4 ms·

A gas engine could certainly tow my race trailer, but at horrific mpg. I have a gas truck (gets a very nice 22mpg on the highway, which was 2mpg off my wife's R

A gas engine could certainly tow my race trailer, but at horrific mpg. I have a gas truck (gets a very nice 22mpg on the highway, which was 2mpg off my wife's RAV4 that seemed like it was powered by hamsters running on a wheel) and towing my trailer it got 3-5mpg. 3 to 5. My diesel gets 12mpg. EGR "messing with" does affect power. EGR lowers combustion temps, and the thermodynamic work the engine is producing is directly affected by the temperature gradient between the combustion chamber and the outside air. Lower temp == lower efficiency. Does cut down on NOx, but let's at least be honest about the negatives. My point is more like this: EGR seems to help with two things, 1. fixes the NOx problem (ok that is legitimate) 2. Injects soot into the engine's intake, covering everything in coke, but at a slow enough rate that they don't fail during the warranty period. Helps with planned obsolescence, considering how everything is made cheaper and crappier now, on purpose so you have to throw it away and buy a new one, no one is going to convince me that #2 isn't a net positive to the OEMs, and it also giving them a darn good reason not to search for other methods to reduce NOx emissions in a way that doesn't help the engines expire more quickly. Like I said, I did not delete my truck, nor would I. I care about the environment and the air we all breathe. But I don't buy that there aren't other ways to solve these issues.

arghwhat 2y ago
> A gas engine could certainly tow my race trailer, but at horrific mpg Gasoline engines actually have their highest fuel-to-power efficiency at full throttle. A more powerful engine just allows you to burn even more fuel to accelerate faster. I suspect that the gas trucks gear ratios just made it unsuitable for towing by putting you way outside the optimum power band at load. This is why I said that power is not the only factor: You need a chassis, brakes, gear ratios and possibly transmission cooling for suited for towing that heavy loads. I stretched a chassis once towing way over the rating - I recommend not doing that. 22 MPG is also pretty bad by today's standards, but I've had engines like that. At 12mpg you're getting very close to the fuel consumption of the compact 48 ton trucks we use in the EU, but they usually have almost 800 HP under the... seat. > EGR "messing with" does affect power. EGR lowers combustion temps .. but let's at least be honest about the negatives. Temporarily, at idle, it does lower efficiency yes. But it's during the phase of engine operation with the lowest possible fuel consumption, and while all the fuel you're burning is thrown out the window. It is also only fully open in a very specific scenario, and otherwise at idle or very low power demand it will only be slightly open. I don't think the cooled cylinder is harmful - it would eventually cool that that temperature at idle even without the EGR, and a hot cylinder preheats gasses on the way in, reducing the possible temperature gradient. > But I don't buy that there aren't other ways to solve these issues. As mentioned in a different comment, the EGR efficiency concern is entirely gone with engine start-stop as the time when it would be fully open is replaced by the engine being off. That improves fuel consumption past a deleted truck. I agree that emissions-related tech is a hack in many ways, but the problem is that internal combustion engines are terrible and hard to fix. For most people, electric already works fine, and most complaining about spec comparisons never need those specs. For others, older technology will stick around for a bit longer until we have mature solutions. Plus, if all regular cars and trucks get replaced by something better, having a few (properly emissions controlled) gas trucks on the road won't matter as much.

arghwhat 2y ago

> A gas engine could certainly tow my race trailer, but at horrific mpg Gasoline engines actually have their highest fuel-to-power efficiency at full throttle. A more powerful engine just allows you to burn even more fuel to accelerate faster. I suspect that the gas trucks gear ratios just made it unsuitable for towing by putting you way outside the optimum power band at load. This is why I said that power is not the only factor: You need a chassis, brakes, gear ratios and possibly transmission cooling for suited for towing that heavy loads. I stretched a chassis once towing way over the rating - I recommend not doing that. 22 MPG is also pretty bad by today's standards, but I've had engines like that. At 12mpg you're getting very close to the fuel consumption of the compact 48 ton trucks we use in the EU, but they usually have almost 800 HP under the... seat. > EGR "messing with" does affect power. EGR lowers combustion temps .. but let's at least be honest about the negatives. Temporarily, at idle, it does lower efficiency yes. But it's during the phase of engine operation with the lowest possible fuel consumption, and while all the fuel you're burning is thrown out the window. It is also only fully open in a very specific scenario, and otherwise at idle or very low power demand it will only be slightly open. I don't think the cooled cylinder is harmful - it would eventually cool that that temperature at idle even without the EGR, and a hot cylinder preheats gasses on the way in, reducing the possible temperature gradient. > But I don't buy that there aren't other ways to solve these issues. As mentioned in a different comment, the EGR efficiency concern is entirely gone with engine start-stop as the time when it would be fully open is replaced by the engine being off. That improves fuel consumption past a deleted truck. I agree that emissions-related tech is a hack in many ways, but the problem is that internal combustion engines are terrible and hard to fix. For most people, electric already works fine, and most complaining about spec comparisons never need those specs. For others, older technology will stick around for a bit longer until we have mature solutions. Plus, if all regular cars and trucks get replaced by something better, having a few (properly emissions controlled) gas trucks on the road won't matter as much.