Functioning Algorithm Of Pilot Lamp To Indicate Operation Of Heating Plugs - Belarus 922.6 Operator's Manual

2.7.2 Functioning algorithm of pilot lamp to indicate operation of heating plugs

As a means of start facilitation, heating plugs (HP) are used in tractors "BELARUS –
922.6" which are mounted in the cylinder unit head. For individual control of heating plug
operation modes and indication of their operation, a heating plug controller unit is used.
The operating principle of the, controlled by the heating plug controller is the following:
The heating plugs are not activated, if the engine temperature exceeds +5°C. In this
case heating plug pilot lamp 4 (Figure 2.7.1) lights up for up to 2 sec. or does not light up at
all.
If the engine temperature is below +5°C, the heating plugs are activated automatical-
ly as the key of starter and instrument switch is turned from position "0" (off) into position "I"
(Instruments on). In this case heating plug pilot lamp 4 lights up in the pilot lamp unit of the
dashboard. The heating plug operation time depends on the engine temperature according
to table 2.7.1. It is necessary to start the engine as lamp 4 goes out after the time specified
in table 2.7.1 is up. After the engine start-up, the heating plugs remain activated for some
time, then they go out. The heating plug operation time after the engine start-up depends on
the engine temperature at the moment of the heating plug activation. (see table 2.7.1).
If within (10 ± 1) sec. after lamp 4 goes out, the engine is not started, the heating
plugs will cut out.
The heating plug operation algorithm has the following emergency modes:
- as the key of starter and instrument switch is turned from position "0" (Off) into posi-
tion "I" (Instruments on) the heating plug pilot lamp starts to flash continuously with ≈ 2 Hz
frequency. This means that there is a failure in the heating plug operation – all heating plugs
are closed-circuit or their connection is disturbed (disconnected from the heating plug con-
trol unit), the heating plug control unit is not powered or the power supply wire is damaged.
In case of short circuit, the heating plug control unit cuts power supply to the heating plugs.
- after the engine start-up the heating plug pilot lamp 4 starts flashing for one minute
with 3 sec. of cycle duration and 0,25 sec. of flash duration. The number of flashes can be
different. The start-up procedure runs in an ordinary way. This means that one or more (but
not all) heating plugs are faulty. The number of flashes within one cycle equals to the num-
ber of faulty heating plugs;
If the specified failure is not eliminated, it may be difficult to start the engine at low
temperature.
- during the pre-start heating before the engine start-up, pilot lamp 4 flashes with 1
Hz frequency. This points at short-circuit of the heating plug temperature sensor, or break-
age in the heating plug temperature sensor circuit (in case of a controller with an external
sensor), or sensor failure. In this case the time of engine pre-start heating as well as plug
heating after engine start-up is set as at the engine temperature of minus 20 ° C according
to Table 2.7.1, with the heating plug actuation delay time within three seconds when the key
of starter and instrument switch is turned from position "0" (Off) into position "I" (Instruments
on).
TRACTOR OPERATION IS FORBIDDEN UNTIL FAILURES OF THE HEATING
PLUG SYSTEM ARE DETECTED AND ELIMINATED. OTHERWISE IT MAY LEAD TO
DISCHARGE OF ACCUMULATOR BATTERIES!
Table 2.7.1. – Heating plug operation time depending on engine temperature
Engine temperature, °С Time of engine pre-start
Above + 5
from + 5 to 0
from 0 to -10
from -10 to -15
from -15 to -20
from -20 to -25
under -25
heating, sec., at least
0
15
20
25
35
42
50
30
922.6-0000010 OM
Time of heating after engine
start-up, sec., at least
0
25
50
75
100
125
150