Can you enjoy both power and efficiency ?
Discussion
RideOrDie said:
I'm not here to argue with people who don't accept change for whatever personal reasons. just search "google chauffeur", I know we wont be seeing this anytime soon, but it was launched almost 10 years ago. Whether you chose to believe it or not (not i'm guessing?), the world is moving closer to "driverless" cars.
Everyone knows that driverless cars are coming. I don't know if you've noticed this, but you're on a site packed with people who know a great deal about the motor industry, and yet you turn up like you've just been given some hot insider tip.Whether you can dynamically adapt an engine to switch between power & efficiency is interesting. I gave you two things to consider in my first reply to this thread. Why don't you look into them instead of whatever this weird thing you're doing is?
trashbat said:
Whether you can dynamically adapt an engine to switch between power & efficiency is interesting.
Ignoring all the b*ll*cks about oil conspiracies at the like, there is no such thing as adapting an engine to switch between "power" and "economy" because in all cases what you care about is efficiency, namely the highest BMEP for the lowest fuel consumption. It doesn't matter if the driver is asking for 3 bar or 16bar, you still always want to burn the least fuel. All modern engines are calibrated to achieve as close to this as is possible, within the limits of the legislation and other driveability factors. These days, ALL engines will be less than 1% away from MBT/LBT at pretty much all loads, except true WOT (and even then, they will be within probably 3%)Max_Torque said:
Ignoring all the b*ll*cks about oil conspiracies at the like, there is no such thing as adapting an engine to switch between "power" and "economy" because in all cases what you care about is efficiency
...
These days, ALL engines will be less than 1% away from MBT/LBT at pretty much all loads, except true WOT (and even then, they will be within probably 3%)
I think you misunderstand what I mean. At any one moment you might be delivering the most efficient answer *that you can* but if you're a great big V8 you're still not the most efficient tool for the task of pootling along when considered objectively. On the other hand your capability does lend itself to much greater available power. ...
These days, ALL engines will be less than 1% away from MBT/LBT at pretty much all loads, except true WOT (and even then, they will be within probably 3%)
Otherwise how do you explain the use of variable displacement? Plus engines already adapt in all sorts of ways, with lean burn and variable timing and everything else so you're kind of talking chicken and egg. I'm no expert but it looks like plenty more can still come of it, camless being one idea.
I am a Diesel engine development engineer, the team I lead is responsible for fuel economy, noise and emissions for a new passenger car engine. To repeat some answers and add my tuppence worth:
1. We do everything we can to minimise fuel consumption, no one from an oil company has ever tried to get us to run inefficiently
2. On an engine by engine basis, you may be able to squeeze a fraction more out, but to get a significant improvement you would have to sacrifice another attribute. For example, controlling NOx makes combustion less efficient, so you could make an engine none-compliant and gain a percent or two, but you would also increase combustion noise.
For more power you could advance the timing, but then you would exceed Max cylinder pressure limits and compromise durability.
In summary, we spend thousands of hours on engine dynos, in cars, on chassis dynos, doing simulations, optimising gear shift strategies (in autos) etc, and the result is pretty much as good as you will get within the legal emissions requirements.
1. We do everything we can to minimise fuel consumption, no one from an oil company has ever tried to get us to run inefficiently
2. On an engine by engine basis, you may be able to squeeze a fraction more out, but to get a significant improvement you would have to sacrifice another attribute. For example, controlling NOx makes combustion less efficient, so you could make an engine none-compliant and gain a percent or two, but you would also increase combustion noise.
For more power you could advance the timing, but then you would exceed Max cylinder pressure limits and compromise durability.
In summary, we spend thousands of hours on engine dynos, in cars, on chassis dynos, doing simulations, optimising gear shift strategies (in autos) etc, and the result is pretty much as good as you will get within the legal emissions requirements.
Edited by jmcc500 on Monday 12th January 23:16
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