CaP'N GRuNGe Posted August 12, 2009 Share Posted August 12, 2009 Define performance please... Quote Link to comment Share on other sites More sharing options...
Clubfoothead Posted August 12, 2009 Share Posted August 12, 2009 Well f*ck, if it ain't perfect from the start, we should just scrap the idea. If yer 6 feet tall and don't like it in the back seat of my Volt you can get a job or walk yer ass maybe. Quote Link to comment Share on other sites More sharing options...
westvirginia Posted August 12, 2009 Share Posted August 12, 2009 Define performance please... He's right about that. It's about the only thing, but... Anyway, there's this video of a 1970-something Datsun eating up other cars (specifically a 'vette) on youtube. They really do get better performance from the electric motors. Quote Link to comment Share on other sites More sharing options...
Kid Cid Posted August 12, 2009 Share Posted August 12, 2009 He's right about that. It's about the only thing, but... Anyway, there's this video of a 1970-something Datsun eating up other cars (specifically a 'vette) on youtube. They really do get better performance from the electric motors. Sure, but if you notice that Datsun is stripped of everything to save weight because the battery is so damned heavy. I'm not saying they can't be quick and efficient (no drive train power loss for instance) but that is a specific case and not really good in every day traffic. You'll also notice that those batteries gie up the power easily butthey don't hold a charge very long. There's a fine balancing act that has to go on there. Electric cars have better performance at lower revs too. Gas engines don't reach peak efficiency until they get around 4-6K RPMs going. That's why they need 6 gears to get to the speeds an electric motor can reach in one. That's not entirely true. You are correct that the power band for most cars is in the 3k+ RPM range, but that has as much to do with gearing as where the engine is producing the most torque. No, the reason internal combustion engines need multiple gears is because they don't have an infinite top end in RPMs like an electric motor does. An electric motor can just keep spinning faster and faster with no incremental powerloss or explosion potential. The reason for gears on an internal combustion engine is that they will eventually explode as the timing betwen when the new gas is vaporized in the cylinder overlaps with the current gas being ignited by the spark. So in order to achieve higher speeds, the gearing needs to be changed to accomodate for the fact that there is a hard limit as to how fast an IC engine can spin. Quote Link to comment Share on other sites More sharing options...
westvirginia Posted August 12, 2009 Share Posted August 12, 2009 Sure, but if you notice that Datsun is stripped of everything to save weight because the battery is so damned heavy. I'm not saying they can't be quick and efficient (no drive train power loss for instance) but that is a specific case and not really good in every day traffic. You'll also notice that those batteries gie up the power easily butthey don't hold a charge very long. There's a fine balancing act that has to go on there. That's not entirely true. You are correct that the power band for most cars is in the 3k+ RPM range, but that has as much to do with gearing as where the engine is producing the most torque. No, the reason internal combustion engines need multiple gears is because they don't have an infinite top end in RPMs like an electric motor does. An electric motor can just keep spinning faster and faster with no incremental powerloss or explosion potential. The reason for gears on an internal combustion engine is that they will eventually explode as the timing betwen when the new gas is vaporized in the cylinder overlaps with the current gas being ignited by the spark. So in order to achieve higher speeds, the gearing needs to be changed to accomodate for the fact that there is a hard limit as to how fast an IC engine can spin. I stand corrected then. Atomic is wrong about everything... Quote Link to comment Share on other sites More sharing options...
I Like Soup Posted August 12, 2009 Share Posted August 12, 2009 I stand corrected then. Atomic is wrong about everything... You are still smart as always! Quote Link to comment Share on other sites More sharing options...
AtomicCEO Posted August 12, 2009 Share Posted August 12, 2009 That's not entirely true. You are correct that the power band for most cars is in the 3k+ RPM range, but that has as much to do with gearing as where the engine is producing the most torque. No, the reason internal combustion engines need multiple gears is because they don't have an infinite top end in RPMs like an electric motor does. An electric motor can just keep spinning faster and faster with no incremental powerloss or explosion potential. The reason for gears on an internal combustion engine is that they will eventually explode as the timing betwen when the new gas is vaporized in the cylinder overlaps with the current gas being ignited by the spark. So in order to achieve higher speeds, the gearing needs to be changed to accomodate for the fact that there is a hard limit as to how fast an IC engine can spin. So what are you disagreeing with me about? The electric motor has better performance at lower revs and at higher revs than an ICE's "power band". This means more torque at more revs and less need for gears. Tell me what is "not entirely true" about what I said. Quote Link to comment Share on other sites More sharing options...
