| 12V190 diesel engines have dominant position in the sector of China's Oil field drilling power machines. The development of 12V190 natural gas drilling engines has a significant meaning both in changing the energy consumption method of China's drilling power machinery in the primary energy and in implementing the emission reduction in the drilling industry. Because the drilling operation is unique with absolutely high requirements in dynamic and economic performance, reliability, automation level and emission reduction, these bring a great challenge for developing 12V190 natural gas drilling engines. Comparing the three intake technologies of Pre-mix port injection, Electronic-Controlled Single-point gas injection (SPI) and Electronic-Controlled Multi-Point gas injection (MPI), it is found that the third technology (MPI) can offer the robust power for drilling operation, which is currently the very advanced although it has the great difficulty in research and development.This paper proposes a gas injection system that has been applied in 12V190EFI-MPI natural gas engines for drilling. Using the methods of theoretical analysis, simulation calculation in conjunction with tests, the researches of the injection structure and the control system has been closely and systemically carried out, building a foundation for the promotion and application of 12V190EFI-MPI natural gas engines.In this paper, these researches and achievements are presented in these aspects.1) Using the CFD analysis, obtain the conclusion of the numerical analysis on EFI-MPI gas injection mixture formation in the intake manifold, design the structures in single-tube injection, define and design the structures of the single-tube injection, twin-tube injection and venturi ring injection. The research and test found that the numerical analysis results agree with the results from tests and applications. For the in-serial intake port applied in the 12V190EFI-MPI engine, the twin-tube injection structure can achieve an optimal effect.2) Provide the basic structure and index of the gas injection control system, analyze and establish the relative control model and offer the control software frame and the key algorithm method. The application results show that the control system enables the drilling engines in response to variable transient load conditions achieving high economy benefit, high reliability and advanced automation and lower emissions.3) Apply the best control theory into the injection control system, providing the solution for trade off of engine dynamic, economy and emissions. The 12V190EFI-MPI control system on such control theory achieves the general and optimal control target4) Propose the concept of the minimized engine control system and introduce it into the practical injection systems, effectively ensuring engines to reliably output power. This concept offers a meaningful reference for researches of natural gas engines for drilling or other applications on high and reliable power.5) Use the modern professional PID algorithm in gas engine subsystems including the stable and transient AFR control system, the speed governing control system and the single cylinder correction control system. The 12V190EFI-MPI gas engine applied with Electronic-Controlled Multi-Point gas injection manifold has used the algorithm method, achieving the perfect transient AFR control, as a consequence, improving engine combustion effect and ensuring each cylinders to uniformly work.6) Finish the experimental research of the injection system of the 12V190EFI-MPI engine, and in detail describe the experiments and analysis methods that have been done to the dynamic engine performance, economic performance, in-cylinder combustion, paralleling and load sharing, emission, reliability and others.The results show that the gas injection system meets the demands of this engine in engineering application. |
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