https://www.autoblog.com/2022/09/07/ford-mach-e-recall-half-shafts/
7 replies (most recent on top)
- Was there any harm done (financially or otherwise) done as a result of axles failing prematurely ?
- Were significant and critical characteristics (SCs and CCs) properly identified on Ford/supplier documents ?
- Who knew what and what was documented (emails, DVP, FMEA, PFMEA, etc.).
@1dlm. You provided a lot of nice data in your comment. Then you ended with a gem. "The grid will be able to handle it because at the end of the day, people CAN'T go without power... " Thanks for the laugh.
Gasoline is forecasted to be NO MORE than $3.60/gallon for the foreseeable future. No need for EVs, unless you want to be an early adopter.
https://www.eia.gov/analysis/
The axle design constraints are well documented and cascaded to the axle engineers by the propulsion system (motor, transmission, etc.) engineers. These values are verified many times (CAE modeling, bench testing, and vehicle testing). There are physical torque sensors on each wheel to directly measure the wheel torque to ensure there is a significant safety factor for each component. The article in the link said the axles had a defect which was not detected. This characteristic should be an inverted delta safety item on the print, so it should be required to be checked 100% by the supplier. There should be 100% documentation of this inspection since breaking axles is a safety issue.
Let me spell it out for you. Mech engineer here.
Electric vehicles have about 1/3 of the complexity of ICE motors. If you look at Tesla's warranty most of it is vehicle build related (self driving cars, body, steering) not driveline / battery related. Ford does fairly well for the amount of different designed vehicles on just vehicle related warranty. Ford struggles with powertrain warranty mostly because of how complex the entire system is.
Ford's number one powertrain related issue is because back in the mid 00'/10s they let complexity get WAY out of hand with transmissions / engine combinations.
ICE motors are stupidly complex, have 35% thermal efficiency (65% gets flushed out the pipes or radiated away) compared to 95% efficiency (converting battery power to motive power). Most turbines at powerplants get ~50% efficiency with cleaner burns AND you could install solar to charge your vehicle. Can't exactly synthesis gas at home.
Electric vehicles are just way simpler DC motors, batteries, control unit, direct drive transmission versus 10-speed that's it. I remember looking at the whole vehicle thinking where is all the junk. No spinning camshafts / crankshafts, pistons, valves, springs, heads, no oil, simplified cooling circuit, fuel injection, throttle body all gone obsolete. Every component adds at least 10 major things that can go wrong that just isn't there anymore.
Add in the fact that Solid Power has a solid state (no liquid electrolyte) which fixes all the safety / fire issues (because liquid electrolyte explodes), 390 wh/kg power density (tesla 220, GM ultium 200) almost double the battery capacity coming out shortly (with theoretical power densities of 1500 wh/kg. Oh and sold state batteries can be charged / discharged faster due to no lithium dendrite reaching across the anode / cathode rapidly discharging catching the electrolyte of fire and exploding.
Oh and lot of the issues with EV vehicles just need to be solved ONCE literally. DC motors just don't have a bunch of stuff to go wrong with. Same thing with batteries, once you figure it out... its over. No special adaption needed versus ICE which each motor had unique sized components.
TLDR: Electric cars are just not that complicated compared to ICE powertrain complexity, require a fraction of the engineering effort and Ford has a backlog of orders FOR YEARS selling vehicles at a premium price. EV is a no brainer. The grid will be able to handle it because at the end of the day people CAN'T go without power, emergency stuff will happen (nuclear plants get built) if it gets that bad or the price of energy increases until secondary power becomes competitive (solar particularly). Start charging people 1000 dollars a month for energy the return of investment of solar starts becoming measured in months not years. Once they are a solar customer they are not going back to grid power (in any meaningful way) FOR YEARS.
Ford can’t make door locks that keep intruders out. Why would we be able to do anything else right?
Well don't forget that the Mach-E is driven by electric motors and these deliver instantaneous torque whereas an ICE delivers torque with some latency. Could this be a factor? Any mechanical engineers care to comment (I am electrical/software).