MoTeC AFM1 User Manual

MoTeC

AFM1

Air Fuel Ratio Meter

5 June, 2003

 Copyright – MoTeC Pty Ltd – 1993-2003

The information in this document is subject to change without notice.

While every effort is taken to ensure correctness, no responsibility will be taken for the consequences of any

inaccuracies or omissions in this manual

.

MoTeC Table of Contents i

Specifications..................................................................... 1

Meter .............................................................................................1

Meter Analog Output .....................................................................1

Sensor ...........................................................................................2

Meter Operation.................................................................. 3

Introduction....................................................................................3

Sensor Placement .........................................................................3

Sensor Life Time ...........................................................................3

Sensor Warm Up...........................................................................3

Power Supply ................................................................................4

Connections ..................................................................................4

Lambda..........................................................................................5

Display...........................................................................................5

Changing the Display Mode................................................5

Engine Tuning ...............................................................................6

Operating Tips...............................................................................6

Analog Output ...............................................................................7

Setting the Output Voltage Range ......................................7

Output Fine Adjustment ......................................................7

Appendices......................................................................... 9

Appendix A - Lambda to Air Fuel Ratio Table..................................................... 9

Appendix B - Sensor Wiring Details .................................................................. 10

Appendix C - Analog Output Wiring Details ......................................................11

Appendix D - Analog Output Modes.................................................................. 12

Appendix E - Analog Output Calibration Levels ................................................ 13

Appendix E - Error Codes ................................................................................. 14

MoTeC Specifications 1

Specifications

Meter

Operating Voltage Range 7 to 16 V DC

Operating Current 0.3 A Max. (Excluding Sensor)

Reverse Voltage - 24 V DC Max.

Transient Protection 10 Joules (100A / 10ms) (Clamping Voltage

24V)

Operating Temperature 0 to 60 deg C

Operating Humidity 0 to 80 % Non Condensing

Measurement Range 0.75 to 1.60 Lambda

Measurement Accuracy ± 1.5% 0.75 to 1.05 Lambda

± 2.5% 1.06 to 1.25 Lambda
± 5.0% 1.26 to 1.60 Lambda

Display Update Rate 3.5 Times per second

Response Time < 150 msec (To 63 % of Final Reading)

Weight 575 g

Dimensions 142 x 48 x 96 mm (WxHxD)

Meter Analog Output

Output Type Isolated (Floating)

Output Isolation 400 V DC Max.

Output Voltage Range 0 to 5 V DC Max. ( Dependant on Range

Selection )

Output Current 1 mA Max.

Response Time 100 ms 0.75 to 0.95 Lambda

150 ms 0.96 to 1.05 Lambda
50 ms 1.06 to 1.60 Lambda
(To 63 % of Final Reading)

2 Specifications

Sensor

Sensor Type Wide Band

Heater Voltage 12 to 14 V DC

Heater Current 1.5 A Nominal (Hot)

5.0 A Max. (Cold)

Operating Temp 250 to 800 C (Heater ON)

450 to 930 C (Heater OFF)

* Life Time > 500 Hrs (Unleaded Fuel)

> 50 Hrs (Leaded Fuel)

Thread Type M18 x 1.5

Note Life Time is dependant on a number of factors - See text.

MoTeC Meter Operation 3

Meter Operation

Introduction

The M oTe C Air Fuel Ratio Meter measures Lambda (or Air Fuel Ratio) over a
wide range of mixtures with fast response time.

The display may be set to Show Lambda or Air Fuel Ratio for either Petrol,
Alcohol, Gas or Diesel.

The Meter provides an Isolated Analog Output Voltage proportional to
Lambda that may be connected to M oTe C Engine Management Systems for
transmission over the M oTe C Radio Link or closed loop control of Air Fuel
Ratio. Alternatively the Output may be connected to an Analog Meter or other
measurement instrument such as a Data Logger or Chart Recorder.

Sensor Placement

The sensor should be placed in the side of the exhaust system and should
protrude into the exhaust gas flow.

The sensor should be placed at least 1m from the exhaust ports to avoid
excessive heat and at least 1m from the open end of the exhaust system to
avoid incorrect readings due to outside oxygen.

The Sensor has an M18 x 1.5 Thread.

Sensor Life Time

The sensor life time is dependant on the type of fuel being used and the
volume of gas flow over the sensor.

Leaded fuel will reduce the sensor lifetime substantially due to lead
contamination of the sensor element.

