Setting Up Closed Loop Fuel Control on Modular ECUs

All Adaptronic ECUs support closed loop fuel control. This article explains what is required and how to configure it. Firstly, and this should be obvious but I'll say it anyway, you have to have your target lambda set correctly in your target lambda map. Secondly, you need some kind of lambda measurement. Normally this would be a wideband lambda sensor, because with a narrowband you can really only know which side of lambda 1 you are, so doing closed loop for another mixture is not possible. If you are running a dual bank engine, then we would recommend enabling the separate bank setting in the engine settings, and running a separate lambda sensor on each bank. Make sure you set the bank configuration correctly, ie whether the cylinder numbers are numbered odd and even or first half and second half. The first oxygen sensor must be for the bank which has cylinder 1 in it (eg the odd bank), and the second one must be the other bank. This also works on engines such as the … [Read more...]

Vibration Testing on Modular ECUs

This is a quick video to show vibration testing of the Modular ECUs. As you may have seen, the Modular ECUs have modules inside which plug in to a main board. We haven’t had problems in the field so far but just to put our and your minds at rest we decided to have them professionally tested by Austest. We tested them to MIL-STD-202G, which is a military specification, and it involves placing the device on a table which vibrates up and down. The frequency is swept from 10 Hz to 55 Hz and back down again, and this is done over a period of 2 hours. The camera here doesn’t really do it justice because the camera shutter speed is only 30 frames per second so all we see is aliasing. At the highest frequency it peaks at 7.5 G up and down and the drive coil takes over a kilowatt of electrical power. I can tell you from actually looking at accelerometer data from cars recorded on race cars that they see nothing like this in the real world! The ECU was powered up during the test and ran … [Read more...]

Injection Timing on Port Injected Engines on Modular ECUs

This article is very brief and just covers the timing of injector outputs on port injection engines. It does not cover direct injection systems. Injector timing on the Modular ECUs can be mapped against RPM and load, and the number represents the end of the injection pulse in degrees BTDC. On a staged injection engine, you can set the injection timing separately for each stage, to promote better mixing, minimise water hammer in the fuel rails and so–on. In terms of appropriate values for injection timing, there are a few possible ways to do it, and to some extent it depends on what you’re trying to optimise. One technique I’ve seen people do is to adjust the injection timing until the indicate air-fuel ratio is richest (given constant fuel delivery), indicating that the combustion is most complete (least air left over). I don’t know if corresponds to any other real world effects such as minimum emissions or maximum torque, both sound reasonable but I won’t … [Read more...]

Cranking Conditions on Modular ECUs

  Cranking conditions are different from when the engine is actually running for several reasons: The engine speed is much lower, eg 180 - 240 RPM The engine speed changes throughout the cycle as each cylinder or rotor does its compression stroke (that’s the characteristic nyeh sound) The battery voltage is much lower than when the engine is running The ECU determines whether the engine is cranking or in its running state by comparing the current engine speed to the cranking RPM threshold. If the engine speed is less than this RPM threshold then the ECU enters cranking mode which has different behaviour from when the engine is running, which is what I will describe in this article. To get an engine to start nicely and reliably, there are a few considerations. The first, and this is often overlooked but it’s crucial, is to have a good trigger setup. The earlier the ECU knows where TDC is and which cylinder it’s up to, the sooner it can start generating … [Read more...]

Transient Throttle Conditions and How to Set it Up on Modular ECUs

This is the middle part of my fuel model talk from PRI in 2016, but I’ll also be discussing settings in the Modular ECU specifically in this article. Firstly let’s discuss what happens in a transient throttle condition – specifically when you open the throttle. We have all driven cars with aftermarket ECUs with no consideration for what happens in a throttle transient condition and we know they feel awful, but to properly understand what needs to be done, we need to understand the physics of what’s actually happening in the engine and why we need to consider transient conditions in the first place. The other consideration, once we know what happens in the engine, is what do we do about it. I’ve seen some other ECUs with up to 8 different tables to make different changes to the amount of fuel injected under transient throttle conditions, and often it’s not clear which one needs to be adjusted. They all interact and as I said in the talk about the steady state fuel model, if you … [Read more...]

