A Study on the Balancing of the Three-Cylinder Engine With Balance Shaft

Document Number: 2000-01-0601

Date Published: March 2000

Author(s):
Kwon-Hee Suh - Kia Motors Corp.
Yoon-Ki Lee - Chonnam National Univ.
Hi-Seak Yoon - Chonnam National Univ.

Abstract:
For the three-cylinder engine whose crankshaft has a phase of 120 degrees, the total sum of unbalanced inertia forces occurring in each cylinder will be counterbalanced among the three cylinders. However, parts of inertia forces generated at the No.1 and No.3 cylinders will cause a primary moment about the No.2 cylinder. In order to eliminate this out-of-balance moment, a single balance shaft has been attached to the cylinder block so that engine durability and ride comfort may be further improved. Accordingly, the forced vibration analysis of the three-cylinder engine must be implemented to meet the required targets at an early design stage. In this paper, a method to reduce noise and vibration in the 800 cc, three-cylinder LPG engine is suggested using the multibody dynamics simulation. The static and dynamic balances of the three- cylinder engine are investigated analytically. A multibody dynamic model of the three-cylinder engine is developed where the inertia properties of the connecting rod, crankshaft, and balance shaft are extracted from their FE- models. The combustion pressures within the No.1 cylinder in three operating conditions (1500 rpm-full load, 4000 rpm-full load, and 7000 rpm-no load) are measured from the actual tests to excite the engine. The vibration velocities at the three engine mounts with and without the balance shaft are evaluated through the real-time vibration analysis. Obviously, it is shown that the vibrations of the three-cylinder engine with the balance shaft are reduced to an acceptable level.

File Size: 206K
Product Status: In Stock

See other papers presented at SAE 2000 World Congress, March 2000, Detroit, MI, USA, Session: Powertrain System NVH (Part C)

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