# Questions tagged [car]

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7 views

### Can the Dynosheet be read as a Fourier transform of some sorts?

I've done some quick google search on dynosheet, and what it does is that it measures the power output of the car with respect to its frequency. My initial understanding of the dynosheet is that it ...
33 views

### Is the effect of weight-to-horsepower ratio linear?

I am wondering if a car that weighs 2,5kg and a engine power output of 1hp would be just as fast when going in a straight line like a 1250kg car with 500hp (they both would have a weight-to-horsepower ...
18 views

### Working Speedometer shows a speed below 0 [migrated]

this is the first time I'm asking anything on this StackExchange, so I'm not sure about they right question format, so I'll get straight to the point. I performed a Gauge Cluster Light Self-Test on my ...
25 views

### What is the effect of caster angle in automobiles? What will happen if we use neutral caster?

What is the effect of caster angle in automobiles and what will happen if we use neutral caster? We study that positive caster makes vehicle more stable at high speeds. It increases lean while ...
1 vote
26 views

### Where is best place to install vortex generators if race car diffuser stall?

If flow separate in high AoA diffuser, vortex generators can help to delay separation. Where is best palce to install VG for flat floor + diffuser configuration , in front leading edge of diffuser or ...
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### Question about torque in car engines

Sometimes people say "The engine of Car A has a higher torque than Car B with both having the same horsepower" My question is : if both cars are equal in horsepower can't we just avail this ...
35 views

### Increasing air velocity through F1 car diffuser

I am looking into F1 car aerodynamics for a course that I am taking. I understand that because of Bernoulli's law, when the velocity increases, the pressure decreases, which is good for F1 cars if we ...
2k views

### When a car with an open differential turns, why does the inner wheel slow down and the outer wheel speed up?

I asked this in the physics stack but hopefully will get more interest here. So I understand that when driving on a curved path, the inner wheel must travel a shorter distance than the outer wheel. ...
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42 views

### Time period of charging a mobile phone via car

As car batteries provide only 12 V instead of ~230-250 V, I assume it takes much longer to charge them compared to a common wall socket?
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1 vote
51 views

### How does one deal with indeterminacy in modeling the motion of vehicles with multiple wheels? (Dynamics Question)

Consider a vehicle with four wheels and suspension (coil and dampers) rolling over an arbitrary surface. What would be the magnitude (not direction) of the normal force on each wheel? Is there a ...
62 views

### How can a car travelling at a higher speed may cause it to lift off from the ground?

Many Sports cars and other high speed and performance ground vehicles have a rear wing attached to its rear, and a splitter attached to its front. From what I understand, the rear wing (which takes ...
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38 views

### How does Kia charge the high-voltage battery in EV mode?

I recently bought a Kia Ceed 2020 PHEV (Plug-in Hybrid Electric Vehicle). Its specs mention a 6-gear Dual-Clutch Transmission (DCT), a 105 kW Internal Combustion Engine (ICE) and a 44 kW Motor-...
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173 views

### How does my automatic car shift without complete temporary loss of acceleration

When my car shifts gears, the car's acceleration never goes to 0. I feel that there is constant torque to the wheels throughout the entire shift. How is this possible during a gear change? ...
89 views

### Is there a way to estimate whether the driver or co-driver picks up the smartphone?

First of all, as I am new in this very corner of stack exchange please help me by selecting the correct tags! I'm interested in finding an alorithm, that estimates wether a phone is picked up from the ...
88 views

### What is pitch stability in cars?

Can reduction in pitching moment of a car be referred to as improved pitch stability? Or is this term strictly only with regards to aircrafts?
43 views

### If body roll of a car is reduced, is the load or weight transfer reduced too?

Will the load transfer or weight transfer be reduced because the body roll is reduced due to stiffening of the suspension ?
1 vote
60 views

