|
Additional heater functional sequence
Additional heater functional sequence
Notes:
-
◆ The additional heater is cut in by the engine control unit and can be switched off by pressing the "Econ" button on the -E87 AC operating and display unit or on the heater controls, if additional heating output is not desired.
-
◆ A -V55 recirculating pump is currently not installed, given that the additional heater can only be switched on with the engine running.
-
◆ Depending on the amount of heat generated by the engine, supplied by the AC heat exchangers, and generated by the heater, the heater unit may remain in the full load, part load or control interval operating statuses for a lengthy period .
-
◆ As the additional heater only operates when the engine is running, it is scarcely perceptible in heating mode. Run-on of the heater can be heard if the engine is switched off, if it was operating when the engine was switched off.
-
◆ The temperature sensor (for the coolant temperature in the heater) is permanently installed (in the heater control unit -J162) and can neither be checked nor removed.
-
◆ The glow plug with flame detector -Q8 is actuated with a regulated voltage to prevent overheating.
-
◆ To ensure that combustion in the heater is always in the optimum range, the metering pump -V54 (clock frequency) and combustion air blower -V6 (voltage) are regulated over the entire sequence.
-
◆ The temperatures given in the functional sequence and function chart are approximate.
-
◆ Contact 3 of the 6-pin connector on the additional heater is connected to the engine control unit on vehicles with diesel engines.
=> Relevant Workshop Manual, Diesel Direct Injection and Glow Plug System; Repair group 01
=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder
-
◆ If in "diesel" type additional heaters, contact 3 in connector B is connected to earth, the additional heater is switched on.
-
◆ If the additional heater does not switch on for vehicles with diesel engine, check the adaption in adaption channel "10" for additional heaters with a control unit as of software version "D50"=> Page01-88
-
◆ If the heater has been locked due to a malfunction (e.g. misfire or overheating) (completely switched off) it cannot be switched on again until the fault memory has been read out and the content of the fault memory erased.
-
◆ If the heater is to be switched off during the start procedure, the instantaneous position reached in the start sequence governs whether the heater is switched off immediately or whether run-on is necessary(burning off, cooling down).
-
◆ The heater switches to control interval if the coolant temperature exceeds 77 °C before reaching full-load mode (e.g. withahot engine).
-
◆ Various additional heater functions are monitored constantly during operation (the additional heater is switched off if a fault occurs):
- Cut-off due to undervoltage if supply voltage drops below specified cut-off voltage (e.g. due to a transition resistance in the power supply)
-Cut-off due to overvoltage if the supply voltage is greater than 15.5 V for longer than 6 seconds.
-Cut-off due to loss of flame if resistance of -Q8 glow plug with flame detector drops below specified value (e.g. loss of flame due to fault in fuel supply).
- Cut-off due to overheating if coolant temperature in heater exceeds 125 °C (e.g. due to lack of coolant, due to a fault in the coolant circuit).
-
◆ The -J162 additional heater control unit also has the auxiliary heater and auxiliary ventilation modes stored. However, an actuation is not provided for on the Audi A2 (no recirculating pump is installed and the required connections are not present).
=> Audi A8 auxiliary/additional heater
=> Audi A6 auxiliary heater
Prerequisites for the sequence described on the following pages (when switching on heater):
Coolant circuit is bled and coolant temperature is less than 20 °C.
Battery -A is sufficiently charged.
Sufficient fuel in tank.
No faults stored in heater fault memory.
Engine running (heater with no recirculating pump -V55, additional heater).
Notes:
-
◆ Only the main items in the function sequence are presented on the following pages. Sequences taking place in the background are marked with a "-"and perceptible sequences (which can be heard or measured with. "▪"
-
◆ As the additional heater is only switched on at outside temperatures of less than +6 °C, Using the vehicle diagnostic, testing and information system VAS 5051 ("Basic setting" function), the additional heater may also be switched on at higher ambient temperatures. This, however, results in deviations for e.g. the various additional heater switching temperatures.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
1
|
Switch-on signal
|
|
|
|
|
Additional heater
▪ From engine control unit (from VAS 5051)
|
|
|
|
2
|
Initiation of start procedure
|
|
|
|
|
- Interrogation of fault memory
Interrogation of heater voltage
Monitoring of all electrical components and input signals.
Interrogation of glow plug with flame detector -Q8
Interrogation of coolant temperature in heater (less than 77 °C)
|
- Fault interlock entered
Voltage is or becomes lower than specified cut-off voltage
Fault detected
Resistance of glow plug with flame detector -Q8 outside specified range.
Coolant temperature (higher than 77 °C)
|
- Termination of starting procedure/fault/off
Termination of starting procedure (entry in fault memory)/fault/off
see above
see above
Switchover to control interval (No. 7)
|
Note:
If the additional heater remains switched on via the "Basic setting" function it remains in full load operation up to a coolant temperature of 115 °C, starting from control interval is possible. The operating time is limited to a maximum of 8 minutes.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
3
|
Start
|
|
|
|
|
- Monitoring as for No. 2
|
=>No. 2
|
=>No. 2
|
|
|
▪ -V55 recirculating pump on (for auxiliary heater only if installed).
