Wankel - will it return?

[New POD]

Yes. It's part of the Frazer-Nash .........STUFF.......

I'm freelancing at Frazer Nash Consultancy at the moment. We are working on the design of submarine engines.

[willswitchengage]

The issue with the engine in current installations is that it can't pull tall gearing. Why do diesels give such great economy? Torque. 1.6 diesel can pull 28mph/1000 rpm easily in something like a small hatchback - and look at what Volvo manage to haul with just a 1.6. 

 

No no no no no no no. Power and torque have nothing to do with fuel efficiency...

 

Specific fuel consumption is how much fuel is consumed per unit of energy output.

 

These plots are roughly the same for both petrols and diesels (I must have posted this jpeg a dozen times on this forum now):

 

 

On this petrol engine the red bit is where the engine burns fuel most efficiently; i.e. at around 2500rpm at a 75% load factor (how far your foot is pressed down). That's the 'sweet spot' that people on pistonheads.com like to say is WEAR ALL THE TORQ IS M8

[Bear]

That makes sense, but where that peak in efficiency/power can only be turned into useful motion with the right gearing. Power and torque have nothing to do with fuel efficiency in terms of input unit/output energy so I should have phrased that differently - but they affect how people use the car to drive at given road speeds. Hence the 1.6 MX5 churning though a gallon every 28 miles at 80mph, when the MG F is nearer a gallon every 38 miles at the same speed.

 

Still, it's nice to have a good discussion about it. There must be a similar map for Wankel.

[Bear]

I'm freelancing at Frazer Nash Consultancy at the moment. We are working on the design of submarine engines.

 

Sssssh, secrets!

 

This stuff was a few years ago, they were demoing a prototype taxi; I think the hybrid research was heading in the direction of a new Bristol, but as it's been a while I can't recall all the details beyond "I read this stuff around the time Kamkorp acquired Bristol". So 2011.