Torque Limitation For Overheat Protection Mode - Yanmar BY Series Service Manual

Engine Faults and Torque Limitations
12/05
Torque Reduction Chart Based on Intake Air Temperature
The intake air temperature will limit the torque at 3000 rpm if the air temperature is increasing.
Engine speed
Torque
Engine
100% (normal operation)
90%
80%
Engine
100% (normal operation)
90%
80%
Torque Limitation for Overheat
Protection Mode
In the case of this mode, there are two possible
situations:
If an electronic fault occurs, it will be displayed on
the display-alarm and a P-Code is saved in the
system. These codes can be read with a diagnostic
tester. A substitute value (fixed value until fault
disappears) is activated (coolant temp=110,
fuel temp=90) and a torque reduction occurs. In this
case, the coolant temperature is also limited by the
torque limit which is described in Torque Limitation
for Failed Sensors Mode on page 13-3. The
substitute value of the fuel temperature is fixed at
90°C (194°F)and that sets a limitation of
approximately 75% from the maximum torque
(Figure 13-1).
Figure 13-1
Figure 13-1
BY Service Manual
2000 rpm
Intake air
Torque [N·m]
temperature [°C]
4BY2-150
295 30-50
265 60-90
240 100-130
6BY2-220
450 30-50
405 60-90
360 100-130
If the coolant temperature is over 108°C (226°F),
an audible alarm sounds and engine overheat is
displayed on the instrument panel display. At 120°C
(248°F) the torque limitation is 30% (Figure 13-2).
If the fuel temperature is too high (over 90°C
[194°F]), this limitation is also active for the
overheat prevention as shown in Figure 13-1. From
100 to 140°C (212 to 284°F) the torque limit is
about 40% of the maximum torque. In this case,
there is not an alarm on the instrument panel
display. In both cases, no P-Code appears.
Figure 13-2
© 2009 Yanmar Marine International
TROUBLESHOOTING
2000 rpm
Intake air
Torque [N·m]
temperature [°C]
4BY2-180
315 30-50
285 60-90
250 100-130
6BY2-260
450 30-50
405 60-90
360 100-130
Figure 13-2
13-5