Radial turbine at the end of the shaft

[elephant]

why on the air intake, the volume of gas available to the exhaust is much greater, right?
I did not really understand what you mean.

[Philippe Schutt]

what I say is only for gasoline engines, and in light foot driving.
I doubt the interest of turbos as they are done in eco driving. pushing the intake gas and then braking with the gas shutter, it seems a little useless.
vacuum at the intake is greater at small engine load. so we can recover this wasted energy when we ride light.
in the exhaust, it's the opposite. we have energy when we press well the gas pedal. Okay, there may be more, especially if you crush well, but in general we roll cool ...

[elephant]

Ok I understood.
In fact, part of the turbo's interest is economic:
the engines are taxed according to their capacity in many countries: long live France which actually taxes the real use of the vehicle through the price of fuel (5 10 hundred more per liter than in Belgium)
a large engine and its accessories is heavier and more cumbersome and also more expensive than a smaller one (in fact the whole car is more expensive)
a turbo is compact
we especially need power from 100 km / h to fight against resistance to progress

[elephant]

I come back on the economic interest of a turbo:

Belgian tariff (approx):

annual taxi charge on a 2 l diesel (turbo or not): around 400 euros

on a 3 liters: more than double, so much so that most of the old used diesel beyond 2,5 liters are exported pcq the people who want to buy them well (lady, a volvo 740 of 200.000 km for 3000 euros it 's is great, comfortable, and still good for 200.000 other km) can not afford the tax.

with a turbo, you have the horses, not the tax (just the insurance RC a little more expensive)

[Philippe Schutt]

In the case of diesel I understand that it is a little different, other influential elements, such as the difficulty of drawing a large power from a small engine.
my depression story is not worth it either for these engines, since there is hardly any.

[Philippe Schutt]

I found on the net that a turbo recovered up to 25% of the energy of the exhaust gases. for a motor having 35% yield with 10% lost in the walls of the cylinder head and cylinders, that makes 14% of the initial energy, more than it takes to feed an alternator.

[Philippe Schutt]

In fact, we can really ask the question of the interest of the turbo in gasoline cars.
Indeed, if we remove the turbo, we can increase the compression ratio resulting in improved efficiency and a better torque curve in low revs (<3000 rpm)
In addition, as long as you drive at partial load 99% of the time, the boost pressure is canceled by the throttle! and the turbo does not win anything at all.
Using the energy in the exhaust to rotate an alternator is necessarily more interesting. It remains to be seen what energy is available in current use.

[elephant]

Well, I do not follow you when you say that you spend 99% of the time at reduced load, unless you are perpetually in the traffic jams of the big cities in which case I pity you with all my heart.
Personally, I am 3 / 4 of time on highways.

a turbo artificially increases engine displacement, which has advantages: tax, vehicle weight and actually:

in town, you have a small engine, quite economical
on the road: you have the necessary horses to fight against resistance to advance.

[Other]

Hello

a turbo artificially increases engine displacement, which has advantages: tax, vehicle weight and actually

I do not think that on a gasoline engine a turbo improves performance. It allows to feed the engine at high speed when it can no longer resiprer and increase the power of a small engine but at the expense of wear and consumption.
The taxation based on engine displacement is not a general rule adopted by all countries, at least in America it is the weight of the vehicle that determines the tax. As long as I will abolish this law, to replace it with a tax based on consumption at 100km or the pure performance of the engine, I see no reason why we should penalize a car with a 3 engine liters that consumes less than one of 1,6litres, this restricts the builders looking for the best performance, it forces them to work in a narrow frame ..
There is a balance in power in a car. Not powerful enough the engine is very solicited its consumption is high and its rapid wear, it is interesting in urban use.
An engine too powerful never use the maximum 1600rpm 100kmh it becomes more economical on the highway than the small engine, it has a great longevity and little maintenance (some never change the oil during the life of the vehicle) engine has large torque little use of the speeds, on the other hand in engine city that clogs, and more greedy than the small motor ...
The turbo is intersting on a diesel engine it is more economical than without turbo if you use the vehicle in the same way as an atmospherique.
On a petrol engine, the turbo has its place to increase the acceleration at high speed and sporty driving, personally I think that if the engine is not powerful enough better to take a bigger ..

Andre