unit) corrects the air-fuel ratio, ensuring it consistently reaches a predetermined value. This calibration method assesses the in-cylinder combustion efficiency by measuring the gaseous components in the exhaust, such as the concentration of oxygen or hydrogen. A higher oxygen content in the exhaust indicates lean combustion and insufficient hydrogen injection, leading to higher emissions and requiring more robust aftertreatment systems. Conversely, a higher hydrogen content indicates rich combustion and excessive hydrogen injection, resulting in increased exhaust temperature and posing a challenge to the reliability of the exhaust manifold and cylinder head. Measuring the exhaust gas component concentration allows the ECU to adjust the engine's air-fuel ratio in real time. If the exhaust gas contains a high amount of oxygen, the hydrogen injection rate is increased to achieve the predetermined air-fuel ratio; if the exhaust gas contains a high amount of hydrogen, the hydrogen injection rate is decreased to achieve the predetermined air-fuel ratio. Operating the engine within a reasonable air-fuel ratio range ensures both emissions control and durability. After multiple measurements and calibrations, the calibration process is complete once the air-fuel ratio stabilizes.

[0007] The calibration method of this invention is applied to the hydrogen engine exhaust gas calibration system of this invention, which includes the hydrogen engine exhaust gas measurement device of this invention. The engine ECU of this invention acquires the crankshaft angle value R of the engine under test, calculates the duration T for controlling exhaust gas entry (i.e., the solenoid valve opening duration) using the formula T = R / engine speed ÷ 60 × 360, and sends this information to the control unit. The cylinder pressure acquisition system observes the cylinder pressure build-up process during engine operation in real time based on the cylinder pressure. The initial cylinder pressure rise corresponds to the compression stroke; a gradual rise followed by a rapid rise indicates ignition, the engine's power stroke. The subsequent cylinder pressure drop indicates the end of the power stroke and the start of the exhaust stroke. The cylinder pressure drop allows the inlet solenoid valve to open. The cylinder pressure acquisition system confirms the solenoid valve opening time based on the cylinder pressure build-up process and sends a signal to the control unit. The control unit then sends control signals to the intake and exhaust solenoid valves. Upon receiving a signal indicating the opening time, the intake solenoid valve opens, while the outlet solenoid valve closes simultaneously. Exhaust gas enters the hydrogen engine exhaust gas measuring device. After the solenoid valve's open duration expires, the intake solenoid valve closes, and the outlet solenoid valve opens. The measured exhaust gas then enters the turbocharger through the outlet solenoid valve, driving the turbocharger worm gear to rotate and ensuring engine power. The engine ECU corrects the air-fuel ratio based on the measurement results from the gas concentration measuring device, ensuring the air-fuel ratio reaches a predetermined value. This process is repeated multiple times until the air-fuel ratio consistently reaches the predetermined value, at which point calibration is complete. Using the hydrogen engine exhaust gas measuring device of this invention, the concentration of gas components in the exhaust gas of a single cylinder can be accurately measured, avoiding measurement errors caused by the mixing of exhaust gas from other cylinders in the exhaust manifold.

[0008] The exhaust gas measurement channel of the hydrogen engine exhaust gas measurement device is designed with an approximately U-shaped tubular structure, which is simple, compact, and occupies little space. The exhaust gas measurement channel includes a measurement chamber, a measurement device interface, an inlet pipe, and an outlet pipe. The inlet and outlet pipes are symmetrically fixedly installed on the left and right side walls of the measurement chamber, forming an approximately U-shaped tubular structure. The solenoid valve assembly includes an inlet solenoid valve and an outlet solenoid valve, which are respectively openable and fixedly installed at the end ports of the inlet and outlet pipes. The measurement device interface is fixedly connected to the measurement chamber. An axial through hole is provided at the center of the measurement device interface for gas intake by the measurement device. The number of measurement device interfaces can be one or more; this invention preferably uses multiple interfaces, allowing for simultaneous measurement of various types of exhaust gases without affecting calibration results. Although this invention uses one or two measurement device interfaces as examples, it does not mean abandoning the protection of technologies with more measurement device interfaces. The measurement device is fixedly connected to the measurement chamber through the corresponding measurement device interface. This measuring device, equipped with multiple measurement device interfaces, can not only calibrate the concentration of gas components in single-cylinder exhaust gas by measuring its concentration, but also connect to other different measuring devices to perform other types of gas measurements simultaneously during calibration. For example, connecting to a particulate matter measuring device can indirectly analyze the sealing condition of piston rings and valve stem seals in the cylinder: since hydrogen engines burn hydrogen and no carbon is present, the generated particulate matter can only be produced by engine oil mixed in the cylinder and burned, thus allowing for assessment of cylinder sealing conditions. This hydrogen engine exhaust gas measuring device can save on measurement and labor costs.

