How does Cruise Control decrease speed?

Question

Hello , i was using my cruise control the other day and i was getting curious on how it really works , sure i know that if it gets too slow the cars engine will run harder to maintain the speed you set it to , but what happens if your going down a large hill or mountain , such as a mountain pass in colorado or something like that. when your vehical is of excess of the speed you set because of gravity , how does the cruise control slow you down? does it apply the cars brakes? and if so does it activate the brake lights? i would like to leave cruise control on while i go down hills to make sure i dont go too fast , but i dunt want the cc to ride my brakes down the hill , thanks for ur input

Answer 1

How does Cruise Control decrease speed?
-It doesn't.

how does the cruise control slow you down? does it apply the cars brakes? and if so does it activate the brake lights?

-The C.C. hitting the brakes would defeat the whole purpose of the C.C.. The C.C. DOESN'T slow you down when going down hill, it basically takes the foot off of the gas pedal to save gas because you are moving faster from gravity pulling you down the hill, therefore saving fuel and getting better fuel milage.

When going up hill, the C.C. gives the vehicle enough gas to make the car go up hill at the speed you want it to so YOU wouldn't YOURSELF hit the gass pedal harder than necessary and waste fuel for no reason.

I always hated it when school bus drivers hit the brakes when going down hills because they were taught to do that.

Answer 2

If your car is going too fast then the cruise will decrease the throttle. If you are going down a very steep grade you will gain speed even though the cruise is not giving it any gas. The cruise will only affect the gas pedal, in most cases.

If you have one of the really expensive cars with adaptive cruise control, the ones that will automatically speed up or slow down depending on the traffic in front of you may hit the brakes if the other car is too close.

Answer 3

If you manually shift the transmission in to 2nd when going down a hill,it will keep the car from speeding up and hold the car's speed you have set on the cruise control.However the engine RPM will increase as a result of the lower gear,good for saving the brakes and staying at a steady speed, but not so good for your fuel mileage.

Answer 4

I've found that using the cruise control more increases my gas mileage. My theory is that the car is better at keeping a constant speed, where I would slow down farther before I sped back up, and you use more gas when you accelerate. I've tested it with my own car, and I do get better mileage the more I use the cruise control

Answer 5

Cruise control monitors the speed of your wheels, and adjusts engine speed, torque, and the gear to maintain constant speed.
Almost all cars don't have cruise control that apply brakes.
You shouldn't be using cruise control on mountains anyway.

Answer 6

cruise control can only control trottle opening it can not apply the brakes, decelleration is caused by a combination of engine brakeing & friction cause by the tires