A work of pure genius! - Brilliant "Revetec" Engine

[Bob]

Lets get this straight. Your saying that provided with say 1 L of fuel, the engine would run for 1 minute at 2000 rpm, producing a specific power (call it 1 watt for simplicity), and and energy output of 60 J. Then at 4000 rpm, your engine would run the same amount of time (1 minute), produce twice the power (2W) and twice the energy (120 J)?

That makes the engine terribly inefficient at 2000 rpm, harnessing only half the energy it does at 4000 rpm from the same amount of fuel. So are you denying that the engine is inefficient at 2000 rpm? Or are you saying its incredibly efficient (relative to normal engines) at 4000 rpm? Or are we misunderstanding?

[shane_trikes]

I've read the posts regarding the Revetec Engine. The negative criticism is unfair and unwarranted. Our company builds three wheel motorcycles (trikes), we have signed a long term deal to put Revetec engines in our trikes. Our trike was the first vehicle to have a Revetec engine fitted, I personally road a trike powered by this engine in Sydney, Australia and Shanghai, China.

Our production trikes are powered by VW Type 1 (1600) engines (built from aftermarket, performance components) ranging in displacement from 1584cc to 2275cc. The Revetec 450cc development engine we fitted to the test trike in Sydney and flown to China for the 2005 Automechanica show.

This 450cc engine produced 'phenomenal' torque and respectable power for its size. It powered our trike (around 450kg) upto 60 km/h (38 mph) in a small side court yard located at the Shanghai Pudong Exhibition Centre. The engine accelerated through 'each' gear in less than 2 seconds (per gear). My first hand experience from driving this engine was of amazement. The torque I experienced during acceleration was consistent from idle to max rev's. I have driven the same trike with this engine in Sydney and so has the chairman of our company (Gordon Subloo). With a passenger on the back, Gordon took the trike upto 70 km/h.

Our performance VW engines have torque curves that come on at between 2,000 to 3,000 rpm depending on the cam and engine displacement. For the Revetec engine to have a torque curve that comes on at 1500 rpm and remains consistent to 4500 rpm+ is amazing. The closest engine group I can compare this with is highway trucks in particular the Mack Maxidyne.

I don't know the fuel efficency results first hand, but I will check my notes.

Like all development engines, the overall package needed more development, but I can tell you from first hand experience that the Revetec engines perform differently to conventional combustion engines used in the Automotive industry.

The Revetec X4 engine is the next generation design of the Revetec concept. It is a monumental step from the flat four design of the 450cc and 1350cc development engines. What Brad has done is cut the number of engine components in half, reduce weight, reduce main shaft flexing, reduce drop/drive shaft flexing, maximize engine balance and reduce reciprocating weight.

How much power will the new Revetec X4 2.4 litre engine develop? What will the drivability of this engine be like? We will know in about 1-1/2 months time.

Our company has the greatest respect for Brad, he is a very talented designer, his concepts and design process is incredible.

Our company first came across Brad and the Revetec engine about 3 years ago, from that point on we have seen the design and concept go through the development process. This journey for the Revetec team has not been easy, but they have proven their technology and engines first hand. When we tested their engines we wanted to know exactly what was being delivered, worts and all. We tested them first, we got on the trike and put the engine through the paces.

Based on our first hand experience with the Revetec Engine Technology we signed up a 10 year contract with the company to only put Revetec engines in our trikes once they finalise the development process and deliver the production ready design. This was a big commitment to make, but the Revetec engine is unlike any other we have come across.

Shane Subloo
Rewaco Pty Ltd
The Hudson Group Pty Ltd

[revetec]

Originally Posted by pneumatic

As a rule of thumb, roughly 1/3 of the energy makes it through as power (similar to your Prius quote), 1/3 is lost out the exhaust and 1/3 is lost through the cooling system.

Mate.........Friction....Pumping Losses.....mechanical losses that dont produce friction (Such as valve springs, down thrust on cranks, side thrusts on pistons)...incomplete combustion....gas flow losses....I can go on.

If your going to make statements be acurate. Post a reputable paper on total engine losses. 1/3 out the exhaust and 1/3 through the cooling system is such a silly statement.

Engine mechanical efficiency is done by measuring BMEP (Cylinder pressure) and comparing it to output. This gives an accurate figure. I have a BMEP tester.

Bob: At 2,000rpm we are comparable with a conventional engine. Our fuel map leans off from there, as the revs increase. Although the spark plug gets the same amount of fuel molecules to fire at higher revs, the fuel mixture decreases. Our fuel map drops to 1/2 the fuel but it was only recently with tests with an independent automotive company tests we demonstrated this outside our company to a third party. Of course before we demonstrated it they didn't believe it (Expected) but after the demonstration and testing over several days and a detailed presentation about why this happens.

