Intake (manifold) tube vacuum suction type gaseous fuel supplying method and device

Abstract

The present invention provides a gaseous fuel supplying method and device which provides power for the flow of gas by utilizing a vacuum (negative pressure) generated in an intake manifold (or an intake pipe on an internal combustion engine without an intake manifold) during operation of an internal combustion engine by reasonably controlling the opening of a suction control valve so that the mixing ratio of gas and air reaches a value required by normal operation of the internal combustion engine. The device for supplying gas by the gas supplying method physically includes six basic parts: azero pressure valve, a suction control valve, an air metering sensor, an air-fuel ratio sensor and a control unit (ECU).

Description

technical field [0001] The invention relates to the field of combustion control, in particular to a gas fuel supply method and device for an internal combustion engine combustion device. Background technique [0002] At present, there are two gas fuel supply methods for internal combustion engines that use combustible gas as fuel: one is the method of supplying gas to the internal combustion engine based on the pressure of the supplied gas itself, and this method is currently the most widely used electronically controlled injection gas fuel Supply method, the premise of this method is that the gas itself already has a certain pressure, so the gas supply device is based on the technical basis of controlling the existing pressure of the gas supply gas to be released stably under a certain pressure; the other is based on the manufacture of external devices The method of air supply is achieved by the suction effect of the mixer. This method is the mixer suction gas fuel supply m...

AI Technical Summary

Problems solved by technology

[0006] The advantages of the electronically controlled injection gas fuel supply method are accurate gas supply control, high fuel combustion efficiency, and less waste, but its shortcomings are also very obvious. In summary, these shortcomings include: 1. The supply of gas fuel High air pressure requirements: because the solenoid valve requires a certain opening and reseating pressure, too low / too high pressure will cause the solenoid valve to fail to open or always open, so low-pressure gas supply gas fuels with lower supply pressure such as pipeline gas It cannot be used in this gas supply method, and when it is used for the gas fuel supply of the internal combustion engine of the automobile, when the ambient temperature is low (generally <10°C), it often causes difficulty in starting or cannot start at all; 2. The air intake of the internal combustion engine Interference: Due to the injection of high-pressure gas fuel into the intake port during intake, this gas fuel injected at high speed in a very short period of time will cause various hydrodynamic effects such as wind curtain effect and space occupation effect , these effects will cause great interference to the inflow of air, thereby affecting the intake air volume of the internal combustion engine, which in turn will cause a series of effects such as unstable working conditions, easy flameout, and power drop of the internal combustion engine; 3. It cannot be applied to small displacement Internal combustion engine: Practical experience shows that for an internal combustion engine with a smaller displacement, the impact of high-speed injection of the same amount of gaseous fuel on the intake air is more obvious. For internal combustion engines with a displacement below a certain value, because the fuel injected at a high speed is basically injected The moment it enters, it occupies the entire intake manifold (or intake pipe) and completely squeezes the air needed for combustion out of the intake pipe, so that the gas inhaled by the internal combustion engine is almost all gas, and there is almost no air. Such a gas internal combustion engine cannot burn Therefore, these internal combustion engines cannot use this method to supply air at all; 4. Low speed, gas fuel cannot be used when starting: due to low speed, the air flow rate entering the intake manifold (or intake pipe) is low when starting, at this time The injection of high-pressure gaseous fuel has a very obvious effect on the intake of air. Therefore, if the internal combustion engine only uses gas as fuel at this time, the working condition will be very unstable, and there will often be situations where flameout or starting is difficult. In order to overcome these The problem is that currently all internal combustion engines that use this method of air supply must be equipped with an auxiliary fuel system. This auxiliary system is responsible for maintaining the stable operation of the internal combustion engine at low temperature and low speed. Switch to the gas fuel supply system to provide gas fuel to the internal combustion engine. Obviously, this auxiliary system not only increases the manufacturing cost and complexity of the internal combustion engine, but also makes the gas internal combustion engine not worthy of its name, and fails to achieve the purpose of energy saving and environmental protection.

[0009] Although the mixer suction gas fuel supply method has the advantages of simple device, low cost, wide input gas fuel pressure range, low pressure gas source such as pipeline gas, and not affected by temperature in winter, its disadvantages are also very obvious. These disadvantages include: 1. Gas fuel cannot be used when the internal combustion engine starts and runs at a low speed, because when the internal combustion engine is just started or runs at a low speed, the air intake is small, and the negative pressure suction effect generated by the hydrodynamic effect is very small at this time. It is not enough to inhale enough gaseous fuel, so the internal combustion engine that uses this method to supply gaseous fuel also has an auxiliary fuel system. This auxiliary system works when the internal combustion engine starts and runs at a low speed. When the internal combustion engine starts to reach a certain speed, the inhaled air is relatively stable. Then switch to the gas supply system and stop working when the internal combustion engine is normally supplied with fuel; 2. The air-fuel ratio control is not accurate: due to the negative pressure generated according to the hydrodynamic effect and the amount of gas inhaled by the internal combustion engine is not a strict function relationship, and no correlation can be established between the magnitude of the negative pressure attraction effect produced by this hydrodynamic effect and other variables, therefore, the ratio between the gaseous fuel and air inhaled by the internal combustion engine using this gaseous fuel supply method has uncertainty This uncertainty makes this gas fuel internal combustion engine have problems such as unstable working conditions, large emissions, and easy flameout; 3. Interference with the intake air of the internal combustion engine: Since the mixer is actually a throttling component, this The throttling part will change the cross-sectional area of ​​the intake port and create resistance to the air flowing in it, and this resistance will reduce the air inhaled by the internal combustion engine, resulting in a decrease in the power of the internal combustion engine, etc.

[0010] To sum up, it can be seen that it is the defect of the gas supply method currently used by gas internal combustion engines that all current internal combustion engines known as gas internal combustion engines actually need to rely on the fuel system as an auxiliary fuel supply system, that is to say, there is actually no one at present. All gas-fired internal combustion engines in the true sense, all internal combustion engines that claim to use gas as fuel are actually internal combustion engines that use gas and fuel oil. Obviously, this kind of internal combustion engine that requires a fuel auxiliary system not only increases the manufacturing and operating costs of the internal combustion engine, but also cannot reflect The effect of gas internal combustion engines on environmental protection and energy saving is not difficult to understand why gas internal combustion engines have not been fully promoted in industries such as automobiles

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