Originally Posted by
revetec
Our output will increase greatly with further top end development. We haven't even tried another camshaft in the engine yet, and the cylinder head has had little development (took me two weeks to fully design with no CFD or flow testing) This will all come to fruition with development with involved manufacturers and our own development.
If you read what I posted I said I know that this particular engine is not designed for producing great power figures and has been optimized for fuel efficiency. I fully believe that you can do better with better top end technology.
Originally Posted by
revetec
Note in the report that we tested up to 3,500rpm at which point the power and torque were still on the rise. The testing we did was on the fuel efficiency side which we proved without a doubt that our bottom end is more efficient than a conventional engine.
If this is the aviation version of the engine then why would you want more than 3500RPM?
Without a doubt? really? I don't see how this single report conclusively proves that your bottom-end technology is more efficient than current designs. You only tested a single RPM point at a single load point which showed (IMO great) BSFC values. You are going to have to make a full BSFC map for the whole operational RPM range and load range. Not that there is an abundance of BSFC maps to compare it to that are publically available. Does anybody know what the currently most efficient petrol engine is?
Originally Posted by
revetec
We had low BMEP which tells us that the top end is not doing an optimum job, but then our output at the target BMEP was good providing unparalleled fuel efficiency.
I will agree that part of the lower BMEP was top end design but didn't you achieve better than this in another test? Also how can your output at your target BMEP be good? (as compared to bad?) there is a direct relation between BMEP and output for any given RPM, the higher the RPM that your target BMEP occurs at, the greater output you will produce at that BMEP. Also the statement "providing unparalleled fuel efficiency" would imply that you have compared your results to another engine. Would you show us what engine you are comparing your results with?
Originally Posted by
revetec
You can go on and on like you have been and I have proved the efficiency to everyone without a doubt. I didn't state that we were going to produce the best power figures in the test, rather than the best efficiency, and I have.
I am fully aware that this engine was not designed with high specific output in mind, also this report is not conclusive proof of revetec fuel efficiency superiority.
Originally Posted by
revetec
So I've proved time and time again your arguments against the engine and now we have top BSFC figures you've decided to now argue outright performance? Well we will prove you wrong once again soon. You'll then argue reliability, which then we will prove. What are you going to argue about then?
I think you meant to write "disproved" but maybe that was a freudian slip Who said I was finished arguing BSFC? as of yet you have data for a single RPM point and a single load (that where any good)... so what? Show me a full RPM and load range graph and that would be closer to proving any gains.
Originally Posted by
revetec
Our 1.35litre engine produced 52kW with 4 valves per cylinder and a CR of 8.5:1 (low as well)
The engine you are talking about (ULPower UL260i) is a 2.6litre (about double) which produces 71kW.
Our last series engine was half the capacity, so let's double the output and we get 104kW.
There you go again completely missing the point... Why are you suddenly comparing an aviation engine to your previous design? I thought the RHL4 was designed for automotive use (you put it in a car remember?) Also where is this "double the output" coming from. The UL260i is comparable to the X4 because it is a 2VPC 4 cylinder aviation engine of roughly the same displacement. It is one of the engines that the X4V2 will be competing with if it comes out on the market. As far as I can see it doesn't have that much to offer (a single highly efficient operating point is about it).
Originally Posted by
revetec
At 3,300rpm which is their peak of 71kw, our RHL4 engine produced 42kW, it's half the capacity.
So let's look at kW per litre at the same RPM...
ULPower UL260i 2.6 litre has 27.3kW@3,300rpm per litre
Revetec RHL4 1.35 litre has 31.1kW@3,300rpm per litre.
So your previous design got better specific power... Does that mean you are going backwards? or maybe this comparison is just flawed.
Originally Posted by
revetec
So now your argument is?
When the X4V2 comes out on the market for aviation engines what exactly is it going to offer over the alternatives?
Don't just say it is more efficient and point out the single point that was tested. You need at the very least a part-throttle full RPM range average to make any big claims (increased bottom end efficiency).
Power, whether measured as HP, PS, or KW is what accelerates cars and gets it up to top speed. Power also determines how far you take a wall when you hit it
Engine torque is an illusion.