All I can say is that on compression, we move the piston up faster than a conventional engine then slow it down somewhat before we fire it. (In a very early prototype we raised the piston to TDC then fired it, held it for 15 degrees at TDC then when combustion was almost finished moved the piston down the stroke) Two things are affected by this: 1) fuel available to the plug for ignition is increased, so the fuel mixture is decreased. The higher the revs the lesser amount of fuel is used to keep the Lambda reading correct. 2) the thermal losses are decreased dramatically due to combustion happing in a more confined area. Latent heat is more readily absorbed by the following charge increasing efficiency. Less heat is lost through the cylinder wall. Also the exhaust temperature has dropped even though the mixture is leaner (about 30% cooler exhaust by our pyro-sensors in each exhaust port)

Now given that the mixture is leaner, the combustion temps are a bit higher than normal, so we use a lower compresion ratio although the BMEP is showing similar cylinder pressures as that of a conventional engine with a higher compression ratio. This reduces pumping losses of the engine. Temp must be kept down to reduce NOX emissions as well.

[revetec]

Originally Posted by shane_trikes

This 450cc engine produced 'phenomenal' torque and respectable power for its size. It powered our trike (around 450kg) upto 60 km/h (38 mph) in a small side court yard located at the Shanghai Pudong Exhibition Centre. The engine accelerated through 'each' gear in less than 2 seconds (per gear). My first hand experience from driving this engine was of amazement. The torque I experienced during acceleration was consistent from idle to max rev's. I have driven the same trike with this engine in Sydney and so has the chairman of our company (Gordon Subloo). With a passenger on the back, Gordon took the trike upto 70 km/h.

The speeds mentioned were is a small courtyard beside one of the halls and can be seen in previously posted pictures in the last page.

Cheers

[revetec]

Below image is of the Chairman and his wife of one of the top 5 vehicle manufacturers in China. This was taken at the China Automechanica Show. More pictures are available through the GTM Trike Website.

[revetec]

Here is a picture of Rewaco's General Manager (Mr Shane Subloo) with his REVETEC powered HS series Trike with the 450cc development engine at Revetec's Sydney Research Facility. His comments about this engine's performance are a few posts previous.

[pneumatic]

Originally Posted by revetec

If your going to make statements be acurate. Post a reputable paper on total engine losses. 1/3 out the exhaust and 1/3 through the cooling system is such a silly statement.

It is the industry accepted rule of thumb. That is why I called it a rule of thumb.

Besides, you can find the same thing quoted on the Colorado State University Internal combustion engines website;
http://www.engr.colostate.edu/~allan...ge3/page3.html

Also exactly the same 1/3 rule can be found in a description of the internal combustion engine by Julius Mackerle (former chief designer of Tatra motor works) in his book air-cooled automotive engines. I guess you think he's silly for making such a statement.

That rule of thumb is fine. If you want to get more exact figures it will depend on what engine your looking at.

[revetec]

Originally Posted by pneumatic

It is the industry accepted rule of thumb. That is why I called it a rule of thumb.

Besides, you can find the same thing quoted on the Colorado State University Internal combustion engines website;
http://www.engr.colostate.edu/~allan...ge3/page3.html

Also exactly the same 1/3 rule can be found in a description of the internal combustion engine by Julius Mackerle (former chief designer of Tatra motor works) in his book air-cooled automotive engines. I guess you think he's silly for making such a statement.

That rule of thumb is fine. If you want to get more exact figures it will depend on what engine your looking at.

Yep quote a guy from the Czech Rep who wrote a book on Air Cooled Engines in 1972 and has a US patent on a heat exchanger.

I suppose its a VW engine and he was trying to make it more efficient. I suppose he would quote 2/3 heat losses because he was trying to flog his patented heat exchanger. Well I don't see them on cars today, he's had 35 years to get it to market! Book must be a great read.

Your link to the University works on bio fuels (diesel) not engine development.


I have presented at Queensland University of Technology, The Institute of Automotive Mechanical Engineers in Melbourne, Presented and ran a seminar at Automechanica in China, Presented to Two major Automotive vehicle manufacturers in Japan, Five Automotive manufacturers in China, the Largest Automotive manufacturer in Malaysia, 2nd largest Automotive manufacturer in Iran, 2 out of the top 3 Automotive manufacturers in India, a top Automotive supplier in the UK and many more. Mostly in the last two years.

