CN108301951A - Measure the device and its test method of natural gas engine gas jet law - Google Patents

Abstract

The invention discloses the devices and its test method that measure natural gas engine gas jet law, including gas cylinder, pressure reducing valve, pipeline, air valve 1, voltage stabilizing gas chamber, fuel gas injection valve, injection valve base, jet pipe, constant volume gas chamber, pressure sensor, temperature sensor, injection valve actuator, data collecting card, computer and air valve 2；Gas cylinder is connected with voltage stabilizing gas chamber by pipeline, and pressure reducing valve and air valve 1 are housed on pipeline；Constant volume gas chamber is the rigid gas chamber of fixed volume, and jet pipe stretches into gas chamber by the connector of special processing, constant volume gas chamber is made to be connected with fuel gas injection valve；Constant volume gas chamber is equipped with pressure sensor and temperature sensor, and sending sensing data to computer by data acquisition device is handled；Constant volume gas chamber is also equipped with the pipeline of exhaust, and air valve 2 is installed on pipeline.The present invention is suitable for the measurement of natural gas engine gas jet law but the measurement of fuel gas injection rule single injection event may be implemented using constant volume area method in unlimited gaseous species.

Description

Device for Measuring Gas Injection Law of Natural Gas Engine and Its Test Method

technical field

The invention belongs to the research field of engine gas injection measurement devices, and in particular relates to a device and a test method for measuring gas injection rules of natural gas engines.

technical background

As the energy consumption of internal combustion engines continues to increase, the problem of emission pollution is becoming more and more serious. Therefore, how to reduce the emission of harmful gases has become a research hotspot. Natural gas is rich in reserves, low in price, and highly applicable. It can work on gasoline engines, ignited by spark ignition, and diesel engines with high compression ratios. The content of nitrogen oxides and sulfur oxides in the emissions formed after the combustion of natural gas is much lower than that of diesel combustion products. Therefore, as an ideal alternative fuel, natural gas is widely used in engines.

In natural gas engines, in order to reduce carbon and hydrogen emissions, in-cylinder direct injection technology and intake port multi-point injection are gradually being valued. In a gas system using high-pressure direct injection, the injection law affects the combustion characteristics, and the injection law of the gas injection valve determines the gas intake rate and the maximum intake quality of the single-cycle gas, which directly affects the engine's power and economy. performance and emission characteristics. Therefore, mastering the actual gas injection process and injection law in the intake port is conducive to the utilization and development of direct injection technology, further solving the problem of insufficient natural gas engine power, reducing emissions and improving fuel economy.

At home and abroad, there is no mature measurement technology or device that can be widely used for the measurement of injection characteristics such as gas injection rules. At present, the methods for measuring the injection characteristics of gas injection valves for the measurement of single injection volume and steady-state flow mainly include Drainage method, mass flow meter method and weighing method, etc.:

1) Drainage method: The principle of the drainage method is to obtain the volume of the jet after conversion according to the amount of water discharged when the nozzle is sprayed. The volume ejected by the nozzle in a single injection is relatively small, so it needs to be weighed after several consecutive injections, and finally the average value is calculated. The error measured by the drainage method is relatively small, but only the total amount of jet can be measured.

2) Mass flow meter method: The mass flow meter method refers to the installation of a mass flow meter at the injection device, after the injection is stable, the flow meter is used to measure, and the computer processes the result. The measurement error of the mass flow meter method is small, and it is generally used to test the steady-state flow of the injection valve.

3) Weighing method: The weighing method is only applicable to the engine bench test, and the error is large, and the accuracy is difficult to guarantee.

In addition, the constant volume method is also suitable for the measurement of gas injection rules, and the measurement accuracy can be guaranteed. The constant volume method refers to injecting gas into a fixed-volume gas chamber with a certain pressure, and calculating the injection law through the pressure change in the gas chamber. Combined with formulas such as the gas state equation to derive, the formula Among them, dm is the instantaneous mass flow rate of the gas injection valve, that is, the injection law.

In summary, natural gas engines are more and more widely used, and mastering the gas injection law is conducive to the development of in-cylinder direct injection technology, thereby promoting the application of natural gas engine technology. Measuring devices and their test methods are necessary.

Contents of the invention

The present invention proposes a test device and test method for measuring the gas injection law of a natural gas engine. The test device is based on the constant volume method, and can realize the measurement of the injection valve injection law of the short pulse width injection of the engine, and is not limited to the natural gas engine. , not limited to the type of gas. Technical solution of the present invention is as follows:

A device for measuring the gas injection law of a natural gas engine, specifically including a gas cylinder (1), a pressure reducing valve (2), a pipeline (3), a gas valve 1 (4), a pressure stabilizing chamber (5), and a gas injection valve (6) , injection valve seat (7), nozzle pipe (8), constant volume air chamber (9), pressure sensor (10), temperature sensor (11), injection valve driver (12), data acquisition card (13), computer (14) and gas valve 2 (15).

