[WEC] Toyota LMP1 Discussion

[MyNameIsNigel]

Thanks for sharing the article dbagtbag. Very interesting indeed.

[Articus]

I'm so confused. I misunderstood an earlier edition of RCE Mag. Vasselon said something along the lines of. The DI engine needed a starter motor. But this car doesn't have DI then does it?

[MyNameIsNigel]

Originally Posted by Articus

I'm so confused. I misunderstood an earlier edition of RCE Mag. Vasselon said something along the lines of. The DI engine needed a starter motor. But this car doesn't have DI then does it?

Like in 2012-2013 (unless I am mistaken), Toyota are doing without a starter motor (to save weight) and exploiting the MGU(s) instead to kick-start the engine.

I believe that Peugeot were also contemplating to do the same with the unraced hybrid Peugeot 908.

[Articus]

Right the words were

Two years ago we had already completed this year's system, but the regulation did not allow us to run it, so we dropped off the front system. The DI engine needed a starter motor but if we installed the rear motor, we could drop off the starter motor

- Hisatake Murata. Hybrid Project Leader. Maybe lost in translation but they are definitively not running it.

What they would have gained from direct injection last year they would lose this year thanks to the new regulations.

[Japanese Samurai]

According to Japanese Autosport (No.1379),
since it became a demerit in the combustion and the weight in the racing,
Toyota did not adopt DI system for TS040.

[dbagtbag]

Originally Posted by Japanese Samurai

According to Japanese Autosport (No.1379),
since it became a demerit in the combustion and the weight in the racing,
Toyota did not adopt DI system for TS040.

Yeah which is interesting. Somehow there is a very mainstream notion floating around that DI is superior technology.

[J Jay]

Originally Posted by dbagtbag

Yeah. I was surprised they were so revealing in this article. Some insane insights from the big guns!

The head honchos must be very confident. to be fair, it's not unfounded based on what we've seen so far!

[Articus]

Konoshita, Murata, and Vasselon are oozing confidence. Trying so hard to play it cool and downplay whereas their simulations are telling them that they will blow everyone away. Vasselon and Konoshita seem to have it out for that Porsche. In the articles I've heard: E-Motors more powerful than the Porsche's. ERS better, Chassis better, Aero Better, Brakes better, Engine better.

[cokata]

17:1 CR will be impressive even for DI/NA petrol engine, but for port injected it's almost hard to believe.That fact that they were running that even with the 3.4l on E10 says that either they are doing something very clever with the intake manifold or the fuel that they have at p1 is extremely good.There isn't even cam phasing/VVL on this engine, how are they doing 17:1 CR is beyond me

[dbagtbag]

Originally Posted by cokata

17:1 CR will be impressive even for DI/NA petrol engine, but for port injected it's almost hard to believe.That fact that they were running that even with the 3.4l on E10 says that either they are doing something very cleaver with the intake manifold or the fuel that they have at p1 is extremely good.There isn't even cam phasing/VVL on this engine, how are they doing 17:1 CR is beyond me

In addition to what you said its most likely they have the scavenging and heat extraction from the cylinders sorted out extremely thoroughly. The air heats up considerably depending on the cylinder block temperature and even more when residual exhaust gasses get trapped. Exhaust gasses are on the order of 800K so even a tiny bit will raise the initial temperature of the fresh charge significantly. Skyactiv petrols do the same thing.

Konoshita, Murata, and Vasselon are oozing confidence. Trying so hard to play it cool and downplay whereas their simulations are telling them that they will blow everyone away. Vasselon and Konoshita seem to have it out for that Porsche. In the articles I've heard: E-Motors more powerful than the Porsche's. ERS better, Chassis better, Aero Better, Brakes better, Engine better.

It seems like that doesn't it? They can't hide it haha

[CyberMotor]

Originally Posted by dbagtbag

Yeah which is interesting. Somehow there is a very mainstream notion floating around that DI is superior technology.

After Audi introduced DI into their prototypes and then road cars, they had an advertisement on TV here in the states showing a huge tanker and 30% of the drums going back onto the tanker. Their message was, "If everyone adopted Audi's Direct Injection technology, we could reduce our fuel consumption by 30%." ... or something similar, since going from memory here.