Read the statement made by the Managing Director of Rewaco. He's a manufacturer and has drove a vehicle with our engine in it which replaced an engine at least three to five times the capacity. Read his comments.

[revetec]

Originally Posted by shane_trikes

I've read the posts regarding the Revetec Engine. The negative criticism is unfair and unwarranted. Our company builds three wheel motorcycles (trikes), we have signed a long term deal to put Revetec engines in our trikes. Our trike was the first vehicle to have a Revetec engine fitted, I personally road a trike powered by this engine in Sydney, Australia and Shanghai, China.

Our production trikes are powered by VW Type 1 (1600) engines (built from aftermarket, performance components) ranging in displacement from 1584cc to 2275cc. The Revetec 450cc development engine we fitted to the test trike in Sydney and flown to China for the 2005 Automechanica show.

This 450cc engine produced 'phenomenal' torque and respectable power for its size. It powered our trike (around 450kg) upto 60 km/h (38 mph) in a small side court yard located at the Shanghai Pudong Exhibition Centre. The engine accelerated through 'each' gear in less than 2 seconds (per gear). My first hand experience from driving this engine was of amazement. The torque I experienced during acceleration was consistent from idle to max rev's. I have driven the same trike with this engine in Sydney and so has the chairman of our company (Gordon Subloo). With a passenger on the back, Gordon took the trike upto 70 km/h.

Our performance VW engines have torque curves that come on at between 2,000 to 3,000 rpm depending on the cam and engine displacement. For the Revetec engine to have a torque curve that comes on at 1500 rpm and remains consistent to 4500 rpm+ is amazing. The closest engine group I can compare this with is highway trucks in particular the Mack Maxidyne.

I don't know the fuel efficency results first hand, but I will check my notes.

Like all development engines, the overall package needed more development, but I can tell you from first hand experience that the Revetec engines perform differently to conventional combustion engines used in the Automotive industry.

The Revetec X4 engine is the next generation design of the Revetec concept. It is a monumental step from the flat four design of the 450cc and 1350cc development engines. What Brad has done is cut the number of engine components in half, reduce weight, reduce main shaft flexing, reduce drop/drive shaft flexing, maximize engine balance and reduce reciprocating weight.

How much power will the new Revetec X4 2.4 litre engine develop? What will the drivability of this engine be like? We will know in about 1-1/2 months time.

Our company has the greatest respect for Brad, he is a very talented designer, his concepts and design process is incredible.

Our company first came across Brad and the Revetec engine about 3 years ago, from that point on we have seen the design and concept go through the development process. This journey for the Revetec team has not been easy, but they have proven their technology and engines first hand. When we tested their engines we wanted to know exactly what was being delivered, worts and all. We tested them first, we got on the trike and put the engine through the paces.

Based on our first hand experience with the Revetec Engine Technology we signed up a 10 year contract with the company to only put Revetec engines in our trikes once they finalise the development process and deliver the production ready design. This was a big commitment to make, but the Revetec engine is unlike any other we have come across.

Shane Subloo
Rewaco Pty Ltd
The Hudson Group Pty Ltd

Did you read it?

[revetec]

Showing compactness of the Revetec X4 2.4 litre engine.

[hightower99]

I have so many questions it hurts...

How can somebody "feel" a "constant torque curve" ???

You don't feel torque you feel the power of the engine accelerating the vehicle right?`

Also I am sure that when people say they want more torque they actually mean to say that they want more low rpm power... so far I haven't been proved wrong in this assumption.... yet...

Next how can the revetec engine produce more torque when running on a lean mixture?

In order for your claims to be true you would have to maintain the same torque at 2000 and 4000rpm but you are saying that you are running on a leaner mixture during 4000rpm operation... How is this possible? I know you are getting "almost" complete combustion (you should be able to get practically complete combustion on lean mix) But if there is less fuel in the chamber then less torque is produced... Max torque is produced with a slightly rich mixture.... Please explain yourself.

I don't understand what you are saying about your lambda readings.... I believe the oxygen sensors measure the amount of oxygen in the exhaust right? well then if the air/fuel ratio is lean for the whole cylinder then the lambda reading would show that. Just because you burn all of the fuel that you do inject doesn't mean that you would get a reading showing 14.7:1... Lambda readings tell you the air/fuel ratio of the whole cylinder (and engine) so running lean and igniting it by concentrating the fuel around the spark plug shouldn't fool the system should it?

