updates 10042023

docs/Fundamentals-Of-Tuning/AFR.md

@@ -1,36 +1,59 @@
-# Air Fuel Ratio 
+# Air Fuel Ratio
 
-What is AFR? Air fuel ratio or AFR refers to the ratio of 
+Air fuel ratio or AFR refers to the mass ratio of air to fuel involved in a combustion cycle. The AFR is important as the amount of fuel injected into the engine is the most significant combustion parameter that the ECU can control. The ECU takes the target AFR and determines the correct mass of fuel to inject based on the mass of air approximated using the temperature and pressure.
 
-## Why AFR Matters 
-
-AFR can impact many factors of how the engine runs including its power, fuel economy, knock threshold, exhaust gas temperature and emissions.
+## Why AFR Matters
 
+An engine operates most efficiently and cleanly when the air-fuel ratio is at a specific value called the stoichiometric ratio. This ratio depends on the type of fuel being used, but for gasoline, it is approximately 14.7 parts air to 1 part fuel (14.7:1). When the air-fuel ratio is at the stoichiometric value, all of the fuel is burned, and there is no excess oxygen or unburned fuel left in the exhaust. This results in the least amount of emissions and the highest fuel efficiency. If the air-fuel ratio is too lean (excess air), there is not enough fuel to burn, and the engine may misfire or stall. If the air-fuel ratio is too rich (excess fuel), there is not enough oxygen to burn all the fuel, and the engine may emit more pollutants, have reduced fuel efficiency, and may even cause damage to the engine over time. Therefore, maintaining the proper air-fuel ratio is essential for optimal engine performance, fuel efficiency, exhaust gas temperature, engine knock and emission control in a car engine.
 
 ## What is Lambda and Why it is a Superior Metric  
 
-Lambda is an alternative method of measuring the combustion efficiency of an engine. There are multiple reasons why it is preferred over AFR but mostly, it is recommended as it is easier to comprehend and tune with. For example, the ideal or stoichiometric AFR for regular petrol is 14.7 (14.7 parts air to 1 part fuel) which corresponds with a lambda of 1. If a car is running 10% lean, the AFR would be 16.17 and lambda would be 1.1. If the car is 10% rich, AFR would be 13.36 and lambda would be 0.9. Looking at lambda, it is instantly obvious what percentage rich or lean the engine is running but with AFR, it requires more effort.
+Lambda, is a dimensionless ratio of the actual air-fuel ratio to the stoichiometric air-fuel ratio. In other words, it is the ratio of the AFR to the stoichiometric AFR (or the measured AFR divided by the stoichiometric AFR). Lambda is a more universal measure of the air-fuel ratio, as it is not affected by the specific fuel being used. The stoichiometric lambda value for any fuel is always 1.0, regardless of the fuel type. For example, if the actual AFR in an engine is 14.7:1 (stoichiometric AFR), then the lambda value is 1.0. If the actual AFR is leaner than 14.7:1, then the lambda value is greater than 1.0, and if it is richer than 14.7:1, then the lambda value is less than 1.0.
 
-Lambda represents the percentage of air in the combustion chamber compared to the amount needed for ideal or stoichiometric combustion to occur. 
-
-lambda is consistent across all types of fuels
+Lambda is preferred in engine tuning because it allows for a more precise control of the air-fuel ratio across different fuels and is generally easier to comprehend. For example, if a gasoline car is running 10% lean, the AFR would be 16.17 and lambda would be 1.1. If the car is 10% rich, AFR would be 13.36 and lambda would be 0.9. Looking at lambda, it is instantly obvious what percentage rich or lean the engine is running but with AFR, it requires more effort.
 
 ## AFR Targets - When to Run Rich, Lean and Stoich  
 
-Reference the operating conditions table for lambda targets
+The ideal AFR targets will vary for every engine however there are guidelines for what the targets should be for each operating zone of the engine. These targets will be represented on an AFR target table or map, shown below, which characterizes the various engine operating conditions for their respective engine RPM and MAP. Generally speaking, running richer will decrease engine response at a gain of extra combustion chamber cooling and slightly higher power to a point. Inversely, running leaner will increase engine response at a loss running hotter and reducing power. 
 
-The idea AFR targets will vary for every engine however there are guidelines for what the targets should be for each operating zone of the engine. These targets will be represented on a lambda target table or map with RPM on the X-axis, mass air pressure (MAP) on the Y-axis and lambda on the Z-axis. This table can be broken down into several zones.
+![image](AFR/AFRTarget.png)
 
-### Idle, Cruising and Engine Braking
+### Idle and Cruising 
+
+For idle, a lambda of 1.0 is generally recommended to achieve a stable idle. When cruising, a lambda of 1.0 is also recommended however this can be raised up to about 1.05 to improve the fuel efficiency of the vehicle on the freeway or traveling a constant speed for long periods of time.
+
+### Low and High Load Vacuum
+
+In the low vacuum section of the map, the engine will only operate here when the engine is under minimum load such as rolling in gear with the throttle closed. To save fuel, the engine can be operated up to about 1.05 lambda here or Deceleration Fuel Cutoff (DFCO) can be enabled to disable to injectors entirely and let the vehicle engine brake. DFCO is found under the _Fuel_ tab in Tuner Studio.
+
+The high vacuum part of the map is typically only used in the short period between high RPM gear changes or throttle lifts. The engine is usually being driven hard if this part of the map is being used so a target lambda of 0.95 to help cool the cylinders is recommended although a value of 1.0 is also acceptable.
 
