The 14 January issue of New Scientist has a good article on clean burn engines. It reports on work by the major manufacturers on the HCCI engine. (HCCI = homogeneous charge compression engine). This is a development of features from both petrol and diesel engines with a view to meeting the coming restrictions on release of NOx and particulates (and a 20% increase in fuel economy). It will most likely introduce solenoid open / close mechanisms because it requires such close control of valve timing. Whoopee, no more busted cam belts!
The development hasn?t reached full operational range yet - it can?t yet fire effectively enough at the extremes of low and high loads. The earliest engines in use might have normal petrol or diesel operation at the extremities and use HCCI in the mid range, where it is most effective. HCCI electric hybrids are also mentioned.
Well worth a buy, New Scientist of course!
|
It will most likely introduce solenoid open / close mechanisms because it requires such close control of valve timing. Whoopee, no more busted cam belts!
Just as well that modern cars never have any failure of their electrical components, then, because with this engine it could cause a nasty valve-meets-piston incident.
|
I imagine you'd design it so that the valve is spring-loaded outwards so that in the event of a solenoid failure the valve fails out of the way of the piston.
Imagine it would be an expensive job to fix if a solenoid did fail, though, as getting to them would be a nightmare.
|
A I have stated on a different thead Sulzer Diesels have had a camless large marine diesel In production for about 4 years.
Soliniods are one way but hydraulics are also used all be it with soilinoids controlling the hydraulics
Don't think i'd like to be the 1st owner of one of these cars!
|
F1 cars have used pneumatic valve operation for somewhile.
True lean burn I thought was killed by the environmental muppets deciding that all engines had to have catalytic converters. I know Ford were working on lean burn at the time and that doesn't work with cats.
Jim
|
|
Surely so long as whatever comes out of the exhaust conforms to some set value then does it matter if it has a cat or not?
|
As I understand it in order to appease the tree huggers the rules were written in such a way that cats were compulsory. Something to do with running at the Stoichiometric point, lean burn engines by their nature don't so cannot meet the legislation.
Jim
|
|
|
