A New Concept of Diesel Combustion by P. H. Schweitzer, Automotive Industries, June 15, 1956. describes the patent 1692107 Nov., 1928 Archaouloff is the first direct injection patent. It describes a combustion chamber injector for a diesel engine.

I understand an M5 is a spark design. The point is the pluses of modern diesels are appearing in gas engines.

I was wrong on the on the M5 throttle. I'll refran from using Road and Track as a technical source in the future.

My 1997 Powerstroke F350 has CDI. They cost $220 a pop, plus O-rings and seals. They are a b?tch to change. That is my second diesel vehicle.
I

 

My dad sent me this URL: http://www.bmwworld.com/engines/valvetronic.htm

The test is as follows:
The 316ti compact is the first production car in the world featuring an engine controlled by a Valvetronic air supply.

Accordingly, the Valvetronic engine no longer requires a throttle butterfly, which has quite literally restricted the free ventilation of the internal combustion engine ever since its invention. Now Valvetronic replaces this conventional function by infinitely variable intake valve lift, offering a quantum leap in technology quite comparable to the changeover from the carburetor to fuel injection. And at the same time clearly proves the outstanding competence and innovative power of BMW’s engineers, Valvetronic going back to a BMW patent and manufactured exclusively on BMW’s own machines and facilities.

Be sure and notice the phrase "the Valvetronic engine no longer requires a throttle butterfly".

Enjoy ACE.

 

opps that should be "text" vs "test".

 

You are right and wrong all at the same time. The M5's V10 is a gasoline motor, and as such will ALWAYS be throttled. Yes, the M5 DOES NOT have a thorttle butterfly, but the lift on the intake valves THEMSELVES is what throttles the amount of air entering the combustion chamber. When the car is, say, idling there's very little lift on the intake valves and thus very little charge is allowed into the cylinder. Basically they just took away the big throttle valve that sat infront of the entire engine and made each and every intake valve a "throttle butterfly."

 

It can be good, but at least in the past (think Chrysler) VTN was just more complication than benefit. It's just more practical in the diesel world.

Dave

 

And that valve timing acts as a throttle. You can't just carry over diesel technology wholesale to a gasoline engine, the whole combustion process is different. As long as your technology is based on igniting a roughly uniform fuel-air mixture you're going to have to live with certain constraints. One of them is mixture strength and that means some kind of throttling at low load. In the past there have been attempts at "lean burn" and "stratified charge" designs. They didn't work very well. Diesel-like direct injection is promising, though. But that's still targeted at low-load operation. High-load won't change a whole lot.

Consider that at WOT your injectors are operating at 90%+ duty cycle -- they're spraying gas into the runners during intake, compression, power, and exhaust. Now how's that going to work with GDI? You'll need larger injectors because you'll only have intake and compression to work with. By the time injection is finished at the end of compression what do you have in the cylinder? A roughly uniform air-fuel mixture that'll have similar octane requirements as today's port fuel injection systems. As W would say, "engineering is HARD!"

Back on topic, lean-burn GDI does have some of the advantages of diesel and technology like VNT can be useful. But you have to weigh what kind of benefit you'll get for the investment and complexity you put in. So far you get a better return focusing your work elsewhere.

Dave

 

the cost and complexity is what is probleatic. but if they were to go down gdi would be very good with two injectors per cylinder... then you could basically have everything, just turn on the other injector in high load, you get hte atomization you get the clean burn, you get low end low load accuracy with low pulse widths and you can have the high end high capacity with equally short widths. you'd prolly have to worry a lil about rejoining particles but that's such a minimum concern when you're at wide open throttle and such, you're never gonna get max efficiency there.

 

Back to the topic of variable turbo nozzle size: I kinda think of it like this: The 2003 EVO's have the 9.8 exhaust housing. The newer ones have the 10.5 housing. The smaller makes for faster spooling but chokes on the top-end. The larger housing makes for slower spooling but makes more power on the top-end. A variable nozzle on the exhaust housing could be like a 8.5 housing but varies to a 11.5 housing, in a linear fashion according to load and RPM's. This is not actually an accurate anology but the effect would be similar...