### Does a single-wheel brake intervention from ESC cause one wheel to be not brakeable by the driver?

Source: https://www.kfz-tech.de/Engl/Buchprojekte/HBremse/ESP3.htm Firstly, I don't know if this is the right StackExchange, but I will try nevertheless. Above I posted a picture of the hydraulic ...
140 views

### Does lowering the ride height of a car 50 mm exactly lower the height of C.G by 50 mm?

Does lowering the ride height of a car $50\ mm$ exactly lower the height of C.G. by $50\ mm$ or is it higher?
51 views

### How come my calculated engine torque is so much less than the manufacturer's specifications?

Here are my calculations. Am I doing anything wrong?
242 views

### Calculating final drive force from engine torque and tyre spin ratio

Trying to build a simplified physics simulation for cars, along the lines of "Car Physics" by Marco Monster. I'm stuck at straight line acceleration. I don't know if I understand the ...
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34 views

### Why do all cars seem to use "reflective" paint?

I'm not just talking about "chromed" parts. I mean the whole "paintjob", which seems to be be designed to reflect the environment as to basically be a mirror (somewhat depending on the color). I don'...
39 views

### Meeting point of turning wheels with rear wheels

I was watching this video about how steering on a vehicle. It states: If you track the meeting point of the left and right wheels, you can see that the meeting point always lies on the rear wheel ...
58 views

### Does the shape of a car really matter for how much gasoline it drinks?

Let's say that we have a mid-1950s "gas guzzler". Now, we take away the exterior "shell"/chassis and replace it with a modern car's. That is, it will visually look just like a modern car from the ...
79 views

### Why does the synchromesh in manual transmissions act on the output shaft?

Wikipedia has a good animation of a manual transmission, but something irks me. If I understood correctly, in the animation, the input shaft is in green, and the output shaft is in cyan. The dog ...
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24k views

### What are those large cylinder "tanks" attached to the outside of trucks for?

I've noticed this a few times, the last time today: It's a big cylinder-shaped "tank" (for water?) outside of the front part of the truck. What's the purpose of this thing?
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252 views

### Why rear wheels of the bus are covered?

There is an airport bus (Germany) which has it's rear wheels covered by the fender. Even front wheels have strange shape of fender around them (tilted toward front). What purpose of that?
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1 vote
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### Standards for safety car seatbelts locking condition

Is there an (international) standard which determines the condition when a car seat belt locks? Which standard is it? Does the standard determines a speed in m/s of the belt, such that it locks if ...
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169 views

### Determine if car is moving forward or backward

I would like to know if there is someway i can figure out if the car wheel is rotating in clockwise or anticlock wise direction. Im working on a project which determines if car rolled back on a hill ...
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101 views

### How is it possible that it took until the 1950s or even longer before they started using car belts and neck-supported seats?

I've spent a large amount of my life thinking back on past times, both long ago and "recently", meaning ~1950s to me. A lot of things make sense, but some things just fundamentally baffle me. One of ...
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28 views

### Emulate normally closed relay with 2 normally open relays

Good afternoon, I have recently ordered a normally closed relay to fix on my car's daylight-running lights. When the main lights come on the DLR should switch-off. Unfortunately amazon has delivered ...
46 views

### Why HMMWV's lights aren't located at the edges?

Hummvee has front lights located far from edges, closer to each other. That makes it harder to see edges of the vehicle in the dark.
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1 vote
73 views

### How fast could a Mini Cooper go in a vacuum?

Lord Evulz just stole the Earth's atmosphere. Our hero must race his trusty old Mini - which he had already prepared to be airtight, to ensure the tires do not explode, with pre-packaged oxygen to ...
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60 views

### What is the voltage at the ground electrode of a spark plug?

Since the voltage required to bridge the gap between the central electrode and the ground electrode of a spark plug can reach up to 40 000V and even more, my question is, how does the battery not die ...
1 vote
62 views

### A few questions about cars

When I start the car, why do I hear the engine working when I'm not pressing the gas pedal? How exactly does the torque and power of the gears work? Torque = Radius * Force Power = Torque * Speed ...
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### Why does a tractor not do wheelie with a lot of weight on the trolley?