Jimmy Neutron Posted August 12, 2009 Share Posted August 12, 2009 Electric engines don't idle. They only use the power when they need it. So, the stop and go shouldn't be as bad as it is in a gas powered car. Not sure that technology they're employing in cars, but most of the wear and tear on my (A/C lifts) industrial batteries occurs in acceleration. Quote Link to comment Share on other sites More sharing options...
I Like Soup Posted August 12, 2009 Share Posted August 12, 2009 So what are you disagreeing with me about? The electric motor has better performance at lower revs and at higher revs than an ICE's "power band". This means more torque at more revs and less need for gears. Tell me what is "not entirely true" about what I said. How does an electric motor on a car perform at over 150mph? Oh wait, there isn't one, see?...you are just wrong... Quote Link to comment Share on other sites More sharing options...
Azazello1313 Posted August 12, 2009 Share Posted August 12, 2009 (edited) the makers of the volt are supposedly aiming for a 0-60 time of 8.5-9.0 seconds. for reference, that's slower than a base model honda civic. not exactly blowing anyone's doors off. Edited August 12, 2009 by Azazello1313 Quote Link to comment Share on other sites More sharing options...
Kid Cid Posted August 13, 2009 Share Posted August 13, 2009 I am essentially disagreeing with your conclusions, not your facts. Electric cars have better performance at lower revs too. Gas engines don't reach peak efficiency until they get around 4-6K RPMs going. That's why they need 6 gears to get to the speeds an electric motor can reach in one. What you says implies that ICE's need gears because their powerband is between 4K and 6K RPM. That is not true. They need gears because of a hard limitation as to the max RPM. So what are you disagreeing with me about? The electric motor has better performance at lower revs and at higher revs than an ICE's "power band". This means more torque at more revs and less need for gears. Tell me what is "not entirely true" about what I said. Once again, an electric motor doesn't need gears because there is no hard limitation (there is one but not likely to be reached in this application) as to the max RPM, therefore it can just keep spinning faster as the operator calls for speed. More torque at more revs has nothing to do with the need for gears. Quote Link to comment Share on other sites More sharing options...
AtomicCEO Posted August 13, 2009 Share Posted August 13, 2009 How does an electric motor on a car perform at over 150mph? Oh wait, there isn't one, see?...you are just wrong... You are wrong. the makers of the volt are supposedly aiming for a 0-60 time of 8.5-9.0 seconds. for reference, that's slower than a base model honda civic. not exactly blowing anyone's doors off. So most articles are quoting the 5-6 seconds time your article originally stated. This article clarifies that the unassisted ICE engine on the car will have a 0-60 of 8.5-9 seconds. Probably best to just wait and see what the car will do with both electric and gas though, because it's still a concept. Quote Link to comment Share on other sites More sharing options...
AtomicCEO Posted August 13, 2009 Share Posted August 13, 2009 I am essentially disagreeing with your conclusions, not your facts. What you says implies that ICE's need gears because their powerband is between 4K and 6K RPM. That is not true. They need gears because of a hard limitation as to the max RPM. What you're saying makes no sense. If the only limitation of ICE is the max RPM, then why not just put one huge gear in it? I know... because it's limited at both the bottom and the top end. Like I've been saying, there is only a narrow range of peak efficiency where torque is maximized with an ICE engine. Whereas... an electric motor has maximum torque available at 0 rpms. Quote Link to comment Share on other sites More sharing options...
millerx Posted August 13, 2009 Share Posted August 13, 2009 Screw the Chevy Volt... I'm waiting for this bad boy!.... Quote Link to comment Share on other sites More sharing options...
I Like Soup Posted August 13, 2009 Share Posted August 13, 2009 You are wrong. So most articles are quoting the 5-6 seconds time your article originally stated. This article clarifies that the unassisted ICE engine on the car will have a 0-60 of 8.5-9 seconds. Probably best to just wait and see what the car will do with both electric and gas though, because it's still a concept. Yep, that Ultimate Aero isn't in production. Just like I thought. :stickingtongueout: Quote Link to comment Share on other sites More sharing options...