▪ Actuation of -Q8 (controlled)
▪ Actuation of combustion air blower -V6 (controlled)
▪ Actuation of metering pump -V54 (controlled)
|
|
|
|
Continued on next page
|
|
|
Note:
The "starting" sequence is described on Pages 01-135.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
3
|
Starting (continued)
|
|
|
|
|
Stabilisation time
▪ Start of full-load combustion
▪ Switching of -Q8 from glow plug to flame detector
Interrogation of resistance of -Q8 (remains hot)
|
Resistance of glow plug with flame detector -Q8 outside specified range.
Resistance of glow plug with flame detector -Q8 still outside specified range after repeated starting.
|
Termination of starting procedure (1x repeated starting)
=>No. 2
Termination of starting procedure (entry in fault memory)/fault/off
|
|
Continued on next page
|
|
|
Note:
The "starting" sequence is described on Pages 01-135.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
4
|
Full load combustion (maximum heat output)
|
|
|
|
|
- Monitoring as for No. 2
|
=>No. 2
|
=>No. 2
|
|
|
- Voltage at heater remains greater than required
No interruption of combustion
Coolant temperature increases and reaches 71 °C
|
- Voltage becomes lower than specified cut-off voltage
Flame goes out
Coolant temperature less than 71 °C
|
- Burn-off (entry in fault memory)/fault/off
Burn-off and re-start =>No. 2
Heater remains in full-load operation until switched off
|
|
Continued on next page
|
|
|
Note:
The "full load and part load" sequence is described on Pages 01-136.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
5
|
Part load combustion (approx. 50% of heat output)
|
|
|
|
|
- Monitoring as for No. 4
|
=>No. 4
|
=>No. 4
|
|
|
▪ Actuation of metering pump -V54 with reduced clock frequency
▪ Actuation of combustion air blower -V6 with reduced voltage
Coolant temperature increases and reaches 77 °C
|
- Coolant temperature remains between 69 and 77 °C
Coolant temperature drops below 69 °C
|
- Heater remains in part load operation until switched off
Heater switches from part load to full load operation =>No. 4
|
|
Continued on next page
|
|
|
Note:
The "full load and part load" sequence is described on Pages 01-136.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
6
|
Burn-off/run-on
|
|
|
|
|
- Monitoring as for No. 2
|
=>No. 2
|
=>No. 2
|
|
|
▪ Metering pump -V54 off
▪ Actuation of combustion air blower -V6 with regulated voltage
▪ Actuation of -Q8 (post-heating, regulated)
▪ Actuation of -Q8 off
Interrogation of resistance of -Q8 (becomes colder)
|
Resistance of glow plug with flame detector -Q8 outside specified range
|
Burn-off (entry in fault memory)/fault/off
|
|
Continued on next page
|
|
|
Note:
The "burn-off/run-on/" sequence is described on Page 01-138.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
7
|
Control interval
|
|
|
|
|
- Monitoring as for No. 2
|
=>No. 2
|
=>No. 2
|
|
|
- Coolant temperature drops below 73 °C
|
- Coolant temperature continues to increase (engine runs and heats up coolant)
Coolant temperature remains between 73 and 77 °C
Coolant temperature drops below 125 °C
|
- Heater remains in control interval until switched off
Fault (entry in fault memory)/off/fault interlock
|
|
Continued on next page
|
|
|
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
8
|
Start from control interval
|
|
|
|
|
- Monitoring as for No. 2
|
=>No. 2
|
=>No. 2
|
|
|
▪ Actuation of -Q8 (controlled)
▪ Actuation of combustion air blower -V6 (controlled)
▪ Actuation of metering pump -V54 (controlled)
|
|
|
|
|
Stabilisation time
▪ Start of full load or part load combustion (depending on coolant temperature)
▪ Switching of -Q8 from glow plug to flame detector
Interrogation of resistance of -Q8 (remains hot)
|
Resistance of glow plug with flame detector -Q8 outside specified range.
Resistance of glow plug with flame detector -Q8 still outside specified range after repeated starting.
|
Termination of starting procedure (1x repeated starting) =>No. 2
Termination of starting procedure (entry in fault memory)/fault/off
|
|
Continued on next page
|
|
|
Note:
Starting from control interval takes place as described on Page 01-135 but because the heater is at operating temperature, the times for the various sequences differ from those for a fresh start (e.g. preheating 20 instead of 40 seconds, fuel supply 30 instead of 56 seconds).
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
9
|
Switch off
|
|
|
|
|
Additional heater
▪ No further signal from engine control unit (from fault reader)
|
|
|
|
Continued on next page
|
|
|
Notes:
-
◆ If heater is in control interval when switched off, it cuts out without burn-off and run-on.
