The Great Powertrain Robbery

[cheb]

An interesting article by John Robinson about stated and actual power outputs.

https://www.motorcyclenews.com/news/201 ... n-robbery/

[Mr. Dazzle]

When you consider all the moving bits, gasses, liquids and electricity flowing about I sometimes think its remarkable engines are as consistent as they are.

[Le_Fromage_Grande]

It's the main way modern engines make more power than old ones, reducing internal friction and reduction of the mass of moving components

[wheelnut]

It's the main way modern engines make more power than old ones, reducing internal friction and reduction of the mass of moving components

I don’t know if it still holds true, but they used to reckon you lost about 30% converting linear to rotational. Hence why rotary engines gave more power from less CC.

[ZRX61]

I recall reading many years ago that it wasn't uncommon to dyno an engine to get an actual number, then they would motor it to get the HP numbers for what it took to turn the cams, drive the alternator, turn the gears, spin the wheels etc.. Then they totaled those various numbers & added them to what the engine actually put out to give the *claimed HP*

[Skub]

JR was always a great read. Quick on a bike too,by all accounts.

[The Spin Doctor]

An interesting article by John Robinson about stated and actual power outputs.

https://www.motorcyclenews.com/news/201 ... n-robbery/

Fascinating... although I was a big JR fan and read everything he wrote, I don't recall that particular article at all... must have been in one of the rare copies I didn't buy.

Great title too.

[Mr. Dazzle]

My second ever "real" job was a place called Integral Powertrain, tis the reason I live in MK. They've since rebranded and switched to be almost exclusively EV, but when I worked there it was still loads of ICE stuff too. The firm was started by (and is still run by) four Cosworth guys, one of whom had the surname Duckworth.

The main thing I did there was examining, modelling and testing cars to see where all their fuel went. So putting loads of sensors on them, building load cells into their driveshafts, building computer models of them and the like. OEMs would ask "why is their car more fuel efficient than ours?" and off we'd go.

You probably wouldn't be surprised to know it's really really hard to measure how much power a car is actually making, how much fuel it uses to do it and where that power actually ends up.

So you probably can get a load more BHP with a fair wind and a squint at your dyno.

[wull]

Keith Duckworth? The fella who started Cosworth along with Mike Costin.

[Mr. Dazzle]

He passed a long time ago. His son Roger was my boss.

Everyone would always go on about "Roger's dad would have done it this way". Took me too long to make the connection

[demographic]

I'm fairly sure I had the PB magazine with the original article in.
Moved house a few times and gave a stack of em to a mate.
For me, PB went rapidly downhill when JR died.
Franklin was editor (I think anyway) and it went a bit Max Power/Loaded. Just wasn't as informative.

I liked Mark Forsythes articles as well, oh and Cathcart.

[Scootabout]

The figure for heat losses is pretty staggering: 352 bhp from the fuel translates to 125 bhp available for propulsion, before mechanical losses. The difference is lost in heat.

[Mr. Dazzle]

The petrol engine is actually not bad as a heater, it's about twice as good at that as it is at moving you

[Le_Fromage_Grande]

My second ever "real" job was a place called Integral Powertrain, tis the reason I live in MK. They've since rebranded and switched to be almost exclusively EV, but when I worked there it was still loads of ICE stuff too. The firm was started by (and is still run by) four Cosworth guys, one of whom had the surname Duckworth.

The main thing I did there was examining, modelling and testing cars to see where all their fuel went. So putting loads of sensors on them, building load cells into their driveshafts, building computer models of them and the like. OEMs would ask "why is their car more fuel efficient than ours?" and off we'd go.

You probably wouldn't be surprised to know it's really really hard to measure how much power a car is actually making, how much fuel it uses to do it and where that power actually ends up.

So you probably can get a load more BHP with a fair wind and a squint at your dyno.

Did you work with Darren Dewsbury?

[Rockburner]

The figure for heat losses is pretty staggering: 352 bhp from the fuel translates to 125 bhp available for propulsion, before mechanical losses. The difference is lost in heat.

And moving parts, noise etc.

when the GPX was flowing 47.2lb/h at 10,200rpm, the potential heat flow into the engine was 896800BTU/h or 352bhp.

Yet only 125bhp is accounted for – 90bhp is useful power, 35bhp in mechanical and pumping losses. The remaining 227bhp is dissipated in heat losses to the engine metal and coolant, heat and noise in the exhaust, and in imperfect combustion.

Why do you think engineers have been chasing a better type of engine for years

[The Spin Doctor]

Why do you think engineers have been chasing a better type of engine for years

Ooo... let me guess... electric?

Efficiency around 80% conversion of electrical energy into mechanical energy in a car. Possibly higher.

[KungFooBob]

I misread the thread title, I was expecting The Great Pottery Throw Down content.

[Rockburner]

Why do you think engineers have been chasing a better type of engine for years

Ooo... let me guess... electric?

Efficiency around 80% conversion of electrical energy into mechanical energy in a car. Possibly higher.

And rotary. My uni 3rd year project was designing and patenting a viable rotary engine design. If I'd done a 4th year I'd have built a prototype.

[Rockburner]

I misread the thread title, I was expecting The Great Pottery Throw Down content.

On a scale of 1-10, how disappointed were you?

[KungFooBob]

I misread the thread title, I was expecting The Great Pottery Throw Down content.

On a scale of 1-10, how disappointed were you?

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