 ### High Load Naturally Aspirated/Boost Transition Zone
 
+For a naturally aspirated (NA) engine, this zone represents the peak operating load which the engine will be placed under. A lambda of about 0.9 is recommended to balance performance with cylinder cooling.
+
+For a forced induction engine, this zone represents the engine's transition into boost. As the engine usually isn't under a lot of load here, a slightly higher lambda of 0.95 is recommended to balance the engine response with some degree cylinder cooling.
+
 ### Medium and High Boost Zones
 
-### Engine Start
+When the engine moves into boost, the engine load increases as does the temperature and pressure of the combustion. Hence, as the boost pressure increases, the AFR needs to get progressively richer. A good starting point for about 200kPa MAP or 14.5PSI of boost is a lambda of 0.78-0.82. For 300kPa MAP or 29PSI of boost, a 0.76-0.8 is generally a good starting range. Of course, every engine will differ so it is important here to research what others have successfully run on similar platforms to you.
 
-### Unused Zones
+### Engine Start and Dead Zone
+
+In both of these zones, their target AFRs do not matter a whole lot. The dead zone will never be operated in and the starting zone will never operate with closed loop fuelling as the lambda sensor will only activate after the car is running. The best configuration for these zones it to copy or transition them from the target AFR columns directly next to them for the sake of smoothness in the map.
+
+### Merging the zones
+
+On the AFR target diagram you will notice that there are gaps in the operating zones. The best way of choosing targets for these zones is to interpolate and smooth their values between the configured parts of the map. Ideally the AFR target map should be smooth with no sudden changes as smooth variations in AFR are required for an engine to operate well.
 
 ## AFR For Different Fuels
 
-Fundamentally, an oxygen sensor works in lambda. It measures the oxygen content in the exhaust relative to the open air and outputs a voltage which the ECU or wideband controller can directly convert to lambda. The ECU then converts this to AFR if required by multiplying the lambda by the stoichiometric value of the fuel (typically 14.7 for unleaded). Regardless of the fuel, the oxygen sensor will read the same lambda for any fuel that is burning at its stoichiometric point. A table is shown below comparing the stoichiometric AFR values of common fuels. https://ftyracing.com/tech/lambda-afr-table/ 
+Fundamentally, an oxygen sensor works in lambda. It measures the oxygen content in the exhaust relative to the open air and outputs a voltage which the ECU or wideband controller can directly convert to lambda. The ECU then converts this to AFR if required by multiplying the lambda by the stoichiometric value of the fuel (typically 14.7 for unleaded). Regardless of the fuel, the oxygen sensor will read the same lambda for any fuel that is burning at its stoichiometric point. A table is shown below comparing the stoichiometric AFR values of common fuels.
+
+| **Fuel Type**     | **Stochiometric AFR** |
+|-------------------|-----------------------|
+| Unleaded Gasoline | 14.7                  |
+| E85               | 9.76                  |
+| E100              | 8.98                  |
+| Diesel            | 14.5                  |
+| Methanol          | 6.46                  |

docs/Intro-Start-Here/Miata-Quick-Start.md

@@ -96,11 +96,11 @@ Now that the MAP line and wideband are connected to the ECU, the remaining wirin
 
 Make sure that you have downloaded the latest version of TunerStudio (TS) from [here](<https://www.tunerstudio.com/index.php/tuner-studio>). Although the base version of the software is free, it is strongly recommended to buy a license for the additional features including auto-tuning and the ability to customize the default dashboard.
 
-Begin the setup by plugging the ECU into the laptop and opening TS. Create a new project and click _detect_ under firmware. Select the COM port corresponding to the FOME ECU in the device list. If the COM port cannot be found or the firmware cannot be automatically detected, click _Other/Browse_ and load the .ini file for the ECU which can either be downloaded or found on the USB device which appears when the ECU is plugged into the computer.
+Begin the setup by plugging the ECU into the laptop and opening TS. Create a new project and click _detect_ under firmware. Select the COM port corresponding to the FOME ECU in the device list. If the COM port cannot be found or the firmware cannot be automatically detected, click _Other/Browse_ and load the .ini file for the ECU which can either be downloaded or found within the ZIP file on the USB device which appears when the ECU is plugged into the computer.
 
