It used to be relatively easy to know your car was leaking oil; there would be a puddle underneath it. But now most cars, especially the nicer ones, are made with plastic or aluminum panels on the bottom for aerodynamic purposes. The downside of this is that if oil leaks it will collect on the plate and you don't know about it until enough has collected that it runs over the sides. By this time it is a pretty big mess and the problem could be getting worse. So cars with these underside panels should have a detector for leaked oil. It could be a moisture sensor, or possibly infrared, located in a key location under the engine-transmission gasket, and trigger an "oil leak" light on the dash.
-- DIYMatt, May 15 2009

oil is everywhere. Some level of seepage is accepted, even in modern cars (this seepage lubricates the seal, extending its life). Oil wouldn't trigger a "water" sensor. I really dislike adding finicky expensive "features" to cars that the users will just be confused by and where the money could have been better spent on simply making the components more robust. BONES
-- WcW, May 15 2009


Hence the infrared sensor. The IR light is aimed at a shiny piece of metal at the very bottom of the car. When nothing is on top of it the light return will be very high. If water gets on there the return would be lower, but still withing parameters. But add some dark oil or other colored fluid and it trips the warning light.
-- DIYMatt, May 15 2009


Well I like the IR sensor idea. Different substances have different IR spectrum absorption characteristics, and the receiving sensor could undergo frequency sweeps to analyse which specific frequencies have been absorbed.
A computer database then identifies the measured substance based on its absorption characteristics.
Similar techniques are used to separate various plastics in recycling centres. [+]
-- skegger, May 15 2009


The undertrays fitted to road cars have, of neccesity, drain features which prevent them from filling up with water. This works just as well with any fluid, so the problem you're trying to solve doesn't exist.
-- Twizz, May 15 2009


Oil spill is often on a very small scale, small enough to become bound to dust&dirt on the undertray, never dripping down. I like the 'something should be done' - aspect of the idea, the 'something' is a little quarterbaked, though.
-- loonquawl, May 15 2009


also: sp: "their"
-- loonquawl, May 15 2009



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