US: Heavy-duty: HHDDT

US: Heavy-duty: HHDDT

Overview

The Heavy Heavy-Duty Diesel Truck (HHDDT) schedule is a chassis dynamometer test developed by the California Air Resources Board in collaboration with West Virginia University.

Contents

 

Categories

United States Test cycles

Description

The test consists of four speed-time modes, including idle, creep, transient and (high speed) cruise.

 

 

Hhddt-creep.png

HHDDT Creep Mode

Hhddt-trans.png

HHDDT Transient Mode

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HHDDT Cruise Mode

 

Selected statistics for the particular HHDDT modes are compared with those for the UDDS cycle in the following table.

 

Statistics for HHDDT And UDDS Schedules
Parameter HHDDT Creep HHDDT Transient HHDDT Cruise UDDS
Duration, s 253 668 2083 1063
Distance, mi 0.124 2.85 23.1 5.55
Average Speed, mph 1.77 15.4 39.9 18.8
Stops/Mile 24.17 1.8 0.26 2.52
Max. Speed, mph 8.24 47.5 59.3 58
Max. Acceleration, mph/s 2.3 3.0 2.3 4.4
Max. Deceleration, mph/s -2.53 -2.8 -2.5 -4.6
Total KE, mph2 3.66 207.6 1036 373.4
Percent Idle 42.29 16.3 8.0 33.4

 

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