Electric fuel pump suitable for fuel containing alcohol

Abstract

The electric fuel oil pump suitable for fuel containing alcohol has a shell, an inner casing inside the shell to constitute together with the shell one cavity serving as the main fuel oil conveying flow channel, and a motor set inside the inner casing and with gap among its parts serving as the secondary fuel oil conveying flow channel. While over 80 % of the fuel oil is conveyed through the main fuel oil conveying flow channel, the rest flows through the secondary fuel oil conveying flow channel to lubricate and clean the inside parts and cool the rotor and the stator, so as to raise the work efficiency of the motor. There are one non-return valve set at fuel inlet hole inside the secondary fuel oil conveying flow channel and one conic friction pair at the lower bearing on the end of the vane wheel to further raise the operation reliability and safety.

Description

technical field [0001] The invention relates to an electric fuel pump used in electric fuel injection vehicles, in particular to an electric fuel pump suitable for transporting alcohol-containing fuel. Background technique [0002] The electric fuel pump is an essential heart component of an EFI car, and its main task is to supply the fuel system with enough fuel with a certain pressure. [0003] Generally, the electric fuel pump used in EFI vehicles is mainly composed of a casing, an electric motor and a pump body driven by the electric motor. Among them, the pump body is set at the lower part of the shell, and the pump body is provided with an oil inlet. When the motor is powered on, the pump body can be driven to work, and the fuel is sucked from the oil inlet and flows through the inside of the electric fuel pump, and then pressed through the oil outlet. supply to the fuel system. In the above structure, the check valve of the electric fuel pump is set at the oil outle...

AI Technical Summary

Problems solved by technology

In the above structure, the check valve of the electric fuel pump is set at the oil outlet, and the oil inlet is an open structure. For the structure with a brushed motor, it is believed that when the oil level in the fuel tank is below the critical point, the engine will Under the stopped working condition, at this time, there is no fuel below the motor check valve, and the entire motor forms a cavity, and the size of the cavity increases or decreases with the oil level of the fuel tank. The package, brushes, commutator, and lead wires exposed in the gas mixture are prone to cavitation. If the engine is started at this time, the movable contacts between the motor brushes and the commutator will generate sparks at the moment of power on and off. If It is the commonly used hydrocarbon-gasoline mixture. Because of its narrow combustion interface, the mixture that is too concentrated and too olefinic will not burn. Polar compounds, which form low-boiling azeotropes after mixing with gasoline hydrocarbons, especially in hot summer, cause the volatility of the entire fuel to be strongly enhanced, the vapor pressure is seriously increased, and the ignition interface is widened. At this time, when the engine is started under the condition that there is mixed gas in the cavity of the motor with low oil level, the dry friction between the motor brush and the movable contact of the commutator will generate electric sparks, which contain alcohol The mixed gas can easily cause deflagration when encountering sparks, causing danger

At the same time, alcohol-containing fuel is corrosive to a certain extent, and its corrosion to oil pump components will cause certain abnormal wear and tear, greatly shorten the service life, and make it scrapped prematurely

A large amount of fuel flowing between the rotor and the stator of the motor will form a large eddy current when passing through, and will form a shear flow when passing through the brushes of the brushed motor, and will generate large resistance, and its size varies with the flow pressure Changes and changes directly affect the efficiency of the motor, especially for alcohol-containing fuels. The vortex formed at high speed will increase the colloid of the fuel, especially for alcohol-containing fuels added with surfactants, which can also cause deterioration of fuel quality.

In addition, the above-mentioned fuel pump adopts only a straight-sided forming connection for the connection between the motor rotor and the impeller. Although this connection has the advantages of simple structure and convenient manufacture, the connection structure of unilateral positioning and matching is difficult when the rotor is running at high speed. At this time, only one point of the impeller hole is stressed, and the neutrality is poor, so not only the wear phenomenon is serious, but also the noise is relatively large.

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