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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.

Although not limited to, these installations are normally used on trucks considered as Medium Duty (Class 6 and 7), as well as Heavy Duty (Class 8).

Because of the intense focus on fuel economy and fuel emission standards, it has become imperative to optimize vehicle drivetrains. In light of this, component efficiencies have become an important factor in the drivetrain decision-making process. It has therefore become necessary to develop a universal standard to judge transmission efficiency. This SAE Recommended Practice specifies a test procedure which maps torque transmittal efficiency and parasitic losses for manual transmissions. The application of this document is intended for manual transmissions used in light (class 4) through heavy truck applications with both simple and compound ratio structures. This document is separated into two parts. The first compares input and output torque throughout a specified input speed range in order to determine the overall transmission efficiency. This test is used to evaluate all forward gears; testing in reverse is optional.

Because of the intense focus on fuel economy and fuel emission standards, it has become imperative to optimize vehicle drivetrains. In light of this, component efficiencies have become an important factor in the drivetrain decision-making process. It has therefore become necessary to develop a universal standard to judge transmission efficiency. This SAE Recommended Practice specifies a test procedure which maps torque transmittal efficiency and parasitic losses for manual transmissions. The application of this document is intended for manual transmissions used in light (class 4) through heavy truck applications with both simple and compound ratio structures. This document is separated into two parts. The first compares input and output torque throughout a specified input speed range in order to determine the overall transmission efficiency. This test is used to evaluate all forward gears; testing in reverse is optional.

Provide standard shift pattern guidelines for manual transmission shift controls in light, medium, and heavy trucks and buses.

Provide standard shift pattern guidelines for manual transmission shift controls in light, medium, and heavy trucks and buses.

Provide standard shift pattern guidelines for manual transmission shift controls in light, medium, and heavy trucks and buses.

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).

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).