2010 ASTON MARTIN V8 VANTAGE engine

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009
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Misfire Monitor

Neural Network Misfire detection is used in order to achieve "full-range" capability. All software allows
for detection of any misfires that occur 6 engine revolutions after initially cranking the engine. This
meets the new OBD-II requirement to identify misfires within 2 engine revolutions after exceeding the
warm drive, idle rpm.
.

Neural Network System

The Neural Net Misfire (NNM) monitor uses a dedicated microprocessor in the PCM along with
crankshaft position, (36–tooth wheel), camshaft position, and engine load to determine engine misfire. A
neural network is different way of computing that uses a large number of simple processing elements with
a high degree of interconnection to process complex inform ation. It is based on the parallel architecture of
the brain. The processing elements have adaptive ch aracteristics (coefficients) that must be learned
through a process called training. During training, the netw ork is fed a sample set of data that consists of
the inputs along with the desired output (e.g. misfire/no misfire). The network coefficients are recursively
optimized so that the correct output is generated fro m the set of inputs and error is minimized. Once the
coefficients have been learned, the network can process "real" data.

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009

Misfire Monitor (continued)


NNM uses a Motorola Star 12 microprocessor in the PCM to perform the NNM calculations. The
Motorola Star 12 is used in all markets for the Ast on Martin application. The neural network size is 23
nodes and 469 coefficients.
Inputs to Neural Net
• Crankshaft acceleration from the crank position (CKP) sensor
• RPM (calculated from CKP)
• LOAD (normalized for air mass and rpm)
• Indication of cam position from camshaft position (CMP) sensor
Output from Neural Net
• Misfire Call: - 0 (indicating no misfire) or 1 (indicating misfire)

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NNM System Hardware Design


PCM MIL


















Generic Misfire Algorithm Processing.


The acceleration that a piston undergoes during a normal firing event is directly related to the amount of
torque that cylinder produces. The calculated piston/cylinder acceleration value(s) are compared to a
misfire threshold that is continuously adjusted based on inferred engine torque. Deviant accelerations
exceeding the threshold are conditionally labeled as misfires.

The calculated deviant acceleration value(s) are also evaluated for noise. Normally, misfire results in a
non-symmetrical loss of cylinder acceleration. Mechan ical noise, such as rough roads or high rpm/light
load conditions, will produce symmetrical acceleration va riations. Cylinder events that indicate excessive
MAF Signal
CKP Signal
Main PPC
Processor
HCS12HCS12LOAD_FG
CKP Signal
Misfire calls, or
Δt’s
Misfire fault counters
Status Flags
CID Signal
Misfire disablements
Profile Learning CKP
-> ACCEL, RPM
CID -> local sync
Signal validation
Profile application
Executes Neural Net
CID Signal

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009
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deviant accelerations of this type are considered noise. Noise-free deviant acceleration exceeding a given
threshold is labeled a misfire.

The number of misfires are counted over a continuous 200 revolution and 1000 (or 4000)
revolution period. (The revolution counters are not reset if the misfire monitor is temporarily disabled such
as for negative torque mode, etc.) At the end of the evaluation period, the total misfire rate and the misfire
rate for each individual cylinder is computed. The misfire rate evaluated every 200 revolution period
(Type A) and compared to a threshold value obtaine d from an engine speed/load table. This misfire
threshold is designed to prevent damage to the cat alyst due to sustained excessive temperature. If the
misfire threshold is exceeded and the catalyst temperature model calculates a catalyst mid-bed temperature
that exceeds the catalyst damage threshold, the MIL blinks at a 1 Hz rate while the misfire is present. If the
threshold is again exceeded on a subsequent driving cy cle, the MIL is illuminated. If a single cylinder is
indicated to be consistently misfiring in excess of the catalyst damage criteria, the fuel injector to that
cylinder may be shut off for a period of time to pr event catalyst damage. Up to two cylinders may be
disabled at the same time. This fuel shut-off feature is used on many 8-cylinder engines. It is never used
on a 4-cylinder or 6-cylinder engine. Next, the misf ire rate is evaluated every 1000 (or 4000) rev period
and compared to a single ( Type B ) threshold value to indicate an emission-threshold malfunction. If a
1000 rev period is calibrated, a single 1000 rev exceedence from startup or four subsequent 1000 rev
exceedences on a drive cycle after start-up is used as the malfunction criteria. If a 4000 rev period is
calibrated, a single 4000 rev exceedence is used to indicate an emission-threshold malfunction.





