SAE J2985:2019 pdf free

SAE J2985:2019 pdf free.Definition and Measurement of Transfer Case Speed-Dependent Parasitic Loss
In a longitudinal mounted drivetrain based vehicle, this term refers to the drive mechanism that distributes power to the front and rear axles. The transfer case may also contain torque management devices. E xternally the transfer case is mechanically connected to the transmission, which provides its input power, and to the front and rear axles via drive shafts, which distribute its output power (as shown schematically in Figure 1). Internally, the transfer case mechanically connects the front and rear outputs via chain or gears. Depending on the design, the transfer case may be electronically or manually shifted between two wheel drive (2WD) and all-wheel drive (AWD) modes or it may only have an AWD mode.
Transfer cases may be single or multi-speed depending on the design and application.A thermocouple is installed in the drain plug (as shown in Figure 3) of the UUT to record the temperature of the oil within the test unit. This temperature is used in conjunction with the AST to establish the temperature state of the UUT. (NOTE: Sump temperature is not included in the AST calculation/definition defined above in Section 3.3.)
The soak time is defined as the minimum amount of time the UUT must be maintained at target average skin temperature in order to achieve repeatable results. An example of the temperature profile for the temperatures included in the AST (defined above in Section 3.3) is shown below in Figure 6 (note that the offset in temperatures T1 and T5 represents standard measurement variation – measurement error, temperature distribution within the cold box, etc.一and is further justification for using an AST instead of individual temperatures). As noted in the figure, an initial (pre) soak of four (4) hours was used followed by a 45 minute soak; the soak requirements are further outlined in Section 4.3.1.2. Should the available cooling system not be capable of reaching an AST of -7 °C±1 °C within 4 hours, additional ‘pre-soak’ time will be required prior to the 45 min additional soak (at target temperature).SAE J2985 pdf free download.