CN210829531U

CN210829531U - Air supplement unit for improving dynamic response of natural gas engine

Info

Publication number: CN210829531U
Application number: CN201921015768.0U
Authority: CN
Inventors: 丁宇; 贲虹凯; 向拉; 崔海宁; 徐珂达
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2019-07-02
Filing date: 2019-07-02
Publication date: 2020-06-23
Anticipated expiration: 2029-07-02

Abstract

An object of the utility model is to provide an improve natural gas engine dynamic response's air supplement unit, including the LNG fluid reservoir, the vaporizer, the gas injection valve, the blender, the compressor, the turbine, the gas holder, the vaporizer is connected to the LNG fluid reservoir, the vaporizer passes through the stabiliser, gas injection valve is connected to the gas filter, the blender is connected to the gas injection valve, the compressor is coaxial with the turbine, the compressor passes through the intake duct and connects the intercooler, the intercooler passes through the air throttle and connects the blender, natural gas engine is connected to the blender, the turbine is connected to the natural gas engine blast pipe, the turbine communicates gas holder and atmosphere respectively through three-way solenoid valve, electric compressor and air supplement pipe are connected respectively to the gas holder, the intake. The utility model discloses after the load change of natural gas engine, can supply required air volume rapidly, promote dynamic response. Under the loading working condition, the dynamic response can be improved under the condition of meeting the air-fuel ratio operation condition.

Description

Air supplement unit for improving dynamic response of natural gas engine

Technical Field

The utility model relates to an engine device, specifically speaking are natural gas engine device.

Background

As emission regulations become more stringent, the use of conventional diesel engines in the marine transportation industry is becoming more challenging. To improve and protect the environment, many countries are beginning to research alternative fuels for conventional engines. Among them, natural gas is receiving wide attention because of its high heat generation, clean emission, large storage capacity, and the like.

The normal pressure ignition temperature of natural gas is about 600-650 ℃, which is far higher than that of diesel oil (about 280 ℃), and the natural gas is difficult to ignite and burn directly in a compression ignition mode, and the natural gas is generally ignited by the diesel oil or a spark plug. The combustion process in the cylinder is an Otto cycle, the working condition loading is limited by the instantaneous air-fuel ratio, and the phenomena of detonation and fire are easy to occur.

The natural gas engine has the defects of insufficient low-speed torque, poor loading performance and the like. Under the loading working condition, gas enters the cylinder to participate in combustion, and because the gas has compressibility in the exhaust pipe, the energy obtained by the turbine rotor after several working processes is continuously increased, but the air inlet pipe has a certain volume, and the supercharging pressure can only be gradually increased. The high-load loading is limited by knocking, the accurate air-fuel ratio needs to be controlled, and a large amount of fuel gas is quickly sprayed to cause the phenomenon that instantaneous mixed gas is too rich and the engine knocks, so that the dynamic response is poor, and the time for the torque to transit to a stable working condition is long.

Disclosure of Invention

An object of the utility model is to provide an overcome the air supplement unit of natural gas engine dynamic response of improving of defect such as natural gas engine dynamic response difference.

The purpose of the utility model is realized like this:

the utility model relates to an improve natural gas engine dynamic response's air supplement unit, characterized by: the LNG tank is connected with the vaporizer, the vaporizer is connected with the gas injection valve through a voltage stabilizer and a gas filter, the gas injection valve is connected with the mixer, the gas compressor is coaxial with the turbine, the gas compressor is connected with the intercooler through an air inlet channel, the intercooler is connected with the mixer through a throttle valve, the mixer is connected with a natural gas engine, an exhaust pipe of the natural gas engine is connected with the turbine, the turbine is respectively communicated with the air storage tank and the atmosphere through a three-way electromagnetic valve, the air storage tank is respectively connected with an electric compressor and an air supplement pipe, and the air supplement pipe is connected with the air inlet channel.

The utility model relates to an improve natural gas engine dynamic response's air supplement unit can also include:

1. the air supply pipe is connected with an outlet pipe of the air compressor through a three-way mixing valve, a first one-way valve is installed on the air supply pipe, a second one-way valve is installed between the air storage tank and a three-way electromagnetic valve, and the ECU is respectively connected with a natural gas engine, a throttle valve, an electric compressor and a clock.

The utility model has the advantages that:

1. the required air quantity can be quickly supplemented after the load of the natural gas engine is changed, and the dynamic response is improved.

2. Under the loading working condition, the air tank supplies air to the mixer to ensure that the fuel gas injection valve can inject a large amount of fuel gas, and the dynamic response is improved under the condition of meeting the air-fuel ratio operation condition.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Detailed Description

The invention will be described in more detail below by way of example with reference to the accompanying drawings:

with reference to fig. 1, the utility model relates to an improve air supplement unit of natural gas engine dynamic response, including LNG fluid reservoir 1, vaporizer 2, stabiliser 3, gas filter 4, gas injection valve 5, compressor 6, mixing valve 7, intercooler 8, throttle 9, blender 10, check valve 11, booster 12, solenoid valve 13, check valve 14, gas holder 15, electric compressor 16, natural gas engine 17, bell 18, ECU 19.

An air supplementing pipe is connected to an air inlet pipe of an intercooler 8 of the device and is controlled by an ECU (electronic control unit).

When the engine load increases, the operation state change signal is generated in the clock 18, and then the ECU19 controls the throttle opening and controls the gas injection valve 5 and the electromagnetic valve 11 to control the air-fuel ratio to be constant.

When the load of the engine is reduced, the ECU controls the opening of the throttle valve to be reduced, the electromagnetic valve 13 is opened while the waste gas bypass valve is opened, the energy of the turbine is reduced, meanwhile, partial waste gas enters the gas storage tank, and therefore the purposes of supplementing gas and storing and reducing the loss of escaping natural gas in the ventilation process are achieved.

