Pressure measuring device comprising oil spraying nozzle with pressure chamber

Abstract

A pressure measuring device comprising an oil spraying nozzle with a pressure chamber comprises the oil spraying nozzle with the pressure chamber, wherein the oil spraying nozzle is fixedly connected with a fixing sleeve; a groove with a downward opening is formed in the fixing sleeve; the fixing sleeve is fixedly connected to the outer periphery of a connecting pressing sleeve in a sleeving manner; oil spraying space is reserved between the upper end surface of the connecting pressing sleeve and the end surface of the top of the groove of the fixing sleeve; a ball of the oil spraying nozzle penetrates in the fixing sleeve and extends into the oil spraying space; the ball and the matched surface at the upper end of the connecting pressing sleeve are sealed in a compaction manner; the ball is provided with an axial drainage hole; the connecting pressing sleeve is provided with a pressure conduction cavity; the pressure chamber is connected with the pressure conduction cavity through the axial drainage hole; the pressure sensor is arranged on the connecting pressing sleeve and is positioned below the pressure conduction cavity; and a plurality of oil drainage holes are uniformly distributed on the periphery of the fixing sleeve and are connected with the oil spraying space. The actual pressure of the pressure chamber can be measured under the actual working state. The pressure measuring device is accurate and reliable in measurement, simple in structure and convenient to assemble and disassemble.

Description

technical field [0001] The invention relates to the technical field of diesel engine fuel injector performance testing, in particular to a device for measuring the pressure of a pressure chamber in a nozzle of a hole-type fuel injector. Background technique [0002] The fuel injector is one of the important components in the fuel injection system of a diesel engine, which has an important influence on the performance and emission of the diesel engine. For the orifice injector, the injector is composed of a pair of precise parts, the needle valve and the needle valve body. Since the circulation flow rate after the needle valve is lifted must meet the requirements of the oil volume of the whole machine, the needle valve body Usually, the pressure chamber structure is adopted. When the oil pump is working, the high-pressure oil enters the pressure chamber of the fuel injector to generate a thrust, which overcomes the spring pre-tightening force and makes the needle valve rise, ...

AI Technical Summary

Problems solved by technology

Since the oil tank is closer to the pressure chamber and spray hole than the oil inlet, it is considered that the pressure of the oil tank can better reflect the actual injection pressure. However, there are still shortcomings in analyzing and studying the injection pressure by measuring the pressure of the oil tank: in the needle valve In the steady state of complete closure, the pressure of the fuel tank is basically the same as the pressure of the fuel inlet of the fuel injector, while the pressure of the pressure chamber of the fuel injector is basically zero. After the needle valve is opened, the high-pressure fuel can only pass through the throttle of the sealing ring. Into the pressure chamber, so the pressure of the pressure chamber has a process of rising sharply, and there will be a certain difference between the pressure of the oil tank and the pressure of the pressure chamber during the injection process, that is to say, although the oil tank is closer to the injection port than the oil inlet Nozzle pressure chamber, but the pressure of the oil tank cannot be completely equivalent to the pressure of the pressure chamber, and there are certain limitations in the study of injection pressure

On the other hand, Chinese patent CN 102192066 B discloses a method for measuring the effective flow cross-sectional area of ​​each hole of a diesel engine fuel injector. It is mentioned that a needle valve lift sensor is installed on the needle valve of the fuel injector. A small piezoelectric sensor can be installed at the pressure chamber, and a miniature piezoelectric sensor can be installed in the pressure chamber for measurement or a clip-on piezoelectric sensor can be developed by itself, which can be clamped on the cylinder above the nozzle pressure chamber for measurement, although the patent proposes that the pressure can be directly The piezoelectric sensor is installed in the chamber, but because the structural size of the pressure chamber is usually relatively small, the specific installation method, installation structure and corresponding measurement results of the sensor are not mentioned, and it measures the pressure above the pressure chamber (such as Sheng tank pressure), so the measured pressure is not the real pressure chamber pressure

Images