Mercedes-Benz Forum banner

41 - 57 of 57 Posts

·
Registered
2014 E250 Bluetec 4-Matic, 1983 240D 4-Speed
Joined
·
9,956 Posts
Drag is proportional to velocity squared, power to velocity cubed.
Yeah.
 P_d = \mathbf{F}_d \cdot \mathbf{v} = \tfrac12 \rho v^3 A C_d


So, as the car doubles its speed, say from 20 mph to 40 mph the resistance that must be overcome by the vehicle propulsion system consume 8 times the power than at 20 mph. This is pretty innocuous until you get much above 40 mph, when doubling the speed eats a lot of added power - gasoline is one source and is relatively familiar to us, a battery is another, far less familiar source of energy.

Jim
 

·
Registered
2008 AMG CLK63 Conv., 2012 R350 4-Matic, Wife's 2015 C300 sedan
Joined
·
9,227 Posts
^ Almost. Resistance force at 20 mph is, say, 20 squared = 400 units of force. Resistance force at 40 mph is 40 squared (assuming the grad coefficient is constant and factors like rolling resistance can be ignored) = 1600 units of force. So speed has doubled (2×) and force has quadrupled (4× or 2 squared x). Power goes from say, 20 cubed = 8000 units of power to 40 cubed = 64000 units of power or up by a factor of 8, which is 2 cubed. It's why adding a fart can muffler to your Corolla won't make it do 150 and why my 475 pony 6.2 CLK63 isn't twice as fast as the 240 pony 2 liter C300 my wife drives.

Power, by the way, is equal to 2 x Pi x revs per second x torque, which means if the torque curve of an electric motor is constant above 0 rpm, it's power output rises linearly with rpm.
 

·
Registered
2006 C230S
Joined
·
43 Posts
Discussion Starter #44 (Edited)
It's going to be interesting to see how it works out for Harley Davidson. I would think the company sees some type of writing on the wall and is ready to give up the traditional HD buyer for a different one. On the other hand, Harley riders pride themselves on being rebels somewhat, not part of the "establishment". Right now you could say the same thing about people who drive EVs
 

·
Registered
2006 C230S
Joined
·
43 Posts
Discussion Starter #45
I was talking with a guy about a motorcycle he had converted to battery awhile back. He was concerned about pedestrians not being able to hear the bike, so he built it with a sound system that would play recordings of a loud V-Twin and different things but he mainly used a recording of George Jetsons space car.
 

·
Registered
2008 AMG CLK63 Conv., 2012 R350 4-Matic, Wife's 2015 C300 sedan
Joined
·
9,227 Posts
I was talking with a guy about a motorcycle he had converted to battery awhile back. He was concerned about pedestrians not being able to hear the bike, so he built it with a sound system that would play recordings of a loud V-Twin and different things but he mainly used a recording of George Jetsons space car.
Whenever I see a troupe of weekend warriors out on their Harleys I always think "right turn Clyde"....

 

·
Registered
2000 S430, 2003 S430, 2003 S600 TT, and 2005 E320 CDI
Joined
·
4,308 Posts
Harley Davidson going total electric too. As is Volvo / Polestar. The EQC due out next year is definitely going to be a pleasant change from earlier MB EV's which I found less than exciting
Actually, that's a smart move on Harley-Davidson's part. Consider the demographic of the typical (today) H-D rider/purchaser. We're talking about people in their 50's and up, generally. That's why H-D came out with their smaller bikes. The problem is that those motorcycles are no more fuel-efficient than my 1994 Honda Civic. Younger folks are looking for "greener" methods of transportation, which means among other things, fuel efficiency.

There was a company producing Diesel-powered motorcycles for a moment, for civilian use. Apparently their military contracts are demanding enough that they simply cannot serve the civilian market, but the fuel-efficiency would've been terrific.

Electric bikes would be even better. In my neck o' the woods, I'm seeing all these electric rent-a-scooters around. Great idea. That's a fine way to get around town. The electric bike would be simply the bigger, higher-speed, trip-capable version of that scooter. However...

...going on trips, the issue of range comes up even more for motorcycles than it does for cars. Even today's cruising bikes typically have only a 200 mile range, compared to my Civic's 400+ mile range. That's not really a problem with internal-combustion bikes, because five minutes, and you're topped back up. How would that be handled with an electric bike?
 

