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  1. JackAction

    What is Engine Load?

    I don't have a copy of J1995, but J1349 (2004) - which is the same standard but for net values instead of gross values - mentions also «A method for determining net full load engine power and torque with a dynamometer». Looking at the definition section: So these values are measured with...
  2. JackAction

    What is Engine Load?

    I can't believe how condescendant you are, but I'm sorry if I'm not sure what you don't understand. This might be a quote of interest from the same earlier post: And before you say anything, torque is directly proportional to mep (in theory; in practice, I know that you have to considered...
  3. JackAction

    What is Engine Load?

    Sorry, it seems only one link can be attached to a post. Here's the file for the Theory of ground vehicles reference. http://files.engineering.com/getfile.aspx?folder=9c499d82-d64f-42a0-b54a-b17fa7837ead&file=theory-ground-vehicles-p227.png
  4. JackAction

    What is Engine Load?

    That seems pretty much the same to me. From the reference in my earlier post (7 Mar 15 02:07): As for a reference for an electric motor, you are right, I did not provide one. There is one I had in mind since the beginning of the thread, but couldn't find a copy of the extract I needed...
  5. JackAction

    What is Engine Load?

    Traction, or tractive force, is the force used to generate motion between a body and a tangential surface, through the use of dry friction. In automotive engineering, the terms [tractive force & tractive effort] are distinctive: tractive effort is generally higher than tractive force by the...
  6. JackAction

    What is Engine Load?

    Power only describes load in an electrical context. In a mechanical context, it is always a force or a torque. Load (disambiguation) But as you said earlier: When comparing 2 engines, if the rpm is the same, power is proportional to the torque so it doesn't make a difference to use one or...
  7. JackAction

    increasing torque without any big modifications

    Maldistribution is not inherent to carburetors, it is inherent to single point fuel mixing. Yes, the AFR might be OK right after the mixing point (carburetor or TBI), but due to the inertia forces, the fuel can leave one point of the air stream to go to another, sometimes accumulating on intake...
  8. JackAction

    Torque and power quiz

    But when you say this, combined with your previous statement «that an ICE is closer to being a constant torque device than a constant power machine» I would think that a downshift is more of a power increase than a torque increase. When you downshift - assuming same throttle opening - the...
  9. JackAction

    Torque and power quiz

    I don't understand what you mean, could you give an example? Like I showed you in my simulator, I don't know anything about engine rpm (or transmission or wheel rpm for that matter) and can still give an estimate of acceleration. What if you have an engine that doesn't rotate, as previously...
  10. JackAction

    Torque and power quiz

    HP might be an arbitrary number, but it is a unit. What this unit represents is power, and that is a very real thing. Power is the result of the combined effect of torque AND rpm. That is what is important to understand. Torque by itself doesn't tell the whole picture, neither does the rpm...
  11. JackAction

    How many intermediate driving gears ?

    It may not be an idler gear, but it may be taken as «an intermediate drive gear», just like the one on the crankshaft side (so you have 2).
  12. JackAction

    How many intermediate driving gears ?

    I would consider this set up as 2 different gear sets (driver-driven) linked by a belt & timing gear set. No idler in there for me. Is a gear in a transmission considered an idler for the gears in the final drive? That system was used on different Toyota engines like the 5S-FE and 4A-FE:
  13. JackAction

    Torque and power quiz

    The closest thing the model will tell you is the lowest time you can possibly take to go from 30 to 70, assuming you can get near peak power. You take the time from 0-30 and subtract it from the time 0-70 and you get the 30-70 elapsed time. I know the situation that you described can happen in...
  14. JackAction

    Torque and power quiz

    First, you must understand the objective of the simulator, which is closely link to the subject of this thread: Identify the important characteristics of a vehicle to achieve a certain level of performance. What do you need to do the ¼-mile in 11 s, reach 150 mph or go from 0-60 mph in less 4...
  15. JackAction

    Torque and power quiz

    So I'm gonna stop right here as I'm not gonna go into a «I'm smarter than you are» discussion. Instead of telling you that I'm smarter than you, I'll show how I smart I am (maybe it's less than you, but I'm still proud of what I accomplished): The simulator from the third link, I wrote it...
  16. JackAction

    Torque and power quiz

    Very simple, and it is all related to what has already been said: «average power» over the «selected rpm range». The useful rpm range for a large truck needs to perform throughout the whole range. Even with a wide power band, they can have like 20 gear ratios; Imagine how many they would...
  17. JackAction

    Torque and power quiz

    Funny, now I'm getting blasted from two different comments that are exactly the opposite of one another: Can't we avoid those rpms or will the revs not drop that low? It doesn't really matter because I'll repeat the only important thing I've said that covers it all (I have enlighten the...
  18. JackAction

    Torque and power quiz

    This is where the «torque» people get lost. You have to compare the torque output at the same vehicle speed, otherwise it is a useless comparison: At a higher speed, the traction force will always be smaller for a given power output. When you «re-gear the whole business», of course the torque...
  19. JackAction

    Torque and power quiz

    The sentence in bold will be true in most cases. We might also reference to a previous quote in this thread: It is obvious that he's talking from experience, we cannot deny the fact that between 2 engines with the same peak power, the one with the highest peak torque will offer better...
  20. JackAction

    Torque and power quiz

    Because it only has half the time to do the work. If you divide the time it takes to do the work by a factor of 2, then you must also divide the amount of work done by a factor of 2 ... if you want to keep the power constant, of course: power = work1 / time1 = work2 / time2 if time2 = time1 /...

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