Tractor carries more than his own weight on its trolley. The linkage between the tractor and the trolley is far away from the tractor. So, the whole weight of the trolley is on the back of the tractor....
1 vote
77 views

### What wheel setup on a small, solar powered car, would have the least rolling friction?

We are attempting to design a solar car. The solar panel 4 1/2" x 13". I like to break these problems into their simplest form, in order to eliminate the least amount of possibilities. So, the goal ...
96 views

### What should be the material and thickness of front pillars to stop car (~1,847kg and ~262 km/h) without killing the driver?

"Tesla Model 3 owner died in a tragic accident with a semi truck. The Model 3 went under the truck’s trailer resulting “in the roof being sheared off as it passed underneath,” which is known as a “...
398 views

### Pivoting trailer gate on multiple axes

I am currently trying to design a rear gate to retrofit to an existing caged trailer (similar to image 3), with the goal of having a system where the rear gate can pivot down (on its bottom edge) to ...
1k views

### Is it true that four-wheel drive is less efficient and if so, why?

I have heard many times that four-wheel drive is less efficient than two-wheel drive. Many car producers have a normal drive mode where only two wheels are powered, and turn the four-wheel drive on ...
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541 views

### Why vehicle horns are tuned to consonant intervals?

The primary purpose of a vehicle (car, locomotive, etc.) horn is to warn other traffic units that something potentially dangerous is about to happen. And so, others must pay attention to the signal. ...
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1 vote
47 views

### Would an afterburner on a turbine drastically improve acceleration lag?

A little bit of context. My friends and I were watching the "Dark Knight Rises" and a discussion about the Batmobiles ensued. I, being a former ME student, said it was stupid that batman has a turbine ...
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30 views

### Sonomotors, Sion: Can this electric car really charge up to 30km only from its solar cells?

Maybe you have heard about Sonomotors and its futuristic electric car, the Sion. If not, here is the link to its website: https://sonomotors.com/ Anyway, the manufacturer claims that this car can ...
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30 views

### Frequency domain analysis of steering system of a car

Can anyone share the equations involved, or some relevant theory material for frquency domain analysis of steering rack and pinion using bode plot?
607 views

### Can a rolling wheel create a side force without first rotating on a vertical axis at its contact patch? [closed]

There is something wrong with the way we describe how a cornering vehicle wheel creates a cornering force. I think a rolling wheel must first rotate on a vertical axis to then create the cornering ...
1 vote
278 views

### Physics of Trailer Hitch Height

I'm modifying a lawn tractor to pull single axle trailers in a woodland environment. They are rear wheel drive, have enough power, but traction is our biggest issue even when using tractor/ATV ...
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1 vote
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### Passing by a semi truck on a highway

So I’m driving down the highway in my sedan on a speed of lets say 60 mph. Why is it that my car sways just before it passes or it passes me? Almost always where the semis first tire is (closest to ...
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### What is the percentage of direct workers in an automotive production plant compared to all the employees?

I am not asking for specific numbers of any production plant. I want to know the general direct worker/employee ratio of a plant. Example: if there are 1000 employees working usually 700 of them are ...
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### Proccess of a 4-wheeled vehicle taking turn

I have observed that when a 4-wheeled vehicle takes a turn, one of it rear tire moves with more speed as compared to the other. For example A car is taking right turn, its right rear tire will be ...
59 views

### What standards exist regarding diagnostic systems in automotive engineering?

I'm designing a diagnostic system that simulates an environment and user input for a dummy vehicle. All possible critical situations are simulated in order to find out whether any errors are triggered,...
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1 vote
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### Working out RPM from car engine's lb ft?

Using an old copy of an automobile magazine, these are the cars with hp and lb ft I am trying to work out the RPM for: 2007 Honda Accord 2.4 sedan, 2.4-liter 187hp 4-cylinder, 164 lb ft pulling power ...
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