This standard covers the dimensions of clearance envelopes for Regular and Heavy Duty Type Truck Transmission Power Take-Offs and is applicable to the chassis clearance required immediately adjacent to the power take-off openings on truck transmissions.
[In the report of the SAE Motor Truck Rating Committee on Ability Ratings published in the January 1940 issue of the SAE Journal, it was recommended that pounds per certified net brake horsepower delivered to the clutch or its equivalent be used as the index of the potential ability of a motor truck or combination. This report defined the term "certified net brake horsepower" in detail and recommended that certain data be provided to support the certification. The accompanying forms provide a method for the presentation of the data specified.]
This SAE Recommended Practice is intended as a guide toward standard practice but may be subject to frequent change to keep pace with experience and technical advances.
Although not limited to, these clutch requirements are normally used on trucks considered as Heavy Duty (Class 8). This SAE Information Report defines and discusses clutch and related component configurations which will become the subject of future SAE Recommended Practices to promote standardization of clutch installations and mounting dimensions for use with pull-type heavy-duty clutches.
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B).
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B).
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B).
The procedure covers the estimation of the total retardation capability available to a specific vehicle from: a Natural retardation (rolling resistance, aerodynamic drag, etc). b Engine drag c Engine, integral automatic transmission, driveline or trailer-axle retarders It assumes that foundation brakes are not used for maintaining speed on long mountain descents. Retardation is rated in terms of the maximum grades on which stable control speeds can be maintained for each gear over the range of highway speeds appropriate to that gear. For each gear, the calculation procedure determines maximum grades for at least four values of control speed ranging from the vehicle velocity corresponding to full load governed engine rpm, to the vehicle velocity corresponding to the engine rpm at minimum (idle) speed. In addition, the calculation procedure provides information on the total retarding power available for each gear.
The accessory components covered by this information report include: air brake compressors, alternators, air conditioning compressors, engine cooling fans and drives, and power steering pumps. The values show an estimate of the average power requirements of known duty cycles of these engine drive accessories.
This report is intended to provide the information to estimate the accessory load of a typical heavy truck or bus. The components covered include: air compressors, alternators, refrigerant compressors, engine cooling fans and power steering pumps. The values show an estimate of the average power requirements and duty cycles for these accessories. This report does not address loads required for engine operation. Required systems include those needed for engine performance such as fuel pumps and electronic control modules (ECM).