CN108317032A - A kind of experimental rig and method measuring natural gas engine gas emitted dose - Google Patents

Abstract

The invention discloses a kind of experimental rigs and method measuring natural gas engine gas emitted dose, belong to technical field of engines, including gas cylinder, Voltage stabilizing module, control module, measurement module and message processing module, gas is exported from gas cylinder, it is input in the fuel gas injection valve in control module after Voltage stabilizing module carries out voltage stabilizing, injection valve actuator in control module controls to adjust the injection cycle and jet pulsewidth of fuel gas injection valve, gas enters measurement module later, measurement module includes two kinds of measurement modules of constant volume and mass flow, second Air Valve Control gas of two intermodules installation is in two mould circulations in the block, to realize the measurement using two methods to fuel gas injection amount, message processing module is for collecting signal and is handled.The present invention realizes the fuel gas injection amount for measuring natural gas engine using two sets of measurement methods in same system, and can be compared two kinds of measurement results, improves measurement accuracy, reduces measurement error.

Description

A test device and method for measuring the gas injection quantity of a natural gas engine

technical field

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

Background technique

With the shortage of energy and the deterioration of the environment, it is urgent to develop and use energy-saving and clean fuels. Among many fuels, natural gas is rich in resources and friendly to emissions, and has recently been highly valued and applied. Natural gas is a gaseous fossil fuel consisting of different types of gases, the main component of which is methane. Compared with traditional petroleum-based fuels such as diesel and gasoline, natural gas has a higher calorific value and a lower fuel-to-air equivalent ratio. After the combustion of natural gas, the emission of carbon oxides and nitrogen oxides is less, the generated soot is lower, and no harmful substances such as lead and benzene will be produced. Therefore, as an ideal fuel for internal combustion engines, natural gas is used more and more widely.

In natural gas engines, in-cylinder direct injection technology can effectively improve intake efficiency, stabilize air supply characteristics, improve engine power, economy and emission characteristics, so in-cylinder direct injection technology has gradually received attention. In a gas system using high-pressure direct injection, the injection quantity affects the combustion characteristics and has an important influence on the development of the engine control system. Mastering the gas injection process in the actual intake port is beneficial to the utilization and development of direct injection technology, so as to further solve the problem of insufficient natural gas engine power and improve the fuel economy of the engine.

At present, there is not yet a very mature and extensive measurement technology or device for measuring injection characteristics such as gas injection volume. Domestic research shows that the methods for measuring the jet characteristics of gas injection valves mainly include drainage method, mass flow meter method, weighing method and constant volume method, etc., and are aimed at the measurement of single injection volume and steady-state flow.

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 jetting. Usually, it is necessary to weigh the total amount after several continuous injections, and finally calculate the average value. The error measured by the drainage method is relatively small, but only the total amount of jet can be measured.

The mass flow meter method refers to installing a mass flow meter at the injection device. After the injection is stable, use the flow meter to measure, and the computer processes the results. The measurement accuracy of the mass flow meter method is high, and it can be used to test the steady-state flow of the injection valve.

The weighing method is only suitable for engine bench testing, and its accuracy is low, making it inconvenient to control errors.

The measurement of gas injection quantity by the constant volume method is evolved from the measurement of the fuel injection law by the pressure method, and has higher precision. The specific operation is: inject gas at a certain pressure into the gas chamber with a fixed volume, and the pressure and temperature changes in the gas chamber will occur. After deriving the gas state equation and other formulas, the injection volume can be calculated.

In summary, mastering the injection characteristics of gas injection quantity is conducive to the development of engine direct injection technology, thereby promoting the application of natural gas engine technology, reducing emissions and protecting the environment. Therefore, a method for measuring gas injection quantity suitable for natural gas engines is invented. device is necessary.

Contents of the invention

The purpose of the present invention is to provide a test device for measuring the gas injection quantity of a natural gas engine that can realize the measurement of the engine gas injection law and can simultaneously use the constant volume method and the mass flow meter method in a set of systems, and use this device to test the gas injection quantity of the natural gas engine. Method for measuring gas injection quantity.