The specifications give approximate lifetimes for Leaded and Unleaded fuel
for a typical high performance engine. Longer lifetimes can be expected for
less demanding applications.

Sensor Warm Up

The Sensor must be hot before any useful measurements can be taken.

4 Meter Operation

Red

Batt

iti

The Sensor has an internal heater to heat the sensor quickly and ensure
adequate temperature when exhaust gases are relatively cold (i.e. when the
engine is under light load).

When the internal heater is used the sensor will normally give good readings
within 2 minutes of applying power.

Power Supply

The Power supply must provide current for both the Meter and the Sensor
Heater Element. The vehicle battery is usually the most convenient source of
power.

Connections

The lead supplied with the Meter should be connected between the Meter and
the Sensor.

Power should be applied to the cable by connecting the Red Wire to Battery
Positive and the Black wire to Battery Negative. This connection powers both
the Meter and the Sensor Heater Element.

The Sensor has two connectors one is for the Sensor Element and the other
for the Heater Element. If the exhaust temperature will exceed 800 deg C the
Heater Element should NOT be connected.

Note If the Heater Element is not connected the sensor warm up time will be

increased and the Sensor may not read correctly if the exhaust gasses
are too cold - see specifications.

ery Pos

Black Battery Negative

MoTeC

Air Fuel Ratio Meter

ve

Refer to Appendix B if full wiring details are required.

MoTeC Meter Operation 5

WARNING Connecting the Meter Sensor Input to anything other than a

M oTe C Sensor may render the meter inoperable requiring factory
repair.

Lambda

Lambda gives a measure of Air Fuel Ratio which is independent of the type of
fuel being used.

Lambda 1.0 corresponds to stoichiometry i.e. when there is no excess fuel
and no excess air.

Lambda > 1.0 => Excess Air (Lean)

Lambda < 1.0 => Excess Fuel (Rich)

Lambda may be directly converted to Air Fuel Ratio for a specific fuel using a
multiplication factor.

A table to convert Lambda to Air Fuel Ratio for various fuels is given in
Appendix A.

Display

The display may be set to Show Lambda or Air Fuel Ratio for either Petrol,
Alcohol, Gas or Diesel.

Changing the Display Mode

Rear Panel Buttons

Mode + -

The display mode may be changed at any time by pressing the MODE
button on the rear of the Meter. As the mode is changed the display will
momentarily show a code to indicate the new mode.

The Meter will remember which mode is selected even when turned off.

When power is applied to the Meter it will momentarily show the
currently selected mode.

6 Meter Operation

The display codes are as follows :

LA Lambda
AF P Petrol Air Fuel Ratio
AF A Alcohol Air Fuel Ratio
AF g Gas Air Fuel Ratio
AF d Diesel Air Fuel Ratio

Engine Tuning

The desired Air Fuel Ratio (or Lambda) is dependant on the tuning objective
i.e. Power, Economy or Emissions.

Normally at Full Load the Engine is tuned for maximum power and at light
loads the engine is tuned for emissions or economy.

The following table gives a guide to the required Lambda values for different
tuning objectives.

Objective Lambda

Power 0.84 to 0.90

Economy 1.05

Emissions 1.00

Note The exact requirements for a specific engine and fuel must be found by

experimentation.

Note On Turbo Engines extra fuel may be desirable to reduce exhaust

temperatures and help avoid knock.

Operating Tips

If the Engine misses for any reason including an over-rich mixture the Meter
may falsely read Lean. This is due to excess air being present in the exhaust
gasses which is caused by incomplete combustion when the engine misses.

Engines with high overlap cams running at low speed may pump air through
the engine resulting in a false lean reading, therefore the meter may need to
read richer than would otherwise be expected.

MoTeC Meter Operation 7

Analog Output

The Analog Output (3 Pin Connector) provides a voltage proportional to
Lambda.

The Analog Output may be connected to M oTe C Engine Management
Systems for transmission over the M oTe C Radio Link or closed loop control of
Air Fuel Ratio.

Alternatively the Output may be connected to an Analog Meter or other
measurement instrument such as a Data Logger or Chart Recorder.

The Output is an Isolated (or Floating) type (i.e. Not Ground Referenced).
Both positive and negative wires must be connected.

Refer to Appendix C for Wiring Details.

Setting the Output Voltage Range

The Analog Output Voltage Range may be configured to suit a number
of different measurement devices.