[0009] Due to the limited space in the engine compartment, the calibration of hydrogen engine exhaust gases is not performed directly on the vehicle, but rather on an engine performance test bench. The hydrogen engine exhaust gas calibration system of this invention includes the aforementioned hydrogen engine exhaust gas measuring device, and also includes an engine performance test bench. The engine under test is mounted on the engine performance test bench. One end of the exhaust manifold of the cylinder under test is fixedly connected to the engine under test, and the other end of the exhaust manifold of the cylinder under test is fixedly connected to the engine exhaust manifold. The engine exhaust manifold is fixedly connected to the turbocharger. The other end of the intake solenoid valve is fixedly connected to the exhaust manifold of the cylinder under test via a flange, and the other end of the outlet solenoid valve is fixedly connected between the engine exhaust manifold and the turbocharger via a flange. The control unit of the engine electronic control system component is electrically connected to the engine ECU, the cylinder pressure acquisition system, the intake solenoid valve, and the outlet solenoid valve, respectively.

[0010] Furthermore, the exhaust gas measurement channel includes a measurement chamber, a measurement equipment interface, an inlet pipe, and an outlet pipe. The measurement equipment interface is fixedly connected to the upper part of the measurement chamber, and the measurement equipment interface and the measurement equipment are fixedly connected. Both the inlet pipe and the outlet pipe are approximately L-shaped pipes. The pipe openings at the short ends of the inlet pipe and the outlet pipe are symmetrically fixedly connected to the left and right side walls of the measurement chamber, forming an approximately U-shaped tubular structure. The solenoid valve assembly includes an inlet solenoid valve and an outlet solenoid valve. One end of the inlet solenoid valve is openable and fixedly connected to the pipe opening at the end of the long inlet pipe, and one end of the outlet solenoid valve is openable and fixedly connected to the pipe opening at the end of the long outlet pipe.

[0011] The shapes of the intake and exhaust pipes of this invention match the shapes of other components inside the engine, ensuring that they do not interfere with each other.

[0012] Furthermore, the measuring equipment includes a gas concentration measuring device, which is fixedly connected to the measuring equipment interface.

[0013] This invention performs calibration by measuring the concentration of gas components in the exhaust gas of a single cylinder. The measuring device used is a gas concentration measuring device, which is fixedly connected to the measuring device interface.

[0014] Furthermore, the exhaust gas measurement channel also includes another measuring device interface, which is fixedly connected to the measurement chamber. The measuring device also includes a particulate matter measuring device, which is fixedly connected to the other measuring device interface. In actual measurement, other measuring devices can be replaced as needed.

[0015] The exhaust gas measurement channel of this invention can be equipped with multiple measurement device interfaces. This invention takes two measurement device interfaces as an example. The measurement devices also include a particulate matter measurement device, a gas concentration measurement device, and the particulate matter measurement device, which are respectively fixedly connected to the two measurement device interfaces. The particulate matter measurement device measures the particulate matter content in the exhaust gas. Simultaneous measurement of particulate matter content does not affect the calibration of the air-fuel ratio after measuring the exhaust gas concentration using the gas concentration device, thus saving measurement and labor costs.

[0016] A hydrogen engine exhaust gas calibration system includes the aforementioned hydrogen engine exhaust gas measuring device, and also includes an engine performance test bench. The engine performance test bench includes an exhaust manifold of the cylinder under test, an engine exhaust manifold, a turbocharger, and an engine electronic control system assembly. The exhaust manifold of the cylinder under test is fixedly connected to the engine exhaust manifold, and the engine exhaust manifold is fixedly connected to the turbocharger. The other end of an intake solenoid valve is fixedly connected to the exhaust manifold of the cylinder under test via a flange, and the other end of an outlet solenoid valve is fixedly connected between the engine exhaust manifold and the turbocharger via a flange. Some components of the engine electronic control system assembly are electrically connected to the intake solenoid valve and the outlet solenoid valve.

