DIY engine control system build

[rowycoracing]

This will be a bit of a different thread but it should be interesting to some. What I am planning to do is build a complete electronic engine control system from scratch. The system will control fuel injection, spark and timing, fuel pressure and delivery, boost, cooling fans etc. It will also be built using closed loop control with a wide band O2 sensor. Why you ask? 1) because I have time and I want to learn how to do it and 2)I've done some research and I think that I can get significantly more performance from some of these bike engines by changing the way the fuel, spark and air are controlled. By that I mean performance that is specifically geared to use in a 800 to 1200 pound buggy as opposed to the way the engines come tuned for emissions legal and for a crotch rocket. Also I want to program the system so that it is very easy to add a turbo to the system. I have access to both an engine dyno and a chassis dyno so as the build goes along I'll be able to test the performance in stock configuration and then doccument inproved performance as I go along. I have lots of research to do to figure out the electronics necessary and the programming that will be needed and my access to the dyno's is limited by the teaching schedule at a local university so this will take a while to get done. So here goes ... Tim

[rowycoracing]

The first task is to build a board that will house all of the relays, breakers and fuses in one compact spot. Also this board will be the termination spot for the entire wiring harness. This way the whole set up will be very compact and easily mounted in a small enclosure that is sealed from he elements. Here I am laying out all the components ... mainly a dozen resistors or so, a few capacitors, some relays and relay sockets and a IC board. There will be fuses and relays to control all the engine functions as well as realys and fuses for other buggy needs like lights etc.

[rowycoracing]

relays, sockets, connectors etc.

[rowycoracing]

I will use standard off the shelf cabling where I can.

[rowycoracing]

Realy board under construction, most of the components soldered in in this shot.

[rowycoracing]

Relay board completed. It has 4 auto resetting electronic relays, four 40 amp relays, 4 blade fuse sockets and termination blocks for all functions such as intake air temp, intake air pressure, boost pressure, throttle position, O2 sensor, up to 12 (3 sets of 4) injectors, coolant temp, oil temp, cam position sensor, RPM sensor, gear position sensor etc. Like I said earlier if I did it right then every wire needed in the harness can come to this one spot.

[rowycoracing]

Now I will build an engine simulator. This will be a fairly simple board that will have potentiometers mounted on it that will produce simulated outputs designed to simulate engine functions. It will output simulated coolant temp, injector function, throttle position, engine rpm, O2 signal etc. The reason for taking this step is to be able to have something that I can test my engine control system with. The potentiomenter will allow me to simulate each parameter through it's full output range without having to try and do that through the engine. This will not be part of the final install, just a way to test the CPU and to diagnose problems is something fails. The simulator board is the one on the left here, I'm soldering some removeable jumpers on the back so I can simulate either a wide band or a narrow band O2 sensor.

[rowycoracing]

OK, the relay board and simulator board are all done. This pic shows what the finished system will look like. The relay board is connected to the aluminum case what will eventually hold the CPU using a standard db37 cable and connectors. That's the whole set up, with the sijmulator board being used only for testing. The relay board is about 3.5" by 5.5" and the CPU enclosure is aboout 4" by 6". The interconnecting db37 cable can be any length I want. The other side of the CPU (shown in the pic where no cable is connected) will output through a standard db9 cable to a laptop for programming and real time engine tuning. There will also be three LED just to idnicate proper power up and basic function. For now that aluminum CPU box is empty ... building the CPU is the next step and it is a lot harder!

[KWiKSand]

Are these boards from megasquirt? http://www.megasquirt.info/index.html

This should be a interesting thread. Thanks for sharing.

[rowycoracing]

Yeah there are several DIY sites out there for this type of thing. Mostly all for cars as far as I have found. Megasquirt is a good one and the megasuiirt boards are a good base to start with because they are rugged and have some circuitry in place. In general I am going to use the megasquirt info and right now I am planning to use magatune for the real time engine tuning. That may change though. And yes the relay board is a megasuirt type board with a couple of circuits added for other buggy functions like lights, an oil cooler fan etc. The simulator is a magasquirt board with the extra O2 circuit added (so I can have a wide band circuit and a narrow band circuit) and two other pots so I can try to use MAP, throttle position and the cam sensor all together. The engine I will be doing this testing on is a 2005 CBR 1000rr which has primary and secondary injectors so I am going to do my own programming to get those working sequentially (that's not something megasquirt does now). I also want to add a timing advance/retard function for when I boost it with the turbo which I think will take some more custom programming unless I can find a DIY specific to that somewhere. Last I'll add direct boost control to the megasquirt board. Should be interesting to see how it performs in the end I think.