Interference!

Wonderful to see that now there is "some level of science" being applied in public discussion as to possible causes and therefore possible robust solutions.

In auto industry, much of the EMI testing is done with pristine "new" components as they are fiitted in the vehicle set-up. Some testing simulates parts of the aging process like temperature cycling and such, but the real world has infinite variations possible.

I have another suspicion that seems to be missed in the electronics world so far. The introduction of the "lead free" solders into manufacturing has brought its own set of challenges. One of those are teh so calledd "tin whiskers" that can develop over time literally growing out of the solder joints. Given the fine pitch of the chips used, it is possible for these to bridge across leads.

I haven't seen any material relating those issues and would be interested if anyone out there is aware of that.

Hi Just an Engineer,

One of those are teh so calledd "tin whiskers" that can develop over time literally growing out of the solder joints. Given the fine pitch of the chips used, it is possible for these to bridge across leads.

A valid concern. Since anything sold to the European market must be RoHS compliant, there must be no lead. This would account for 100% of automobiles manufactured currently. I don't know when the car manufacturers started to comply with this, but I bet it has been at least 2 years.

I just have one question. Why did they do away with manual accelerator linkages in the first place?

Mike

One of the reasons they did away with mechanical linkages because they used to stick on!

(If incorrectly adjusted, they could end up locking like a cam and not being able to turn off.)

why remove mechanical throttle.

simple to comply with emission and economy, the engine management needs control of everything, including the throttle.

the ecu can then control precisely the exact timing, when the plug fires in each cylinder, and adjust fuel injection into each cylinder, all this comes at a price you need to be able to control all the parts of the engine, No good doing all that and leaving the dumb driver to interfere with all the precision by putting his/her foot down.

new fly by wire cars, you put your foot down, the ecu looks at all its inputs and checks to see if it can give you the throttle if yes you go fast if not you don't.

Other problems with emi testing is i am led to beleive is the tests are carried out with single frequencies, and thus if there are multiple frequencies as in an igniton system, it can produce a wide rang of frequencies at the same time.

as an example the company i used to work for ATLET fork lift trucks were tested for EMI compatability, but the test was never prefomed at the sort of power levels found if a mobile phone is place in the pencil holder which is just above the ac contoller on the UNS and UHS range of trucks, and as such all sorts of strange faults occured on these trucks. Event though as i say they conformed to EMI specs