Liquefied natural gas is discharged from the LNG tank 1, sequentially enters the vaporizer 2 through a pipeline to be heated and vaporized, is filtered by the gas filter 4 after being stabilized by the pressure stabilizing tank 3, is controlled by the gas injection valve 5 to enter the mixer 10 to be mixed with pressurized air, and finally enters the cylinder 17 of the natural gas engine to be combusted. The flow rate of the natural gas injected from the gas injection valve 5 is controlled by the ECU19 according to the engine operating condition and the amount of air taken into the cylinder.

The ECU19 is a miniaturized computer management center that takes signal (data) acquisition as input, performs calculation processing, analysis and judgment, decides a countermeasure, and then issues a control command to instruct an actuator to operate as output.

After being pressurized by the compressor 6, the air enters the intercooler 8 to reduce the temperature of the pressurized air, then enters the mixer 10 through the throttle valve 9 to be mixed with vaporized natural gas, and finally enters the cylinder of the natural gas engine 17 to be combusted.

The air storage tank 15 maintains a constant pressure of 2-3 bar, and when the pressure of the air storage tank 15 is insufficient, the ECU19 controls the electric compressor to input compressed air into the air storage tank 15.

At steady state conditions, the turbocharger on the natural gas engine 17 can provide sufficient air flow. Under the low-load loading working condition, the proportion of gas and air entering the air cylinder does not accord with the operation standard of a natural gas engine due to the pressurization delay of the air compressor 6, so that the mixing valve 7 is started to enable the air supplementing device to supplement air. High-pressure gas in the gas storage tank passes through the one-way valve 11 and the mixing valve 7 and enters the intercooler 8 together with the pressurized air. When the ECU19 receives a change signal of the clock 18, the opening of the throttle valve 9 is controlled to increase, and meanwhile, the air replenishing device is started to replenish air. Air in the air storage tank 15 enters the air inlet channel through the one-way valve 11 and the mixing valve 7 through the air supply channel, and the air inlet channel is positioned behind the air compressor 6 and in front of the intercooler 8. And the ECU adjusts the opening of the throttle valve and the air supply flow according to the running parameters fed back by the engine.

When the load is high, the natural gas engine is limited by the instantaneous excess air coefficient, and the air-fuel ratio needs to be strictly controlled. When the clock sends a loading signal, the gas injection valve 5 increases the gas injection amount. And simultaneously, opening the air supplementing channel to enable air to enter the air supplementing channel. The ECU19 calculates the air-fuel ratio based on an oxygen sensor at the exhaust pipe to coordinate the make-up air pressure and flow.

When the waste gas bypass valve needs to be opened during high-load stable operation, the electromagnetic valve 13 is opened, so that waste gas enters the gas storage tank 15 through the one-way valve 14 and is mixed with compressed air. Because the waste gas contains natural gas escaping in the ventilation process, the natural gas can also be mixed with the air in the air storage tank 15 and enter the cylinder together to participate in combustion during air supplement. When the air content in the air storage tank 15 is kept above 80% and below 80%, the electromagnetic valve 13 is controlled to discharge the waste gas into the atmosphere.

The pressure in the air supply channel is less than the back pressure of the compressor so as to prevent the compressor from being damaged

When the engine load is changed by pushing the bell 18, the ECU19 controls the opening of the throttle valve 9 and controls the air reservoir 15 to supply air to the intake pipe according to the engine state.

When the ECU19 receives a clock loading signal, the air storage tank 15 is controlled by the electronic control unit to supply air to the air inlet pipe, and after the loading process is finished and the working condition is stable, the electromagnetic valve 11 is closed to stop supplying air.

When the working condition is stable, the electromagnetic valve 11 at the air supply pipe is closed, the electric compressor 16 is started to supply air to the air storage tank 15, and the pressure in the air supply tank 15 is stabilized at 2-3 bar.

When the waste gas bypass valve needs to be opened in the stable operation under the high-load working condition, the ECU controls the electromagnetic valve 13 to enable part of waste gas to enter the gas storage tank. When supplementing the gas, the natural gas escaping from the ventilation process may also participate in the combustion.

The electromagnetic valve 13 is controlled by the ECU, and stops when the concentration of the tail gas in the gas storage tank reaches a certain value, so that the content of the air in the gas storage tank is maintained. Allowing the exhaust gas to escape into the atmosphere.

Claims

1. The utility model provides an improve air supplement unit of natural gas engine dynamic response which characterized by: the LNG tank is connected with the vaporizer, the vaporizer is connected with the gas injection valve through a voltage stabilizer and a gas filter, the gas injection valve is connected with the mixer, the gas compressor is coaxial with the turbine, the gas compressor is connected with the intercooler through an air inlet channel, the intercooler is connected with the mixer through a throttle valve, the mixer is connected with a natural gas engine, an exhaust pipe of the natural gas engine is connected with the turbine, the turbine is respectively communicated with the air storage tank and the atmosphere through a three-way electromagnetic valve, the air storage tank is respectively connected with an electric compressor and an air supplement pipe, and the air supplement pipe is connected with the air inlet channel.

2. The gas supplementing device for improving the dynamic response of the natural gas engine as claimed in claim 1, wherein: the air supply pipe is connected with an outlet pipe of the air compressor through a three-way mixing valve, a first one-way valve is installed on the air supply pipe, a second one-way valve is installed between the air storage tank and a three-way electromagnetic valve, and the ECU is respectively connected with a natural gas engine, a throttle valve, an electric compressor and a clock.