Gas filling control system and method of LNG double-gun gas filling machine

Abstract

The invention provides a gas filling control system and method of an LNG double-gun gas filling machine. The gas filling control system comprises two gas filling systems, wherein each gas filling system comprises a gas filling gun, a liquid phase pipeline, a gas return gun, a large circulation pipeline, a small circulation pipeline and an electronic meter controller; each liquid phase pipeline isprovided with a liquid phase valve and a liquid phase flow meter; each gas filling gun is connected with the downstream end of the corresponding liquid phase valve; the upstream end of each liquid phase flow meter is connected to a liquid inlet in parallel; the upstream end of each large circulation pipeline is an idle gas filling gun inserting opening; the upstream end of each small circulation pipeline is provided with a gas phase flow meter connected with the corresponding gas return gun, and the downstream end of each small circulation pipeline is connected with the corresponding large circulation pipeline; the downstream end of each large circulation pipeline is connected to the corresponding gas return opening in parallel; each liquid phase pipeline is positioned on the upstream portion of the corresponding liquid phase flow meter and connected with the corresponding large circulation pipeline through a gas return valve; each electronic meter controller is electrically connectedwith the corresponding liquid phase flow meter, the corresponding gas phase flow meter, the corresponding gas return valve and the corresponding liquid phase valve; and the two electronic meter controllers conduct signal transmission through a communication line. By means of the control method, the running states of the two gas filling systems are subjected to interaction control.

Description

technical field [0001] The invention relates to the technical field of liquefied natural gas for vehicles, in particular to a control method for an LNG double-lance filling machine. Background technique [0002] LNG (Liquefied Natural Gas), the English abbreviation for liquefied natural gas. It is a clean and efficient energy source, mainly composed of methane. LNG is a liquid obtained by cooling gaseous natural gas at normal pressure to -162°C. [0003] The LNG filling machine is a device used to fill liquefied natural gas into the gas storage cylinders of natural gas vehicles, and has the functions of metering and pricing. With the gradual increase in the number of natural gas vehicles, more and more gas stations have begun to use LNG double-gun gas dispensers. The basic control principle of the LNG dispenser is described in Appendix A of "GBT 36126-2018 Liquefied Natural Gas Dispenser for Automobiles". There are four conversion processes in the entire operation of the L...

AI Technical Summary

Problems solved by technology

When only one filling system of this design is used, since the other filling system is in an idle state, the return valve of the filling system in the idle state needs to be kept normally open, so that the pipeline of the filling machine The liquid in the tank does not hold pressure after being vaporized, but when one gas filling system is filled and the other gas filling system is idle, there is no coordination between the two gas filling systems, which will lead to serious diversion. The air port is sent to two air filling guns, which will seriously affect the filling efficiency

When using two gas filling systems to fill at the same time, when one of the gas filling systems is filled, it will turn into an idle state and the return valve will open, but because the pressure of the LNG storage tank is higher than the pressure of the LNG gas storage container of the car Much lower, thus causing a large amount of liquid to flow back into the LNG tank, causing the other filling system to quickly reduce the flow rate, automatically ending the filling early if it is not filled

In the prior art, although some manufacturers use throttle valves that can adjust the flow rate to solve this problem, it will greatly increase the cost of the gas dispenser

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