Throttle Controllers

[JPortici]

one of our products' aim is to reduce "throttle lag" as in this iDrive box.
Yes, it's exactly as pressing the throttle pedal differently.
Yes, it's perceived as reduced lag.
Yes, it sells real good.

Why it works?
1) The throttle is the only way we have to command the car to accelerate, a change in response can be easily perceived and for most people more responsive = better. So there is an important psychological factor at work.
2) Most "ECO" or "SPORT" modes at their core will change the curve of the throttle, many will stop at that.
3) Most first stage tuners, will also change the throttle response map so the driver perceive more sensitivity. On newest cars, some will stop at that.
4) Bonus: Some cars will accelerate differently if they perceive that the throttle pedal is put down faster (not talking about kickdown of course)

[SilverSolder]

It is always fun to customise your car.  The advent of electronics and computerized controls just means the nature of how we modify has changed, and will continue to change.

Imagine how guys will be modifying their cars in the year 2100....   hacking their self driving cars by implanting an Arnold Schwarzenegger core in its neural network!

[JPortici]

Mmmh, hacking a tesla should be fun. There are already reports of guys that "enabled" performance mode via canbus, sold a box to do that, and tesla giving them the giant middle finger via an OTA update that detected the box. I mean, what if i am OKAY with losing the warranty and modifying my own car, at my own risk?
Teslas are a good representative of the car of the very near future will be: connected, that can be monitored without your explicit say-so, not really yours anymore. a cloud based car. (others are already catching up)

[james_s]

The Tesla drivetrain is very impressive, but the connected aspect is a total non-starter for me. No way I would ever buy one, not gonna happen, ever. A Tesla motor and battery with an open source controller in a cool 80s-90s car would be awesome though.

My dad had a Tesla for a while before he passed away, like my grandfather he loved gadgets but I was just not impressed. I remember at one point he picked my brother up somewhere and saw a notification that the car had an update available, so he let it go ahead and update thinking it would take a few minutes, turned out they had to sit there for around 30 minutes with the car inoperable while it updated

[SilverSolder]

Ordinary cars get updated too, it just isn't wireless (it happens during dealer servicing).  I can see arguments in favour of doing the updates via the Internet, but there are many arguments for not doing so too!

In the long term, I think @JPortici is right:

[...] Teslas are a good representative of the car of the very near future will be: connected, that can be monitored without your explicit say-so, not really yours anymore. a cloud based car. [...]

That whole idea just rubs me the wrong way,  yet another item that we are not permitted to own outright but instead have to expend a daily effort (some percentage of our working life) to not just maintain, but also create profit for various corporations involved in the process.

I have nothing against corporations making a profit...   when I purchase something from them.   I don't like paying for the same item over, and over, and over...   it seems the holy grail of modern marketing is to try to pretend that any product is now a "service" rather than a "product".   

On one level they are right, of course...  even your underwear is a "service" in that it has to be washed and replaced at regular intervals -  but the question is, why would I outsource those processes to a corporation and subscribe to my underwear?? 

[james_s]

On one level they are right, of course...  even your underwear is a "service" in that it has to be washed and replaced at regular intervals -  but the question is, why would I outsource those processes to a corporation and subscribe to my underwear?? 

You know, I think I'd rather subscribe to underwear than subscribe to software. I'm happy to use the same version of MS Office for 20+ years, I mean name one tangible improvement to that product in the last decade, I can't think of one. I am not going to wear the same pair of underwear for 20 years though I have to expend effort washing it and replace it when I notice it getting worn out. If I could pay a modest fee to always have a supply of clean new underwear on hand and never have to wash or maintain it, that almost sounds appealing.

[SilverSolder]

On one level they are right, of course...  even your underwear is a "service" in that it has to be washed and replaced at regular intervals -  but the question is, why would I outsource those processes to a corporation and subscribe to my underwear?? 

You know, I think I'd rather subscribe to underwear than subscribe to software. I'm happy to use the same version of MS Office for 20+ years, I mean name one tangible improvement to that product in the last decade, I can't think of one. I am not going to wear the same pair of underwear for 20 years though I have to expend effort washing it and replace it when I notice it getting worn out. If I could pay a modest fee to always have a supply of clean new underwear on hand and never have to wash or maintain it, that almost sounds appealing.

