ESE's works engine tuner

[speedpro]

If you can start it cold without the "choke" you're off in the right direction I reckon.

[Frits Overmars]

Have just returned from taking away the Americas Cup of Karting in Vegas. We dominated/won S4 = Senior Stock Moto with over 80 entries, the locals very unhappy about being dicked by a first timer foreigner in the class,Matt Hamilton from ChCh

Congrats, Wob.

One thing they got very wrong was trying to get good AFR numbers, all the time. My approach was that on the stand, with no load, the motor should be able to react instantly to full throttle from idle.

During my visit to the Ignitech headquarters (remember the picture of the Warshaw pact bunker?) there was a very nicely-built V-6 prototype bike for which the Ignitech people had just finished mapping the injection. I was invited to turn the throttle and, mean bastard that I am, I cracked it wide open in a split second a couple of times. Each time the bike reacted with a bang and a blue flash out of the mufflers. The Czechs looked less than happy and I had to comfort them by saying that no-one would ever do that with a 200 HP bike in gear.

[Frits Overmars]

Attachment 290412
This time I am going asymmetric with the smaller number one injector for start up and low end running in the left hand transfer and the bigger of the two secondary injectors in the rear boost port and the smaller of the two secondarys in the right hand transfer on the rotary valve side. Under WOT and full power I am aiming to have all three injectors pumping and for starting and trickling around it will be running only on the smallest and most sheltered injector.

TeeZee, it seems to me as if the spray from the outer injectors will hit the cylinder sleeve almost immediately. I fear that the fuel droplets will combine into large drops before they have had a chance to mix with the airflow.

[TZ350]

TeeZee, it seems to me as if the spray from the outer injectors will hit the cylinder sleeve almost immediately. I fear that the fuel droplets will combine into large drops before they have had a chance to mix with the airflow.

It has run with a right hand and central injector so there is hope but I share your concern.

[Frits Overmars]

It has run with a right hand and central injector so there is hope but I share your concern, and I am getting desperate.

Desperate comes with the job, so you must be on the right track . I know the feeling: you think you have not achieved anything in weeks.
But when you look back on the past year, you'll find that you have in fact accomplished quite a lot.

[RAW]

Have just returned from taking away the Americas Cup of Karting in Vegas.
We dominated/won S4 = Senior Stock Moto with over 80 entries, the locals very unhappy about being dicked by a first timer foreigner in the class,Matt Hamilton from ChCh
One thing I learned was that they are now " addicted " to reading the data logger.
I concentrated on the piston crown and plug reading combined with a weather station and chased the jetting every heat,and we won most of them.
The data is perfect for getting gearing and chassis setup nailed with the on board accelerometers, and is what we use here as well.
But the data they use includes an O2 sensor ( in the muffler ) and is dead reliable, so I bought a kit for my dyno.
Will let you guys in on how it goes and the relevance of the readings Vs on track performance.
One thing they got very wrong was trying to get good AFR numbers, all the time.
My approach was that on the stand, with no load, the motor should be able to react instantly to full throttle from idle.
The logic being that going into the apex on zero throttle the usual next action is to floor it, with almost zero initial airspeed over the nozzle.
To get this to work the idle circuit must be well over rich and act like an accelerator pump in a 4T would.
This gives instant response off turns, and was a big part of the overall jetting strategy to win going away in the final.

Congrats Wobbly, I have a question though with the rich condition at zero throttle how does the pipe behave as I would have thought the rich mixture strength would exert a cooling effect upon the pipe and as such would slow it down to much ?

[Drew]

TZ, is it possible to simply lower your fuel rail pressure to stop the over fueling?

Rather than trying to make the injectors pulse shorter than they want to like.

[TZ350]

TZ, is it possible to simply lower your fuel rail pressure to stop the over fueling? Rather than trying to make the injectors pulse shorter than they want to like.

That is a good suggestions, thanks, I just might have to incorporate an adjustable fuel regulator.

My problem with the single injector is, that 2ms at 3-5,000rpm becomes way to long at 11-13,000 rpm and the injector needs to fire for more than 360 degrees. Like you suggest controlling the rail pressure might help.

An injector that is on for 2ms at 3k rpm (my idle speed), needs to be on for 8ms at 12k rpm or 576 degrees or 1.6 revolutions to more or less deliver the same amount of fuel per cycle. Not such a big problem for a 4T but a 2T.....

