7afe lean burn engine - tech

[KinLoud]

At pick a part otahu yesterday...
Saw a AT211 7afe powered Corona premio? with a 7afe "lean burn" engine
No distributor, twin coil pack DLI (distributor less ignition)
It has a sensor that plugs into the end of the head where the distributor goes on earlier versions. It picks up where the exhaust cam is in it's cycle.
It also has a crank angle sensor!
Just waiting to be the basis of a 7age maybe? Good for rwd setup as no big hole needed for the distributor?

BUT!!!!!
It also has a sensor that screws into the front end of the head just below the cam pulley. This sensor looks a bit like a temp sensor and the tip of it ends up either just above the intake or exhaust valve or in the combustion chamber itself.
I put a screwdriver down the hole and it would stop the engine from being turned - so the screwdriver was either jambing a valve or the piston!!
Any idea what the sensor does and where the tip of it ends up???

Ken
Hamilton
021 408 863

[no_8wire]

hmm was the engine ok? might go have a look...how much do they charge again?

[Mr Revhead]

thats a sensor for combustion pressure according to the epc

[slighty_sykotic]

What the hell does it want to know that for?!?

--Sykotic

[Mr Revhead]

lean burn.... so im guessing it makes some pretty fine calculations....

[slighty_sykotic]

Why did they make them? low emissions? or low fuel use?

[Lloyd]

Emisions from memory, they dont really save you any petrol (well, GDIs don't). Those GDIs are great for filling up the inlets with gunk as well

[KinLoud]

I don't think its a DGI (direct gasoline injection).
Maybe it senses any knock directly? Rather than via the block.

Ken
Ham
021 408 863

[KinLoud]

Just doing the old google "satisfy my curiosity" thing...
Found a bit more info:
http://www.sae.org/technical/papers/930882
It says:
"A combustion pressure sensor (CPS) has been developed to measure combustion pressure in an engine cylinder. The CPS has been installed in the advanced Toyota lean burn engine for a Japanese commercial car on October 1992. The control system with the CPS is useful for improvement of fuel consumption efficiency and emission of the commercial car.

The CPS was installed in the first cylinder of the engine and measures the combustion pressure. In this system, the engine torque caused by a cycle combustion was calcualted with the pressure signal of the sensor in real time. The sensor was especially designed to detect the lean burn limit with torque variations by means of unstable combustions.

The CPS for the lean burn control system realizes advanced performances, durability, reliability, with the minimum components and the reasonable cost. This paper shows the structure and characteristics of the CPS, in detail."

SO... it detects torque variations by sensing combustion pressure - so it can detect the lean burn limit with torque variations by means of unstable combustions.

Also look at page 17 and 18 in the article. It discusses detecting knock.
http://www.delphi.com/pdf/techpapers/2000-01-0932.pdf
Also look at page 4 and 5 here. Talks about the toyota system.
www.deh.gov.au/atmosphere/fuelquality/p ... ryapp1.pdf

A bit techie I know but all interesting.

Ken
Ham
021 408 863