The benefits touted included both increased efficiency as well as increased power. So, yes, I bit into that notion.

[chernaudi]

The Audi commercial was for their TDI diesel stuff that they started to sell in NA at the time.

But the fact is that Audi boosted their fuel economy with the R8 by nearly 10% when they switched to DFI on it.

Maybe DFI doesn't work with NA/non turbo engines, though Porsche used DFI on the RS Spyder.

Other than fuel mileage, DFI engines do have better low end/mid-range torque. But where diesel or gasoline DFI is at it's best is part load. Maybe Toyota does figure that with LM being nearly 90% full throttle and most of the WEC tracks being point and squirt Tilkedrome, that DFI won't be that big of a help to them.

[GasperG]

Normal driving cycle is not exactly race driving cycle

[dbagtbag]

Originally Posted by chernaudi

The Audi commercial was for their TDI diesel stuff that they started to sell in NA at the time.

But the fact is that Audi boosted their fuel economy with the R8 by nearly 10% when they switched to DFI on it.

Maybe DFI doesn't work with NA/non turbo engines, though Porsche used DFI on the RS Spyder.

Other than fuel mileage, DFI engines do have better low end/mid-range torque. But where diesel or gasoline DFI is at it's best is part load. Maybe Toyota does figure that with LM being nearly 90% full throttle and most of the WEC tracks being point and squirt Tilkedrome, that DFI won't be that big of a help to them.

The C6R C7R and 458 are also DI

[chernaudi]

I was talking about the R8 race car raced by Audi from 2000-2006. 2001 was the first year with DFI on the car and it was claimed that a near 10% jump in fuel economy was encountered, good for 1 more lap per stint at LM.

The Lamborghini Huracan has both DFI and port injection. I assume that such a scheme is currently banned under ACO rules.

[Articus]

We've also seen time and time again the Ferrari's in GTE making 1 less pitstop than everyone else in WEC and Le Mans despite the smaller tank size.

[NelisB]

Originally Posted by dbagtbag

The C6R C7R and 458 are also DI

Only the GT1 version of the C6.R though. The street car didn't have DI so no DI allowed under GTE rules.

[GTfour]

Originally Posted by NelisB

Only the GT1 version of the C6.R though. The street car didn't have DI so no DI allowed under GTE rules.

The C7.R has DI this year.

[NelisB]

Originally Posted by GTfour

The C7.R has DI this year.

Because the C7.R has a DI engine in it's street form.
In fact they are using the DI system developed for the GT1 on this years GTE car.

[J Jay]

Originally Posted by GasperG

Normal driving cycle is not exactly race driving cycle

And the power/consumption requirements for GT aren't exactly the same as LMP. DI is great for a number of scenarios, but being part of a KERS-hybrid powertrain in an NA engine isn't one of them!

Still finding that compression ratio staggering, I'd love to see the innards of that engine.

[cokata]

Originally Posted by Articus

We've also seen time and time again the Ferrari's in GTE making 1 less pitstop than everyone else in WEC and Le Mans despite the smaller tank size.

The main (only) benefit in a racing loads for DI is the ability to run higher CR, but if you can already get 17:1 without it, you can save yourself the extra weight and complexity.At such a height ratio you are getting into diminishing returns and pushing in past that point ain't gonna yield better BSFC

[dbagtbag]

Originally Posted by cokata

The main (only) benefit in a racing loads for DI is the ability to run higher CR, but if you can already get 17:1 without it, you can save yourself the extra weight and complexity.At such a height ratio you are getting into diminishing returns and pushing in past that point ain't gonna yield better BSFC

Not to mention high pressure pumps are power sucking vampires.

Pump power = Pressure rise across pump * Flow rate

Pumping tons of fuel (like a race car uses) at 200-300 bar can cost considerably more power than flowing the same at 2-3bar.

TBH if I didn't read this article I would have thought a small turbocharged engine (no supercharging) with thermal recovery was the way to go. It really goes to show that these cars are designed and built by utter geniuses.

