How much do you know about powder metallurgy parts in oil pumps? Currently, engine oil pumps and automatic transmission oil pumps mostly use quantitative oil pumps. Quantitative oil pumps are generally external gear pumps, internal gear pumps, or internal gear pumps. Various structures are made of powder metallurgy.
Quantitative oil pump, the size of its oil output increases with the increase of engine speed, and the relationship between the two is linear. In order to ensure the minimum oil output at low speeds and the minimum oil pressure at high speeds, the oil pump will be designed to be larger, which places higher requirements on the layout of the engine compartment. At the same time, when the engine is at a high speed, excess lubricating oil will return from the oil circuit, resulting in increased engine power consumption. The variable oil pump will adjust the oil pressure and oil volume according to the working conditions of the engine, so as to achieve the purpose of fuel saving.
Research data shows that in engines with fixed displacement oil pumps, when the speed is greater than 2500r/min, about 50% of the powered oil flows directly to the oil pump inlet cavity or oil pan through the pressure relief valve, bringing energy The use of variable oil pumps instead of quantitative oil pumps can generally save 2% to 5% of fuel, and reduce CO2 emissions by 1% to 2%.
Variable displacement pumps generally have external gear pumps, vane pumps and sliding vane pumps. For external gear pumps such as Volkswagen’s EA888 project, one of the gear’s axial position is fixed, and the other gear’s axial position is adjusted with pressure. When idling, both gears are fully meshed. When the speed increases, the pressure of the oil pump also changes. As it rises, the meshing part of the gear becomes shorter after the spring is compressed, so that the flow of the oil pump can be adjusted at any time. The gears of this type of pump are manufactured by powder metallurgy.
The vane variable pump (see Figure 4) is mainly composed of a stator, a rotor and a blade, and the stator and the rotor are both powder metallurgy parts. The working principle of the vane variable pump is to adjust the eccentricity by pressure to adjust the flow rate. The principle of the sliding vane variable pump is basically the same as that of the vane variable pump, and the flow is adjusted by adjusting the eccentricity. The sliding piece is a steel piece, the middle sleeve is connected with the sliding piece, the outside is the sliding sleeve, and the middle is the rotor. These three pieces are all powder metallurgy parts.