The purpose of the present invention is achieved like this:

The invention discloses a test device for measuring the gas injection quantity of a natural gas engine, which comprises a gas cylinder 1, a voltage stabilizing module, a control module, a measuring module and an information processing module;

The pressure stabilizing module includes a pressure reducing valve 2, a first pipeline 3, a first air valve 4 and a pressure stabilizing air chamber 5, the first pipeline 3 connects the gas cylinder 1 and the stabilizing air chamber 5, the pressure reducing valve 2 and the first air valve 4 is installed on the first pipeline 3, and the pressure reducing valve 2 is installed between the gas cylinder 1 and the first gas valve 4;

The control module includes a gas injection valve 6, an injection valve seat 7, a nozzle pipe 8 and an injection valve driver 15. The gas injection valve 6 is fixed on the injection valve seat 7 by bolts, and is connected with the pressure stabilizing chamber 5 and the injection valve driver 15 respectively. connected with each other, the nozzle pipe 8 protrudes from the back of the gas injection valve 6;

The measurement module includes a constant volume measurement module and a mass flow measurement module. The constant volume measurement module further includes a constant volume gas chamber 9, a pressure sensor 10, a temperature sensor 11 and a second air valve 12. The mass flow module further includes a second pipeline 13 and a mass flow rate measurement module. Flow meter 14, pressure sensor 10 and temperature sensor 11 are installed on the constant volume gas chamber 9, one end of constant volume gas chamber 9 links to each other with spray pipe 8, and the other end is connected with second pipeline 13, is installed on the second pipeline 13 The second air valve 12;

The information processing module includes a data acquisition card 16 and a computer 17. One end of the data acquisition card 16 is connected to a pressure sensor 10 and a temperature sensor 11, and the other end is connected to a computer 17. The computer 17 is also connected to an injection valve driver 15.

Preferably, the pressure reducing valve 2 is installed near the gas outlet of the gas cylinder 1 .

Preferably, the sectional area of the nozzle pipe 8 is larger than the flow sectional area of the outlet of the gas injection valve 6 .

Preferably, the size of the constant-volume air chamber 9 can be flexibly adjusted, and can be calculated according to the size of the gas injection valve 6 used.

Preferably, the pressure sensor 10 , the temperature sensor 11 and the nozzle 8 are installed on the same side of the constant volume air chamber 9 .

Preferably, the injection valve driver 15 includes a control unit to adjust and control the injection cycle and injection pulse width of the gas injection valve 6 .

The invention also discloses a method for measuring the gas injection quantity of a natural gas engine, which includes a constant volume method and a mass flow meter method. The constant volume method is realized by a constant volume measurement module, and the mass flow meter method is realized by a mass flow measurement module. The control of the second air valve in between can realize the sequential measurement of the constant volume method and the mass flow meter method. The specific implementation method is realized through the following steps:

(1) The gas is output from the gas cylinder and enters the first pipeline, after being decompressed by the pressure reducing valve and the first gas valve, it flows into the pressure stabilizing air chamber to stabilize the pressure;

(2) The gas stabilized by the pressure-stabilizing air chamber enters the gas injection valve through the pipeline, and the injection valve driver controls and adjusts the injection period and pulse width of the gas injection valve, so that the gas is injected into the constant-volume air chamber at a certain pressure ;

(3) Close the second gas valve, use the constant volume method to measure the gas injection amount, the pressure sensor and the temperature sensor monitor the pressure and temperature changes in the constant volume gas chamber, the data acquisition card collects the signals monitored by the pressure sensor and the temperature sensor, and sends the signal transmission to a computer for processing;

(4) Open the second gas valve, and use the mass flow meter method to measure the gas injection volume. The gas flows into the mass flow meter after passing through the constant volume gas chamber, and the mass flow meter measures the injection volume of the gas flowing through it.

The beneficial effects of the present invention are: the test device for measuring the gas injection quantity of a natural gas engine disclosed by the present invention includes a constant volume measurement module and a mass flow meter measurement module, and the second gas valve between the two modules controls the flow of gas, thereby It is realized that two sets of measurement methods are used to measure the gas injection quantity of the natural gas engine in the same system, and the two measurement results can be compared, which improves the measurement accuracy and reduces the measurement error.