I have 360 degrees or 4.6ms to get everything done at 13,000 rpm. The transfers are open for only 130 degrees or 1.4ms at 13k. 2-3ms injection time means building up a cloud of rich mixture in the transfer duct before the transfers open, but not starting so early that the mixture gets lost in the crankcase leaving the current cycle lean and the following one rich.

Lean - Rich - Lean - Rich - Lean - Rich ...... the right amount of fuel over time but down on power each cycle.

For power, the answer is for each cycle to ingest all the fuel injected each time.

Which makes direct injection such a good idea but how they manage to do it in the very limited (< 1ms or 80 deg @ 14k) time available beats me.

[Drew]

That is a good suggestions, thanks, I just might have to incorporate an adjustable fuel regulator.

My problem with the single injector is, that 2ms at 3-5,000rpm becomes way to long at 11-13,000 rpm and the injector needs to fire for more than 360 degrees. Like you suggest controlling the rail pressure might help.

An injector that is on for 2ms at 3k rpm (my idle speed), needs to be on for 8ms at 12k rpm or 576 degrees or 1.6 revolutions to more or less deliver the same amount of fuel per cycle. Not such a big problem for a 4T but a 2T.....

I have 360 degrees or 4.6ms to get everything done at 13,000 rpm. The transfers are open for only 130 degrees or 1.4ms at 13k. 2-3ms injection time means building up a cloud of rich mixture in the transfer duct, but not starting so early that the mixture gets lost in the crankcase leaving the current cycle lean and the following one rich.

Lean - Rich - Lean - Rich - Lean - Rich ...... the right amount of fuel over time but down on power each cycle.

For power, the answer is for each cycle to ingest all the fuel injected each time.

Which makes direct injection such a good idea but how they manage to do it in the very limited (< 1ms 80 deg @ 14k) time available beats me.

Hmm. Low tech solutions are all my brain are capable of. I envisage a simple diaphragm that operates a needle valve that precedes the standard fuel rail regulator.

A piggy back controller in the injector circuit could be a timing solution. That's all a power commander is, I have one that's called a 'juice box'. It's a 'two brothers' product.

They're programmable separately to the ecu, it would double your range of adjustment. Something to think about anyway.

[wobbly]

The initial tuning run we did with the USA setup, Matt said it simply didnt light up off the slow turns - even though he felt, and the data showed it was way too short geared.
So I calculated to correct gear set ( 1/2 tooth off the rear ) and then set in on re jetting the carb.
On the data it was going to around 1220*F on the top ( though only overeving to 12300 in every gear ) and would drop the egt to 870* on the slow turns.
The AFR showed a lean spot at 15:1 on each gearchange blip ( we were the only people blipping the downchange - I insist its learned as it keeps the kart running straight under heavy trail braking to the apex ) and then
showed another lean spot as the throttle was punched.
With my new + 2 pilot sizes and the air screw at 1-1/2 as it should be , and lifted needle setting it would react flawlessly to full throttle from idle on the stand.
On track there was no lean spot on the blip and the egt only dropped to 820*, so not enough to affect the pipe badly.
From reading the plug and the piston we eventually hit 1280*F and this equated to 12.9 AFR when in the overev at 12600 in 6th gear.
With the new gearing and leaner top it gained 8Km/Hr, making late braking dives down the inside when in the shute to turn 1 way easy.

[Flettner]

Foundry day was successful, 360 cases cast. Need to tidy them up, send off to get heat treated ( CC601 ) to T6. Casting is to suit YZ 250T gearbox. This is the engine that will have the computer controlled throttle via the rotary valve timing gibb ( slide ). Will run on E85. Cases are water cooled via the cavity behind the RV and under the crank case where the engine mount runs. Reverse cylinder and crank rotation.

[TZ350]

This is a great project, please keep posting pictures as the machining progresses.

[TZ350]

Mercury Racing Outboard

6000-Series Arctic Cat 600 C-TEC2: Clean-Technology 2-Stroke Engine

The all-new 600 Clean-Technology 2-Stroke (or "C-TEC2" for short) is the first snowmobile engine designed engineered and produced by Arctic Cat.
It features a bunch of interesting technology like Dual-Stage Injection, unique open-window pistons, electronic oil metering and more, all of which reflects decades of engine design knowledge from the same Arctic Cat engineers who created the laydown engine, Exhaust Pipe Temperature Sensor and batteryless EFI.