Kid Cid Posted August 13, 2009 Share Posted August 13, 2009 What you're saying makes no sense. If the only limitation of ICE is the max RPM, then why not just put one huge gear in it? I know... because it's limited at both the bottom and the top end. Like I've been saying, there is only a narrow range of peak efficiency where torque is maximized with an ICE engine. Whereas... an electric motor has maximum torque available at 0 rpms. No, it's just that you don't understand how gears work. If you have a gear ratio of 1:1 then you get one revolution of the tire for every revolution of the engine crankshaft. That means that the maximum spead of the vehicle is limited by the maximum speed of the engine. Depending on the size of the tire, a 1:1 ratio will give a maximum speed of approximately 10 mph. Additional gears at higher ratios will allow for higher speeds. It has nothing to do with torque, it has to do with the max number of RPMs an ICE can produce. Since an electric motor has no limit to how fast it can spin, a gear ratio of 1:1 works just fine because there is no limitation. Quote Link to comment Share on other sites More sharing options...
AtomicCEO Posted August 13, 2009 Share Posted August 13, 2009 No, it's just that you don't understand how gears work. If you have a gear ratio of 1:1 then you get one revolution of the tire for every revolution of the engine crankshaft. That means that the maximum spead of the vehicle is limited by the maximum speed of the engine. Depending on the size of the tire, a 1:1 ratio will give a maximum speed of approximately 10 mph. Additional gears at higher ratios will allow for higher speeds. It has nothing to do with torque, it has to do with the max number of RPMs an ICE can produce. Since an electric motor has no limit to how fast it can spin, a gear ratio of 1:1 works just fine because there is no limitation. I still have no idea what point you are trying to make. Electric motors have maximum torque available at 0 rpms. Combustion engines have a power band that requires you to get up to speed to reach maximum torque. This is why ICE engines need gears. This is also why gas engines are less efficient at starting, because they are not utilizing the strength of the engine at low revs. This causes you to have to pour gas into the engine just to get it moving from 0 mph. You have yet to address this in any way. Quote Link to comment Share on other sites More sharing options...
Kid Cid Posted August 13, 2009 Share Posted August 13, 2009 I still have no idea what point you are trying to make. Electric motors have maximum torque available at 0 rpms. True statement Combustion engines have a power band that requires you to get up to speed to reach maximum torque. also a true statement This is why ICE engines need gears. Not completely true although it is a part of the equation. This is the point I've been trying to make all along, that gearing is not a factor entirely of torque and when it is available, something that you've very carfully tried to ignore This is also why gas engines are less efficient at starting, because they are not utilizing the strength of the engine at low revs. This causes you to have to pour gas into the engine just to get it moving from 0 mph. You have yet to address this in any way. I didn't have to address this in any way because it was ancilliary to the point I was trying to make and not incorrect Quote Link to comment Share on other sites More sharing options...
bpwallace49 Posted August 13, 2009 Share Posted August 13, 2009 I am still waiting for my damn flying DeLoreon with a "Mr. Fusion" reactor on the back that runs on garbage . . . . . frackin layaway . . . Quote Link to comment Share on other sites More sharing options...
AtomicCEO Posted August 13, 2009 Share Posted August 13, 2009 Electric cars have better performance at lower revs too. Gas engines don't reach peak efficiency until they get around 4-6K RPMs going. That's why they need 6 gears to get to the speeds an electric motor can reach in one. Quote Link to comment Share on other sites More sharing options...
I Like Soup Posted August 13, 2009 Share Posted August 13, 2009 What about a car that has 4 gears? 5 gears? 6 gears? 7 gears? Were you specifying 6 gears for a reason or was that just a mention of 6 gears as it is more common on manual cars nowadays? Quote Link to comment Share on other sites More sharing options...
Azazello1313 Posted August 13, 2009 Share Posted August 13, 2009 The GM EV1 has estimated energy consumption ratings of 30 kW-hr/100 miles City and 25 kW-hr/100 miles Highway as listed by the DOE/EPA. so that's, what, 15-20% less efficiency in city driving versus highway for an electric car? that is pretty much right in line with gas cars, no? Quote Link to comment Share on other sites More sharing options...
AtomicCEO Posted August 13, 2009 Share Posted August 13, 2009 What about a car that has 4 gears? 5 gears? 6 gears? 7 gears? Were you specifying 6 gears for a reason or was that just a mention of 6 gears as it is more common on manual cars nowadays? You just blew my mind. Quote Link to comment Share on other sites More sharing options...
dmarc117 Posted August 13, 2009 Share Posted August 13, 2009 this is much cheaper http://homebiodieselkits.com/ Quote Link to comment Share on other sites More sharing options...
I Like Soup Posted August 13, 2009 Share Posted August 13, 2009 You just blew my mind. Yeah, you have to get up pretty early in the morning to hang with me... Actually, you made specific mention of the gears, so I was gonna ask earlier. But now that we've come full circle, here I am! Quote Link to comment Share on other sites More sharing options...
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