·
Registered
2008 AMG CLK63 Conv., 2012 R350 4-Matic, Wife's 2015 C300 sedan
Joined
·
9,227 Posts
HD came out with their smaller bikes mainly for the far East market (where they're also made). They do face a demographic problem in the US where their typical rider is fast hitting 60+ (and not mph).
Electric bikes? They're even racing them in their own class at the Isle of Man TT, have been for a few years now, so yet again the infernal combustion engine seems doomed.
Me? Hyabusa powered mobility scooter please!
 

·
Registered
2014 E250 Bluetec 4-Matic, 1983 240D 4-Speed
Joined
·
9,956 Posts
Tesla uses a two speed transmission already. To maintain a lighter propulsion system they run a very high speed motor (original induction motors topped out near 14,000 rpm) and a two speed transmission. After some early teething problems (pun not intended) they seem to have arrived at a reasonably robust solution.

Jim
I looked into the Tesla Model 3 and it does not employ a two speed transmission - it uses a fixed transmission. Sorry, should have checked before I assumeed their initial induction motor two speed transmission carried on to the Model 3.

Jim
 

·
Registered
2006 C230S
Joined
·
43 Posts
Discussion Starter #50
Our C230S has been almost trouble free until recently. It's been in and out of the shop for about three months now. Currently throwing three codes and dying intermittanly. And I'm unable to deal with it properly due to health problems of my own. Electric simplicity and dependability is seeming very attractive right now.
 

·
Registered
2008 AMG CLK63 Conv., 2012 R350 4-Matic, Wife's 2015 C300 sedan
Joined
·
9,227 Posts
What's wrong with your C230S then?
 

·
Registered
2006 C230S
Joined
·
43 Posts
Discussion Starter #52
It starting abruptly dying a few days ago. It seems to run great, but then it will just die. And the last time had a problem starting back up. The only two codes I'm reading are P2004 which has remained after replacing the manifold a few months ago and P0410. But I replaced the relay and pulled the hose off and it is pumping air at start up. Also an 18month old AGM battery suddenly went bad. There is also a warning listed: "closed loop using 02 sensor for fuel" so Im guessing maybe camshaft position sensor?
But I haven't been feeling well, so the they have been running diagnostics on me at the medical center as well. I don't want to talk about where they plug in the OBII reader.
 

·
Registered
2008 AMG CLK63 Conv., 2012 R350 4-Matic, Wife's 2015 C300 sedan
Joined
·
9,227 Posts
P2004 seems to be a common problem with a relatively easy fix:

P0410 may be a secondary problem caused by P2004.

Camshaft position sensors are about $20 each on line and take 15-20 minutes each to change (BTDT on my CLK63).

"O2 sensor for fuel" probably means your O2 sensors in the exhaust are kaput. You don't say how many miles your car has done, but since its a C230 (not made AFAIK since 2008) it's a fair bet it's kaput. Not really expensive, just a PITA to get at.

Batteries don't last like they used to, and if the car is parked up a lot, they can drain to the point where the diode inside them won't allow them to be recharged.

Look up you model year and post on the C-class page and you'll get more (and probably better) advice there.
 

·
Registered
2006 C230S
Joined
·
43 Posts
Discussion Starter #54
It just rolled over 150000mi. Maybe the O2 sensor went bad because the secondary air pump wasn't working for awhile? It seems like we have perhaps several overlapping problems. I don't feel like I could replace the 02 sensor myself so I might just let a technician do the position sensor as well.
I did also see a nice white newer C-Class at a dealership nearby 😄
 

·
Registered
2008 AMG CLK63 Conv., 2012 R350 4-Matic, Wife's 2015 C300 sedan
Joined
·
9,227 Posts
I'd start with the 02 sensor. It sounds weird but dodgy temperature sensors in the thermostats can also generate fake error codes. The sensor, not the thermostat itself, goes bad, so your car will run and not overheat. The fuel injection system in that era car relies on the temperature sensor to read engine temperature and thus set the fuel / air mixture, and if that sensor's bad it means the fuel in won't tally with the smog out reading/calculation. BTDT too with both my CLK63 and the wife's CLK350, both 08 models.
 

·
Registered
2006 C230S
Joined
·
43 Posts
Discussion Starter #57
So, I took it to a technician to see what he thought, and he replaced the Cam Shaft Position sensor. The CEL came back on the next day with the same codes, P2004 and P0410. But it seems to be running fine and hasn't stalled again, so hoping for the best.
 
41 - 57 of 57 Posts
Top