Described air valve 1 (4) is installed on the pipeline (3), between pressure reducing valve (2) and pressure-stabilizing air chamber (5); Air valve 2 (15) is installed on the pipeline (3), pipeline and the spray pipe (8) are positioned at both sides of the constant-volume air chamber (9); after the spray pipe (8) stretches out from the gas injection valve (6), it enters the constant-volume air chamber (9), and the described spray pipe (8 ) is a straight-through nozzle.

The pressure-stabilizing air chamber (5) is connected to the gas injection valve (6) through a pipeline (3); the gas injection valve (6) is fixed on the injection valve seat (7), and is fixedly connected by bolt connection; The cross-sectional area of the nozzle pipe (8) is greater than the outlet flow cross-sectional area of the gas injection valve (6); the joint of the nozzle pipe (8) is specially processed. .

The injection valve driver (12) contains a controller, and the controller adjusts and controls the injection period and the injection pulse width of the gas injection valve (6); the size of the constant volume gas chamber (9) depends on the gas injection valve ( 6) to design, the volume size of the constant volume air chamber (9) is not a fixed value, and the volume changes with the gas injection valve (6); the injection valve driver (12) links to each other with the computer (14).

Described pressure sensor (10) and temperature sensor (11) are high-precision sensors; Pressure sensor (10) and spray pipe (8) are installed on the same side of constant volume air chamber (9), and temperature sensor (11) is installed on The other side of the constant volume air chamber (9) is connected with the data acquisition card (13) with the pressure sensor (10) and the temperature sensor (11).

An experimental method for measuring the gas injection law of a natural gas engine, specifically comprising the following steps:

(1) The gas valve 1 (4) is opened, and the gas flows from the gas cylinder (1) through the pressure reducing valve (2) along the pipeline (3) into the pressure stabilizing chamber for pressure stabilization; the injection valve driver (12) controls and adjusts the gas injection valve (6) injection cycle and injection pulse width; gas flows into the nozzle pipe (8) through the injection valve, and then enters the constant volume gas chamber (9) by the nozzle pipe (8);

(2) spray gas with a certain pressure in the constant volume gas chamber (9), pressure sensor (10) and temperature sensor (11) measure the pressure P of gas, temperature T information, and the signal that measures is passed into computer ( 14) Process the obtained signal according to the injection law;

(3) After the experiment is over, open the gas valve 2 (15) to remove the gas in the constant-volume gas chamber (9) to reduce the pressure.

Described step (2) specifically comprises:

The injection law described satisfies the Wherein dm is injection rule, V is the volume of constant-volume gas chamber (9), m is gas mass, M is molar mass, T is the absolute temperature measured by temperature sensor (11), and P is the pressure signal measured by pressure sensor (10) , R is the molar gas constant.

Description of drawings

Figure 1 is a schematic structural diagram of the test device for measuring the gas injection law of a natural gas engine.

Detailed ways

The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, so that the design objectives and advantages of the present invention can be more easily understood.

In conjunction with Fig. 1, technical scheme of the present invention is achieved in that the present invention comprises gas bottle (1), pressure relief valve (2), pipeline (3), gas valve 1 (4), pressure-stabilizing air chamber (5), Gas injection valve (6), injection valve seat (7), nozzle pipe (8), constant volume gas chamber (9), pressure sensor (10), temperature sensor (11), injection valve driver (12), data acquisition Card (13), computer (14), air valve 2 (15). The gas cylinder (1) is connected to the pressure-stabilizing air chamber (5) through a pipeline (3), and the pipeline (3) is equipped with a pressure reducing valve (2) and an air valve (4). The pressure reducing valve (2) can control and adjust the pressure of the gas coming out of the gas cylinder (1), and the gas valve 1 (4) can control the transmission of gas. The gas flowing out from the pressure-stabilizing chamber (5) flows into the gas injection valve (6), and the injection valve driver (12) controls and adjusts the injection cycle and injection pulse width of the gas injection valve (6). The gas injection valve (6) is fixed on the injection valve seat (7), and the connection method is bolt connection. After the nozzle pipe (8) stretches out from the gas injection valve (6), it enters the constant volume air chamber (9). Nozzle (8) is a straight-through nozzle, and pressure sensor (10), temperature sensor (11) and nozzle (8) are located on the same side of the constant volume air chamber (9), which can prevent the jet stream from directly impacting the pressure sensor, thereby affect the measurement results. After the data acquisition card (13) collects the signals of the temperature sensor (11) and the pressure sensor (10), they are handed over to the computer (14) for processing. After the end of the test, the gas in the constant volume air chamber (9) is controlled by the gas valve 2 (15) to achieve the effect of depressurization.

