Questions tagged [automotive-engineering]

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By approximately what ratio does power steering (on a car) amplify the torque applied?

Power steering on a car is a form of torque amplifier: the driver applies X Nm (or ftLb) of torque, and the power steering adds Y torque - but maintaining the same angle of turn. But what's the ...
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29 views

What is the average energy loss due to rolling friction in contemporary motor vehicles?

Around what percent of energy provided by gasoline is lost as heat due to rolling friction in vehicles? Is this number higher for larger vehicles likes trucks than smaller vehicles like bikes? ...
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24 views

What is the minimum frictional force required for a vehicle to operate smoothly, retain traction, and prevent any skids?

I am not looking for a specific number of course. I know that it may perhaps vary with different vehicles. However, I'm trying to figure out how to theoretically calculate the minimum necessary ...
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Is there a reason (in terms of the physics involved) why it is better to push start a car in 2nd gear rather than 1st?

I am struggling to understand why it is recommended to push start a car in 2nd gear rather than 1st - in terms of the physics involved, I fail to see a reason why this would be the case. I have ...
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Electronic Pressure Control, EPC

In short, the question is: How the EPC affects an automatic transmission? I'm planning to build an automatic transmission controller module, TCM for 4F27E Ford transmission. So far I haven't found an ...
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3answers
65 views

Why do custom engines typically specify a type like “Ford” or “Chevy”?

I notice that when custom car engines are sold they nearly always have a big name type name like "Ford" or "Chevy". Is this because the block and crankshaft comes from those companies and the custom ...
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1answer
48 views

Car trajectory with angled rear wheels (non-Ackerman)

Consider a four-wheel steering vehicle in which: The front wheels follow Ackerman condition The rear wheel are rotated with a fixed angle (dir == dor in the picture below, and such angles do not ...
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2answers
65 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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1answer
39 views

Measuring fracturability / airborne fuzziness of carbon fiber tow vs stainless steel tow

My friend uses carbon fiber tow in creating a component for automobile machines. However the carbon fiber is actually much tougher than it needs to be. As a risk manager in software I am concerned ...
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how to calculate required torque and rpm to through a 160 gram cricket ball horizontally at 160km/h velocity?

I am going to design a bowling machine. In this design, I'm going to use two motors that are being placed vertically and their shaft are attached with two horizontal identical wheels with a space of ...
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34 views

How to compare multiple data acquisition systems?

for an application of displacement measurement under 1 kHz, I have 3 options to choose from. the application is automotive. unfortunately I don't have deep electronics knowledge and the catalogues ...
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59 views

What is the rationale for a 6x6 truck chassis with 2 axles front vs. 6x6 chassis with 2 axles rear?

What is the rational for these two different 6x6 truck chassis arrangements? Is it merely a matter of intended distribution of weight across the chassis while in use? As in, two axles up front to ...
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1answer
41 views

Headlight auto-dimmer in newer cars

My RAM truck has a feature that intrigues me and I want to know how it works. In auto-dimmer mode, the truck will automatically put on low beams headlights when there is on-coming traffic at night, ...
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1answer
22 views

Max torque given in engine specification is indicated torque or brake torque?

I want to calculate brake torque from indicated torque for motorcycle.
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1answer
61 views

How don't dog clutches collide?

I'm learning about how dog clutches work particularly in sequential transmissions. I'm having a hard time understanding the principle which ensures dogs will always mesh correctly. I can easily ...
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1answer
33 views

Fastening rotating surfaces

This is probably very well explained but I'm lacking the terminology knowledge and that's keeping me from finding the information I need. I have a frame to which I need to attach a weight carrying ...
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47 views

How fast could a human pedal a car? [closed]

Suppose that we were to install bicycle pedals into a passenger car, say a civic coupe, in such a way that pedaling is as mechanically efficient as riding an ordinary bike. Further suppose that we ...
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3answers
51 views

Could an EV reverse to brake?

One of the benefits of electric cars is that many parts can be eliminated, simplifying the overall system. Could EVs eliminate brakes as well by slowing the car down using reverse torque from the ...
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1answer
37 views

What is the Source of the 10% Trailer Tongue Weight Recommendaton?

Throughout the trailer, hitch, and tow vehicle industry a recommendation of 10% tongue weight for a tow-behind trailer and 15% for a 5th wheel trailer seem universal. They have even been changed to 10%...
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What are the advantages of parallel pushrod configuration?

A topic that came up in a recent discussion was pushrod engines (specifically V2 configuration in a motorcycle) with four cams. After some googling, I was able to find an example in the Harley-...
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1answer
47 views

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....
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1answer
36 views

Inertial Forces while analysing forces on a Piston in a Slider - Crank Mechanism?

I get that we are analysing the Piston in a non-inertial frame of reference, but the point of my question is that according to D'Alembert's Principle, whenever an inertial force comes in the line of ...
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1answer
24 views

Can a car's Electronic Stability Control (ESC) operate using electromagnetic braking?

The Wikipedia article for ESC describes the process as using hydraulic anti-lock brakes. However, is it possible for electromagnetic braking to be used instead, with an electic motor/generator in ...
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1answer
54 views

Car's shock absorbers' damping ratio

I'm trying to find a suitable shock absorber for a small ATV with a specific value (to be determined later). But everywhere I look, no one seems to be giving the damping ratio of the shock absorbers. ...
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1answer
26 views

Efficiency of a fully-engaged friction clutch

I'm wondering whether there are any notable losses in a typical automobile clutch when fully engaged. Only losses that come to mind: material twisting with torque changes slipping due to imperfect ...
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1answer
20 views

Regarding rubber vibration properties

I read an article in a textbook which says stiffer rubber increases vibration damping and softer rubber increases vibration isolation. Can anyone explain this how? What is the difference between ...
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1answer
50 views

Regarding automotive engine mounts

How are automotive engine mounts tuned to behave differently for different frequencies, like they are soft for high frequency low amplitude vibrations and hard for low frequency high amplitude ...
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68 views

Why are tri-axle trailers with single wheels more stable than double wheels?

