F1 engine braking explained?

As I understand it:

All engines will have engine braking. When you aren't on the gas but still in gear, the cylinders still cycle. When you aren't exploding gas to gain energy, the compression part of the cycle acts to slow the rotation of the engine and thus the wheels.

F1 engines in the past could control this engine braking by automatically adding fuel to reduce the effect. This can give optimum braking without locking the wheels. The driver usually wants to apply maximum braking force until the wheels start to lock. If the rear wheels begin to lock before the fronts, the ECU could give a little gas to the engine to reduce the engine braking. This effectively moves the brake bias towards the front mid corner. If the fronts are locking first then more engine braking can be used to move the brake bias towards the rear.

The engine mapping programs were also adjustable on the drivers steering wheels.

The new ECU's don't allow for this ECU controlled engine braking. It still exists however and can be controlled.... with the drivers right foot!

 

I think the good drivers already do this. There were a couple throttle/brake trace comparison between Schumacher and Barrichello in the past. Schumacher used to use like 5-10% throttle while braking to push the weight a bit rearwards to prevent the front tires from locking. Barrichello used to be either on the brake or the throttle. There was a tangible improvement in lap time that could be attributed to brake/throttle overlap.

Removing the electronic braking help in 2008 may mean that the drivers may be adjusting the front/rear bias of the car a lot more to compensate.

 

While I have no specific facts - doesn't it seem like a rather minor factor when they are already braking so hard under downforce as to pull 4g or so anyway, and that most times I see a wheel lock it is one of the fronts?

 

This advanced engine braking is the exact reason you don't ever see the rear wheels lock. The system blips the throttle to prevent it. If the front wheels are going to lock, the driver must relax the brakes to fix the fronts, then the system must increase engine braking to fully exploit the rear tire. This requires driver input which means the front tires may lock anyways.

This year the driver's corner to corner adjustment of the brake bias will be all the more important.

 

OK, I take your point. My general instincts still tell me that this should matter little when the brakes must have about 8 times the power of the engine anyway, --- but ---

My general instincts sometimes tell me to disbelieve quantum mechanics, dark matter, and dark energy as well.

 

It's the ability to use the brakes and throttle to help "balance" the car, as well as have the car turn in response during braking be controlled differently.

Under braking, if you have more front brake bias you will have understeer, more rear brake bias, oversteer. If you tune the understeer/oversteer relationship to what you want for corner exit, that may be very different than what you want on corner entry. What they were doing was adding more rear brake bias, which would have made the car oversteer, but then added a bit less engine braking to "tune" the understeer/oversteer relationship under braking.... This way the driver could have the car set up for a more stable corner exit, but could get the car to "turn in" under braking better... It was easier to tune the "engine braking" part of the equation than it was to try to adjust the brake bias.

Now the driver has to do it with his right foot.. If he feels the car starting to oversteer under heavy braking he will add some power, if if the car is pushing under corner entry he can take some power out.

 

The guys who left foot brake (or have been left foot braking) will probably have the advantage when it comes to modulating the brake/throttle during corner entry.

 

I don't have any numbers either and I'm not sure where you got 8 times, but if the discs are giving 8 times the force of the engine braking then engine braking makes up 11.1% of the braking. Not an insignificant portion.

 

Does anyone in F1 right foot brake anymore??I know Ruebens still does from time to time.....

 

I can't imagine that the way he stops and slows down his car is up to chance or "what he feels" that day. I assume if he right foot brakes, then he does it all of the time.

 

Brakes produce much energy. It's often said when slamming someones car that "one of my wheels under braking produces more power than your engine" < Or something to that effect. Also 11.1% of anything in an F1 car isn't anything to scoff at.

 

MS uses left foot braking and RB used right foot braking at that time

 

That is exactly what I said. If the cars brakes produced 8 times as much force as the engine braking, then the engine braking provides 11.1% of the stopping power. 11.1% is a large portion! Need me to clarify any more?

And as for Rubens left and right foot stuff.... He was known to have switched and I think switched back at some point when he was struggling to find speed.

 

When Rubens switched to Honda, the car was set up in a way that did not allow for right foot breaking. He really struggled, complained, and eventually Honda reworked the pedal set up to allow him to right foot break....Jensen still worked him over.

Mark

 

I was watching Pirates of the Caribbean, I guess I missed the "n in" from "Not an insignificant portion."

 

I still don't understand this year's rule about no engine braking. It sure sounded like they were engine braking to me.

 

The ECU doesn't reduce braking power anymore as it used to by applying power to overcome the rear brakes and reduce lock up. They still have the obvious engine braking effect when decellerating in gear with the clutch engaged.

 

He used to switch all the time. First started left foot braking in Suzuka in........03??? can't remember exactly. Was known to change track to track and corner to corner.

As did Schuey, there was an article with him driving a 575M F1 and he exclusively right foot braked, just because it "felt better at this track"

 

Okay, that was what was confusing me; thank you for clearing that up.

I guess I'm still left not understand some aspect of this new "no engine braking" rule. But then again, I'm so mechanically declined, it's nearly impossible for me to understand the dynamics of engines and ECUs and stuff like that anyway. I guess I'll just watch and enjoy. Again, thanks for clearing up the decelerating thing for me.

 

They used the engine, controlled by the ecu, as an anti-lock brake system for the rear. They just had to control front wheel lock up. Now it's like they're driving a 20 year old car with a lot of power.