F1 engines were running at 17:1 CR some time back. DO they still run this high a CR?
Will turbo engines be anywhere close to this? typically they were around 10:1
CR will be higher than 10:1. The new turbo engines will be managed throttle less and have injection at the end of the compression phase. The old engines were port injected with toluene fuel to avoid knocking. Nowadays they achieve the same thing by injecting very late and with super high pressure in the compression phase.WilliamsF1 wrote:F1 engines were running at 17:1 CR some time back. DO they still run this high a CR? Will turbo engines be anywhere close to this? typically they were around 10:1
Very unlikely. The Ferrari 458 Italia engine spec. Btw. this is a direct injected engine:strad wrote:Static compression will have to be somewhere around 9 or 10 to 1 at max.
Engine
Type V8 – 90°
Total displacement 4499 cc (274.5 cu in.)
Maximum power 570 CV (425 kW)** @ 9000 rpm
Maximum torque 540 Nm (398 lbs/ft) @ 6000 rpm
Specific power output 127 CV/l
Compression ratio 12.5:1
I think the only reason to make the compressor, turbine, and MGU on a common shaft would be if the battery pack was allowed to spool the shaft via the MGU. In the absence of that, why would you use a common shaft? Wouldn't it just be an awkward turbo with lots of inertia and lag?WhiteBlue wrote: According to latest info they will have one unit which will have a compressor, a turbine and an MGU on one shaft. The MGU will be allowed to feed electric power to the rear wheel MGU but not to the battery. It is not clear if the turbo MGU is allowed to use battery power to spool up the compressor. That may come at a later time.
The Honda Ra-168-E already had a 9.4:1 CR twenty five years ago and the Panamera turbo with old FSI technology has 10.5:1. This leads me to believe that F1 state of the art engines with superior efficiency requirements will have nearer to 12:1 CR. We will see.747heavy wrote:^^ odd choice for a comparsion, as the 458 has a N/A engine not a turbo.
Perhaps a Porsche Cayenne turbo (10,5:1) or BMW N74 (10:1) is a better choice.
Renault Sport's managing director Jean Francois Caubet told AUTOSPORT: "We have had a four-cylinder [powerplant] on the dyno and the sound is nearly the same as the V8 running at 12,000-14,000rpm. With the V6, with one exhaust, the sound will be very good."
from: http://www.autosport.com/news/report.php/id/92873"The rules look like they are heading towards a rev limit of 15,000rpm, and the fuel flow limit is intended to drive the operating speed of these engines up towards the upper end of that range, rather than the lower," he added.
"There is a detail in the rules that makes it interesting for the engine people to push the rpm up above 10-11,000rpm, where the engines would have perhaps naturally ended up in the previous incarnation of the rules.
The Honda Ra-168-E already had a 9.4:1 CR twenty five years ago and the Panamera turbo with old FSI technology has 10.5:1. This leads me to believe that F1 state of the art engines with superior efficiency requirements will have nearer to 12:1 CR. We will see.WhiteBlue wrote:747heavy wrote:^^ odd choice for a comparsion, as the 458 has a N/A engine not a turbo.
Perhaps a Porsche Cayenne turbo (10,5:1) or BMW N74 (10:1) is a better choice.
Hmm, they said the fuel-flow limits remained the same that were written for the inline-4. So I think we'll have boost limit.747heavy wrote:Renault Sport's managing director Jean Francois Caubet told AUTOSPORT: "We have had a four-cylinder [powerplant] on the dyno and the sound is nearly the same as the V8 running at 12,000-14,000rpm. With the V6, with one exhaust, the sound will be very good."from: http://www.autosport.com/news/report.php/id/92873"The rules look like they are heading towards a rev limit of 15,000rpm, and the fuel flow limit is intended to drive the operating speed of these engines up towards the upper end of that range, rather than the lower," he added.
"There is a detail in the rules that makes it interesting for the engine people to push the rpm up above 10-11,000rpm, where the engines would have perhaps naturally ended up in the previous incarnation of the rules.
makes you wonder what this "detail" will be, a gradual fuel flow limit or a boost limit perhaps.
You obviously do not understad that they use direct injection where the compression happens 95% before you inject. The injection is so late that you practically compress only air and no "mixture".strad wrote:There are limits to the amount you can compress the mixture without detonation that have nothing to do with what year it is.
Ringo is correct.