The Automotive Technicalities: How Stuff Works??

[TSIVipul]

Hello guys, as the name suggests, this thread is where we can ask or share various technical aspects of automobiles. Here we can ask various queries of ours and get our doubts clarified. This thread will help the members who are not in the technical field understand the technical aspects and can serve as a good knowledge sharing thread for members who are from technical fields. The questions can be any, weather related to electrical, mechanical or electronics..any, only they need to be automotive!!

So here are some of my questions:

• How are petrol engines turbocharged?
• I have read somewhere that direct injection increases low end torque. How?
• How is AWD system ran if the engine is transversely mounted?
• Basically in common rail technology, a single fuel pump is used. How it makes the engine more efficient as well as better performing than MPFi?
• I have heard that for optimum performance, the gear ratios should be set considering the power/torque vs rpm curve of the engine. How it is done?
• What are these low rolling friction tyres, how do they work? In fact how are they different from our regular tyres?

More to come..

 

[dhruvpandit]

Nice thread vipul,
Your idea and questions both are good.

I an answer how petrol TC works afaik, they transfer heat from exhaust to intake manifold and provide heated air intake, which helps afm to burn faster and maximum.

I may be wrong, but its best of my knowledge.

I am also waiting for other answers

 

[jayadev]

This is the engine bay of our Frieghtliner truck and I have marked the TC circuitry hope the pic is self explanatory.



High pressure engine exhaust or burnt fuel gases turns the turbine 1 at high rpm which is shafted to turbine 2.the turbine 2 pulls the fresh air from air box or air filter with greater force which is passed through intercooler to be cooled and made dense for better oxygen contents .
If required I will post the other side too,IC to engine.

 

[jayadev]

Below is pic of our Toyota Hilux Pick up (twin brother of Toyota Fortuner in India).where engine is transversely mounted (In our ford engine is longitudinally mounted)

This is 4x4,where we can engage all 4 wheel by flicking a lever.
In AWD the flicking part is controlled automatically by electronic circuitry inside the engine when any of the wheel looses Traction

 

[TSIVipul]

Thanks for your input guys.

@Jayadev:
First one I guess is a turbo diesel. Actually I know the turbocharging of diesels but how are petrols turbocharged? I mean there is a difference in ignition type and all, also I have heard that turbocharging in petrol engines is a more complex process.

BTW..the pictures have created some more questions, which I'll be putting up later.

 

[jayadev]

Basic operations and working principle are same in both petrol and diesel turbos.

Petrol turbos are quite faster than diesel ones where it requires optimum control which is done by electronics.

 

[sethumurugan]

Vipul, thanks for starting such a wonderful thread

Hey friends, this may be basic, but I know our experts can explain in simple way to me.

1. what are the differences in different fuels like petrol, diesel, LPG and CNG?
2. how this makes the differences in engine and how it works?
3. what will happen if use different fuel than the expected one [diesel in case of petrol and vice-verse, LPG in case of CNG and vice-verse]
4. why only petrol vehicle can be converted to LPG and why not diesel engine
5. why only LPG can be replaced petrol not CNG?

 

[TSIVipul]

Basic operations and working principle are same in both petrol and diesel turbos.

Petrol turbos are quite faster than diesel ones where it requires optimum control which is done by electronics.

Buddy if possible, then kindly elaborate on turbo petrols.
Actually in the diesel engines it's only air that enters the cylinder and gets compressed but in petrols it's the air + fuel mixture that enters the cylinder and hence I guess turbocharging should be different in petrols..eh, I am confused!!

Vipul, thanks for starting such a wonderful thread

Hey friends, this may be basic, but I know our experts can explain in simple way to me.

1. what are the differences in different fuels like petrol, diesel, LPG and CNG?
2. how this makes the differences in engine and how it works?
3. what will happen if use different fuel than the expected one [diesel in case of petrol and vice-verse, LPG in case of CNG and vice-verse]
4. why only petrol vehicle can be converted to LPG and why not diesel engine
5. why only LPG can be replaced petrol not CNG?