Misfire Monitor Operation :
DTCs P0300 to P0312, P316 ,P1309, P1310, P1311
Monitor execution Continuous, misfire rate calculated every 200 and 1000 or 4000 revs
Monitor Sequence none
Sensors OK CKP, CMP, ECT
Monitoring Duration Entire driving cycle ( see disablement conditions below )

Typical misfire monitor entry conditions Minimum Maximum
Time since engine start-up 5 seconds
Engine Coolant Temp 20 oF 250 oF
RPM Range idle as per Directive
Profile correction factors learned in KAM Yes

Misfire Monitor temporary disablement conditions ( other than entry requirements )
Closed throttle decels (negative torque, engine being driven)
Engine Torque Reduction Modes
Accessory load-state change (A/C, power steering)
EGR Monitor Flow Test

Typical misfire monitor malfunction thresholds :
Type A (catalyst damaging misfire rate) misfire rate is an rpm/load table ranging from 40% at idle to
4% at high rpm and loads.
Type B (emission threshold rate) 1% to 5%

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009
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HO2S Monitor

Front HO2S Signal

The time between HO2S switches is monitored after vehicle startup and during closed loop fuel
conditions. Excessive time between switches or no switc hes since startup indicate a malfunction. Since
'lack of switching' malfunctions can be caused by HO2S sensor malfunctions or by shifts in the fuel
system, DTCs are stored that provide additional information for the 'lack of switching' malfunction.
Different DTCs indicate whether the sensor was st uck lean/disconnected (P1131, P1151), stuck rich
(P1132, P1152) or stopped switching due to excessive long term fuel trim corrections (P1130, P1150).

HO2S 'Lack of Switching' Operation:
DTCs Bank 1 – P0132, P2195, P2196
Bank 2 – P0152, P2197, P2198
Monitor execution continuous, from startup and while in closed loop fuel
Monitor Sequence none
Sensors OK TP, MAF, MAP, ECT, CHT, ACT, IAT
Monitoring Duration 30 to 60 seconds to register a malfunction

Typical HO2S 'Lack of Switching' entry conditions : Minimum Maximum
Throttle Position part throttle
Idle State (not at idle, part throttle)
Engine Load 20% 60%
Time since engine start-up 180 seconds
Inferred Exhaust Temperature 800 oF

Typical HO2S 'Lack of Switching' malfunction thresholds:
< 5 switches since startup after 30 seconds in test conditions
> 60 seconds since last switch while closed loop
> 30 seconds since last switch while closed loop at Short Term Fuel Trim limit

HO2S lack of switching temporary disablement conditions (other than entry requirements) :
Air Charge Temperature, ACT (or IAT) < -20 °F (minimum Cold Climate Test Temperature).
Failure of the sensors mentioned in the above “Sensors OK” section.

The HO2S is also tested functionally. The response rate is evaluated by enteri ng a fixed frequency square
wave, fuel control routine. This routine drives the air/fuel ratio around stoichiometry at a calibratable
frequency and magnitude, producing pr edictable oxygen sensor signal amplitude. A slow sensor will show
a reduced amplitude. Oxygen sensor signal amplitude below a minimum threshold indicates a slow sensor
malfunction (P0133 Bank 1, P0153 Bank 2).

HO2S Response Rate Operation:
DTCs Bank 1 - P0133, Bank 2 - P0153
Monitor execution once per driving cycle
Monitor Sequence none
Sensors OK ECT, IAT, MAF, MAP, VSS, CKP, TP, CMP, no misfire DTCs
Monitoring Duration 4 seconds

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009
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Typical HO2S response rate entry conditions : Minimum Maximum
Short Term Fuel Trim Range 90% 110%
Engine Coolant Temp 150 oF 240 oF
Intake Air Temp 140 oF
Engine Load 20% 50%
Vehicle Speed 37 mph 55 mph
Engine RPM 1500 rpm 3000 rpm
Time since entering closed loop fuel 10 seconds

Typical HO2S response rate malfunction thresholds:
Voltage amplitude: < 0.4 volts

HO2S response rate temporary disablement conditions ( other than entry requirements ) :
Disabled if a lack of switching fault is present, also sensors noted in “Sensors OK” section.


Rear HO2S Signal.

A functional test of the rear HO2S sensors is done dur ing normal vehicle operation. The peak rich and lean
voltages are continuously monitored. Voltages that exceed the calibratable rich and lean thresholds
indicate a functional sensor. If the voltages have not ex ceeded the thresholds after a long period of vehicle
operation, the air/fuel ratio may be forced rich or lean in an attempt to get the rear sensor to switch. This
situation normally occurs only with a green catalyst (< 500 miles). If the sensor does not exceed the rich
and lean peak thresholds, a malfunction is indicated.

Rear HO2S Check Operation:
DTCs Bank 1 - P0136, Bank 2 - P0156
Monitor execution once per driving cycle
Monitor Sequence after 'Upstream Response' test
Monitoring Duration 20sec for excursion

Typical Rear HO2S check entry conditions : Minimum Maximum
Inferred exhaust temperature range 400 oF 1600 oF
Rear HO2S heater-on time 120 seconds
Throttle position part throttle
Engine RPM (forced excursion only) 1000 rpm none

Typical Rear HO2S check malfunction thresholds:
Does not exceed rich and lean threshold envelope: Rich < 0.25 volts
Lean > 0.65 volts

Rear HO2S temporary disablement conditions (other than entry requirements) :
None.

