Digital MAP/TPS module to be used with Ignitech TCIP4 ignition unit.

cape

cape

Hero member
Location
Finland
Years ago, I presented an analog MAP/TPS system, which was designed by a fellow club member ltmt7. It has served well, but times change, things evolve and now it’s time to go digital.

I have designed a new module, based on programmable ATtiny85 microcontroller. Since it is digital, there is no ripple (or it is filtered) and the signal from MAP- and TPS-sensor to TCIP4 ignition unit is stable. The module can be used with Hall-effect TPS sensor or one build with potentiometer and spur gears on carburetor.

The ATtiny85 program handles MAP and TPS signals individually. The sensors must be calibrated; that is, the minimum and maximum voltage signals entered into the program must correspond to the actual readings. The program reads the voltage from the sensors and ATtiny85 analog input (ADC) coverts them into digital values between 0-1023. These values are then used for MAP and TPS scales, 0-100 %. Then the program calculates engine load percentage by combining the values and converts them to 8-bit PWM-signal between 31-204, values equal voltage between 0,6-4,0 V. The signal is a weighted average, MAP 40 % and TPS 60 %. Finally, the signal is sent to TCIP4 pin 6 via RC-filter, which converts it to stable analog DC-voltage. This all is done several times per second.

On TCIP4.exe program, the TP min. % is set to 0,6 V and max. % to 4,0 V. These voltage values are based on motorcycle standards, OEM-sensor values and Ignitech TCIP4 ignition unit sensor input safety limits. There’s no need to change these in the future.

I will make these to order. If interested, send me an email.

In the attached image, the microcontroller is not in place, but the sensor measurement points on its carrier are visible.

Cheers,

Sami
 

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  • MAP-TPS_module.jpg
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The MAP refers to "manifold absolute pressure" which in simplified terms is how much air is flowing though the intake manifold by measuring the air density. As you open the throttle more, the air density in the intake manifold goes up. This is a good thing to know as air density drops as you go up in altitude.

This is not to be confused with manifold vacuum as that is only the difference between the manifold and the atmospheric pressure.

The TPS is the throttle position sensor. Which is measuring how far the throttle is open.

With the MAP and TPS information you can determine engine load since we now know how far the throttle is open and how much air is going in to the motor. Is the motor producing 50 HP at sea level or 50 HP at the top of the Alps? On the top of the Alps, you will be using more throttle as the air density is lower but the same amount of air will be entering the cylinder as at sea level to achieve the same power output.

A bike with a carb will run rich at altitude as the more you open the throttle, the jets and needles will pass more fuel. The carb can't see the air density has gotten lower as it has no MAP sensor.

I first thought he was talking about fuel injection as these two sensors (and others) are needed but I now see the signals are going to an Ignitech module????
 
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I am also amazed at the technical understanding involved - but even though I have the TCIP4 I have no idea exactly what your module does, Cape!

I've bought a TPS unit but have yet to fit it to my FCR Keihins - a quick look shows that the throttle shaft is too close to my RH fuel tap.

If I ever do manage to fit it I was under the impression I simply wire it to the TCiP4 and programme it as per the Ignitech instructions.
 
Vince said:
Cape was saying ages ago insanely improved MPG
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From what? A MAP, a TPS or both? And what does the module do? I like the idea of no more pinking and the concept that the engine gets what it needs, not a default fuel-igniton control system based on revs, not throttle position or what the engine is actually doing (manifold pressure). Throw in exhaust temp and O2 sensors and you've got the lot. By that time, you should have fitted EFI!
 
No idea, but I said there were very big MPG improvements. Like going from 50mpg to 70mpg. It caught my attention back then.
 
What does the module do? It reads the voltage from MAP sensor and throttle position sensor. Then it manipulates/calculates the readings and sends it to TCIP4 as a steady voltage between 0.6-4.0 V. Ignitech TCIP4 uses this voltage to adjust a 3D advance map (TP voltage 0-100%). You can also use a raw voltage from the sensors, but TCIP4 really doesn’t like that. It can go to fail-safe mode if the voltage variation is too big.

Note! I have also added a fail-safe mode to the module program. If either or both sensors fails (like giving voltage outside the safety limits…broken wire…shorted +5 V power supply) the module goes to fail-safe mode and output voltage drops to 0 V. In this case TCIP4 uses only base advance curve. There is also an option to use a led light to indicate module's fail-safe mode.
 
Hope I get it right: Basically this is to adjust ignition timing depending on the load of the engine and the air density, so the bike runs smoother, ignition gets adjusted to what the engine can cope with in that special load/altitude situation rather than living with extensive compromises. This allows for an ignition map (3D) instead of a simple curve. This results in less throttle opening needed to accelerate the same way => less fuel consumption due to less fuel wasted that the engine can't cope with.

Does everyone need one? potentially not. But if you want your bike to run better, this can be a way to do that. However, you need an Ignitech and someone able to adjust the map accordingly as well as the TPS and MAP sensors I think.

For me with my limited knowledge about ignition timing and the few Kilometers I ride these days, I think it is a bit over the top. Next bike will have fuel injection, that is for sure...
 
I think a couple of tech-savvy blokes are running this locally, along with an Air-Fuel meter to adjust the jetting.
 
Laverdalothar said:
Hope I get it right: Basically this is to adjust ignition timing depending on the load of the engine and the air density, so the bike runs smoother, ignition gets adjusted to what the engine can cope with in that special load/altitude situation rather than living with extensive compromises. This allows for an ignition map (3D) instead of a simple curve. This results in less throttle opening needed to accelerate the same way => less fuel consumption due to less fuel wasted that the engine can't cope with.

