Performance Analysis On The Second Order Balance Mechanism Of The In-line Four-cylinder Diesel Engine

The in-line four-cylinder diesel engine is more and more widely used because of its compact size and obvious advantage of matching. However, due to its specialty of machinery, the second order reciprocating inertial force of this kind of engine are added together in its four cylinders. It induces low frequency vibration of the in-line four-cylinder diesel engine and brings disadvantageous effect on this kind of engine. Assembling second order balance mechanism on the engine in order to reduce the vibration caused by second order reciprocating inertial force is becoming a developmental tendency.The characteristic of the force induced vibration in in-line four-cylinder diesel engine was analyzed. The principle of the design for second order balance mechanism was illuminated. A kind of second order balance mechanism installed on DEUTZ 226B in-line four-cylinder diesel engine was designed. Due to the machinery characteristic of this diesel engine, non full-length and A style balance mechanism served as a fitting manufacture of this kind of engine was chosen. The second balance mechanism designed in this paper is compact, and it can balance 100% of second order reciprocating inertial force of DEUTZ 226B in-line four-cylinder diesel engine, but it doesn't balance the second order lateral torque of the engine.The finite element model of the mechanism shaft of the second order balance mechanism was built. In virtue of the analytical software ANSYS, the stress and strain of the mechanism shaft of the second order balance mechanism was analyzed. Thestress in dangerous section was 0.561×10~8 Pa under the work state of 10000 r/min.The result reveals that the mechanism shaft is safe sufficiently.Dynamic lubrication was selected in the second order balance mechanism. The work state of lubrication of the balance mechanism was predigested, and the steady-state isothermal EHL model in line contacts of the balance mechanism was built. This model was deal with. The EHL numerical solution calculating program is made up by using latest numeric analyzing software MATLAB7.0, and by which the pressure distribution and film thickness distribution of the lubrication system of this balance mechanism are obtained.Different work states were selected, the states of lubrication system was analyzed. The result revealed that thinnest film thick became larger quickly with the rotate speed's becoming rapid. In the range of 0～3000 r/min. The thinnest film thick became largest in the range of 3000～4000 r/min, and then it became thinner slowly, and it became steady finally when the speed got to 10000 r/min. The thinnest film thick maintained 10—30 μm in the range of work rotate speed, and the lubrication system could achieve sufficient film lubrication. The result revealed that the disadvantageous state of lubrication appeared in the range of slow rotate speed; the state of lubrication became better quickly with the rotate speed's becoming rapid; The best state of lubrication appeared in the range of 3000 ～ 4000 r/min; The state of lubrication changed faintly with the rotate speed's becoming rapid, but it maintained in a steady and favorable state.