I'm revising for the UK LGV theory test. One of the questions goes something like this: Which axle configuration is most effective at preventing petrol tankers from rolling over? A. Tandem ...
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64 views

Get engine rpm using accelerometer

I'm studying the possibility to read an engine RPM by reading the vibrations of it. Basically an engine is "oscillating" on a car chassis on all 3 axes (X, Y, Z) but mostly on the Y one. When ignition ...
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1answer
30 views

Measuring Torque in a bicycle [closed]

How to measure torque in a bicycle? how much newtons will produce by the pedal of the cycle ?
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26 views

Calculation of reference vehicle speed using wheel speed sensors and longitudinal acceleration

I am curious why the speedometer in most passenger cars almost always uses the highest wheel speed, even if the rest of the wheels are stationary. Is this intended to be a safety feature of some sort? ...
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1answer
76 views

How can I connect F=ma to Drag=1/2*Cd*(rho)*V^2*A?

I previously posted a different question that was very vague. I have kept working on the problem, and now I have a different question. Please let me know if I should have just added it to the old ...
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1answer
71 views

Is it possible to move gear on a shaft in one moment and in the other allow it to rotate freely?

Before I describe the problem I would just like to say that I'm no engineer this is my hobby, all I know is from google or if someone told me or from books. Something obvious to you may not be obvious ...
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30 views

How does polygonal effect affect the effect of angular synchronization in car engines' timing train drive?

Is a regular roller train drive used in most car engine's timing chain drive? If so, wouldn't the polygonal effect affect the accuracy of strict angular synchronization between the camshafts and the ...
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1answer
33 views

Effect of Pressure on Combustion efficiency (of hydrogen) in excess air

Can somebody explain relation between combustion efficiency and pressure in lean mixtures using any kind of chart or mathematical equations? At first glance I thought, combustion efficiency increases ...
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30 views

Is there some temperature at which all “5w” oils should have about the same viscosity?

Is there some temperature at which all "5w" motor oils should have about the same viscosity? (5w-20, 5w-30, 5w-40, 5w-50, etc.) I am looking for SAE or ASTM wording or chart that says it straight ...
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2answers
61 views

Calculate engine oil pressure

How you would calculate engine oil pressure of an engine? I've noticed on my car I just got, it uses a pressure switch in the oil system to measure engine oil pressure it seems in my case the switch ...
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3answers
101 views

Will electroplating a ventilated brake rotor with copper improve its cooling capacity and maximum its lifespan?

Since copper is excellent at dissipating heat and does not rust, I am surprised that brake manufacturers do not electroplate cast iron/steel brake rotors with a thin layer of copper (~.5mm). There are ...
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1answer
108 views

Ackerman steering

I'm designing a steering mechanism following the Ackerman principle. I've met the condition that my steering arms' normal projections must cross in the middle of the rear axle however when I do a turn ...
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1answer
24 views

Is a starter relay needed to supply the current to the starter motor solenoid?

Considering the fact that the starter solenoid needs a maximum of 50 Amps initially (in order for the pinion gear to engage to the flywheel through the plunger and lever) and then some 8 Amps during ...
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1answer
33 views

Is starter motor running if I hold the ignition switch at the START position?

Suppose that the engine cranking has been successful but I keep holding the ignition switch at the START position instead of releasing the switch to go at the RUN position. Does this mean that the ...
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2answers
75 views

Bike wheel sizes

I was passing by a row of motorbikes and mopeds yesterday, and noticed they all have really small radius wheels compared to bicycles. Not all motorbikes are equal (some motorbikes are literally ...
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1answer
47 views

Car dc starter motor-starting resistor

Does a car starter motor use a starting resistor to limit the high starting current? What is the type of connection between field coil and armature? Series, parallel or mixed?
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1answer
41 views

Pacejka “Magic Formula” tire models origin of the name

It might be a little off topic but I'm trying to find source for why is that model called magic formula? I read that it's a simple function of commonplace functions, a data fitting. Is it simply an ...
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2answers
51 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 ...
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1answer
56 views

Working of spider gear in differential axle wheel mechanism

What causes the spider gear to spin about it's own axis while the vehicle is taking a turn?
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1answer
52 views

What are the non-practical features of a sterling engine that cause the internal combustion engine to be used instead?

What are the non-practical features of a sterling engine that cause the internal combustion engine to be used instead (in a car)? (e.g. price, size, the power to weight ratio, etc.) Can you name any ...
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1answer
18 views

Calculate exhaust with expansion chamber muffler

I have a book with the formulas to calculate the length of engine exhaust pipe, but these formulas don't take into account the muffler. If I add an expansion chamber, how the calculated length change?
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PLEASE ANSWER Sterling vs Combustion Engine

This may be difficult to answer but, theoretically, if you had a car with a sterling engine that produces say approximately 300 horsepower how much of any specific heat source would need to be used if ...
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1answer
45 views

Calculate Rolling Resistance Experimentally

I am trying to calculate the exact rolling resistance ($F_{rr}$) of my car. The approach I am going with is a coastdown test at a low speed so no drag slows down the car. From there I am going to ...