TS and Gary, you're both welcome to complicate the model all you want.
greatest contribution to wear reduction
- Thread starter bonnie john
- Start date
- Status
- Joined
- Sep 28, 2002
- Messages
- 39,793
- Joined
- Sep 28, 2002
- Messages
- 39,793
and that approximately 84 % of the ring wear occurred during
the first approximately 22 minutes of operation
Sure looks like "90% of wear occurs at startup" thing to me.
the first approximately 22 minutes of operation
Sure looks like "90% of wear occurs at startup" thing to me.
So the solution is a pre-lub system? maybe the auto manufacturers don't install pre-lub systems because they want our engines to eventually break lol
- Joined
- Sep 28, 2002
- Messages
- 39,793
Depends on who you ask and how they use the term "startup" now doesn't it? Apparently SAE type engineers define startup as anything other then steady state. Now I guess that if they further classified it to "initial startup" ...then differeneces could be more easily determined.
No, the solution is block warmer and low-sulfur fuel.
Try this, replace the two brackets at the end with parethesis:
http://hosting.dynamis.net/littlerocket/MMCAllAluminumCylinderBlock[2ZZ-GE].pdf
Recall the original premise was "cold-start wear".
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=015963;p=1#000001
I define a "cold-start" as when the engine is at ambient atmospheric temperature, started and run up to operating temps. Obviously, the length of "cold-start" wear event will vary according to the temperature of the engine and how long it takes to ramp up to operating temperature. It's also the reason a range of miles was given in the first model I spoke of. The higher range is for extremely cold temps for a poorly maintained engine (e.g., bad thermostat).
Help might be on the way:
http://www.prod.exxonmobil.com/refiningtechnologies/pdf/SCFSpring2002PTQ.pdf
I leave it to others to see if any of this actually transpired in the U.S or if it got derailed.
http://www.prod.exxonmobil.com/refiningtechnologies/pdf/SCFSpring2002PTQ.pdf
I leave it to others to see if any of this actually transpired in the U.S or if it got derailed.
- Joined
- Sep 28, 2002
- Messages
- 39,793
Do you mean low sulfur gasoline in general ..or any specific ppm
According to one site ..it started in 04 and will be completed by 08 to convert the entire gasoline supply
or am I having an episode
Go for it. Good work so far, as we know more than we did.quote:
Originally posted by Gary Allan:
Do you mean low sulfur gasoline in general ..or any specific ppm
I am not sure about all the equations (even after 3 semesters of calculus) but start up is defined as the period beginning after a minimum of 4 hours of rest after the engine has been running. The resting is at STP. If my chemistry is still in there - about 75 F. It might be 73 F, related to the Kelvin scale.
The start up period is that amount of time before a steady state of wear occurs, about 20 - 30 minutes in test engines. The rate of wear is higher at the start of the interval and slows to meet the steady state level.
Start up wear is significant and shown to be so many times over. It is usually tested at an ambient temperature of 75 F, not freezing temperatures as one may initially believe.
aehaas
The start up period is that amount of time before a steady state of wear occurs, about 20 - 30 minutes in test engines. The rate of wear is higher at the start of the interval and slows to meet the steady state level.
Start up wear is significant and shown to be so many times over. It is usually tested at an ambient temperature of 75 F, not freezing temperatures as one may initially believe.
aehaas
I just realized even a propane engine generates water vapour, which would condense on cold starts, and disrupt bore lubrication. The hot coolant bottle idea might work to reduce startup wear, but it would add weight.
"1struck, as usual, looks like you need help with math too."
Since you got the same numbers that I did, I guess you need help too.
A 200 mile commute, or 400 miles a day isn't that uncommon, considering delivery, sales, etc., so there should be LOTS of vehicles with a million miles, instead of very, very few. In the example that you provided the guy drove 800 miles a day, with what I would guess be one cold start.
Since you got the same numbers that I did, I guess you need help too.
A 200 mile commute, or 400 miles a day isn't that uncommon, considering delivery, sales, etc., so there should be LOTS of vehicles with a million miles, instead of very, very few. In the example that you provided the guy drove 800 miles a day, with what I would guess be one cold start.
Does someone actually have to explain this to you, or are you just trying to push someone's button?
If it's the former, reread this:
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=015963;p=2#000028
In case someone needs a reference:
"Wear tests with neutron bombarded compression rings in fired engine tests including a gamma ray spectrometer have shown that the piston ring wear rate during the start-up period was up to 45 times
the steady-state wear rate, and that approximately 84 % of the ring wear occurred during
the first approximately 22 minutes of operation (Perrin et al., 1995)."
From here (page 73:
http://virtual.vtt.fi/inf/pdf/tiedotteet/2002/T2178.pdf
Toyota did interesting study showing ring wear inversly proportional to temperature of coolant and directly proportional to sulfur in fuel:
http://www.sae.org/technical/papers/2000-01-1231
(sorry can't find the free full version)
These studies are usually not discussed on BITOG much because they prove that there are factors more important than oil type or brand.
"Wear tests with neutron bombarded compression rings in fired engine tests including a gamma ray spectrometer have shown that the piston ring wear rate during the start-up period was up to 45 times
the steady-state wear rate, and that approximately 84 % of the ring wear occurred during
the first approximately 22 minutes of operation (Perrin et al., 1995)."
From here (page 73:
http://virtual.vtt.fi/inf/pdf/tiedotteet/2002/T2178.pdf
Toyota did interesting study showing ring wear inversly proportional to temperature of coolant and directly proportional to sulfur in fuel:
http://www.sae.org/technical/papers/2000-01-1231
(sorry can't find the free full version)
These studies are usually not discussed on BITOG much because they prove that there are factors more important than oil type or brand.
quote:
Originally posted by TooSlick:
You two are like some old married couple...
To the woodshed, both of you! All these technologies are on their way, and on the road in some cars today. The current generation Prius (MY 2004-now) has built-in block heating AND a form of pre-lube system. Upon shutdown, the car pumps 3L of hot coolant into a thermal bottle that's capable of keeping it at or near op temp for three days (I assume that time drops with ambient temps, to some extent). As soon as you turn the drive system on, it immediately heats itself by quick-pumping that coolant back into the block and head of the gas engine (keep in mind that generally, the gas engine won't fire up until this is done; your're on electrics until then).
Because of the large number of starts the gas engine endures (it's on and off all the time, so not many are true "cold" starts), the system "pre-lubes" the gas engine by quickly spinning it up (via the electric motors) before giving it fuel and spark. As you learn the car, you start to feel this momentary "spin up" and can use it as a sign to back off and "cancel" the gas engine lightoff, if you happen to by trying to maximize gas mileage at that moment.
Oh yeah, the manual recommends the use of the lowest sulphur fuel you can find, which I find odd, as sulphur content isn't exactly a heavily advertised aspect of gas quality.
- Status
Similar threads
- Sticky
