LDV(laser Doppler velocimetry) measurements were conducted at a total of four planes at 0.4 speed ratio. The speed ratio of 0.4 is 1600rpm of impeller and 633rpm of turbine speed. Even at the speed ratio 0.4, fluid flow at the gap region between the impeller and turbine and impeller exit was leaving the impeller and flowing up behind the turbine, and flows were affected by the turbine blade as it passed, negatively effecting converter efficiency. In the gap region, fluctuations make a clear sinusoidal trend unclear. The rise and fall of the flow rates in a broad sense, indicate a dependency based on the passage of the turbine blade in front of the impeller passage exit but a sinusoidal trend is not evident from this data.

LDV(laser Doppler velocimetry) measurements were conducted on the exit region of the impeller passage and the gap between the impeller and turbine blades under 0.8 speed ratio. The 0.8 speed ratio has an impeller speed of 2000rpm and a turbine speed of 1600rpm. A periodic variation of the mass flow rate is present in many of the measurements made. The frequency of this variation is the same as the frequency of the turbine blades passing the impeller passage exit. It is found that the instantaneous position of the turbine had effect on fluid flow inside the impeller passage and gap region. This study would aid in the construction of higher accuracy CFD models of this complex turbomachinery device.

The general auto transmission uses the torque converter that has a good vibration damping force by launching performance and damping effect as power transfer unit. The vehicle equipped with auto transmission uses Lock up clutch system to improve the fuel efficiency. The Lock up clutch system is the major factor of the devices that increase the torque from engine to transmission in specific condition and also consist of the damper springs to transfer the torque stably. Damper spring controls the vibration of power transfer units and improve the impression of riding and durability, by being damping function on change torque from engine. In addition, not only the appearance and performance, but also these sensitive qualities as like vibration and noise can also be main factor to buy a car. Recently, in order to absorb the low vibration caused by vehicle structure vibration, the Low-stiffness damper has been on the rise. The damper spring should be considered and designed, considering the engine characteristic and direct connect of lock up clutch due to the stiffness of the spring and hysteresis has a major effects to the damper characteristic. This study can be used for analyzing the major factors to effect the NVH characteristic by evaluating the damper’s hysteresis according to change of spring stiffness.

Because industrial Vehicles drive and work under heavy load condition, the gear ratio of transmission and the stall torque ratio of torque converter is high. Recently, to reduce the cost of vehicle, many people have interest in applying multi-phase torque converter to vehicle and reducing the gear step. In this study, the target performance of vehicle is analyzed and the performance matching of multi-phase torque converter is studied to equip torque converter to heavy duty folk lift vehicle.