45
votes
Accepted
Why do the brakes "freeze" the suspension?
I made a crude sketch illustrating the relevant points of the shown image.
Brakes engaged:
The center of gravity is above ground, the brakes "try" to slow down the car, the car itself "...
- 8,448
20
votes
Accepted
Turbo equivalent on electric motors
The "take some of the output force to reuse it as input" can be interpreted as regenerative braking, but the big differences are:
Regenerative braking takes power back from the wheels while turbo ...
- 1,739
17
votes
Turbo equivalent on electric motors
No, there isn't any equivalent. A turbo is used because combustion engines are inherently inefficient: they convert chemical energy into mechanical energy, using an awkward detour via heat. ...
- 435
17
votes
Turbo equivalent on electric motors
regenerative braking
This question and answer regarding the subject matter has some very good information in it as well the answer reveals a mathematical paradox with regenerative braking
What is ...
- 33k
15
votes
Why does brake pedal ever move
You are correct, the brake pedal should only move when any of the 4 or more slave cylinder pistons move (some vehicles may have multiple cylinders in a caliper).
Once the pistons of the slave ...
- 24.9k
14
votes
What is torque steer?
Torque steer is where a front wheel drive car pulls to the left or right under hard acceleration. This is relatively common in older front wheel drive cars, but as it is negligible in low powered cars ...
- 18.6k
13
votes
Accepted
How do electric car transmission systems work?
I'm sure it can be done different ways, but I'll describe the Nissan Leaf, since it is one of the true electric cars on the market today (not a hybrid gas/electric).
The Nissan Leaf does not use a ...
- 153k
10
votes
Accepted
Why do electric motors produce peak torque instantly vs gasoline engines
Torque in almost all electric machines is a function of current. For permanent magnet machines, torque is roughly proportional to current and for the series-wound machines, torque is roughly ...
- 2,083
10
votes
Why do the brakes "freeze" the suspension?
As it turns out the answer is very obvious and frankly quite simple.
Consider a 1 meter long plank.
Now if you lift up the right side of the plank by 10 cm (0.1 meter), the left side moves a bit to ...
- 1,344
10
votes
Accepted
Purpose of small forward-facing deflectors in front of rear wheels
These are called wheel flaps or sometimes wheel spats and on some cars you see them on the front wheels too.
The purpose is just as you have noted, aerodynamics. The leading edge of the tires is a ...
- 12.1k
8
votes
Accepted
How to convert Amp Hours to CCA?
While you'd want to believe there's a relationship between CCA (or even CA) and AH, there really isn't a simple one. The reason you cannot just convert it over, even with a rule of thumb, is because ...
- 153k
6
votes
Accepted
What is surface charge and how does it affect battery testing?
I have often heard this term as well, but have never known the technical reasons or the actual root cause of what is known as a "surface charge". To figure it out, I took a gander at a website called ...
- 153k
6
votes
Accepted
Why does the impeller of a torque converter sit behind the turbine?
Looking at the design, you can see the input shaft of the transmission goes all the way through the torque converter and sits in the front part where the turbine is. The splined part at the input ...
- 153k
5
votes
Multiple Batteries Charging
When you put two batteries in parallel they will share the charge among themselves.
For example, if you connect two batteries together, one fully charged and one dead the resultant combination gives ...
- 16k
5
votes
How would a car handle differently if it had independent brake controls, like a pedal bike?
So, this all gets down to physics - inertia primarily.
following assumes braking to a wheel-lock
When you brake heavily, front only, the rear will try to lift, this will reduce traction of course on ...
- 3,284
5
votes
How to convert Amp Hours to CCA?
As Paulster2 suggested, CCA (cold cranking amps) and Amp-hours are not related. Trying to convert one into the other is like trying to convert miles per hour (MPH) into miles per gallon. While miles ...
- 12.2k
5
votes
Why do electric motors produce peak torque instantly vs gasoline engines
To expand on @Autistic's answer…
There is no need for a transmission with an electric vehicle (assuming that the speed and characteristics of the motor match the application – for applications where ...
- 14.4k
5
votes
Work over time; humans versus automobiles
The engine creates those 390 Nm per rotation, and at peak flywheel
torque (≈ 2000 RPM), it rotates about 33 times per second.
Considering work over time, that results to some 110 horsepower.
I ...
- 39.1k
5
votes
Accepted
Can car alternator be used to save fuel by using it as a regenerative system at the same time?
What you describe, in somewhat inaccurate general terms is something that is in place today in hybrid vehicle designs.
The specifics you've presented have multiple technical problems, especially the ...
- 4,455
4
votes
Turbo equivalent on electric motors
You could capture the heat from the electric motor, and convert that into more energy using a thermoelectric device.
University of Florida research
- 1,308
4
votes
Accepted
Triangular/Parallel four-link suspension system, how it works
The suspensions pictured are of the racing variety. They have small bushings in them making flexing difficult. This is probably why you have a difficult time with them. Racing suspensions are ...
- 16k
4
votes
How to convert Amp Hours to CCA?
There is a rule of thumb doing the rounds AH * 7.25 = CCA, but this is not guaranteed as not all batteries are created equal....
And just to note, we here in Europe also use CCA as well - having ...
- 34.6k
4
votes
Accepted
Why does the wheel size affect the cars gearing?
The answer lies in the rpm conversion to ground travel. Any gearing in a motor vehicle is designed to provide sufficient torque to begin moving (with load, of course) and to keep the engine in the ...
- 4,455
4
votes
Accepted
Why do most cars have positive offset wheels from the factory?
Positive offset allows the steering axis to move toward the centerline of the tire. This dimension, the distance of the centerline of the tire to the steering axis, is called the scrub radius.
A 0 or ...
- 712
4
votes
Accepted
Oxygen sensor "clean air source"?
According to Auto Service World, oxygen sensors requiring reference air can get it in several ways:
Some O2 sensors were designed with laser welded “waterproof” housings and thereby seal the ...
- 156
4
votes
Confused as to how components are powered
If you think about it, the electricity is available at the wall socket, but technically, the power doesn't come from there. It is routed to the wall socket via wiring. A vehicle is no different. Power ...
- 153k
3
votes
How would a car handle differently if it had independent brake controls, like a pedal bike?
It would surely handle differently, and that's why this is also done, but automatically. There's a brake pressure distributor in your car that distributes pressure depending on different factors, eg. ...
- 2,944
3
votes
Multiple Batteries Charging
When you connect the batteries together in parallel you force all of the batteries to the same voltage – this causes the more charged batteries to discharge into the less charged batteries until they ...
- 14.4k
3
votes
How does a timing light detect the electricity in the plug wire?
Most timing lights have a magnetic pickup that will 'detect' current flowing through the spark plug wire. This triggers the strobe to flash. The signal is not amplified, it closes a switch. I do ...
- 8,443
Only top scored, non community-wiki answers of a minimum length are eligible