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009
[email protected] AML EOBD Monitors 07 ROC.doc Page 13 of 43

Differential Pressure Feedback EGR System Monitor

Where a vacuum driven EGR valve is used on the base application, the EGR System Monitor will consist
of a series of electrical and functional tests for the various aspects of system operation. First, the
Differential Pressure Feedback EGR (DPFE) sensor input circuit is checked for out of range values (P1400
P1401). The Electronic Vacuum Regulator (EVR) output circuit is checked for opens and shorts (P1409).


EGR Electrical Check Operation:
DTCs P1400, P1401, P1409
Monitor execution continuous, during EGR monitor
Monitor Sequence none
Monitoring Duration 4 seconds to register a malfunction

Typical EGR electrical check entry conditions:
EGR system enabled

Typical EGR electrical check malfunction thresholds:
DPFE sensor outside voltage: > 4.96 volts, < 0.195 volts
EVR solenoid smart driver status indicates open/short



The differential pressure indicated by the DPFE sensor is also checked at idle with zero requested EGR
flow to perform the high flow check. If the differen tial pressure exceeds a calibratable limit, it indicates a
stuck open EGR valve or debris temporar ily lodged under the EGR valve seat (P0402).

EGR Stuck open Check Operation:
DTCs P0402
Monitor execution once per driving cycle
Monitor Sequence Done after P1400 and P1401 tests
Sensors OK CPS, ECT, IAT, MAF, MAP, TP
Monitoring Duration 10 seconds to register a malfunction

Typical EGR stuck open check entry conditions : Minimum Maximum
EVR Duty Cycle (EGR commanded off) 0% 0%
Engine RPM (after EGR enabled) at idle at idle

Typical EGR stuck open check malfunction thresholds:
DPFE sensor voltage at idle versus engine-off signal: > 0.6 volts

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009
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After the vehicle is started, during vehicle acceleration, the differential pressure indicated by the DPFE
sensor at zero EGR flow is checked to ensure that both hoses to the DPFE sensor are connected. Under
this condition, the differential pressure should be zer o. If the differential pressure indicated by the DPFE
sensor exceeds a maximum threshold or falls below a minimum threshold, an upstream or downstream
DPFE hose malfunction is indicated (P1405 P1406).

EGR Hose Check Operation:
DTCs P1405, P1406
Monitor execution once per driving cycle
Monitor Sequence Done after P0402 test
Sensors OK MAF, MAP
Monitoring Duration 2 seconds to register a malfunction

Typical EGR hose check entry conditions : Minimum Maximum
EVR duty Cycle (EGR commanded off) 0% 0%
Mass Air Flow 8 lb/min
Inferred exhaust back pressure 13 in H2O

Typical EGR hose check malfunction thresholds:
DPFE sensor voltage: < -7 in H2O, > 7 in H2O


After the vehicle has warmed up and normal EGR rates are being commanded by the PCM, the low flow
check is performed. Since the EGR system is a closed loop system, the EGR system will deliver the
requested EGR flow as long as it has the capacity to do so. If the EVR duty cycle is very high (greater
than 80% duty cycle), the differential pressure indicated by the DPFE sensor is evaluated to determine the
amount of EGR system restriction. If the differential pr essure is below a calibratable threshold, a low flow
malfunction in indicated (P0401).

EGR Flow Check Operation:
DTCs P0401
Monitor execution once per driving cycle
Monitor Sequence Done after P1405 and P1406 tests
Sensors OK CPS, ECT, IAT, MAF, MAP, TP
Monitoring Duration minimum 70 seconds to register a malfunction

Typical EGR flow check entry conditions: Minimum Maximum
EVR Duty Cycle 80% 100%
Engine RPM 2500 rpm
Mass Air Flow Rate of Change 6% prog. loop
Inferred manifold vacuum 6 in Hg 10 in Hg

Typical EGR flow check malfunction thresholds:
DPFE sensor voltage: < 6 in H2O

EGR Monitor temporary disablement conditions ( other than entry requirements ) :
Non-operational when base feature disabled, including matching base feature temperature disablement.
Low Barometric Pressure Conditions.
Reporting of faults suppressed below 32° F to prevent mis-diagnosis due to ice. Monitor is still operational
and continues to check, reporting any faults when temperature > 32 °F.

AML EOBD System Operation Summary

Rory O’Curry Aston Martin Lagonda CONFIDENTIAL 1 May 2009



Dual MAF Diagnostic
Dual MAF Hardware

The V8 uses a common dirty air pick-up, which feeds twin air filters and MAF meters before recombining the two air streams in a junction prior to the throttle.
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FilterFilter

Filter Filter

Filter Filter

Filter Filter

MAF
meters















Normal Operation Side Wind or Partial
Blockage Backflow
Total Blockage
MAF meters receive an
equal share of the airflow. One MAF meter receives
an airflow greater than the total engine consumption. One MAF meter
receives airflow equal to the total airflow.
MAF meters receive
unequal airflows. This is due to severe side
wind. Fault judgement is
de
pendant on severity.
This can either be due
to a side wind or a partial blockage. One MAF meter will
measure zero airflow and this needs to be
determined to prevent false circuit faults.
Low engine airflow
conditions are
particularly susceptible to side wind. Fault judgement is
dependant on severity.
Fault judgement is
dependant on severity.