Dual-Stage Injection: At lower engine loads, the system injects fuel directly into the combustion chamber, on top of the piston. At higher engine loads fuel is also injected into the crankcase area and into the transfer ports, improving the fuel/air transfer time for added efficiency while also lubricating vital engine components



Slotted Piston: The unique open-window/slotted piston design allows fuel/oil mix to be injected into the crankcase area and then into the transfer ports as part of the Dual-Stage Injection design. Key to this design is the injection of fuel (with oil) at the piston rod bearing.



Fuel Injectors: Lightweight, low pressure Dual-Stage injectors feed fuel into both the combustion chamber, crankcase, and cylinder ports through the cylinder wall. Integrated with EPTS and APV exhaust valves, this clean-burning design helps the C-TEC2 600 achieve Tier III EPA regulations. The cylinder-mounted fuel injectors are supplied with 58-psi fuel pressure and are controlled by the fuel management system using variable injection timing and duration.

Electric Oil Pump: Controlled by the engine management system, an electric oil pump delivers the precise oil requirements, from engine idle to full-throttle, adjusting oil consumption from sea level to high altitude. Oil is injected into the air intake flanges and the fuel rail for full engine lubrication including the pistons.
Fuel oil ratios can be as high as 65:1 depending on load, which is why the C-TEC2 uses so little oil (and why the engine requires the oil formulated specifically for it).

Oil & Fuel Mix in the Rail: For maximum bearing life,a small amount of oil is delivered to the fuel rail and mixed with the fuel prior to injection. When the fuel is injected and travels through the piston skirt slot, the piston pin bearing receives added lubrication to ensure optimal bearing life even in the most extreme situations.
This is another key difference from high-pressure DI systems which require a return fuel loop back into the fuel tank, thus preventing oil from being injected into the rail (instead, oil is injected directly into the engine). The lack of oil lubrication via the fuel spray is a huge challenge for other systems.

Knock Sensor: An engine knock sensor detects detonation due to fuel octane, quality and/or ethanol content. Based on information from the knock sensor, the engine management system adjusts ignition timing and fuel delivery for optimum performance and combustion. If fuel quality is such that the combination of reduced engine timing and a richer fuel/air mixture can’t prevent detonation, the engine goes into safe mode until fuel quality improves. The engine is designed for 91 octane fuel.

Air-Only Throttle Bodies: Two 47-mm new-generation throttle bodies flow air into the crankcase. In addition to flowing only air (and not fuel), these throttle bodies are shorter and lighter than those used with previous engines.

[TZ350]

Air Assisted Direct Injection Combustion System. Orbital Australia Pty. Ltd., based out of Perth, Western Australia, developed their Orbital Combustion Process that is based around their highly patented Air Assisted Direct Injection, also referred to as AADI. These injectors are similar to current fuel injectors in terms of operating pressure but also utilize compressed air (supplied by an air compressor) to further atomize the fuel, preparing it for the combustion process. This air-assist atomizes the fuel droplets down to 6-10 micron SMD, which is the industry benchmark. (SMD = Sauter mean diameter: a way of comparing the atomization performance of different injectors).





A cross section of an Orbital/Synerject Air Assisted Direct Fuel Injector.

This technology is utilized by a host of Orbital licensees such as Aprilia’s DiTech engines, Mercury Marine’s OptiMax outboards, and Tohatsu’s TLDI outboards, which are all gasoline two-stroke applications. The application of this AADI to two-stroke engines changes the emissions and fuel consumption of these engines dramatically in a positive way. In fact, fuel consumption drops some 40 percent (giving parity with four-strokes) and emissions drop in the order of 80 percent over a carbureted two-stroke. This is not only due in part to the direct injection, but the fact that the injection only occurs after both intake and exhaust ports are covered by the piston, therefore, not allowing any raw air/fuel mixture to escape out of the exhaust port as it would have in a carbureted two-stroke.

Another key technology that the Hirth heavy fuel engines employs in these innovative engines is the use of carbon (graphite) pistons. These pistons have thermal expansion that is virtually nil and allow piston-to-cylinder wall clearances of 0.0005 compared with a typical 0.005 for aluminum pistons. The composite unit utilizes two piston rings, with the design intent of being utilized for centering purposes only. While being shown this remarkable piece of engineering, Jason Wright of Recreational Power Engineering www.RecPower.com, U.S. distributor of Hirth-Engines as well as Powerfin Propellers, demonstrated that by dragging the skirt of the piston across a piece of paper, it left a mark just like a pencil!

[chrisc]

"The factory team"

Those nights working on the EFI 2T catching up with you Rob?