Different Ways of Handling Changes in Temperature on Modular ECUs

Like it or not, engines need to operate over a range of temperatures, both ambient and the temperature of the engine itself. The engine has to be above the ambient temperature because it generates heat, and the only way to get rid of the heat is to have it above the ambient temperature. The higher the temperature, the faster the heat rejection by Newton’s Law of Cooling, so most engines are designed from the factory to run a bit under the boiling point of water. However we want the air temperature going into the engine to be as cold as possible to maximise its density, subject to other considerations such as fuel condensing out of suspension and so on. Fuel can also change in temperature, although that’s discussed in the injector model video, not in this one. Because of all these factors, what ECUs have traditionally done is to have a set of coolant temperature based fuel trims and air temperature based fuel trims. Often these tend to interact and produce unexpected results. … [Read more...]

How Fuel Mass is Converted to Milliseconds on Modular ECUs

If you’ve see the other videos or articles about how the ECU calculates the amount of fuel to be delivered, you’ll have seen that the end result of those is in the units of fuel mass, not milliseconds. This article explains how the ECU converts from fuel mass into milliseconds, and a bit about how injectors behave. Firstly, let’s talk about injectors. A fuel injector for low pressure EFI, as used on every port injected engine, is an electromechanical device. It has mechanical and electrical properties which are often not that well understood. In this description I’m going to talk about fuel pressure. When I talk about fuel pressure, I’m talking about the differential fuel pressure across the injector, ie the fuel gauge pressure minus the manifold gauge pressure. If you have a manifold referenced regulator, this should be pretty much constant. The fuel injector is designed so that the fuel pressure holds the injector closed. The injector contains an electromagnet, … [Read more...]

How We Do Injector Testing

This article describes briefly how we do injector testing. I can’t tell you all the secrets, because some of them are not mine to share I’m sorry to say. Firstly I want to give a big thank you to Paul Yaw from Injector Dynamics who has helped me understand a lot of the issues in testing injectors. Thank you! The setup to test the injectors is mechanically fairly simple. Test fluid is stored in a conventional fuel cell. This goes through a 100 micron filter, and then into a high pressure EFI pump. Fuel tank (on right), fuel filter, then fuel pump. Power supply at the bottom, and modified ECU at the top left. At the back you can see a tank, which is filled with pressurised air. The liquid then goes through a 50 micron filter, before going to an FPR2000 pressure regulator. From there, the fuel is filtered again using a 10 micron filter, and after that it goes into the injector test rail, after which is the final pressure sensor. After the fuel goes through the injector, it … [Read more...]

Fuel Model in Modular ECUs

Hello all, in this article I’ll describe the fuel model in the Modular ECUs. This is based on a talk that I gave at PRI in 2016, but in this talk I’ll talk specifically about where the settings are for the Modular ECU. In this talk I’m only talking about steady state tuning. However you need to understand this to be able to learn about transient fueling, and injector modelling. So if you like this is the first part of my PRI talk, but with specific reference to the Modular ECU settings. We’ve all seen the famous Greg Banish, Calibrated Success T-shirt which you can buy from Summit Racing, and I’m wearing mine now actually. I’m not sure I understand whether Mr Banish was expressing frustrating saying that it’s simple, why don’t people understand it – or if he’s making a joke and saying that actually there are many different terms in this equation, and if you don’t understand them all then you can get lost quickly. But either way, if it looks intimidating to you now, you’ll understand … [Read more...]

Flex Fuel Tuning on Modular ECUs

Since E85 has become commonly available, it has become a popular choice of fuel for performance tuners, because it's relatively cheap and similar octane level to race fuel. However it's not available everywhere, and often people with street driven cars, where it is legal to do so with an aftermarket ECU, want to have the option to switch to E0 or any other blend of ethanol and petrol / gasoline. Also, while where I live in Sydney we have E85 at the pump, apparently in the US it's quite common for "gas stations" to advertise the fuel as E85, but the ethanol content can be as low as 50%, which makes it E50. So if you want to be able to run different fuels without draining the tank, or use "pump E85" in the US, then you need a system that can handle any ethanol percentage in the fuel. This configuration is called "flex fuel" and is supported by all the Modular ECUs, and all the Select ECUs except the base model e420d. This article describes how to set up flex fuel on the Modular … [Read more...]