[0017] The other end of the intake solenoid valve is fixedly connected to the exhaust manifold of the cylinder under test via a flange, and the other end of the outlet solenoid valve is fixedly connected between the engine exhaust manifold and the turbocharger via a flange. After the gas concentration measuring equipment completes the measurement and analysis, the exhaust gas enters the turbocharger through the outlet solenoid valve, driving the turbocharger turbine to work, ensuring that the engine power is not lost. Because the calibration process is repeated multiple times until the air-fuel ratio reaches the predetermined value and stabilizes, it will not end until then. If the exhaust gas is released, there will be no exhaust gas to drive the turbocharger turbine, which will cause a loss of engine power. This is because the engine needs high intake pressure to ensure power output, and the turbocharger is the means to provide high intake pressure. The turbocharger needs the engine exhaust gas to drive the turbine to work, driving the turbocharger pressure end to compress fresh air and increase the intake pressure. If the exhaust gas is released, there will be no turbine to drive, and some boost pressure will be lost, which will cause a loss of engine power. The design of this invention avoids this problem.

[0018] Furthermore, the engine electronic control system components include a control unit, an engine ECU, and an in-cylinder pressure acquisition system. The control unit is electrically connected to the engine ECU, the in-cylinder pressure acquisition system, the intake solenoid valve, and the exhaust solenoid valve, respectively. The engine ECU includes a crankshaft position sensor.

[0019] The control unit is electrically connected to the engine ECU, the in-cylinder pressure acquisition system, the intake solenoid valve, and the exhaust solenoid valve. The engine ECU has a built-in crankshaft position sensor. When measurement and calibration begin, the engine ECU obtains the solenoid valve opening duration based on the formula T = R / engine speed ÷ 60 × 360 using crankshaft angle information acquired from the crankshaft position sensor, and sends this information to the control unit. The in-cylinder pressure acquisition system determines the solenoid valve opening time based on the cylinder pressure buildup under real-time in-cylinder conditions. That is, the intake solenoid valve can be opened when the cylinder pressure begins to drop and the engine finishes its working stroke and begins the exhaust stroke. The control unit sends the solenoid valve opening time and duration to the solenoid valve assembly, enabling precise measurement of the concentration of the analyte in the exhaust gas at any given time. Based on the detection results, the engine ECU corrects the air-fuel ratio to control it to a predetermined value.

[0020] A calibration method for a hydrogen engine exhaust gas calibration system, applied to the aforementioned hydrogen engine exhaust gas calibration system, comprises the following steps:

[0021] S1. Connect the engine to be tested to the engine performance test bench;

[0022] S2. Obtain the crankshaft angle R of the engine under test, and calculate the duration T for controlling the exhaust gas entry.

[0023] T = R / engine speed ÷ 60 × 360;

[0024] The real-time pressure value p inside the engine cylinder is obtained, and the start time t of exhaust gas entry is determined based on the preset correspondence between the engine cylinder pressure value and the start time of exhaust gas entry.

[0025] S3. Based on t and T, control the amount of exhaust gas entering, measure the concentration of the component to be tested in the exhaust gas, and after the measurement is completed, the exhaust gas is discharged into the turbocharger. Based on the measurement results, the air-fuel ratio is corrected to control the air-fuel ratio to reach the predetermined value.

[0026] S4. Repeat the above steps multiple times to correct the air-fuel ratio. When the air-fuel ratio continuously reaches the predetermined value for a set time, the calibration ends.

[0027] Furthermore, steps S2 and S3 specifically include:

[0028] The engine ECU obtains crankshaft angle information from the crankshaft position sensor and calculates the solenoid valve opening duration based on the formula T = R / engine speed ÷ 60 × 360; the in-cylinder pressure acquisition system determines the solenoid valve opening time based on the correspondence between the in-cylinder pressure value and the start time of exhaust gas entry.

[0029] The control unit obtains the duration of electromagnetic opening and the opening time of the electromagnetic valve. The control unit controls the intake solenoid valve to open and the exhaust solenoid valve to close at the same time, controlling the amount of exhaust gas entering. The gas concentration measuring device measures the exhaust gas. Based on the measurement results, the engine ECU corrects the air-fuel ratio and controls the air-fuel ratio to reach the predetermined value.

[0030] Furthermore, the engine ECU corrects the air-fuel ratio in the following steps: if the exhaust gas contains more oxygen, the amount of hydrogen injection is increased to control the air-fuel ratio to a predetermined value; if the exhaust gas contains more hydrogen, the amount of hydrogen injection is reduced to control the air-fuel ratio to a predetermined value.

