Zap!


#1

What are some of the functions on the new cars that are better handled by electric or electronic replacements(the B-17 was said to be more survivable in combat then the B-24,because the B-17 had more electric servos and what have you then the B-24,the B-24 apparently had more hydraulic servos and actuators( I know that what I said was about aircraft-but doesnt the same thing apply to cars) it seems that hydraulics have one inherent weakness( a finite supply of working fluid) for what its worth ,anyone care to voice an opinion?-Kevin


#2

I dunno but in an airplane, if you shoot through a hydraulic line, any devices on that particular line aren’t going to work. I believe what happened to the Sioux City crash was that a section of the tail was hit and severed the entire system. So they had to steer using the engines.


#3

Fuel management.
Gage management.

My personal opinion is that driving functions that are taken over by electronic systems do not improve the vehicle’s safety, and in some cases may even create a vehicle that’s less safe than one without, especially when they override the driver’s decisions (like ABS) and/or cause the driver to become less involved in the process of driving.

And IMHO all electronic systems in a car that are involved with the driving function should be able to be disabled (turned off) by the driver. And all should have redundant manual backup systems.


#4

I think it depends on the maturity of the technology and how well designed the mechanical and electronic systems are. (including the software) Most everything now that can be replaced by electronics has been–fuel delivery, electronic throttles, ignition systems, steering. Most are pretty reliable, but some of the electronic throttles and steering just don’t have the good feel and tactile feedback of their mechanical predecessors. And I don’t completely trust electric steering yet vs. good old hydraulic-assisted that’s been around for decades.

One nice thing about electronics though is that they give you an incredible level of control over systems a lot simpler than implementing the same thing mechanically. For example, with electric steering, it’s very easy to make steering effort harder for high speed driving, while making the wheel easy to turn when parking. With electronic throttle, you don’t need a separate cruise control unit, and traction and stability control don’t need add ons either.


#5

Good points,I’m ambivalent about electric steering and I would feel better if airliners had a few redundant systems on the craft,to steer and control,etc.An EMP event is going to knock out a lot of electrical systems(we are overdue for one ,caused by the Sun)-Kevin


#6

@kmccune: I share your feelings, but it would take a heck of an event on the sun to cause an EMP similar to firing off a nuke. Though a major flare or “coronal mass ejection” does wreak havoc with satellites, the power grid, and lots of sensitive electronics. Planes are pretty well shielded overall, and are normally struck by lightning quite often, with few ill effects. A solar event strong enough to down an airplane would probably be not so great for its occupants as well.

There are quite a few redundant systems on any commercial aircraft. Most jets have 3 hydraulic systems for example. After the Sioux City crash, I believe a FOURTH hydraulic system was added for backup as well, at least on that model of aircraft. Commercial airliners have 3 autopilot systems, of which at least two must agree or the system is disabled. Even cars with electronic throttles have multiple potentiometers whose position must agree or the throttle is disabled.


#7

It seems like, gradually, we are going to electric actuators and assists for nearly everything. Even drones ! The computer talks to these systems more easily and reliability is enhanced. Besides, saving weight is always a commendable reason to go electric.


#8

The electric vs hydraulic debate has raged for years. Even fly-by-wire aircraft still have the hydraulics for the heavy lifting. Electrical servos will always be larger and heavier than hydraulics. I can make a very strong hydraulic actuator from aluminum, an electric servo MUST be made from copper and magnetic steel or iron to work. We don’t yet have magnetic aluminum. The wire to carry the power is aluminum or copper and it rivals a hydraulic pipe, with oil for weight/foot. An all-electric servo plane of any size would be very heavy. RC models and small drones work dandy, however.

Using electric stuff on a car, however, allows it to only consume power when needed rather than the pump always turning. electric assist steering, for example, only draw power when needed. A hydraulic system draws way more energy than needed running down the highway just so there is enough available to park.

The electronic control issue is a separate one. Computers “help” keep the driver from hurting themselves and can control hydraulic or electric systems. Opinions aside, the data collected on ABS, stability control, traction control, active dampers and the like proves they help even expert drivers control the car. Years ago, these systems were on every Formula 1 car. They were banned to put more of the driver back into racing.


#9

So Many aircraft have redundant systems plust multiple different systems.
Even my old Cessna 172 had three different systems for the instruments…vacuum, electric, and mechanical.
– If some gauges died…not all of them would. you’d still have some of the instruments active and most likely compensate for the dead ones.