[chernaudi]

Only why that works is with diesels, which rely on high compression ratios for efficient combustion (they also rely on DFI to atomize the fuel into tiny droplets that can be quickly vaporized during compression ignition), but with the current road car DFI diesels, you can run somewhat lower ratios for equal efficiency, which allows the engine to be smaller.

The compression ratio for the Audi R8 TFSI 3.6 V8 was claimed by Audi to be about 12.5:1, which is typical for a forced induction gasoline racing engine of that period (NASCAR Winston Cup (now Sprint Cup) engines were rumored to be pushing diesel territory prior to 1997 when compression ratio was limited to 14:1 (it's now 12:1), rumors of 20:1 weren't uncommon, though 17:1 was probably more realistic, and that was in the mid 1990s).

By comparison, I don't think that Audi ever released any official numbers themselves, but the R10's 5.5 TDI V12 was estimated to have a 15:1 to 18:1 compression ratio.

Add to that the fact that the Audi diesel racing engines are probably over-square designs, that's the range that they've probably stuck to and is similar to modern DFI diesel engines. That's why aluminum can be used for engine blocks now like on gasoline engines.

[dbagtbag]

Originally Posted by chernaudi

Only why that works is with diesels, which rely on high compression ratios for efficient combustion (they also rely on DFI to atomize the fuel into tiny droplets that can be quickly vaporized during compression ignition), but with the current road car DFI diesels, you can run somewhat lower ratios for equal efficiency, which allows the engine to be smaller.

The compression ratio for the Audi R8 TFSI 3.6 V8 was claimed by Audi to be about 12.5:1, which is typical for a forced induction gasoline racing engine of that period (NASCAR Winston Cup (now Sprint Cup) engines were rumored to be pushing diesel territory prior to 1997 when compression ratio was limited to 14:1 (it's now 12:1), rumors of 20:1 weren't uncommon, though 17:1 was probably more realistic, and that was in the mid 1990s).

By comparison, I don't think that Audi ever released any official numbers themselves, but the R10's 5.5 TDI V12 was estimated to have a 15:1 to 18:1 compression ratio.

Add to that the fact that the Audi diesel racing engines are probably over-square designs, that's the range that they've probably stuck to and is similar to modern DFI diesel engines. That's why aluminum can be used for engine blocks now like on gasoline engines.

With NASCAR they were able to run higher because they had restrictor plates. You draw much less air and that lowers the initial charge temperature. 20:1 is very high, but with a restrictor it is believable to me.

And you're right, lower compression ratios can be beneficial to a diesel and the sweet spot seems to be around 14~16:1. When you run lower CRs you get better fuel penetration through the combustion chamber and the charge burns more evenly. In addition to that you have more flexibility with your injection timing so you can leverage the correct crank angle for more torque. This tends to lead to lower maximum chamber pressures and this coupled with what you said allows for an aluminium block!

I love engine tech =D

[cokata]

Originally Posted by chernaudi

Only why that works is with diesels, which rely on high compression ratios for efficient combustion (they also rely on DFI to atomize the fuel into tiny droplets that can be quickly vaporized during compression ignition), but with the current road car DFI diesels, you can run somewhat lower ratios for equal efficiency, which allows the engine to be smaller.

The compression ratio for the Audi R8 TFSI 3.6 V8 was claimed by Audi to be about 12.5:1, which is typical for a forced induction gasoline racing engine of that period (NASCAR Winston Cup (now Sprint Cup) engines were rumored to be pushing diesel territory prior to 1997 when compression ratio was limited to 14:1 (it's now 12:1), rumors of 20:1 weren't uncommon, though 17:1 was probably more realistic, and that was in the mid 1990s).

By comparison, I don't think that Audi ever released any official numbers themselves, but the R10's 5.5 TDI V12 was estimated to have a 15:1 to 18:1 compression ratio.

Add to that the fact that the Audi diesel racing engines are probably over-square designs, that's the range that they've probably stuck to and is similar to modern DFI diesel engines. That's why aluminum can be used for engine blocks now like on gasoline engines.

Why would you have to make a V6 4l engine with ~5000rpm redline oversquare, or am i missing something