System and method for controlling uniformity of gas injection amount of natural gas engines for vehicles

Abstract

The invention discloses a gas injection quantity uniformity control system and control method of a natural gas engine for a vehicle, which includes an ECU, a natural gas supply bottle and an injection system equal to the number of cylinders of the engine, and each injection system includes at least one gas rail and The injection unit connected to the ECU has a metering unit between the air inlet of each air rail and the high-pressure solenoid valve. Each metering unit includes a millisecond-level rotameter connected to the ECU. The millisecond-level The rotameter can measure the transient flow of natural gas at the millisecond level. After adopting the above-mentioned structure and method, the uniformity of natural gas injection volume can be significantly improved, the control problem caused by the consistency of nozzles in the natural gas engine control system can be solved, the state of the injection system can be monitored in real time, and the stable torque output of the natural gas engine can be maintained, which is beneficial The development of in-cylinder direct injection lean-burn natural gas engine is applicable to natural gas engines of various displacements.

Description

technical field [0001] The invention relates to a gas injection device and injection method of an electronically controlled injection natural gas engine, in particular to a control system and a control method for the uniformity of gas injection quantity of a natural gas engine for a vehicle. Background technique [0002] The existing heavy-duty natural gas engine in China is refitted from a diesel engine. The electronically controlled injection system of the engine is mainly composed of a single-point injection system of the inlet mixer type. This injection system is similar to the carburetor injection system of a gasoline engine. The air inlet is fully mixed, and two sets of gas rails plus one set (up to a dozen) of injectors for gasoline engines are used to measure the amount of natural gas injected. This metering and natural gas-air mixing method is likely to cause longer gas propagation delay channels and a greater impact on the air charge coefficient, large engine cycle...

AI Technical Summary

Problems solved by technology

When the solenoid valve injection is used for natural gas injection, although the injection pulse width can be controlled, natural gas is sensitive to the variable aperture in the solenoid valve nozzle, and is limited by factors such as nozzle processing consistency and gas throttling pressure fluctuations, and the flow rate of the fluid cannot be controlled. Ensure consistency, resulting in poor flow consistency and poor control of injection uniformity

[0007] In addition, at present, there is no relevant work at home and abroad on the high-response dynamic flow measurement of the small flow rate of the natural gas injection system for vehicles.

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