 ![image](Miata-Quick-Start-Images/newproject.png)
 
-In the next dialog choose between lambda or air fuel ratio (AFR) as your display units. lambda is recommended as it is easier to comprehend and tune with. For example, the ideal or stoichiometric AFR for regular petrol is 14.7 (14.7 parts air to 1 part fuel) which corresponds with a lambda of 1. Lambda represents the percentage of air in the combustion chamber compared to the amount needed for ideal or stoichiometric combustion to occur. If a car is running 10% lean, the AFR would be 16.17 and lambda would be 1.1. If the car is 10% rich, AFR would be 13.36 and lambda would be 0.9. Looking at lambda, it is instantly obvious what percentage rich or lean the engine is running but with AFR, it requires more effort. __The only time AFR should be selected here is if you are using an external wideband controller__.
+In the next dialog choose between lambda or air fuel ratio (AFR) as your display units. lambda is recommended as it is easier to comprehend and tune with. For example, the ideal or stoichiometric AFR for regular petrol is 14.7 (14.7 parts air to 1 part fuel) which corresponds with a lambda of 1. Lambda represents the percentage of air in the combustion chamber compared to the amount needed for ideal or stoichiometric combustion to occur. If a car is running 10% lean, the AFR would be 16.17 and lambda would be 1.1. If the car is 10% rich, AFR would be 13.36 and lambda would be 0.9. Looking at lambda, it is instantly obvious what percentage rich or lean the engine is running but with AFR, it requires more effort. **The only time AFR should be selected here is if you are using an external wideband controller**.
 
 In the third dialog box, configure it as shown in the image below but select the com port which corresponds to your ECU. If unsure, go to the device manager on your computer and it should list the COM port number next to the name of the ECU. Click _Test Port_ and if successful, move to the next dialog.
 
@@ -144,7 +144,7 @@ Start the car and plug the laptop in. Within 30 seconds, the lambda gauge should
 
 ![image](Miata-Quick-Start-Images/VE.jpg)
 
-The general way to tune the VE table is to go through all the cells which the engine will operate within and to adjust the VE percentage until the lambda gauge matches the value in the _Target Lambda Table_ shown below and in TS found under _Fuel_ > _Target Lambda_. For example, if the lambda gauge shows 1.1 and the target lambda for that engine state is 1.0, the corresponding VE cell needs to be increased by 10%. The target lambda table supplied with the Miata base map should be sufficient to start with but you can modify it later to make the engine run richer or leaner under certain conditions such as boost or highway cruising respectively. 
+The general way to tune the VE table is to go through all the cells which the engine will operate within and to adjust the VE percentage until the lambda gauge matches the value in the _Target Lambda Table_ shown below and in TS found under _Fuel_ > _Target Lambda_. For example, if the lambda gauge shows 1.1 and the target lambda for that engine state is 1.0, the corresponding VE cell needs to be increased by 10%. The target lambda table supplied with the Miata base map should be sufficient to start with but you can modify it later to make the engine run richer or leaner under certain conditions such as boost or highway cruising respectively.
 
 ![image](Miata-Quick-Start-Images/targetlam.jpg)
 
@@ -158,4 +158,4 @@ Next, click the tab labelled _Tune Analyze Live! - Tune For You_ to bring up the
 
 Now that the autotuner is set up, start the car and click _Start Auto Tune_ on the autotuner. Let the car idle in park whilst it gets up to the minimum temperature. While this happens, you can attempt to change the idle cells in the VE table to get them to a lambda of 1. Once the car has warmed up, **smoothly** drive it around going through the gears and all the way through the rev range. A mix of flat, uphill and downhill driving in different gears is optimal to tune the majority of the engine's operating range. After you are sufficiently happy, click _Stop Auto Tune_, turn the engine off and click _Save on ECU_. You will want to repeat this process several more times, every time dropping the _Cell Change Resistance_ and _Authority Limits_ to slowly refine your VE table.
 
-When you are satisfied with your VE table, turn closed loop fuel correction and _Deceleration fuel cut off (DFCO)_ back to true. You don't actually need DFCO to be enabled although it will save fuel by turning the injectors off when the car is rolling in gear. Your Miata should now be relatively safe to drive but this is only the start of the tuning journey. As you read through the more advanced guides in this wiki, you will learn about all of the different ways the ECU can be configured to improve the drivability and squeeze every drop of performance out of your Miata.
+When you are satisfied with your VE table, turn closed loop fuel correction and _Deceleration fuel cut off (DFCO)_ back to true. You don't actually need DFCO to be enabled although it will save fuel by turning the injectors off when the car is rolling in gear. Your Miata should now be relatively safe to drive but this is only the start of the tuning journey. As you read through the more advanced guides in this wiki, you will learn about all of the different ways the ECU can be configured to improve the drivability and squeeze every drop of performance out of your Miata.