1
1
Dana torque converter: What are the output characteristics of a hydraulic torque converter?
Release date:
2022-09-05 17:20
Source:
Dana torque converter: What are the output characteristics of a hydraulic torque converter?
When a torque converter is used in conjunction with an engine, the relationship among the input speed MB, the mechanical transmission speed MT, the clutch speed K, and the turbine speed nT is referred to as the torque converter’s output characteristic. Different slip ratios of the hydraulic torque converter result in distinct output characteristics. So, for the Dana torque converter: what is the output characteristic of a hydraulic torque converter?
Dana torque converter: What are the output characteristics of a hydraulic torque converter?
1. To compare different through‑flow torque converters, assuming that their effective radius D, peak efficiency η*, and transmission ratio i* are all identical, the forward‑flow torque converter can achieve a higher turbine shaft speed. At a given transmission ratio, it delivers a greater drive speed, fundamentally enhancing both low‑speed and high‑speed operating efficiency. Moreover, the turbine shaft produces a larger output torque, thereby improving the overall traction performance of the machine.
2. Since the torque of the pump impeller decreases as the transmission ratio iTB increases, more torque can be delivered from the engine during startup. As engine speed rises, higher vehicle speeds can be achieved, and the efficiency curve of the output characteristics becomes broader. Therefore, employing a front‑through‑type hydraulic torque converter helps enhance both traction performance and acceleration capability.
3. The input characteristics of the torque converter describe the relationship between the input shaft torque MB and its rotational speed nB at various transmission ratios, expressed as iTB, MB = F NB. When the engine is directly connected to the pump impeller of the hydraulic torque converter, the torque produced by the torque converter constitutes the engine’s load; consequently, the engine’s effective output power ne and torque Me are equal to the pump impeller’s power NB and torque MB, respectively.
4. Based on the inherent characteristics of the torque converter, MB is determined by establishing the correspondence between iTB and MB. This allows us to obtain the relationship between the pump impeller’s torque and its rotational speed for any given iTB, expressed as MB = F(Nb). Consequently, the input characteristics of the torque converter operating in conjunction with the engine can be derived.
5. Gasoline engines exhibit significant torque variations, with an adaptation coefficient of approximately 1.25 to 1.45. Therefore, a hydraulic torque converter with a certain degree of positive throughput should be selected, enabling the engine to deliver high torque during startup and its full rated power under nominal operating conditions, thus ensuring good start-up performance and acceleration. For fluid‑type hydraulic torque converters, the MB value varies with iTB; MB represents a family of parabolic curves that pass through the origin of the input characteristic curve and traverse the entire torque converter.
6. When the torque converter is in the lock‑up mode, i.e., iTB = 0, there exists an engine operating point that corresponds to both high efficiency and coupling conditions of the torque converter. Consequently, the engine’s operating region is defined by the position of a parabola, within which specific fuel consumption is minimized.
7. If a non‑through‑flow torque converter is selected, the engine can operate only at a single operating point—either at maximum torque or at maximum power. Choosing the engine’s maximum‑torque point yields better launch and acceleration performance, but it prevents the engine from delivering its full power output, resulting in poorer high‑speed cruising performance.
Dana torque converter
Follow us English:
010-82370469
Beijing Express Trading Co., Ltd.
