Lead reduced uncontrolled ignition in gasoline/petrol engines so a particular fuel could be used in a higher compression ratio car with a more advanced spark, and sold for a higher price meaning more profit for the marketers who could sell a fuel which would do the job without having to buy the better quality components.
The car driver got more bang for buck, the oil company sold higher margin fuel, the refiners just clipped the ticket, the lead producers were very very happy, the children behind the exhaust pipe and eating the crops on which the lead landed and drank the water got brain damage.
Unfortunately, the lead fouled the combustion chamber meaning carcinogenic lead scavengers had to be added to the fuel. The deposits increased the compression ratio leading to increased knock and engine damage. The lead also fouled the oil and dropped out as "grey paint" around the inside of the oiled part.
People working on engines and exhausts were normally sub-clinically lead poisoned.
I have never seen efficiency data to demonstrate that there was actually an increase in kilometres per dollar and I suspect that the effect of the lead was to retard the ignition rather than to simply avoid knock which has the same effect as retarding the spark, which means more fuel is burned due to lower thermodynamic efficiency.
Shell invented "Spark Aider" and started selling it in 1986. We [in BP Oil] took a look at it and I decided they had made a big bungle. They released in just as hot weather arrived but they didn't do what they should have done which was boost octane number at the same time. Then people would have noticed a good improvement in their cars. All they noticed was engine knock!! Formula Shell was a disaster. Serve them right.
My theory was that marketing flim flam fools ran away with some good R&D work, cheap-skated the motorist, and bungled the whole thing. My initial reaction when I first saw it was "Oh no, we are doomed" but after a week of investigation and pondering, I decided "Ha ha, they are doomed". Sure enough, the hot weather came and they crashed.
Back to lead, it was a stupid thing. It was simply unnecessary and was another cheap-skate way of making money from ignorance.
The Los Angeles smog did the USA a HUGE favour. It was because of smog that catalytic converters were required and because of platinum incompatibility with lead that the lead was removed. As a result, the USA avoided 30 years more of lead pollution and brain damage.
To this day, there are still places which allow lead in petrol.
0.25IQ points doesn't sound much. "Hey we have 100 of them! I can spare a couple". But somebody with 30 more IQ points than that person can figure out the economic cost and it is in the umpty mega$billions. Think salary differences between 100 IQ point people and 120 IQ point people and 140 IQ point people.
Mqurice |