LOL yes, you make a good point...   Office is still decently usable in its latest incarnation precisely because they haven't changed much - other than the "paint job"! 

[IDEngineer]

A couple of random thoughts to share on various responses in this thread:

* Some throttle position sensors (TPS's) use a dual potentiometer where the slopes are inverted relative to each other. The ECU understands this and correlates the detected throttle position based on the (intentionally dissimilar) values it reads from the two pots. This prevents a short across the two pots from being missed. If EITHER pot's value doesn't correlate with the other, the ECU (at least) gives a warning and (at worst) goes into "limp mode" where RPM's are severely limited - basically enough that you're not stranded but not fast enough to put you in too much danger since as far as the ECU is concerned, you no longer have actual control of the engine.

* The terms "leading throttle" and "lagging throttle" have a couple of definitions depending upon context. This thread has used one, but the more common I hear is the relationship between the engine loading and the throttle position. To illustrate an extreme example of "throttle lag", imagine a moving car where you've completely released the throttle but left the clutch engaged. The engine compression is now acting as a brake, slowing the car, so the throttle is "lagging" behind what is necessary to match the losses and maintain speed. On the other end, a "leading throttle" is enough throttle that the engine, while under load, is causing the vehicle to accelerate (and thus the engine RPM's are climbing). If you think about it, lagging vs. leading will engage/load opposite faces of the gear teeth in the drivetrain. Somewhere in the middle is the sweet spot where the engine just matches the drivetrain... and the gears sort of "float" mid-tooth with little sustained loading in either direction.

* "Lag" has other uses too. For example, "turbo lag" refers to the delay between increased power demand from an engine and the spinup of an exhaust-driven turbocharger to provide increased ("boosted") intake air pressure. This is very common on modern diesel engines, virtually all of which have turbos (and those turbos recover ~50% of otherwise lost energy out the tailpipe, one reason diesels are so much more efficient). For those engines where such lag is intolerable, superchargers are the answer; they are driven directly from the crankshaft and so immediately track the engine's behavior. The tradeoff is sustained efficiency... the supercharger consumes some power even when not required and fully bypassed, whereas a turbocharger can always recover some otherwise lost power and the ECU knows how to accommodate that thanks to the countless sensors measuring everything. Hence turbochargers are better for long term sustained applications (over the road trucking, marine, etc.) while superchargers prevail for high performance engines requiring rapid acceleration (racing cars, racing boats).

Opinion time: I deplore the drive-by-wire, integrated design of today's cars. As much as I'm fully immersed in modern technology, there are times when it's possible to overdo it. I do not want a steering wheel position sensor driving a linear positioner to steer the front wheels... it's far less reliable than a simple shaft driving a rack-and-pinion. The latter will fail gracefully and allow me to control the car to a safe stop, but a failure of almost any component in an electronic steering system means you no longer control your vehicle. There is no graceful degradation.

Granted, some things like fuel injection (and its associated ECU and sensors) are definitely worth it. But they don't threaten the ultimate safety of the car. If the engine stops, you can still coast to a safe stop most of the time. But pushbutton "shifters" or (heaven help us) KNOBS that in reality just control a bunch of transmission solenoids? Seriously, I rented a pickup truck from Hertz recently and its automatic transmission was controlled by a rotary KNOB. I sat there dumbfounded for a while, utterly speechless at the concept of replacing a very straightforward shaft or cable system with switches, wires, and solenoids. That is NOT progress, people. Not everything on the planet needs to help you play "astronaut". Some things should just work nice and simple.

Perhaps the best example of this over-technology is touchscreens in cars. Seriously? Instead of a nice tactile rotating temperature control that I can operate by feel while keeping my eyes on the road, you want me to be a distracted driver while I look over at the screen, work my way through several menu layers, finally find the temperature controls, and then carefully align my finger with the up or down arrow? This is no different than using a smartphone while driving, which is illegal in a growing number of jurisdictions. I'm waiting for the lawsuit where someone claims "distracted driving" from a touchscreen led to an accident that killed someone. They don't want ME on that jury, because my 100% objective opinion as an Engineer is that touchscreens make cars more dangerous, period, full stop.