Does everyone need one? potentially not. But if you want your bike to run better, this can be a way to do that. However, you need an Ignitech and someone able to adjust the map accordingly as well as the TPS and MAP sensors I think.

For me with my limited knowledge about ignition timing and the few Kilometers I ride these days, I think it is a bit over the top. Next bike will have fuel injection, that is for sure...
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Yes, you got it right.

If you have Ignitech TCIP4 installed on your bike, why wouldn’t you have MAP-sensor, TPS and the module as well. It makes a huge difference.
 
And pretty safe with that revert to stock if a sensor fails built in. Reducing the effect if any pinging occurs.
 
cape said:
Yes, you got it right.

If you have Ignitech TCIP4 installed on your bike, why wouldn’t you have MAP-sensor, TPS and the module as well. It makes a huge difference.
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Thanks Sami. So to be clear, the Ignitech will operate with a connection to a TPS, but not with the reliability your module brings? As I mentioned, I have a TPS but haven't had the time to devote to installing it,. I haven't even got the thing back on the road after my minor stack yet! And i know it will be tricky with my Keihin setup. A MAP sensor would be a lot easier as my inlet manifold already has a spigot for a vacuum takeoff (probably for the fuel tap on the GSXR the carbies came off.be?

How tricky would the setup of the 3D map
 
Not sure how clear it became, but this device is intended to be used with Ignitech or possibly some similar ignition control unit. Ignitech accepts TPS (throttle position sensor) or MAP sensor (manifold absolute pressure sensor), but not both. Ignitech accepts just one input signal monitoring load level of the engine. This device accepts TPS and MAP signals and feeds a single signal to the Ignitech unit. The unit does combining and filtering for these signals.

The unit has a microcontroller. Microcontroller is a so called single chip computer, that includes a microprocessor, memories and I/O devices such digital to analog and analog to digital converters. This device accepts also very complicated algorithms how to combine these signals, but this depends of the used program.

On the previous Laverda MAP, TPS, and MAP/TPS setups that I have seen in Finland this far, the main purpose was to add vacuum advance function which was not originally used on these bikes. In many cases these enabled more or less improvements in fuel consumption.

The device has some reliability features. The most usual situation is that if the output of any sensor or this unit itself fail, in most usual situations the output voltage goes to minimum or maximum value. The ignition unit is to be programmed such a way that on both ends there is the standard curve without any vacuum advance. This combining unit detects if any of the two sensors fail and zeroes the vacuum advance, and optionally turns on a LED to indicate a sensor fault. If the LED goes on, in most situations the fault is on one of the other sensors or their wiring.

-Jouni
 
Vince said:
I think a couple of tech-savvy blokes are running this locally, along with an Air-Fuel meter to adjust the jetting.
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I think that's true. A couple of blokes are developing these in Finland. I'm not involved, but have suggested some improvements.

-Jouni
 
cape said:
I’m not an expert when it comes to 3D map. Mine was made by a friend of mine. In the attached image you can see my current 3D advance settings, they have been working fine.
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From my interpretation of your map, max advance at virtually any throttle setting above closed throttle is 32 degrees. So why would 37 degrees be programmed in if it's never going to eventuate? My (meagre) understanding is that you want to lower ignition advance when opening the throttle at certain rpm (looks like mid rev range) would result in pre-ignition or pinging. Once you're over a certain rpm advance should just be set as if there were no TPS?
 
piranha-bro2 said:
From my interpretation of your map, max advance at virtually any throttle setting above closed throttle is 32 degrees. So why would 37 degrees be programmed in if it's never going to eventuate? My (meagre) understanding is that you want to lower ignition advance when opening the throttle at certain rpm (looks like mid rev range) would result in pre-ignition or pinging. Once you're over a certain rpm advance should just be set as if there were no TPS?
Click to expand...
Not really. At higher rpm and low LOAD (determined by TPS/MAP combined by this unit) you dial in more advance to (long story short) improve fuel consumption. The typical 2D map which is just a curve rising with RPM up to a (usually) max of whatever the engine likes (on a triple 32deg) is to allow for 100% load and avoiding pinging. But at 4000rpm cruising along the freeway with 10% throttle there is very little load on the engine, less heat etc, so the engine can take way more advance at that point without pinging or melting the pistons. At 4000rpm and 10% and 37deg, it makes more power than 4000rpm, 10% and 32deg, so you can cruise along at say 5% throttle instead of 10 - so you get your improved fuel consumption. Once you give it the beans, it backs off advance to levels which will avoid pinging and heat problems.

That's my only slightly informed take on it at least. My EFI system is load based (TPS+MAP vs rpm) and is mapped for similar very high ignition advance at low load.
 
breganzane said:
Not really. At higher rpm and low LOAD (determined by TPS/MAP combined by this unit) you dial in more advance to (long story short) improve fuel consumption. The typical 2D map which is just a curve rising with RPM up to a (usually) max of whatever the engine likes (on a triple 32deg) is to allow for 100% load and avoiding pinging. But at 4000rpm cruising along the freeway with 10% throttle there is very little load on the engine, less heat etc, so the engine can take way more advance at that point without pinging or melting the pistons. At 4000rpm and 10% and 37deg, it makes more power than 4000rpm, 10% and 32deg, so you can cruise along at say 5% throttle instead of 10 - so you get your improved fuel consumption. Once you give it the beans, it backs off advance to levels which will avoid pinging and heat problems.

That's my only slightly informed take on it at least. My EFI system is load based (TPS+MAP vs rpm) and is mapped for similar very high ignition advance at low load.
Click to expand...
Awesome explanation! Thanks Steve.
 
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