[0031] Furthermore, a particulate matter measuring device is fixedly connected to the test chamber. During the calibration process, the particulate matter measuring device measures the number of particulate matter in the exhaust gas to determine the sealing condition of the piston rings and valve stem seals in the cylinder: if particulate matter is detected, the cylinder's sealing performance is poor; if no particulate matter is detected, the cylinder's sealing performance is good.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. This invention provides a method for calibrating the exhaust gas of a hydrogen engine, which is applied to a hydrogen engine exhaust gas calibration system. The method determines the opening time of the solenoid valve through an in-cylinder pressure acquisition system, and the engine ECU calculates the opening duration of the solenoid valve based on the crankshaft angle. The opening time and duration of the solenoid valve are sent to the control unit to control the opening and closing of the solenoid valve of the hydrogen engine exhaust gas device. The gas composition concentration of the exhaust gas is accurately measured, and the engine air-fuel ratio is adjusted by the ECU to reach a predetermined value. The calibration principle is simple, the operation is convenient, the time and effort are saved, and the test progress is fast.

[0034] 2. The hydrogen engine exhaust gas measuring device of the present invention has a simple structure, occupies little space, and has low cost;

[0035] 3. After the measurement is completed, the exhaust gas is discharged into the turbocharger by opening the solenoid valve at the outlet of the exhaust pipe connected between the engine exhaust manifold and the turbocharger, thus ensuring engine power.

[0036] 4. The measuring chamber is equipped with multiple measuring device interfaces that can be connected to different measuring devices, enabling other measurements of the exhaust gas to be performed simultaneously with the gas component concentration calibration, thus saving measurement costs. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the hydrogen engine exhaust gas measuring device of the present invention;

[0038] Figure 2 This is a schematic diagram of the exhaust gas measurement channel of the present invention;

[0039] Figure 3 This is a schematic diagram illustrating the working principle of the calibration method for the hydrogen engine exhaust gas calibration system of the present invention.

[0040] Figure 4 This is an analytical diagram of the cylinder pressure acquisition system of the present invention;

[0041] Figure 5 This is a comparison chart of the adjustment speed of the calibration method of the present invention and the method of manually adjusting the air-fuel ratio using the cylinder pressure curve.

[0042] In the picture:

[0043] 1. Exhaust gas measurement channel; 1.1. Measurement chamber; 1.2. Measurement equipment interface; 1.3. Inlet pipe; 1.4. Outlet pipe; 2. Solenoid valve assembly; 2.1. Inlet solenoid valve; 2.2. Outlet solenoid valve; 3. Measurement equipment. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0045] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0046] It should be noted that the terms "front", "rear", "inner", "outer", "left", "right", etc., used in this invention to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0047] It should be noted that any symbols and or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0048] The embodiments of the present invention, namely an embodiment of a hydrogen engine exhaust gas measuring device, system, and calibration method, are described below in conjunction with... Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 Please provide a detailed explanation.

[0049] Example 1:

[0050] See Figure 1 As shown, a hydrogen engine exhaust gas measuring device includes an exhaust gas measuring channel 1, a solenoid valve assembly 2, and a measuring device 3. The exhaust gas measuring channel 1 is an approximately U-shaped tubular structure. The solenoid valve assembly 2 is fixedly connected to the pipe openings at both ends of the exhaust gas measuring channel 1, and the measuring device 3 is fixedly connected to the middle of the exhaust gas measuring channel 1.

[0051] See Figure 2 As shown, the exhaust gas measurement channel 1 includes a measurement chamber 1.1, a measurement device interface 1.2, an inlet pipe 1.3, and an outlet pipe 1.4. The measurement device interface 1.2 is fixedly connected to the upper part of the measurement chamber 1.1. The measurement device interface 1.2 and the measurement device 3 are fixedly connected. The inlet pipe 1.3 and the outlet pipe 1.4 are both approximately L-shaped pipes. One end of the short pipes of the inlet pipe 1.3 and the outlet pipe 1.4 are symmetrically fixedly connected to the left and right side walls of the measurement chamber 1.1 to form an approximately U-shaped tubular structure. The solenoid valve assembly 2 includes an inlet solenoid valve 2.1 and an outlet solenoid valve 2.2. One end of the inlet solenoid valve 2.1 is openable and fixedly connected to the pipe opening at the other end of the inlet pipe 1.3, and one end of the outlet solenoid valve 2.2 is openable and fixedly connected to the pipe opening at the other end of the outlet pipe 1.4.

