TJ engine pnematic circuit

[roncierem]

Good evening, I recently saw the Modatek video in which they showcased their TJ cutaway (https://modatek.co.uk/wp-content/upload ... away-2.mp4).
and, I still have lots of questions about this engine.
So I wondered how their pneumatic air circuit was organized ? Mainly because I have not succeeded in identifying the elements of the said circuit in particular the pump or compressor which, well compresses the air "over 80 bars".
Is the pump on the same shaft as the waterpump an hydraulic pump or the one for the pneumatic valve springs ?
Is the pump after the scavenge pumps is here to reduce oil pump losses ?
Also while asking, where is the alternator located ?

Perhaps someone's could clarify that for me.
I should probably ask Brian.G because he is quite an expert about TJ and Cosworth engines in general.

[LaplacesDemon]

The pneumatic feed pressure for these engines was in the 10-15 bar range. 80 bar is most likely quoted as air spring pressure at maximum lift. It is a function of feed pressure and pneumatic chamber compression ratio.

[NL_Fer]

I believe the compressor was in the garage and sometimes during the final stages of the race a driver would take a late pitstop and an engineer would connect a hose somewhere on the engine cover to pressurise the system if it lost to much.

Remember that the valves are still actuated by the camshaft, the pneumatic is only to replace the valve spring and the gas shouldn’t leak to much.

[Zynerji]

I believe the compressor was in the garage and sometimes during the final stages of the race a driver would take a late pitstop and an engineer would connect a hose somewhere on the engine cover to pressurise the system if it lost to much.

Remember that the valves are still actuated by the camshaft, the pneumatic is only to replace the valve spring and the gas shouldn’t leak to much.

It was cycled tho due to heat expansion of the gas, right? I always wondered how the valving worked on this system...

[roncierem]

It was cycled tho due to heat expansion of the gas, right? I always wondered how the valving worked on this system...

The valves in the engine work like this viewtopic.php?f=4&t=24821.
They therefore have one-way valves for the HP and LP. The high pressure gas supply must be regulated. I have no idea what happens on the LP side.

Also if it comes from an air tank which "refuel" the car, it would probably be like with Russel at the Styrian GP (https://youtu.be/tr4gf_iae20?t=149).

[coaster]

The video does not shed light which gasflow is independant of the other.
There are 3 systems of airflow;
1/ Intake valve
2/ Scavenge pump
3/ Pnuematic valve
They are all seperate, the valves use a gas bottle, the scavenge keeps negative pressure in the crankcase, intake explains itself easily.