Detroit Diesel DDEC VI Application And Installation page 336

FEATURES
Figure 5-27 Progressive Shift Chart - Represents Default
An alternate use for the Progressive Shift option would be to encourage a driver (or force him/her)
into top gear. Normally this condition exists when the gearing selected at the time of order allows
a Vehicle Limit Speed to be reached in a gear lower than top gear. See see Figure 5-28.
5.22.2 LOW RANGE #1
The low range #1 area of operation is bound by a maximum vehicle speed, a maximum engine
speed and a maximum turn-off speed. In the first illustration (see see Figure 5-27) the default
values are 12 MPH (approximately 19.3 kmh), 1400 RPM and 1800 RPM, respectively. During
vehicle acceleration, when the vehicle speed is below selected maximum vehicle speed for range
#1, the maximum rate the engine can be accelerated is reduced to 33 RPM/s. During light
load operation, the driver will feel this and be encouraged to up-shift to regain his/her rate of
acceleration. If the engine continues to be operated above the low range #1 maximum speed, it
may eventually reach the low range #1 turn-off speed. When the low range #1 turn-off speed is
obtained, no additional increase in engine speed will be allowed. At this point, the transmission
must be up-shifted if the vehicle is to continue accelerating.
5.22.3 LOW RANGE #2
The low range #2 area of operation is bounded by a maximum speed (MPH), a maximum vehicle
speed and a maximum engine turn-off speed. In the first illustration (see see Figure 5-27) the
default values shown are 27 MPH (approximately 43.5 km/h), 1600 RPM and 1800 RPM,
respectively. (The lower vehicle speed boundary is the low range #1 maximum speed value.)
The engine acceleration rate for low range #2 is 25 RPM/sec.
5-124
All information subject to change without notice. (Rev. 01/07)
7SA827 0701 Copyright © 2007 DETROIT DIESEL CORPORATION