About Cylinder Pressure
About Cylinder Pressure
(OP)
Hi all,
I am working on engine bearing testing systems. I have problem with to determine engine bearing specific loads in the SI and CI ICE.
I would like to learn when the internal combustion engines should give maximum cylinder pressure value? During Maximum Torque or During Maximum Power? Which conditions will give more cyclic stress - load upon the conrod bearing? This is very important for me to make real test our engine bearings. Are there anybody offer me practical methods to determine peak cylinder pressure and maximum specific load on the conrod engine bearings?
happy new year,
I am working on engine bearing testing systems. I have problem with to determine engine bearing specific loads in the SI and CI ICE.
I would like to learn when the internal combustion engines should give maximum cylinder pressure value? During Maximum Torque or During Maximum Power? Which conditions will give more cyclic stress - load upon the conrod bearing? This is very important for me to make real test our engine bearings. Are there anybody offer me practical methods to determine peak cylinder pressure and maximum specific load on the conrod engine bearings?
happy new year,





RE: About Cylinder Pressure
Don't forget that the inertial loads are very significant and those go up with the square of RPM. The peak tensile load on the connecting rod generally happens near TDC between the exhaust and intake strokes. At TDC between compression and power strokes (during combustion) the inertial load on the connecting rod is tensile and the cylinder pressure load is compressive. Which one is greater than the other ... will vary.
RE: About Cylinder Pressure
But the most mechanical stress occurs when the fuel ignited not after it burned.
never ignite the engine less than 8 degrees BTDC, after that it starts to erodes the conrod bearings
RE: About Cylinder Pressure
RE: About Cylinder Pressure
Really??
Typical MBT ignition timing on an automotive gasoline engine running under load (when it matters) is 20 - 35 degrees BTDC depending on how good or bad the combustion chamber is. (A good fast-burn chamber will need less ignition timing to achieve best torque.)
Here is a randomly selected ignition timing map. RPM is increasing across the top, engine load increases as you go down because the chart is done in terms of trapped air mass per stroke.
http://www.castlehillexhaust.com.au/files/hsvspark...
24 degrees BTDC, or pretty close, ignition timing at full load at 2800 rpm and up.
RE: About Cylinder Pressure
RE: About Cylinder Pressure
I said "never ignite the engine less than 8 degrees BTDC" means (ingition <8 ) I generally tune up more than x>8
RE: About Cylinder Pressure
RE: About Cylinder Pressure
I enlightened your given valuable informations
RE: About Cylinder Pressure
Overrev = fracture, due to some combination of tension and bending.
Some highly turboed engines have had rods shorten and/or buckle.
Jay Maechtlen
http://www.laserpubs.com/techcomm