Design And Research Of Diesel Engine Power Field Test System

Diesel engine is the power heart of oil drilling rig.Its working status directly affects the safety and reliability of oil drilling rig.As an important index for evaluating the power performance of diesel engines,the power needs to be measured in the process of diesel engine maintenance and repair.The internal structure of diesel engine is complex.When working,the cylinder body has high temperature,high pressure and intense vibration.After a long-time operation,the power performance of diesel will gradually decrease,resulting in a phenomenon of insufficient power.If the power of diesel drops too much,it will bring more security risks,and it is necessary to stop working immediately and overhaul the diesel engine.Therefore,in order to ensure the safe production of drilling workover rigs,it is very necessary to study the power test of diesel engine.However,the promotion and application of diesel engine power test technology in the production site face two major difficulties:First,the existing mature power test equipment could not be directly applied to the job site;Second,due to the limited working environment of diesel in the field,the development of high-precision small power test instruments is very difficult.Therefore,according to the technical requirements of diesel engine power field testing,the key technology research and system development of diesel engine power test were carried out,and the test and result analysis were carried out.The results of the study are as follows:(1)Based on the diesel engine no-load power measurement technology,according to the deficiencies of the existing test methods for equivalent inertia of diesel engines.A new method for measuring the equivalent inertia of a diesel engine based on the "backward drag method" was proposed.Through the analysis of the basic principle of the test method,the average power calculation model of the diesel engine was established,and the data processing method of the instantaneous speed curve is obtained.(2)Combining with the characteristics of and the portability of the layout and the test system in production field,a diesel inertial moment testing system and a diesel engine instantaneous speed signal acquisition system based on the "backward drag method" were developed.And the equivalent moment of inertia test under various conditions was carried out by using the diesel engine equivalent moment of inertia test system.Then,a data processing algorithm based on the moving average principle was established.Besides,the diesel engine no-load power test was performed by using the diesel engine’s instantaneous speed signal acquisition system,a linear fitting algorithm based on least-squares method was obtained.(3)The data processing software of the equivalent inertial inertia of diesel engine was programmed with Visual C++ language,and the efficient calculation of the equivalent moment of inertia test was realized.And the influence on the stability of the test results of six factors,including the sampling frequency,acceleration range et al.were obtained by analyzing the calculated values of the equivalent moments of inertia.Then,through comparison of the theoretical calculation and test value for the inertial inertia of the crankshaft of the diesel engine,the accuracy of the equivalent rotation inertia testing method of the diesel engine was verified;Based on this test method,the average power of the diesel engine was obtained by linearly fitting and calculating the average power of the test data of the no-load power test of the diesel engine.Finally,the bench test of the diesel engine power was carried out,and the the feasibility and correctness of power test method was verified by comparing the test value of the bench test power with power test value.