Driving is changing

[Green RT]

There is a great quote in a current NY Times article about automated driving systems in cars.

 

“People don’t realize that when you step on antilock brakes it’s simply a suggestion for the car to stop,” said Clifford Nass, a director at the Center for Automotive Research at Stanford. How and when the car stops is left to the system.

 

NY Times article

[Downs]

“People don’t realize that when you step on antilock brakes it’s simply a suggestion for the car to stop,” said Clifford Nass, a director at the Center for Automotive Research at Stanford. How and when the car stops is left to the system.

 

Not exactly accurate with pretty much all ABS cars. You have a direct link to the brake system and control it directly. The ABS (or stability system which uses the ABS pump among other things) system only steps in when you exceed the available traction while braking.

[upflying]

This is also true with acceleration. When you step on the gas, you are suggesting acceleration. The PCM/ECU decides how much throttle is applied.

 

[Danny caddyshack Noonan]

Actually, it is the friction coefficient that decides if you'll stop, or go, or not.

[elkroeger]

The more things change, the more they stay the same. We had several VWs when I was a kid. Everything you did behind the wheel was a mere suggestion. I recall how the whole family would hold our breath if dad attempted to pass (usually reserved for miles-long straightaways...).

[Paul Mihalka]

In older times it was the car telling you what's ahead. The first car I drove regularly was my dad's 1947 Studebaker Champion. You had to shift down way before the next hill and the tires started squealing way before the next turn.

[Downs]

Only on Throttle by wire applications. In cars without throttle by wire you still have a direct connection to the throttle butterfly the computer adjusts fueling and timing though.

[Joe Frickin' Friday]

Only on Throttle by wire applications. In cars without throttle by wire you still have a direct connection to the throttle butterfly the computer adjusts fueling and timing though.

 

Electronic Stability Control (ESC) became mandatory in the US starting with the 2009 model year; it was phased in over several years, and for 2012 and later all passenger cars are required to have it. I'm not aware of any cars that implement ESC without also using electronic throttle control. To control a skid, the computer has to be able to control engine power output; when a skid first starts, power output can be reduced instantly by retarding spark timing, but for sustained/large cuts in power output, the computer has to be able to override the accelerator pedal and move the throttle.

[Bill_Walker]

“People don’t realize that when you step on antilock brakes it’s simply a suggestion for the car to stop,” said Clifford Nass, a director at the Center for Automotive Research at Stanford. How and when the car stops is left to the system.

 

Not exactly accurate with pretty much all ABS cars. You have a direct link to the brake system and control it directly. The ABS (or stability system which uses the ABS pump among other things) system only steps in when you exceed the available traction while braking.

 

But it's becoming less true all the time. Consider, for example, all hybrids and electric cars. Initial application of the brake pedal engages regenerative braking from the electric drive system, using the electric motor as a generator. A harder push on the pedal activates the mechanical friction brake system. That's all managed by the computers.

[russell_bynum]

Only on Throttle by wire applications. In cars without throttle by wire you still have a direct connection to the throttle butterfly the computer adjusts fueling and timing though.

 

Electronic Stability Control (ESC) became mandatory in the US starting with the 2009 model year; it was phased in over several years, and for 2012 and later all passenger cars are required to have it. I'm not aware of any cars that implement ESC without also using electronic throttle control. To control a skid, the computer has to be able to control engine power output; when a skid first starts, power output can be reduced instantly by retarding spark timing, but for sustained/large cuts in power output, the computer has to be able to override the accelerator pedal and move the throttle.

 

Yup. It's very annoying.

[Joe Frickin' Friday]

Yup. It's very annoying.

 

I don't know where the yaw sensor is typically located, but if you could find it and unplug it, I wonder if that would be enough to disable it - or if that would disable the car completely.

 

[russell_bynum]

Yup. It's very annoying.

 

I don't know where the yaw sensor is typically located, but if you could find it and unplug it, I wonder if that would be enough to disable it - or if that would disable the car completely.

 

Our new Honda (Fit) has a button that disables traction control. You have to do it every time you start the car.