Description of drawings

Fig. 1 is the structural representation of the natural gas engine gas law test device in the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

In conjunction with Fig. 1, the present invention discloses a test device for measuring the gas injection quantity of a natural gas engine, comprising a gas cylinder 1, a voltage stabilizing module, a control module, a measuring module and an information processing module; the stabilizing module includes a pressure reducing valve 2, a first Pipeline 3, first gas valve 4 and pressure-stabilizing gas chamber 5; control module includes gas injection valve 6, injection valve seat 7, nozzle pipe 8 and injection valve driver 15; measurement module includes constant volume measurement module and mass flow measurement module The constant volume measurement module includes a constant volume gas chamber 9, a pressure sensor 10, a temperature sensor 11 and a second air valve 12, and the mass flow module includes a second pipeline 13 and a mass flow meter 14; the information processing module includes a data acquisition card 16 and computer 17 .

The first pipeline 3 connects the gas cylinder 1 and the pressure-stabilizing gas chamber 5 , the pressure reducing valve 2 and the first gas valve 4 are installed on the first pipeline 3 , and the pressure reducing valve 2 is located between the first gas valve 4 and the gas cylinder 1 . The pressure reducing valve 2 can control and adjust the pressure of the gas coming out of the gas cylinder 1, and the first gas valve 4 can control the transmission of the gas. The gas flowing out of the pressure-stabilizing chamber 5 flows into the gas injection valve 6 , and the injection period and pulse width of the gas injection valve 6 are controlled and adjusted by the injection valve driver 12 . The gas injection valve 6 is fixed on the injection valve seat 7, and the connection mode is bolt connection. After the nozzle pipe 8 stretches out from the gas injection valve 6, it enters the constant volume gas chamber 9. The pressure sensor 10, the temperature sensor 11 and the nozzle 8 are located on the same side of the constant-volume air chamber 9, which can prevent the jet flow from directly impacting the pressure sensor, thereby affecting the measurement effect. After the data acquisition card 16 collects the signals of the temperature sensor 11 and the pressure sensor 10, the signals are handed over to the computer 17 for processing. When the second gas valve 12 is opened, the gas flowing out of the constant volume gas chamber 9 flows into the mass flow meter 14 after passing through the second pipeline 13 .

The invention also discloses a method for measuring the gas injection quantity of a natural gas engine, which includes a constant volume method and a mass flow meter method. The constant volume method is realized by a constant volume measurement module, and the mass flow meter method is realized by a mass flow measurement module. The control of the second air valve in between can realize the sequential measurement of the constant volume method and the mass flow meter method. The specific implementation method is realized through the following steps:

(1) The gas is output from the gas cylinder and enters the first pipeline, after being decompressed by the pressure reducing valve and the first gas valve, it flows into the pressure stabilizing air chamber to stabilize the pressure;

(2) The gas stabilized by the pressure-stabilizing air chamber enters the gas injection valve through the pipeline, and the injection valve driver controls and adjusts the injection period and pulse width of the gas injection valve, so that the gas is injected into the constant-volume air chamber at a certain pressure ;

(3) Close the second gas valve, use the constant volume method to measure the gas injection amount, the pressure sensor and the temperature sensor monitor the pressure and temperature changes in the constant volume gas chamber, the data acquisition card collects the signals monitored by the pressure sensor and the temperature sensor, and sends the signal transmission to a computer for processing;

(4) Open the second gas valve, and use the mass flow meter method to measure the gas injection volume. The gas flows into the mass flow meter after passing through the constant volume gas chamber, and the mass flow meter measures the injection volume of the gas flowing through it.

Among them, when the gas injection quantity is measured by the constant volume method, the second gas valve 12 is closed, and the gas is injected into the constant volume gas chamber 9 at a certain pressure, combined with the gas state equation Carry out derivation to calculate the injection volume. When the gas injection quantity is measured by the mass flow meter method, the second gas valve 12 is opened to allow the gas to flow out of the gas cylinder, pass through the constant volume gas chamber, and then flow into the mass flow meter.