[0052] The measuring device 3 includes a gas concentration measuring device, which is fixedly connected to the measuring device interface 1.2.

[0053] Example 2:

[0054] A hydrogen engine exhaust gas measuring device includes an exhaust gas measuring channel 1, a solenoid valve assembly 2, and a measuring device 3. The exhaust gas measuring channel 1 is an approximately U-shaped tubular structure. The solenoid valve assembly 2 is fixedly connected to the pipe openings at both ends of the exhaust gas measuring channel 1. The measuring device 3 is fixedly connected to the middle of the exhaust gas measuring channel 1.

[0055] The exhaust gas measurement channel 1 includes a measurement chamber 1.1, a measurement device interface 1.2, an inlet pipe 1.3, and an outlet pipe 1.4. The measurement device interface 1.2 is fixedly connected to the upper part of the measurement chamber 1.1. The measurement device interface 1.2 and the measurement device 3 are fixedly connected. The inlet pipe 1.3 and the outlet pipe 1.4 are both approximately L-shaped pipes. One end of the short pipes of the inlet pipe 1.3 and the outlet pipe 1.4 are symmetrically fixedly connected to the left and right side walls of the measurement chamber 1.1 to form an approximately U-shaped tubular structure. The solenoid valve assembly 2 includes an inlet solenoid valve 2.1 and an outlet solenoid valve 2.2. One end of the inlet solenoid valve 2.1 is openable and fixedly connected to the pipe opening at the other end of the inlet pipe 1.3. One end of the outlet solenoid valve 2.2 is openable and fixedly connected to the pipe opening at the other end of the outlet pipe 1.4.

[0056] The measuring device 3 includes a gas concentration measuring device, which is fixedly connected to the measuring device interface 1.2.

[0057] The exhaust gas measurement channel 1 also includes another measurement device interface 1.2, which is fixedly connected to the measurement chamber 1.1. The measurement device 3 also includes a particulate matter measurement device, which is fixedly connected to the other measurement device interface 1.2.

[0058] Example 3:

[0059] The present invention also provides a hydrogen engine exhaust gas calibration system, including the aforementioned hydrogen engine exhaust gas measuring device. The hydrogen engine exhaust gas measuring device has only one measuring device interface 1.2, and a gas concentration measuring device is fixedly connected to the measuring device interface 1.2. The hydrogen engine exhaust gas calibration system also includes an exhaust manifold of the cylinder under test, an engine exhaust manifold, a turbocharger, and an engine electronic control system assembly. The exhaust manifold of the cylinder under test, the engine exhaust manifold, and the turbocharger are all fixedly connected inside the vehicle. The exhaust manifold of the cylinder under test is fixedly connected to the engine exhaust manifold. The engine exhaust manifold is fixedly connected to the turbocharger via a flange. The other end of the inlet solenoid valve 2.1 is openable and fixedly connected to the exhaust manifold of the cylinder under test. The other end of the outlet solenoid valve 2.2 is openable and fixedly connected to the flange connecting the engine exhaust manifold and the turbocharger. Some components of the engine electronic control system assembly are electrically connected to the inlet solenoid valve 2.1 and the outlet solenoid valve 2.2.

[0060] The engine electronic control system components include a control unit, an engine ECU, and an in-cylinder pressure acquisition system. The control unit is electrically connected to the engine ECU, the in-cylinder pressure acquisition system, the intake solenoid valve 2.1, and the exhaust solenoid valve 2.2. The engine ECU includes a crankshaft position sensor.

[0061] Example 4:

[0062] This invention also provides a hydrogen engine exhaust gas calibration system, including the aforementioned hydrogen engine exhaust gas measuring device. The hydrogen engine exhaust gas measuring device has two measuring device interfaces 1.2, with a gas concentration measuring device and a particulate matter measuring device respectively fixedly connected to the two measuring device interfaces 1.2. The hydrogen engine exhaust gas calibration system also includes an exhaust manifold of the cylinder under test, an engine exhaust manifold, a turbocharger, and an engine electronic control system assembly. The exhaust manifold of the cylinder under test, the engine exhaust manifold, and the turbocharger are all fixedly connected inside the vehicle. The exhaust manifold of the cylinder under test is fixedly connected to the engine exhaust manifold, and the engine exhaust manifold is fixedly connected to the turbocharger via a flange. The other end of an inlet solenoid valve 2.1 is openable and fixedly connected to the exhaust manifold of the cylinder under test, and the other end of an outlet solenoid valve 2.2 is openable and fixedly connected to the flange connecting the engine exhaust manifold and the turbocharger. Some components of the engine electronic control system assembly are electrically connected to the inlet solenoid valve 2.1 and the outlet solenoid valve 2.2.