I would also like to point out that a slightly more accurate rule of thumb is 3/10 of the burned fuel's energy is produced as output power as motive force to the wheels. 2/10 is lost through the cooling system. This includes the power needed to pump coolant around the system as well as the actual heat energy dissipated by the system. Keep in mind that on an engine producing 150kW motive power, 100kW of energy is lost throught the cooling system. 4/10 is lost as heat and kinetic energy in the exhaust. Exhaust can be as much as 1000 degrees C and is normally over 800 degrees C for normal cars. 1/10 of the burned fuel's energy is lost through heat that doesn't go through the cooling system.

[pneumatic]

Originally Posted by revetec

Yep quote a guy from the Czech Rep who wrote a book on Air Cooled Engines in 1972 and has a US patent on a heat exchanger.

I suppose its a VW engine and he was trying to make it more efficient. I suppose he would quote 2/3 heat losses because he was trying to flog his patented heat exchanger. Well I don't see them on cars today, he's had 35 years to get it to market! Book must be a great read.

The book is 100's of pages, it has a ridiculous amount of research and work put into it. There's a lot more air cooled engines in the world than just the VW engine you know.

If you want a source that you can't pick holes in, then look at the Bosch Automotive Handbook, a well known resource in the industry. It too agrees with the 1/3 rule (but expands the ranges to 30-35%).

Look, I think the X4 looks really interesting. I am not denying that. It looks smaller and lighter, but by how much is yet to be seen. And your X4 is a radial engine, so to get a better idea of size you really need to compare it with the complexity and size of a radial conventional engine;


2.8L 7 cylinder radial motorcycle engine (not the best comparison, but it is cool);


I think Shane's comments are great, and his opinion is encouraging for the success of your motor. But it still does nothing to prove your efficiency claim. That is after all, what I have been asking for more information on all along.

[jediali]

Originally Posted by hightower99

I have so many questions it hurts...

so have I - where have you been?, good to have you back- and on form. I agree with most of your points here. On the feeling torque agenda - is an engines responsiveness anything to do with instantaneus torque? In my car i know the engine is struggling when i lose the ability to swiftly increase the engine speed with the throttle, suggesting no more pulling ability left.

Since power comes from 1)displacement 2)torque 3)engine speed more low down power is technically more torque. Also, objectively speaking, a flat torque curve would suggest a linear power curve, hence linear acceleration (at low speeds, before exponential wind resistance effects de-linearise the system) can be observed. Compare this with a peaky NA engine or a HP turbo engine where torque comes in surges the acceleration also hapens in surges. The differences may be very subtle...just a thought mate

[jediali]

theres always a simple solution.........

[hightower99]

Originally Posted by revetec

I think you guys are not reading my posts properly. I have stated that the Lambda was reading a mixture of 14.7:1 air/fuel mixture in both RPM ranges. The tests were performed without any lean burn built into the program also. The fuel consumption was measured by a metering system into the Dyno test cell. So the total fuel consumption/usage was actually measured, not just from the fuel maps and compared to power/torque output to get an overall efficiency. So we did have "The Same Fuel Flow Rate" in Hightower99's words.

So no it was not running rich at 2,000rpm.. Jeeesh....Because if it was, the emissions would be through the roof.

Ok if the Lambda says you are running 14.7:1 air/fuel ratio then that is for the whole cylinder... if it isn't then the system has a serious flaw. If you where running 14.7:1 air/fuel ratio during both 2000 and 4000rpm then you needed to inject MORE FUEL when you where running at 4000rpm. That is just simple math. You need to explain where your advantage is?

Originally Posted by revetec

BTW Hightower: I read your signature comments and I think you should talk to Mazda. I met with the Managing Director of the Research and Development department in Hiroshima, Japan last year. One of his first comments to us was he was not interested in power, he stated that torque is the all important thing. This guy is in charge of the development of the engine rotary engine your making coments about. I'm not trying to stir you up, just telling you the facts of what was said.

I think you might have misunderstood what he said I would bet money that he said something closer to "I don't care about Peak Power... the torque curve is more important" this would be an intelligent and true statement. To believe that he said he wasn't interested in the power curve at all is ridiculous. Again I believe that even when he said torque is important he meant low rpm power and the shape of the power curve as this determines the driveablity of the engine. I talked to a engineer from japan and he said he knew that torque was more important than peak power... He took me driving in two civics he had been working on. One was pretty much stock 2001 civic with 1.7L I4 and 5 speed manual. It had 111lbs-ft. of torque and 117hp. The other one he had put a small tubo on that boosted peak torque to 201lbs-ft. but power was only increased to 130hp. He then did some hard accelerating with me in the passenger seat and showed me some dyno charts. The turboed Civic did pull really hard compared to the stock one even though the peak hp was only 130hp (only 13hp more than stock). The interesting thing was the dyno charts that showed 30-45hp increase over stock between 2000 and 6000rpm.