Technology is wonderful. But it's not a universal solution for all situations. Sometimes an array of sensors, harnesses, motors, and solenoids just isn't better than a shaft or a cable. If you want to play "Space Shuttle Pilot" play a video game at home.

/rant

[SilverSolder]

[...] I'm waiting for the lawsuit where someone claims "distracted driving" from a [built-in car] touchscreen led to an accident that killed someone.  [...]

It will happen eventually - and if there are enough accidents where this is a factor, it could mean an expensive recall.  Notice how manufacturers seem to have gone away from this approach in the last couple of model years? - probably some engineer with a clue has raised the issue internally, but the world will never hear about it due to the implications.

[Sal Ammoniac]

I remember at one point he picked my brother up somewhere and saw a notification that the car had an update available, so he let it go ahead and update thinking it would take a few minutes, turned out they had to sit there for around 30 minutes with the car inoperable while it updated

My Tesla never updates unless I give it permission to do so for every update, and when I do it explicitly says how long the update will take. A typical update takes 25 minutes, and I always do them after I park the car for the night.

[Circlotron]

imagine a moving car where you've completely released the throttle but left the clutch engaged. The engine compression is now acting as a brake, slowing the car,

Wouldn't that braking effect instead be the pumping losses from the engine trying to draw in air against a closed throttle? Not the same as compression braking in a diesel where you may have an exhaust valve timed to release compression at the top of the stroke (and make a LOT of noise!) so that the energy used in compressing the air is not recovered on the expansion stroke. That may sound like I'm being pedantic and picking on your words, but no offence meant.  We engineers tell it like it is. I do understand though the idea of simplifying descriptive terms for a given audience.

[NiHaoMike]

I do not want a steering wheel position sensor driving a linear positioner to steer the front wheels... it's far less reliable than a simple shaft driving a rack-and-pinion. The latter will fail gracefully and allow me to control the car to a safe stop, but a failure of almost any component in an electronic steering system means you no longer control your vehicle. There is no graceful degradation.

Are there any production cars that are completely drive by wire with no mechanical connection from the steering wheel? I'm under the impression that every power steering system ever used in a production car worked in parallel with the traditional rack and pinion system.

[james_s]

Are there any production cars that are completely drive by wire with no mechanical connection from the steering wheel? I'm under the impression that every power steering system ever used in a production car worked in parallel with the traditional rack and pinion system.

I think it's currently required by law, I could be wrong but I have never seen a fully drive by wire car. It would not surprise me at all if somebody made one at some point though.

[hans]

I don't know about cars.

I do know about steer-by-wire in tractors. John Deere 7R/8R have been using such systems for certainly more than 6 years now. They use a digital potentiometer with quad-level redundancy (4x PWM wires) and a single actuator to control the resistance.

Oh and you should hear the number of warnings/beeps if one of those PWM wires fail... At that point you're not allowed to engage the machine into drive anymore IIRC

They even market it as a comfort feature, as the steering sensitivity(+resistance) can change for road speeds and soil work/maneuvering speeds.

[Monkeh]

imagine a moving car where you've completely released the throttle but left the clutch engaged. The engine compression is now acting as a brake, slowing the car,

Wouldn't that braking effect instead be the pumping losses from the engine trying to draw in air against a closed throttle? Not the same as compression braking in a diesel where you may have an exhaust valve timed to release compression at the top of the stroke (and make a LOT of noise!) so that the energy used in compressing the air is not recovered on the expansion stroke. That may sound like I'm being pedantic and picking on your words, but no offence meant.  We engineers tell it like it is. I do understand though the idea of simplifying descriptive terms for a given audience.

You're quite correct, the intake vacuum provides the braking effect. If it were merely compression (and subsequent decompression..) you'd only be gaining braking from mechanical losses in the engine, which are small. A N/A diesel has almost no engine braking due to this.