 

And even with it off, you still have the fly by wire throttle...which I'm not opposed to in theory, but in practice I don't like it. My biggest beef is that it's inconsistent about how it behaves when I lift (for example, when shifting gears) and the result is that is hard to rev-match. I assume that's because of the fly-by-wire throttle since otherwise there's nothing special about the car.

 

Regarding Traction Control...the car has less horsepower than my motorcycle. Traction control is just not necessary and it's always kicking in when it doesn't need to.

[Joe Frickin' Friday]

Our new Honda (Fit) has a button that disables traction control. You have to do it every time you start the car.

 

And even with it off, you still have the fly by wire throttle...which I'm not opposed to in theory, but in practice I don't like it. My biggest beef is that it's inconsistent about how it behaves when I lift (for example, when shifting gears) and the result is that is hard to rev-match. I assume that's because of the fly-by-wire throttle since otherwise there's nothing special about the car.

 

Regarding Traction Control...the car has less horsepower than my motorcycle. Traction control is just not necessary and it's always kicking in when it doesn't need to.

 

Keep in mind that traction control and electronic stability control are two different things.

 

TC mitigates wheelspin when you step on the gas a bit too hard and lose static traction. It's not mandated by law, and it's common for cars to have a switch on the dashboard that allows TC to be temporarily disabled so you can do long, smoky burnouts. Drivers who lack a delicate touch on the accelerator pedal may find TC useful in snowy/icy conditions, but my experience has been that it's pretty damn easy to just ease up on the throttle when you notice the wheels are spinning.

 

ESC manages both the throttle and the brakes to prevent sideways skids that can lead to rollover crashes or side impacts, and to my knowledge can't readily be disabled (unless maybe you start disconnecting critical components like the yaw sensor).

[russell_bynum]

Good point. I know that I can disable the traction control on the Fit and that does allow wheelspin. I haven't tested to see if that also disables stability control.

[philbytx]

Except when you have an off switch mate!!!

Thankfully, our Optima has one.......

[russell_bynum]

Except when you have an off switch mate!!!

Thankfully, our Optima has one.......

 

Yeah, that's what we're talking about. I'm not sure if the switch on ours just disables TC or if it disables TC and ESC both.

[lkraus]

TC mitigates wheelspin when you step on the gas a bit too hard and lose static traction. It's not mandated by law, and it's common for cars to have a switch on the dashboard that allows TC to be temporarily disabled so you can do long, smoky burnouts. Drivers who lack a delicate touch on the accelerator pedal may find TC useful in snowy/icy conditions, but my experience has been that it's pretty damn easy to just ease up on the throttle when you notice the wheels are spinning.

 

In 2WD vehicles, I've been "stuck" several times when only one wheel has no traction on ice and very wet ground. That wheel will spin while the other driving wheel, with good traction available, remains motionless. Traction control will apply the brake to only the spinning wheel so that I can drive out using the other wheel.

[russell_bynum]

TC mitigates wheelspin when you step on the gas a bit too hard and lose static traction. It's not mandated by law, and it's common for cars to have a switch on the dashboard that allows TC to be temporarily disabled so you can do long, smoky burnouts. Drivers who lack a delicate touch on the accelerator pedal may find TC useful in snowy/icy conditions, but my experience has been that it's pretty damn easy to just ease up on the throttle when you notice the wheels are spinning.

 

In 2WD vehicles, I've been "stuck" several times when only one wheel has no traction on ice and very wet ground. That wheel will spin while the other driving wheel, with good traction available, remains motionless. Traction control will apply the brake to only the spinning wheel so that I can drive out using the other wheel.

 

A limited-slip diff solves the same problem without the annoying side-effects of TC.

[SuperG]

On most late model BMW cars traction and stability controls can be disabled separately. A DTC multi function button is staring at you right in the middle of the dash just above the hazard /4 way flasher button.

 

To stay on topic, driving is changing.

BMW also employes

active braking, active steering as well.

active steering not only changes servo assist pressure but also changes wheel turning angle in relation to steering wheel angle. Meaning the steering wheel angle vs. actual tire/wheel angle is speed sensitive and controlled by computer.