-
◆ The "burn-off/run-on/" sequence is described on Page 01-138.
|
|
|---|
|
No.
|
Control sequence
|
Possible cause of deviation
|
Continuation of sequence following deviation
|
|
10
|
Burn-off
|
|
|
|
|
- Monitoring as for No. 2
|
=>No. 2
|
=>No. 2
|
|
|
▪ Metering pump -V54 off
▪ Recirculating pump -V55 off
▪ Actuation of combustion air blower -V6 with regulated voltage
▪ Actuation of -Q8 (post-heating, regulated)
▪ Actuation of -Q8 off
Interrogation of resistance of -Q8 (becomes colder)
▪ Off
|
Resistance of glow plug with flame detector -Q8 outside specified range.
|
Burn-off (entry in fault memory)/fault/off
|
"Heater starting" sequence
|
|
|---|
|
Sequence
|
Duration
approx.
|
Actuation
|
Resistance measurement
|
|
|
|
-V6
with
|
-V54
with
|
-Q8
with
|
-Q8
|
|
- Commence starting sequence
|
-
|
0 V
|
0 Hz
|
0 V
|
no
|
|
- Flame detector interrogation
|
1 second
|
8 V
|
0 Hz
|
0 V
|
yes
|
|
▪ Preheating
|
40 seconds
|
8 V
|
0 Hz
|
10 V
|
no
|
|
▪ Fuel pre-supply
|
3 seconds
|
0 V
|
2 Hz
|
9 V
|
no
|
|
▪ Fuel supply
|
56 seconds
|
2 to 5 V
|
1 Hz
|
9 V
|
no
|
|
- Stabilisation time
|
15 seconds
|
5 V
|
1 Hz
|
9 V
|
no
|
|
▪ Fuel supply
|
50 seconds
|
4 to 12 V
|
1 to 3 Hz
|
9 V
|
no
|
|
- Flame detector interrogation
|
45 seconds
|
12 V
|
3 Hz
|
0 V
|
yes
|
|
- End of starting sequence
Start of "full load" combustion ()
|
|
|
|
|
|
Notes:
-
◆ 1 Hertz (Hz) corresponds to 1 pulse per second
-
◆ The voltages, times and frequencies given in the table are approximate values regulated by the control unit on the basis of measured values (voltage, temperature, etc.).
"Heater full load/partial load combustion" sequence
|
|
|---|
|
Sequence
|
Duration
approx.
|
Actuation
|
Resistance measurement
|
|
|
|
-V6
with
|
-V54
with
|
-Q8
with
|
-Q8
|
|
- End of starting sequence
|
-
|
12 V
|
3 Hz
|
0 V
|
yes
|
|
- Full load combustion
|
Until coolant temperature in heater reaches 71 °C)
|
12 V
|
3 Hz
|
0 V
|
yes
|
|
▪ Switching from full load to part load operation
|
5 seconds
|
from 12 V
to
7 V
|
from 3 Hz
to
1.5 Hz
|
0 V
|
yes
|
|
▪ Part load combustion
|
Until coolant temperature in heater drops below 69 °C or reaches 77 °C
|
7 V
|
1.5 Hz
|
0 V
|
yes
|
|
Continued on next page
|
|
|
|---|
|
Sequence
|
Duration
approx.
|
Actuation
|
Resistance measurement
|
|
|
|
-V6
with
|
-V54
with
|
-Q8
with
|
-Q8
|
|
▪ Switching from part load to full load operation (if coolant temperature drops below 69 °C
Full load combustion
|
Up to 50 sec.
|
from 7 V
to
12 V
|
from 1.5 Hz
to
3 Hz
|
0 V
|
yes
|
|
- Switching from part load operation to control interval (if coolant temperature drops below 77 °C
▪ Burn-off/run-on ()
|
-
|
7 V
|
1.5 Hz
|
0 V
|
yes
|
Notes:
-
◆ 1 Hertz (Hz) corresponds to 1 pulse per second
-
◆ The voltages, times and frequencies given in the table are approximate values regulated by the control unit on the basis of measured values (voltage, temperature, etc.).
"Burn-off, run-on" sequence
|
|
|---|
|
Sequence
|
Duration
approx.
|
Actuation
|
Resistance measurement
|
|
|
|
-V6
with
|
-V54
with
|
-Q8
with
|
-Q8
|
|
- Switching from partial load operation to control interval
Switch-off of heater during full load or partial load operation
Starting procedure terminated because of fault
|
-
|
7 or
12 V
|
1.5 or
3 Hz
|
0 V
|
yes
|
|
▪ Burn-off (of heater)
|
15 to
60 sec.
|
4 to
12 V
|
0 Hz
|
6 to
8 V
|
no
|
|
▪ Cooling down (of heater)
|
0 to
120 sec.
|
8 to
12 V
|
0 Hz
|
0 V
|
no
|
|
▪ Switching to control interval
▪ OFF
|
-
|
0 V
|
0 Hz
|
0 V
|
no
|
Notes:
-
◆ 1 Hertz (Hz) corresponds to 1 pulse per second
-
◆ The voltages, times and frequencies given in the table are approximate values regulated by the control unit on the basis of measured values (voltage, temperature, etc.) and the last operating status.
|