[0063] The engine electronic control system components include a control unit, an engine ECU, and an in-cylinder pressure acquisition system. The control unit is electrically connected to the engine ECU, the in-cylinder pressure acquisition system, the intake solenoid valve 2.1, and the exhaust solenoid valve 2.2. The engine ECU includes a crankshaft position sensor.

[0064] Example 5:

[0065] This invention also provides a calibration method for a hydrogen engine exhaust gas calibration system, applied to the aforementioned hydrogen engine exhaust gas calibration system, comprising the following steps:

[0066] S1. Connect the engine to be tested to the engine performance test bench;

[0067] S2. Obtain the crankshaft angle R of the engine under test, and calculate the duration T for controlling the exhaust gas entry.

[0068] T = R / engine speed ÷ 60 × 360;

[0069] See Figure 4 As shown, the real-time pressure value p inside the engine cylinder is obtained, and the start time t of exhaust gas entry is determined based on the preset correspondence between the engine cylinder pressure value and the start time of exhaust gas entry.

[0070] S3. Based on t and T, control the amount of exhaust gas entering, measure the concentration of the component to be tested in the exhaust gas, and after the measurement is completed, the exhaust gas is discharged into the turbocharger. Based on the measurement results, the air-fuel ratio is corrected to control the air-fuel ratio to reach the predetermined value.

[0071] S4. Repeat the above steps multiple times to correct the air-fuel ratio. When the air-fuel ratio continuously reaches the predetermined value for a set time, the calibration ends.

[0072] Steps S2 and S3 specifically include:

[0073] The engine ECU obtains crankshaft angle information from the crankshaft position sensor and calculates the solenoid valve opening duration based on the formula T = R / engine speed ÷ 60 × 360; see Figure 4 As shown, the in-cylinder pressure acquisition system determines the time when the solenoid valve can be opened based on the correspondence between the in-cylinder pressure value and the start time of exhaust gas entry.

[0074] The control unit obtains the duration of electromagnetic opening and the opening time of the electromagnetic valve. The control unit controls the intake solenoid valve to open and the exhaust solenoid valve to close at the same time, controlling the amount of exhaust gas entering. The gas concentration measuring device measures the exhaust gas. Based on the measurement results, the engine ECU corrects the air-fuel ratio and controls the air-fuel ratio to reach the predetermined value.

[0075] The engine ECU corrects the air-fuel ratio in the following steps: if the exhaust gas contains more oxygen, the amount of hydrogen injection is increased to control the air-fuel ratio to a predetermined value; if the exhaust gas contains more hydrogen, the amount of hydrogen injection is reduced to control the air-fuel ratio to a predetermined value.

[0076] Figure 4 This is an analysis diagram of the in-cylinder pressure acquisition system. The vertical axis represents in-cylinder pressure, and the horizontal axis represents crankshaft angle. Figure 4 The cylinder pressure build-up process during engine operation can be observed. The initial rising portion of the curve in the graph represents the compression stroke, followed by a rapid rise after a period of flattening, signifying ignition and the engine's power stroke. The subsequent drop in cylinder pressure indicates the end of the power stroke and the start of the exhaust stroke. The inlet solenoid valve opens when the cylinder pressure begins to decrease. The in-cylinder data acquisition system determines the solenoid valve opening time based on the cylinder pressure build-up process and sends a signal to the control unit. The control unit then sends a control signal to the solenoid valve assembly.

[0077] The calibration method used in this embodiment and the existing method of manually adjusting the air-fuel ratio using cylinder pressure curves both adjust the air-fuel ratio by regulating the hydrogen injection quantity. A comparison of the two methods yields a graph.

[0078] Before using this method After using this method Number of adjustments 15 4 Time required (minutes) 30 8 Injector adjustment amount (baseline 1.0) 0.01 0.5 Final injection volume 1.12 1.12 and Figure 5 It can be determined that the calibration method of the present invention is far superior to the existing adjustment method, saving time and effort.

