conclusion(induction system)

[e_peña]

so as to conclude we can say that:

A)f1 engines have inlet trumpets for multiple reasons but on of the most important is to allow the fuel/air mix to vaporize well enough by the time it reaches the combustion chamber, since they dont have long intake manifolds, the trumpets are designed to give some "extra time" to the mixture.

B) their intake manifolds are wide and short to provide more power at high rpm,since its shape is wide and short it allows the engine to "breath" better at high rpm,Due to the fact that the mixture finds less restriction coeficient than in a long and narrow one.

C) they dont have direct fuel injection because it woulnt be the best way to take advantage of every power stoke, since the mixture isnt turned fast enough into a gas.

am i right?

thanx.

[Chris Gamlin]

A) Not Really - the inlet trumpets are situated before the throttle body, so there is no fuel in the trumpet, only air (sorry if my previous post wasn't too clear on this). Fuel is introduced in the throttle body. The trumpet optimises the flow of air into the throttle body, and as you have got more air, you can supply more fuel, hence more power.
B) Correct
C) Partly correct, the main arguments against direct injection would be that it mainly helps emmisions and fuel consumption, which are less important than outright power in an F1 car. Another thing which I didn't mention before, cylinder pressures and temperatures inside an F1 engine are substantially greater than in a road car (18000rpm instead of 6000rpm, and higher compression ratio), which make direct injection that much more difficult, as the injector nozzle has to be able to perform in this extreme environment. To inject fuel directly into the combustion chamber would require the fuel to be at an extremely high pressure.

Chris

[THR]

saying that tho..
nothing is impossible. and im sure they are all thinking about direct injection, and its the way to go!

more power, less feul. more effiecent. less parts.

good things to have!

[ma]

Mostly wrong conclusions.

The length of the trumpets is set by the rpm range that the engine builder is trying to tune to.

Just with an exhaust system, the intake side is subject to reversion "pulses" as the valves open and close. These pulses are a "slug" of low pressure that travels back up the intake runner, hits the end of the trumpet, and then reverses & travels back down the runner. The pulses travel at the speed of sound.

Timing the return of each low pressure pulse to the combustion chamber is critical if maximum efficiency is to be gained. The higher the rpm range being tuned to, the shorter the runner length.

You can note this length dependency on some of the better modern cars with small engines - the intake runners are quite long for better efficiency at low revs, and the higher power that that efficiency gives the engine. If that same engine is re-tuned for racing, the runners will be quite short in comparison.