For Sale: A selection of pre-owned Hondas

[ogden]

"... a Wankel engine ... uses more fuel and oil than a conventional engine ..."

"... far more efficient than a conventional engine"

Umm, which is it?

[ogden]

Of Honda's oval-pistoned folly...

Originally Posted by Scoobs

Doesn't make it bad......just uneconomical to produce on a mass market scale.

It was, basically, an attempt to solve a problem that didn't exist.

Honda wanted to build a V8 for competition in a series where the rules only allowed four cylinders. The *good* way to solve the problem of building a V8 is to build a V8. The four cylinder limit was a purely artificial constraint and even Honda realised that the effort required to try and make the oval-pistoned V4 work was more than would be required to get equivalent performance from a conventional V4. That's why it never made it into mass production *or* achieved any competitive success, and that's why I call it a folly.

Honda have a long record of this. Look at the RC45 - they spent years of effort and immense amounts of money trying to get it to the point where it could compete against the twins of the time. They're a Japanese firm - face is important to them, and to admit defeat wasn't really an option. As soon as they'd proven they could do it, to save face, they took the sensible decision to kill it off and built a twin like everyone else. I'm amazed they gave up on the NR so quickly

These days they even cheat at it. They had their 800cc MotoGP engine in development for a year before the rules changed - a change they instigated. And yet they still got squashed by Ducati to the point that people wondered if Ducati had kept the 990cc engine and just changed the stickers!

Folly after folly after folly. That's Honda for you.

Originally Posted by ogden

"... a Wankel engine ... uses more fuel and oil than a conventional engine ..."

"... far more efficient than a conventional engine"

Umm, which is it?

Efficiency doesn't always go on how much fuel and oil it uses.

Seems your just after an argument tbh. If your that bothered, pull your own finger out your backside and do some of your own research.

[ogden]

Originally Posted by Daimo

Efficiency doesn't always go on how much fuel and oil it uses.

Quite. Efficiency goes on how much power it gets out for fuel put in. But if a wankel engine "uses more fuel" then either it's inefficient or we're comparing, if not apples with oranges, then Cox's Orange Pippins with Bramleys.

Originally Posted by Daimo

Seems your just after an argument tbh. If your that bothered, pull your own finger out your backside and do some of your own research.

C'mon, at least give me a Wikipedia link or something.

You name me a 1.3 NA engine that can make 230bhp............... It is an efficient engine.

The previous RX7 model used a twin 654cc rotar to make a 1.3 engine (some are 1.3's, some are classified as a 2.6, which they are not) and two turbos to have over 280bhp....

Do it yourself if you want to know that much about it. Not hard. MAZDA ROTARY ENGINE

[ogden]

That "1.3 litre" (and I'll come to that in a moment) engine is making 176bhp per litre. That's roughly equivalent to a ZX10R as it leaves the showroom. Not exactly groundbreaking.

As I understand it, each rotor has three combustion chambers and each chamber burns once per rotor revolution and the rotor is geared down 2:1 to drive the crank. So that's equivalent to a three cylinder otto-cycle reciprocal engine with similar swept volume. Per rotor. So your 1.3 litre engine is arguably (and god knows I'm sure we could argue about it all day) a 4 litre engine, at which point the 230bhp it puts out doesn't look quite so impressive after all.

Reciprocating piston engines are a bit like telescopic forks - they're not, in theory at least, the best solution out there, but they've had so much development put into them that they're about as good as you're going to find in the real world for most practical purposes. As much as I respect Mazda for persisting with the technology, your comparison with Honda's oval pistons is quite apt - they're both trying to solve a problem which doesn't really need to be solved. They're vanity projects.

[embee]

Have to have a little go here...............

The reason the piston engine as we know it still rules is that the technical challenges it poses can be solved effectively at low cost and it can be made durable.

I used to be in a group who evaluated "ideas" and novel engine proposals. Nearly all of them fell into one of a small number of boxes, where either they were simply different shaped mechanisms wrapped round the same engine cycle, or were actually perpetual motion machines, or would require some technology which didn't currently exist to solve particular issues.

A common one was "this engine is far more efficient and lighter than current ones, with far fewer moving parts, all that is required is to solve the gas sealing issue and how to lubricate the parts". Well I'm afraid that gas sealing and lubrication (also cooling) are fundamental issues in the real world. Anything other than round bores and rings pose difficulties in gas (and oil) sealing, the oval piston design was a nightmare by all accounts.

This is the reason why many of these sort of ideas tend to come from keen individuals rather than companies, the engineers working in engine manufaturers realise that some things just can't be done cost effectively with today's technology. Some issues, like wankel rotor seals, can be done to an acceptable level, but it'll never reach the same cost effectiveness and durability of a "conventional" round piston design.

Don't think that manufacturers aren't continually striving for improvements and are prepared to adopt novel concepts, look at the latest valve gear systems, direct injection gasoline technology, sequential-turbo diesels, and variable geometry induction+exhaust systems for example.

Manufacturing technology is behind a lot of innovation, the ideas are already there, as soon as it can be made cheaply in volume it'll be done.