Considering that the gas injection valve of a high-power engine may have leakage, the gas leakage mass during the closing stage of the gas injection valve during the test cycle needs to be removed during calculation. Among them, Δm is the jet quality of the injection valve once, P ₁ is the pressure before the injection in the constant volume air chamber 9, P ₂ is the pressure when the gas injection is completed and the pressure in the container reaches a stable level, f is the test period, and L is the injection valve Leakage rate, a is the jet duration.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. a kind of experimental rig measuring natural gas engine gas emitted dose, it is characterised in that：Including gas cylinder (1), voltage stabilizing mould Block, control module, measurement module and message processing module；

Voltage stabilizing module includes pressure reducing valve (2), first pipe (3), the first air valve (4) and voltage stabilizing gas chamber (5), and first pipe (3) is even Gas cylinder (1) and voltage stabilizing gas chamber (5) are connect, pressure reducing valve (2) is mounted on the first air valve (4) in first pipe (3), pressure reducing valve (2) peace Loaded between gas cylinder (1) and the first air valve (4)；

Control module includes fuel gas injection valve (6), injection valve base (7), jet pipe (8) and injection valve actuator (15), gas injection It penetrates valve (6) to be bolted on injection valve base (7), be connected respectively with voltage stabilizing gas chamber (5) and injection valve actuator (15) It connects, jet pipe (8) stretches out afterwards from fuel gas injection valve (6)；

Measurement module includes constant volume measurement module and mass flow measurement module, and constant volume measurement module includes constant volume gas chamber again (9), pressure sensor (10), temperature sensor (11) and the second air valve (12), mass flow module include second pipe again (13) and mass flowmenter (14) pressure sensor (10) and temperature sensor (11), constant volume gas, are installed on constant volume gas chamber (9) One end of room (9) is connected with jet pipe (8), and the other end is connected with second pipe (13), and second pipe is equipped with second on (13) Air valve (12)；

Message processing module includes data collecting card (16) and computer (17), and data collecting card (16) one end is connected with pressure biography Sensor (10) and temperature sensor (11), the other end are connected on computer (17), computer (17) also with injection valve actuator (15) it is connected.

2. a kind of experimental rig measuring natural gas engine gas emitted dose according to claim 1, it is characterised in that： Near the pressure reducing valve (2) is mounted at the gas outlet of gas cylinder (1).

3. a kind of experimental rig measuring natural gas engine gas emitted dose according to claim 1, it is characterised in that： Described jet pipe (8) sectional area is more than fuel gas injection valve (6) outlet stream sectional area.

4. a kind of experimental rig measuring natural gas engine gas emitted dose according to claim 1, it is characterised in that： The size of the constant volume gas chamber (9) can flexible modulation, can be calculated according to the size of the fuel gas injection valve (6) used.

5. a kind of experimental rig measuring natural gas engine gas emitted dose according to claim 1, it is characterised in that： Pressure sensor (10), temperature sensor (11) and the jet pipe (8) is installed on the same side of constant volume gas chamber (9).

6. a kind of experimental rig measuring natural gas engine gas emitted dose according to claim 1, it is characterised in that： The injection valve actuator (15) includes control unit, the injection cycle and injection pulse width of adjusting control fuel gas injection valve (6).

7. a kind of method measuring natural gas engine gas emitted dose, which is characterized in that including constant volume area method and mass flow Meter method, constant volume area method realize that mass flowmenter method is realized by mass flow measurement module, is passed through by constant volume measurement module Constant volume area method can be achieved for the control of second air valve of two intermodules and the priority of mass flowmenter method measures, concrete implementation side Formula is realized by following steps：

(1) gas exports from gas cylinder and enters first pipe, and voltage stabilizing gas chamber is flowed into after pressure reducing valve decompression and the first air valve Carry out voltage stabilizing；

(2) gas after voltage stabilizing gas chamber voltage stabilizing enters fuel gas injection valve by pipeline, and injection valve actuator is to fuel gas injection valve Injection cycle and jet pulsewidth controlled to adjust, to certain pressure spray gas into constant volume gas chamber；

(3) the second air valve is closed, fuel gas injection amount, pressure sensor and temperature sensor monitors constant volume are measured using constant volume area method The indoor pressure, temperature variation of gas, data collecting card collect pressure sensor and the signal of temperature sensor monitors, and will letter Number being transferred to computer is handled；

(4) the second air valve is opened, fuel gas injection amount is measured using mass flowmenter method, gas flows into quality stream after constant volume gas chamber Gauge, mass flowmenter carry out injection measurement to the combustion gas flowed through.