I wish cars and trucks did this so as not to be one hundred percent in the dark or un-operable.
They divided the brakes, front and back, many years ago so you’d have something at least, but too many people panic and think they have zero brakes without even trying them more.

panic coupled with zero knowledge is what resulted in wrecks for those chevys.
With the ignition off you loose POWER to the brakes and steering …but it’s still there to use if you’d bother to try.


#10

One reason airplanes cost so much is all the redundant systems. It’s a lot less critical to have them in a vehicle that you can just pull to the side of the road and call AAA when it breaks. :wink:


#11

The switch to electric power steering was driven by gas mileage standards (CAFE) dictated by the EPA. Every tiny fraction of miles per gallon counts when you sell millions of cars. Electric power steering so far has proven less reliable that hydraulic.

I have had cars with power steering since 1965 and have never lost power assist due to the sytem failing.

However, I believe it will just be a matter of time before all cars subject to CAFE standards will have electric power steering.


#12

There were various other reasons that B-24s seemed to be more prone to shoot-downs than B-17s. The fuel pumping and transfer system on a B-24 was a bit of a Rube Goldberg affair concentrated in the top of the fuselage between the two wing roots above the bomb bay and was VERY prone to leaking. If you look at pictures of B-24s at cruise, it isn’t unusual to see the bomb bay doors cracked just a bit to vent off gasoline fumes. Smoking was also usually prohibited in the aircraft. Needless to say, a solid hit in this area that produced a spark usually resulted in fatal conflagration. (And yes, the German fighter pilots were VERY aware of this fact.) Also, the layout of the craft, high shoulder mounted wings vs the low mounted wing for the Fortress made it much trickier to land gear up, both on land and water, and usually meant writing off the aircraft afterward. The wing itself, a high aspect Davis airfoil design, while more efficient, seemed to be less tolerant of damage.

I have electronic steering in my Cruze, and I like it just fine. It has good roadfeel, and the steering is very precise. I’ve lost a power steering belt before, and a hose now that I think of it, so a failure of a hydraulic steering system isn’t all that unusual. Also, the electronic engine management controls are heads and shoulders better than the first vacuum hose driven attempts at engine management.


#13

Fuel pumps that pump just the needed amount of fuel, returning none back to the tank; radiator fans that turn just fast enough to keep the coolant at spec, but not faster; water pumps that pump only the flow of coolant needed. Those all seem like good places for electric motors.

Modern cars though host a bevy of small electric motors, stepper motors and the like, to control the mirrors and the windows and the door locks and the HVAC doors, and those can be a reliability problem.


#14

Well I guess when all is said and done ,modern aircraftare extremely safe and reliable,(airliners in particular) use an extremely powerful and reliable source of power,far surpassing the old piston engine(these turbines almost have heirloom quality when compared to the old"Wasp" and “double wasp” engines)[miss the sound though]
But about the power of a solar event,in the late 19th century parts of Europe bore the brunt of a significant solar event,it melted telegraph wires and set crossties on fire,so its something to be aware of-Kevin


#15

@GeorgeSanJose: I think most fuel injection systems nowadays are returnless systems. (though the pump does not vary its speed) I’m not aware of variable-speed electric cooling fans in cars, though I wouldn’t be surprised if someone has them, or will in the near future. Electric water pumps for the cooling system have been used in racing for decades I think. Which makes sense, you don’t really need to be driving a water pump from an engine cruising at 8,000+ RPM.

I have never had a power seat, power mirror, or other power feature fail on a car, other than the driver’s side window motor on an LTD I once had. (which naturally failed in the down position during a rainstorm)


#16

Actually, I’m more concerned with those lithium batteries catching fire in cars, planes, and other devices like phones and computers, rather than the device failures themselves. I’m just not comfortable with the safe guards yet and wouldn’t really want a Tesla sitting in my garage.


#17

Having read a considerable amount about Tesla’s work in preventing the lithium ion cells from overheating as well as preventing the “cascading failure” effect of a cell failure, I’m inclined to think that Tesla has done a far better job in these areas than the company that’s developing the lithium ion packages for aircraft.

However, bing, I understand your concern. It’s early yet. There’s not enough if-field data yet to really know if there are hidden problems lurking.


#18

I worked before retiring on avionics. at that time many military aircraft used a system called 1553B. it was a system which communicated between aircraft equipment via two electronic cable systems, dual redundancy, one cable down one side; the other down the other. So, if one got shot, the other still worked.

Interestingly, I looked up the horribly expensive equipment we used to test them, the Loral SBA 100F. Google took me to a Tesla page.