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Originally Posted by serialk11r
NO no no. EGR decreases the temperature of combustion because there's less fuel. Since there's less combustible mix, it's actually harder to ignite. Colder spark plugs won't do you any good.
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OK, well now I'm confused. Allpar says the exhaust gas does not replace any air or fuel, but you're saying it does?
Quote:
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(Note that the exhaust adds to the fuel and air; it doesn’t replace any of it).
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Quote:
Originally Posted by serialk11r
EGR increases the mass of gas but that doesn't do anything. You need pressure. EGR is only to dilute the intake mix so you need to suck in more of it (which takes less energy because the engine has constant stroke volume and the energy to create the manifold vacuum is by far greater than the energy required to accelerate the air down the intake tracts). If it's not cooled EGR, the charge starts out hotter and you lose efficiency from that, but gain most of it back from the pumping loss reduction.
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Doesn't an increase of mass on the top of the piston increase the pressure on the piston? Similar to if you put a mouse on your head vs. putting an elephant on your head, the heavier (massive) one is going to put more pressure on you.
Does hot(ter) EGR decrease efficiency or power? I only wonder, because I'm thinking about how a HAI increases efficiency, but lowers power and (controversially) hot fuel vaporizes easier. Also, how does one tell if their EGR is cooled or not? Is there a seperate 'radiator' of sorts?
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Questions:
1. Theoretically, if one were to lower the combustion temperature (no matter how that happens), would colder spark plugs help, or is the hot/cold spark plugs a different thing?
2. I'm wondering, if increasing EGR, as well as increasing air charge (turbo), could the efficiency be exponentially increased (or at least increased more than one of them separatly)? This would help create a lot of pressure on the piston, (or) open the throttle body more (depending on how you look at it), decreasing vacuum losses.