Appendix D Shows the Output Voltage Ranges for the different modes.

Note that different Output Voltage Ranges may be required for different
types of M oTe C ECUs

Rear Panel Buttons

Mode + -

To enter the Range Select Mode hold down the MODE button as the
power is applied to the meter. The display will then show the currently
selected range (AO 1 to AO 9). To change the range press the MODE
button until the desired range appears.

Cycle the Meter power to resume normal Operation

Output Fine Adjustment

To allow for inaccuracies in the measuring device the Analog Output
voltage gain may be adjusted ± 10 %.

8 Meter Operation

A. Adjustment During Range Selection

The Analog Output may be adjusted while in the Range Select Mode
(i.e. While The Display is Showing AO 1 to AO 9).

During Range Selection the Analog Output voltage will be set to a
predetermined level which is dependant on the selected range.

Appendix E shows the voltage level and corresponding Lambda value
for the various output modes.

The + and - buttons may be used to adjust the output voltage to give
the correct reading on the measurement device.

B. Adjustment During Normal Operation

The + and - buttons may be used to adjust the output voltage to give
the correct reading on the measurement device.

Adjust so that the reading on the measuring device corresponds exactly
to the reading on the Meter display.

Note The adjustment should be checked at two or more points

covering the extremes of the normal operating range.

MoTeC Appendices 9

Appendices

Appendix A - Lambda to Air Fuel Ratio Table

Lambda Air Fuel Ratio

0.70 10.3 4.5 10.9 10.2

0.75 11.0 4.8 11.6 10.9

0.80 11.8 5.1 12.4 11.6

0.85 12.5 5.4 13.2 12.3

0.90 13.2 5.8 14.0 13.1

0.95 14.0 6.1 14.7 13.8

1.00 14.7 6.4 15.5 14.5

1.05 15.4 6.7 16.3 15.2

1.10 16.2 7.0 17.1 16.0

1.15 16.9 7.4 17.8 16.7

1.20 17.6 7.7 18.6 17.4

1.25 18.4 8.0 19.4 18.1

1.30 19.1 8.3 20.2 18.9

1.35 19.8 8.6 20.9 19.6

1.40 20.6 9.0 21.7 20.3

1.45 21.3 9.3 22.5 21.0

1.50 22.1 9.6 23.3 21.8

1.55 22.8 9.9 24.0 22.5

1.60 23.5 10.2 24.8 23.2

Petrol Alcohol LPG Diesel

10 Appendices

F

Appendix B - Sensor Wiring Details

emaleMale

Grey

Black

White
White

1
2

2
1

FemaleMale

Sensor ­Sensor+
Battery ­Battery+

Battery Negative

Battery Positive

4
3
2
1

Meter

MoTeC Appendices 11

Appendix C - Analog Output Wiring Details

Positive (Red)

Negative (Black)

Connect the Negative wire to the 0V reference point on the measuring device.

Connect the Positive wire to the positive input on the measuring device.

1
2
3

Meter (3 Pin)

12 Appendices

Appendix D - Analog Output Modes

Mode Use Lambda

0V 1.6V 5V

AO 1

AO 2

AO 3 General Purpose 0.75 1.00

AO 4 General Purpose 0.75 1.25

AO 5 General Purpose 0.75 1.75

AO 6 General Purpose 0.70 0.95

AO 7 General Purpose 0.70 1.20

AO 8 General Purpose 0.70 1.70

AO 9 Through Connection

Note The Maximum measurable value of Lambda is 1.60 therefore Modes 2,

M oTe C 2D/3D-V4

M oTe C 2D/3D-V3 & M4

(Exact Sensor Volts)

5 and 8 will never reach 5Volts.

0.50 1.75

0.00 1.60

N/A N/A

MoTeC Appendices 13

Appendix E - Analog Output Calibration

Mode Voltage Lambd

a

AO 1 4.0V 1.5

AO 2 1.0V 1.0

AO 3 3.0V 0.9

AO 4 2.5V 1.0

AO 5 3.75V 1.5

AO 6 4.0V 0.9

AO 7 3.0V 1.0

AO 8 4.0V 1.5

AO 9 0.8V N/A

14 Appendices

Appendix E - Error Codes

Error No Meaning

1 High Sensor Voltage - Possible short to Battery Voltage

2,3,4,5,6,7

Consult M oTe C

Notes

Notes