Sensors and Measurement

[Randy Van der Ree]

Hi, how r u folks, My team and I would try to go to the 2005 Formula SAE (first year), and my assignations are the electric and electronic system of the car we want to make, Right now I am studying the sensors of the motor that we bought a Suzuki GSX-R600, and have some difficulties on how to measure the temp of the motor and the RPM, if anyone have some infromation that caould help me for initiation would be greatfull.
http://www.fsae-luz.org

[Randy Van der Ree]

Hi, how r u folks, My team and I would try to go to the 2005 Formula SAE (first year), and my assignations are the electric and electronic system of the car we want to make, Right now I am studying the sensors of the motor that we bought a Suzuki GSX-R600, and have some difficulties on how to measure the temp of the motor and the RPM, if anyone have some infromation that caould help me for initiation would be greatfull.
http://www.fsae-luz.org

[B Lewis @ PE Engine Management]

Hi Randy,

What kind of info are you looking for? I think that I could probably help you out.

[Randy Van der Ree]

HI brian, as I said before we bought a SUZUKI GSX-R600, This motor brings a:
camshaft position sensor
crankshaft position sensor
Temperature sensor
Intake air temperature sensor
Intake air pressure sensor
Throtle position sensor
Gear Position sensor
Coolant temperature sensor
We need to mesaure the RPM and temperature on the dashboard, where can I get the electrical singal to measure these parameters. if they are all coneccted to the ECM

[B Lewis @ PE Engine Management]

Randy,

RPM - The signal coming out of the sensor will be a sine wave whose frequency corresponds to RPM based on the number of teeth on the wheel. You will have to do some conditioning by measuring the period to get RPM.

Coolant Temperature Sensor - This type of sensor is a thermistor which means it's resistance changes as a function of temperature. When connected to the ECM, it is part of a voltage divider. This means that you will be able to measure a voltage off of one side of the sensor. This voltage will correspond to temp. Be carefull, though. If you use a measurement device with low impedence (<100kohms) you may pull the signal down. Also, the voltage will not be linear with temperature. A curve defines the relationship. See PE Support (http://www.pe-ltd.com\support.htm) and download the data sheet for the GM sensor. This will give you a good idea what the cal will look like. There is also a sample circuit. Good luck.

[Randy Van der Ree]

Thank you very much Brian, your information has been very helpfull, I am thinking to use an amplifier, for the signal of the termistor, and maybe a frequencimeter for the RPM

[RiNaZ]

hey brian, this may sound stupid, and of course, im not an engine guy ...

i was at Motec seminar, and they were talking a lot about dynoing the engine. My question is, why do you need to dyno an engine? cant you just take a stock engine and just use it for the competition?

Maybe you can gain a little bit hp by dynoing the engine, but im sure the stock one has already been dynoed by the factory before they were even sold.

[formula_geek]

RiNaZ-

Unfortunately (or fortunately depending on how you approach it), the designers of this competition have introduced a rule that throws a curve ball at the "take a stock engine and just use it for the competition" theory. A cursory glance at the rules shows that all the air an engine uses in FSAE must be drawn through a 20mm diameter orifice.

Most motorcycle engines used in this competition are near the 600cc displacement limit, almost universally an inline four cylinder. These engines come equipped from the factory with four approx. 40mm diameter carburetors, or in some instances a factory fuel injection system with throttle bodies of approximately the same size. That is reducing the intake area by a factor of 16!

To make a long story short, to overcome this teams build a custom manifold utilizing a single throttle body connected to a converging/diverging nozzle that is 20 mm at the throat, as well as a custom 4-1 (or 4-2-1) exhaust system.

It takes more than good guesswork to setup fuel and injection maps for the custom engine control systems utilized by almost all teams. This is where the dyno comes in.

[Ben Beacock]

Our GSXR has ran reasonably well for the last 2 years with a stock engine controller. neither time was by choice, since last year it was supposed to run with a piggyback fuel controller that didn't work out, and this year was supposed to be a full custom ECU (just ran out of time to get it running right)
The engine will run oddly when cold, and use too much fuel, but it is very reliable.

[RiNaZ]

Ohhhh ... now i see. Thanks FGeek for the explaination http://fsae.com/groupee_common/emoticons/icon_smile.gif

[B Lewis @ PE Engine Management]

Couldn't have said it better myself. Although if you are methodical about your testing and have some seat time you can do quite nicely without a dyno.

While we're on the subject of tuning, I saw quite a few teams re-packing mufflers at competition to cut down on noise. In most cases, this effectively wipes out any tuning time that you had on the engine because of the change in restriction. PLEEEASE do yourself a favor and make sure you can pass noise early in the design so all of your tuning is valid.

[Randy Van der Ree]

HEy yo'll. because of the change of the intake (restriction) I imagine that the parameters of the ECU has to be changed, for better performance, How can I change the stock engine controller? are they accesible? or do u buy new ECU's for programing it yourselve

[B Lewis @ PE Engine Management]

Randy,

You have several options here. You can use a stand alone engine controller like ours, Motec, SDS, Haltech, etc. or you can use a piggyback system like the PowerCommander. The piggyback system modifies the outputs from the stock ECU based on your programming. It's less expensive but has less flexibility also. I am not aware of anyway to get access to the stock ECU.