Teams from India

[happypranav]

MCoach,

If engine is made of lower cc, what will be affected more hp or torque (because engine displacement should not always be used to compare engines but their torque and horsepower ratings will be a much better way to compare). And what design factors in Engine affect torque and hp.

I have info that inline engines provide less torque than V engines irrespective of displacement, is it right, if yes what affects high torque.

What I know is higher rpm will give more hp and torque, and if this is the case engine design will be based on running it to high rpm.

[happypranav]

Originally posted by Bemo:
Enzo Ferrari also said that "aerodynamics is for people who don't know how to build engines."

Well that is very very sensible !

[Bemo]

I get the feeling, you are mixing up some things. In general power is torque multiplied with rpm. So if you assume constant torque power is linear increasing with higher rpm.

If you have an naturally aspired engine, increasing torque very soon means increasing displacement which means the engine gets bigger and heavier. That's why racing engines are usually running at very high speeds.

[JWard]

Bemo, is it also worth making a couple of notes about efficiency at this point? High revving engines are not so efficient as they have less time for the increase in pressure in the cylinder (due to the 'burn' event) has less time to act on the cylinder - because a cycle of the engine is happening over less time (hence low revs often means efficient torque). Also, high revving engines have higher friction losses. So do multiple cylinders for the same displacement (4 cylinders total 600cc has greater surface area the piston moves over than a single cylinder of 600cc).

Please correct me if / where I'm wrong. It's also not very eloquently put - apologies if it reads poorly)

[Bemo]

First of all, I used to be a frame guy in our team, so I'm far from being an engine expert.
But the basic things I know

Of course high reving doesn't help with efficiency. That's one of life's compromises. That's why you want high torque at low engine speeds in a series like FSAE.

[Claude Rouelle]

To Happypranav

Don't take this the wrong way Pranav, but here you are giving a perfect example of asking questions in the wrong order.

The quote from Bemo could not be more right. That is exactly the issue that you and many other news teams have. They try to copy other cars. The question on pullrod which was posted on the forum today has the same taste. News team students often open the LEGO box (which in that case in the picture of other cars on the internet) and choose and assemble on CAD and/or in the shop components which could make the car work but they probably won't know why. Remember that the goal of FSAE / FS is not only to make a car which runs but a car which is competitive AND UNDERSTAND WHY

Functions creates Forms. Making the list of the questions of what determines a good car requires discipline, honesty and freedom of mind and also the time and courage to assemble and integrate good education material.

That is why designing and building a FSAE / FS car in India is a bigger challenge than in any other country I know. Indian students has been taught for years to regurgitate at exams what teachers told them. Teachers rarely challenge students outside the teaching material and students are rarely allowed to ask questions. And at the end of the school the automotive industry hire students on grades, not on skills.

Abstractive (if that word exists) thinking (In that case what are the goals to achieve and what are the criteria which define a good car and a good team) is a challenge that you have to impose to your self before even thinking about designing, manufacture and assemble a car.

I have made similar statements with different words and I will continue to do so because my experience is that it takes a lot of time to integrate such messages/. I know: it is only several years after I graduated that some of my teachers advice started to make sense. We never stop learning and we never learn well fast enough ....

“Human beings, who are almost unique (among animals) in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so” Douglas Adams

[happypranav]

And at the end of the school the automotive industry hire students on grades, not on skills.

Every Automotive Industry hiring students in India must understand this.
Claude, (I don't know if I am asking correct question or not but I cannot stop myself) What can we do to change this mindset of industries ?

[RenM]

Regarding the engine questions i think its much more demonstrative to look at the formulas.

Derived from the first law of thermodynamics an engines Power can be calculated as:

P=k*n*H_G*V_d*VE*eta_e

with

k= factor for 2/4 stroke engines (4 stroke: k=0.5 as only every second rev is used to generate power)
n= engine revolutions
H_G= Heating value of the gas mixture (influences by your Air to Fuel Ratio and Fuel)
V_d= Engine Displacement
VE = Volumetric Efficiency - a measurement of how effective your gas exchange works (at VE=1 the cylinder is filled with the engine displacement at ambient density)
eta_e = the effective efficiency of the engine, consists of internal efficiency + mechanical efficiency

Now you can play around with the formula and see the effects.
If you half your engine displacement, your engine has to ref twice as fast to get the same power as your torque is decreased. (P=M*n) Of course different engine layout result in different efficiencies but especially in fsae with the air restrictor they almost level each other out. Cars with 1 Cylinder engines are usually more efficient then cars with a 4 Cylinder engine because of their much lower weight.

Now you can also see that talking about Torque as an absolute number can be very misleading as it doesn't allow a direct comparison between 2 engines. Torque can always be transformed by a gearbox, whereas the power stays constant (not regarding losses in the gearbox).


Whats important for FSAE as MCoach pointed out already is that you will want high power over a broad usable rev range.
If you can achieve that the driver doesn't have to care too much about the gear he is using to get a good acceleration.

[Claude Rouelle]

To HappyPranav

Claude, (I don't know if I am asking correct question or not but I cannot stop myself) What can we do to change this mindset of industries ?

The pessimistic (realistic?) answer.
Nothing. It will take another 2 to 3 generations or something worse: a war, a civil war a major economic crisis - if that happens we will all be somewhat shaken whatever the country we live in because everything is global nowadays, a revolution (social and or cultural).
If you have the chance get out of there and like many other Indians I know get out of India and study abroad. If you do so you will probably do like 90 & of them; you won't want to get back.

The optimistic answer
- You are already helping. Just speaking about that in this forum helps.
- Speak about this with other people; rich and poor, old and young.
- Vote. I hate politics. but everything is politic. Democracy is maybe not the best form of society which could exist but it is the best one that humans have been able to create. Vote. Make your voice heard . Vote for people who fight corruption, fight for equal gender rights, access to education and health but also push citizens to acquire the sense for responsibility and ethics. Many people want rights but forget about the notion of duties.
- Travel. Open your mind and your eyes. I always have thought that if more young people like your would travel there would be less wars. It is not about accepting other ideas but it is about accepting that other cultures have different ideas.
- Stay away from negative people. In universities try to get closer to positive teachers who look at their job as a mission to improve the world. I met a few of them in IIT universities and I was VERY impressed not only by their knowledge but by their drive to improve the well being of their fellow citizens. If necessary relocate and go to an other university.
- Be demanding to your teachers as much as you feel you are demanding to yourself. Teachers are paid because they have school that are populated by students like you. You are their customer. They owe you. You are entitled to a good education. As so are your parents you have invested in you. There is nothing wrong by asking a teacher "I did not get it, this is what I don't understand, can you please explain better or a different way?"
- Believe in your self. Believe in your self more than in anybody else. And never, ever give up your dreams and your ideals.

I wish I had a miracle answer but India is a huge country with a lot of inertia and complexity (and fascinating mysteries) so I guess the road to improvement is a long road you have to walk one step at a time.

[happypranav]

Now you can also see that talking about Torque as an absolute number can be very misleading as it doesn't allow a direct comparison between 2 engines. Torque can always be transformed by a gearbox, whereas the power stays constant (not regarding losses in the gearbox).

What I think is torque is reported at the engine and not at the wheels, so the gearbox is irrelevant to the reported value. Sure, you can always lower the gear ratio to increase the torque at the wheels, but if you redline at 1.5mph, you haven't helped yourself any unless your goal is to power the car. Please do correct if I am wrong.