Let me try answer them one by one..

• Difference between fuels is of their calorific value, ignition temperature and I guess petrol and diesel are liquid fuel and gases are dry ones..DOES IT MAKE ANY DIFFERENCE?? EXPERTS..
  
• For diesel engines higher compression is required and for petrols, a lower compression is required. I think Jayadev can explain it better using pics, though I can explain it but it will be easy to understand if pics are there.
  
• The engine won't work or won't work smoothly...eh, I need technical experts again.

BUDDY, YOUR BASIC QUESTIONS ARE VERY TOUGH..

 

[jihu123]

My uncle has a Hyundai Gets with him right now. Its his brother's vehicle! The vehicle is not well maintained. Well, coming to my question.

While engaging first gear/reverse gear & especially when parking. The car automatically gets accelerated without even touching the accelerator pedal. The RPM too increases at that time. Why is it so?
One of my cousin said that, it might be doing that to make the engine warm.

 

[sethumurugan]

Ha Ha.. Sorry Vipul.

 

[Rajvel]

My uncle has a Hyundai Gets with him right now. Its his brother's vehicle! The vehicle is not well maintained. Well, coming to my question.

While engaging first gear/reverse gear & especially when parking. The car automatically gets accelerated without even touching the accelerator pedal. The RPM too increases at that time. Why is it so?
One of my cousin said that, it might be doing that to make the engine warm.

Thats due the torque.
You can get more torque in diesel engines than petrol one.
Even my question is "why diesel engines have more torque than petrol one"
Experts help.

 

[TSIVipul]

My uncle has a Hyundai Gets with him right now. Its his brother's vehicle! The vehicle is not well maintained. Well, coming to my question.

While engaging first gear/reverse gear & especially when parking. The car automatically gets accelerated without even touching the accelerator pedal. The RPM too increases at that time. Why is it so?
One of my cousin said that, it might be doing that to make the engine warm.

If it's a diesel version than the torque does it all and if it's a petrol version then...I don't know

Ha Ha.. Sorry Vipul.

No need for sorry sirji..it was all that your basic questions were either long-answer type or were tough for me. And being an engineer, I don't answer long answer type questions until the carry 10 marks!!

Even my question is "why diesel engines have more torque than petrol one"
Experts help.

As much I remember, first of all higher compression ratio and secondly comparatively heavier components are responsible for higher torque of diesels.

 

[jihu123]

Thats due the torque.
You can get more torque in diesel engines than petrol one.

If it's a diesel version than the torque does it all and if it's a petrol version then...I don't know

Its a petrol one. I believed that it has been tuned like that by someone!

 

[Rightnow]

I guess I am posting query on right thread:

Can anyone tell me what should I do to get knowledge on working of cars? I mean something like - a starter's guide to become a car mechanic. Any books, references, online stuff, or anything else. My idea is to:

- Know what all components make it to a basic car
- understand what operations are carried out mechanically inside a car
- and to know what functions do the components perform in whole chain of operation

I am serious on this guys, so please let me know where can I get the knowledge from.

 

[TSIVipul]

I guess I am posting query on right thread:

Can anyone tell me what should I do to get knowledge on working of cars? I mean something like - a starter's guide to become a car mechanic. Any books, references, online stuff, or anything else. My idea is to:

- Know what all components make it to a basic car
- understand what operations are carried out mechanically inside a car
- and to know what functions do the components perform in whole chain of operation

I am serious on this guys, so please let me know where can I get the knowledge from.

Buddy, it's going to be painfully long, covering it all will take months.

Here is a new query:
New land rover discovery comes with some kind of integrated chassis in which engine bay and passenger compartment are built as a monocoque while gearbox and suspension are on the ladder chassis.
CAN ANYONE EXPLAIN ME WHAT SORT OF DESIGN THIS ONE IS AND HOW IS IT POSSIBLE TO MAKE SUCH DESIGNS??