[0079] Example 6:

[0080] This invention also provides a calibration method for a hydrogen engine exhaust gas calibration system, applied to the aforementioned hydrogen engine exhaust gas calibration system, comprising the following steps:

[0081] S1. Connect the engine to be tested to the engine performance test bench;

[0082] S2. Obtain the crankshaft angle R of the engine under test, and calculate the duration T for controlling the exhaust gas entry.

[0083] T = R / engine speed ÷ 60 × 360;

[0084] The real-time pressure value p inside the engine cylinder is obtained, and the start time t of exhaust gas entry is determined based on the preset correspondence between the engine cylinder pressure value and the start time of exhaust gas entry.

[0085] S3. Based on t and T, control the amount of exhaust gas entering, measure the concentration of the component to be tested in the exhaust gas, and after the measurement is completed, the exhaust gas is discharged into the turbocharger. Based on the measurement results, the air-fuel ratio is corrected to control the air-fuel ratio to reach the predetermined value.

[0086] S4. Repeat the above steps multiple times to adjust the air-fuel ratio. See Figure 4 As shown, the calibration ends when the air-fuel ratio reaches the predetermined value for a set time.

[0087] Steps S2 and S3 specifically include:

[0088] The engine ECU obtains crankshaft angle information from the crankshaft position sensor and calculates the solenoid valve opening duration based on the formula T = R / engine speed ÷ 60 × 360; see Figure 4 As shown, the in-cylinder pressure acquisition system determines the time when the solenoid valve can be opened based on the correspondence between the in-cylinder pressure value and the start time of exhaust gas entry.

[0089] The control unit obtains the duration of electromagnetic opening and the opening time of the electromagnetic valve. The control unit controls the intake solenoid valve to open and the exhaust solenoid valve to close at the same time, controlling the amount of exhaust gas entering. The gas concentration measuring device measures the exhaust gas. Based on the measurement results, the engine ECU corrects the air-fuel ratio and controls the air-fuel ratio to reach the predetermined value.

[0090] The engine ECU corrects the air-fuel ratio in the following steps: if the exhaust gas contains more oxygen, the amount of hydrogen injection is increased to control the air-fuel ratio to a predetermined value; if the exhaust gas contains more hydrogen, the amount of hydrogen injection is reduced to control the air-fuel ratio to a predetermined value.

[0091] A particulate matter measuring device is also fixedly connected to the test chamber. During the calibration process, the particulate matter measuring device measures the number of particulate matter in the exhaust gas to determine the sealing condition of the piston rings and valve stem seals in the cylinder: if particulate matter is detected, the cylinder's sealing performance is poor; if no particulate matter is detected, the cylinder's sealing performance is good.

[0092] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A calibration method of a hydrogen engine exhaust gas calibration system, characterized by, The hydrogen engine exhaust calibration system comprises a hydrogen engine exhaust measuring device and an engine performance test bench, The hydrogen engine exhaust measuring device comprises an exhaust measuring channel (1), an electromagnetic valve assembly (2) and a measuring device (3), the exhaust measuring channel (1) is a tubular structure in the shape of U, the electromagnetic valve assembly (2) is fixedly connected to the pipe mouths at the two ends of the exhaust measuring channel (1) respectively, and the measuring device (3) is fixedly connected to the middle part of the exhaust measuring channel (1). The engine performance test bench comprises an exhaust manifold of a to-be-tested cylinder, an engine exhaust manifold, a supercharger and an engine electronic control system assembly, the exhaust manifold of the to-be-tested cylinder is fixedly connected to the engine exhaust manifold, the pipe mouth at the gas outlet end of the engine exhaust manifold is fixedly connected to the supercharger, the electromagnetic valve assembly (2) comprises an air inlet electromagnetic valve (2.1) and an air outlet electromagnetic valve (2.2), one end of the air inlet electromagnetic valve (2.1) is fixedly connected to the exhaust manifold of the to-be-tested cylinder through a flange, one end of the air outlet electromagnetic valve (2.2) is fixedly connected to the engine exhaust manifold through a flange, and part of the components of the engine electronic control system assembly are electrically connected with the air inlet electromagnetic valve (2.1) and the air outlet electromagnetic valve (2.2). The calibration method of the hydrogen engine exhaust calibration system comprises the following steps: S1, connecting a to-be-tested engine to an engine performance test bench; S2, obtaining a crank angle value R of the to-be-tested engine, calculating a control duration T of exhaust gas entering, ， obtaining a real-time in-cylinder pressure value p of the to-be-tested engine, and determining a start time t of exhaust gas entering based on a preset corresponding relationship between the in-cylinder pressure value and the start time of exhaust gas entering; S3, controlling the amount of exhaust gas entering based on t and T, measuring the concentration of a to-be-tested component in the entering exhaust gas, discharging the exhaust gas into the supercharger after the measurement is completed, and correcting the air-fuel ratio based on the measurement result to control the air-fuel ratio to reach a predetermined value; S4, repeating the above steps multiple times to correct the air-fuel ratio multiple times, and ending the calibration when the air-fuel ratio reaches the predetermined value continuously for a set time.