The measurement steps of the present invention are as follows: first open the gas valve 1 (4), and the gas flows into the pressure-stabilizing air chamber from the gas cylinder (1) through the pressure-reducing valve (2) along the pipeline (3) to stabilize the pressure; the injection valve driver (12) Control and adjust the injection cycle and injection pulse width of the gas injection valve (6); the gas flows into the nozzle pipe (8) through the injection valve, and then enters the constant volume gas chamber (9) by the nozzle pipe (8); ) to inject gas at a certain pressure, the pressure sensor (10) and temperature sensor (11) measure the pressure P and temperature T information of the gas, and transmit the measured signal to the computer (14) to process the obtained signal according to the injection law After the experiment finishes, open gas valve 2 (15) and the gas in the constant volume air chamber (9) is got rid of, and depressurizes.

The pressure sensor (10) and the temperature sensor (11) perceive and measure the change of pressure and temperature, and the gas state equation Derivation, differentiate both ends of the gas state equation, and get the formula In the formula, dm is the injection law, V is the volume of the constant volume gas chamber (9), m is the gas mass, M is the molar mass, T is the absolute temperature measured by the temperature sensor (11), and P is the temperature measured by the pressure sensor (10). Pressure signal, R is the molar gas constant.

The above examples are only used as examples to better illustrate the present invention, and are not intended to limit the implementation, nor limit the patent scope of the present invention. Any equivalent structure or other obvious changes made by using the description and drawings of the present invention are also included in the scope of patent protection of the present invention.

Claims (7)

1. the device for measuring natural gas engine gas jet law, specifically includes gas cylinder (1), pressure reducing valve (2), pipeline (3), air valve 1 (4), voltage stabilizing gas chamber (5), fuel gas injection valve (6), injection valve base (7), jet pipe (8), constant volume gas chamber (9), pressure Sensor (10), temperature sensor (11), injection valve actuator (12), data collecting card (13), computer (14) and air valve 2 (15)。

2. the device according to claim 1 for measuring natural gas engine gas jet law, it is characterised in that：Institute The air valve 1 (4) stated is mounted on pipeline (3), between pressure reducing valve (2) and voltage stabilizing gas chamber (5)；Air valve 2 (15) is mounted on pipe On road (3), pipeline is located at the both sides of constant volume gas chamber (9) with jet pipe (8)；Jet pipe (8) enters after fuel gas injection valve (6) stretching Constant volume gas chamber (9), the jet pipe (8) are straight-through jet pipe.

3. the device according to claim 1 for measuring natural gas engine gas jet law, it is characterised in that：Institute The voltage stabilizing gas chamber (5) stated is connected with fuel gas injection valve (6) by pipeline (3)；Fuel gas injection valve (6) is fixed on injection valve base (7) it on, is fixedly connected with bolt connecting mode；Described jet pipe (8) sectional area is more than fuel gas injection valve (6) outlet stream section Product；Described jet pipe (8) connector passes through special processing.

4. the device according to claim 1 for measuring natural gas engine gas jet law, it is characterised in that：Institute The injection valve actuator (12) stated includes controller, the injection cycle and injection arteries and veins of controller adjusting control fuel gas injection valve (6) It is wide；The size of the constant volume gas chamber (9) is designed according to fuel gas injection valve (6), and the volume size of constant volume gas chamber (9) is not It is fixed value, volume changes with the difference of fuel gas injection valve (6)；Injection valve actuator (12) is connected with computer (14).

5. the device according to claim 1 for measuring natural gas engine gas jet law, it is characterised in that：Institute The pressure sensor (10) stated is high-precision sensor with temperature sensor (11)；Pressure sensor (10) is installed with jet pipe (8) The same side in constant volume gas chamber (9), temperature sensor (11) are mounted on the other side of constant volume gas chamber (9), with；Pressure sensor (10) it is connected with data collecting card (13) with temperature sensor (11).

6. measuring the experimental method of natural gas engine gas jet law, specifically comprise the following steps：

(1) air valve 1 (4) is opened, and gas flows into voltage stabilizing gas chamber along pipeline (3) through pressure reducing valve (2) from gas cylinder (1) and carries out voltage stabilizing；Spray Penetrate injection cycle and jet pulsewidth that valve actuator (12) controls to adjust fuel gas injection valve (6)；Gas flows into spray by injection valve It manages (8), then constant volume gas chamber (9) is entered by jet pipe (8)；

(2) gas is sprayed with certain pressure into constant volume gas chamber (9), pressure sensor (10) and temperature sensor (11) measure The pressure P of gas, temperature T information, and the signal measured is passed to computer (14), gained signal is carried out according to jet law Processing；

(3) it after testing, opens air valve 2 (15) and excludes the gas in constant volume gas chamber (9), be depressured.

7. a kind of experimental method for measuring natural gas engine gas jet law according to claim 6, special Sign is that the step (2) specifically includes：

The jet law meetsWherein dm is jet law, and V is constant volume gas chamber (9) volume, and m is gas Quality, M are molal weight, and T is the absolute temperature that temperature sensor (11) measures, and P is the pressure that pressure sensor (10) measures Signal, R are mol gas constant.