I saw a Frito-Lay truck (local) recently that bragged that it was both “100% electric” and had a speed limit of 55 mph.
I wondered if these two claims had anything whatsoever to do with each other. Could an electric truck have an actual programmed limitation that could keep it from going over 55? I know I’m asking this just because “electric,” and that it could just be saying that their drivers are sternly told not to go above 55, but seeing both these claims on the back door made me curious.
I was told that my Volt had a device making speeds of over 100 mph impossible. I haven’t tested it yet
I don’t see any reason that it couldn’t be done.
Not sure in this specific case, but in general - yes it is certainly plausible
Yes. It is called a governor and many “neighborhood electric vehicles” (NEVs) have them by law as they are approved only up to a certain speed limit.
Here’s how some disable them btw … only where legal to do so, of course!
Any vehicle can have a speed limiter.
Plenty of regular old internal combustion powered vehicles have limiters or governors installed on them. It was possible to have mechanical devices that did it in the old days, but now with electronic engine controls it’s trivially easy for carmakers to program in maximum speeds.
Don’t know from automobiles, but when my mother and I recently got to “ride The Tide”, Norfolk’s new electric train system, I had occasion to ask a couple questions of the operator. It is likewise restricted to speeds no greater than 55 mph. (Which incidentally makes it no good for pushing my DeLorean. On the other hand, Doc only needed the train because unleaded gasoline wasn’t available in 1885).
A friend of mine recounted driving his mother’s Taurus in the 1990’s, which had a speed limit of about 100mph built in. He said at about 160kmh the engine suddenly dies. Since he did not take his foot off the accelerator, the engine kicked back in with a jolt once he had lost a few mph - and accident waiting to happen.
My BMW salesman mentioned that the standard models (in Canada?) are governed to 210kmh by the engine computer. This is not due to legal or control reasons, but for liability. The tires on the stock model are not rated above that, and the are concerned about lawsuits from accidents if drivers habitually exceed the tire’s spec and may experience tire failure.
(I can assure you the 323i would do 205kmh no problem…)
There is a sort of a legal reason, though. At least in the US, the tires must be rated up to the vehicles top speed. Since BMW doesn’t want to put super expensive Z rated tires on their cheaper models, they just limit the top speed instead.
I had a BMW with a speed limiter. It kicked in at 118 mph and I hit the limit a few times. The first time it happened, I thought something was wrong with the engine. It didn’t die but it lost some power. You could push the accelerator down to the floor and it wouldn’t go any faster.
Lot’s of vehicles have speed limiters and have for years as others have noted. They are probably easier to design for electric vehicles than for gas powered powered motors but the idea is the same.
The Prius has one, so not only is it possible, but there’s a well known example. Consumer cars like the Prius have them to protect the battery/engine though, so their limit is like 105mph or something, instead of 55mph or 65mph or whatever a fleet might want to use. And many fleet vehicles have governors. Most FedEx vehicles do, for example.
look up the"MyKey" feature on Ford vehicles.
Why so low, though? Wouldn’t you want just a little bit of wiggle room, and not the required speed for non-freeways (which most often is going to be exceeded by traffic, making driving at 55mph really dangerous)? Does this truck avoid out-of-town highways altogether?
My Mercedes has a driver-adjustable limit. I can set the limit in 5mph increments anywhere between 20mph and some upper bound that I haven’t tried yet. It’s a very weird feeling to have your right foot flat to the floor and to be pootling along at 30mph, but quite useful.
As mentioned above, computerised engine management and electronic throttle control make this trivially easy to do in any modern car.
Taking the OP’s question in its simplest form, yes, electric vehicles can have a preprogrammed speed limit. And as has been pointed out, many of them do. It need not be a terribly low limit. The Tesla Model S Roadster is limited to 134 MPH; at this speed, the electric drive motor is at its redline limit of 16,000 RPM. Even though it is capable of propelling itself to faster RPM/MPH, the car is protecting itself by preventing that from happening, since it would likely damage the motor.
Since the drivetrain of electric cars is typically computer-controlled, speed limits are trivially easy to implement: just a few lines of computer code that tell the controller to drop the motor torque output when the speed limit is reached.
Rev limiters have been a standard feature of conventional cars for a couple of decades now. Just as with electric vehicles, it’s been easy to implement, since the engine is controlled by a computer. It used to be that the computer would just interrupt the ignition when redline was reached, and in some cases chop the fuel injection. Late-model cars all have electronic throtlte control, so now the computer can just back off of the throttle, resulting in less disturbing noises from the engine bay when you bump up against redline. Since the computer is now also paying attention to road speed (ABS, traction control, and stability control are all being integrated with engine control), it is likewise trivially easy to implement top-speed control for a conventional-drivetrain vehicle.
My Mustang has a “Valet Tune” that I can switch to if someone else has access to the car and I don’t trust them to not be stupid. It’s limits RPM and top speed.
Yes, my Escape has this. I set my key to be the “My Key” and now my top speed is limited to 80 mph. The other key, which is safely in my kitchen drawer, is like the sys admin key and can change that, but I think it’s kind of funny and I never need to go over 80 anyway.
In addition to the speed limit, the My Key feature mutes the radio if you’re moving forward without your seat belt attached, and it limits the volume of the radio to about halfway up. It only goes to five and a half now.
And the number one reason is… to keep the vehicle within the speed rating of the OEM tires. Very common for Mercedes and other euro sport sedans - and common for Euro and US models to have two different settings.
In the UK, all Heavy Goods Vehicles are limited by law to 56mph, and have been for quite some time.
This used to be accomplished by a mechanical limiter, but is now of course just done through the ECU, like the rev limiter.
I’ve heard tales of drivers who disabled their limiters, apparently it was once as easy as pulling out the fuse, becoming increasingly complicated as lawmakers reacted and mandated to, presumably, link the limiter with some other vital function so the truck could not run with the limiter disabled.
One such tale involved a friend of my father’s, who was caught out when his tachograph charts were reviewed by The Ministry. He was called into the office and told,
“We have reviewed your charts and found that you exceeded the 56mph limit on all of them” To which he replied
“Well I do let her run on a bit coming down the hills”. There was a pause, during which the ministry man picked up the sheaf of paper charts, selected one and held it up, then said,
“Could you show me this hill, where you sat at a steady 65mph for 83 miles, Mr. Trucker?” (name changed to protect the guilty)