2. The calibration method of the hydrogen engine exhaust gas calibration system according to claim 1, characterized by, The steps S2 and S3 specifically comprise: The engine ECU acquires the crank angle information of the crank position sensor, and based on the formula Obtain the electromagnetic valve opening duration; the in-cylinder pressure acquisition system determines the electromagnetic valve opening time based on the corresponding relationship between the in-cylinder pressure value and the exhaust gas entry start time; The control unit obtains the electromagnetic valve opening duration and the electromagnetic valve opening time, the control unit controls the air inlet electromagnetic valve to open while the air outlet electromagnetic valve is closed, controls the amount of exhaust gas entering, the gas concentration measuring device measures the exhaust gas, and the engine ECU corrects the air-fuel ratio based on the measurement result to control the air-fuel ratio to reach a predetermined value.

3. The calibration method of claim 2, wherein, The engine ECU corrects the air-fuel ratio, and the specific steps are as follows: if the exhaust gas contains more oxygen, the hydrogen injection amount is increased to control the air-fuel ratio to reach a predetermined value; if the exhaust gas contains more hydrogen, the hydrogen injection amount is reduced to control the air-fuel ratio to reach a predetermined value.

4. The calibration method of claim 3, wherein The particulate matter measuring device is also fixedly connected to the test cavity, and measures the number value of the particulate matter in the exhaust gas in the calibration process to judge the sealing condition of the piston ring and the valve oil seal in the cylinder: if the particulate matter is detected, the sealing property of the cylinder is poor; if no particulate matter is detected, the sealing property of the cylinder is good.

5. A hydrogen engine exhaust gas calibration system, characterized by, A calibration method for performing the hydrogen engine exhaust calibration system according to any one of claims 1-4.

6. The hydrogen engine tail gas calibration system of claim 5, wherein, The engine electronic control system assembly comprises a control unit, an engine ECU and an in-cylinder pressure acquisition system, the control unit is electrically connected to the engine ECU, the in-cylinder pressure acquisition system, an air inlet electromagnetic valve (2.1) and an air outlet electromagnetic valve (2.2) respectively, and the engine ECU comprises a crankshaft position sensor.

7. A hydrogen engine exhaust gas measuring device characterized by comprising: The exhaust measuring channel (1) comprises a measuring cavity (1.1), a measuring device interface (1.2), an air inlet pipe (1.3) and an air outlet pipe (1.4), the measuring cavity (1.1) is fixedly connected with the measuring device interface (1.2), the measuring device interface (1.2) is fixedly connected with a measuring device (3), the air inlet pipe (1.3) and the air outlet pipe (1.4) are both approximately L-shaped pipes, the short pipe end of the air inlet pipe (1.3) and the short pipe end of the air outlet pipe (1.4) are fixedly connected with the left and right side walls of the measuring cavity (1.1) to form an approximately U-shaped tubular structure, the other end of the air inlet electromagnetic valve (2.1) is fixedly connected with the long pipe end of the air inlet pipe (1.3), and the other end of the air outlet electromagnetic valve (2.2) is fixedly connected with the long pipe end of the air outlet pipe (1.4).

8. The hydrogen engine exhaust gas measurement device according to claim 7, characterized by, The measuring device (3) comprises a gas concentration measuring device, which is fixedly connected with the measuring device interface (1.2).

9. The hydrogen engine exhaust gas measurement device according to claim 8, characterized by, The exhaust measuring channel (1) further comprises another measuring device interface (1.2), which is fixedly connected with the measuring cavity (1.1), and the measuring device (3) further comprises a particulate matter measuring device, which is fixedly connected with the other measuring device interface (1.2).

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