Electric Supercharger to replace exhaust turbocharger?

JohnWilder

Veteran Member
Joined
Jul 13, 2013
Location
Breckenridge, TX
TDI
2003 Jetta 5 spd manual
Just looked at the ecotech engine, and see that it works on the 2 cycle principle, which is also what the Wankel engine worked on and why no one makes them anymore that I'm aware of. I'm not an engineer, but from the cutaway drawing provided in the article it looks like something that would attract folks who don't understand how engines work. It doesn't matter how much money a person has if they don't have a basic understanding of how an engine works. Two pistons in each cylinder and only one attached to the crankshaft? Sounds great but what do the "free" pistons do?
I love ring dings, had quite a few motorcycles with engines of that design, and still have some yard equipment. The EPA doesn't like two strokes even more than they don't like diesels, and likely for better reasons. If this is a piston port design which is what it looks like it's about as ecological as pouring crude oil on coal, and lighting it off at atmospheric pressure out in the back yard. To get by the EPA it'd need more pollution control equipment than the local coal fired power plant.[/QUOTE]
Actually, the Wankel is a 4 stoke engine. The problem with the Wankel is sliding seals. Sliding seals have been the weak point in many designs. Piston rings are sliding seals. However if you can keep the speed below about 3200 ft/min they will live very well. In a 4 stroke system then are very well lubricated also. The tips seals of the Wankel is it's problem. The shape of the chamber has a much higher surface area to volume ratio than in a piston engine. As such the cooling loses are much higher. As such they get poor fuel economy.
 

robnitro

Veteran Member
Joined
Jan 19, 2004
Location
NYC area, NY
TDI
2001 Jetta TDI GLS silver
If you take a look at the 120A alternator at approx 14v, the max power you can do is
120 x 14 = 1680w. 746 w per hp, so pretty much MAX 2 hp from the alternator.

What electric boosted turbos help in, is at low rpm, where you don't need too much power to compress the air (function of work of compressor= pressure x flow), but to help out the weak exhaust pressure.

Perhaps also with the battery, you can surge past 2 hp of energy for a short time to spool the turbo quickly.
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
Just looked at the ecotech engine, and see that it works on the 2 cycle principle, which is also what the Wankel engine worked on and why no one makes them anymore that I'm aware of. I'm not an engineer, but from the cutaway drawing provided in the article it looks like something that would attract folks who don't understand how engines work. It doesn't matter how much money a person has if they don't have a basic understanding of how an engine works. Two pistons in each cylinder and only one attached to the crankshaft? Sounds great but what do the "free" pistons do?
I love ring dings, had quite a few motorcycles with engines of that design, and still have some yard equipment. The EPA doesn't like two strokes even more than they don't like diesels, and likely for better reasons. If this is a piston port design which is what it looks like it's about as ecological as pouring crude oil on coal, and lighting it off at atmospheric pressure out in the back yard. To get by the EPA it'd need more pollution control equipment than the local coal fired power plant.
Actually, the Wankel is a 4 stoke engine. The problem with the Wankel is sliding seals. Sliding seals have been the weak point in many designs. Piston rings are sliding seals. However if you can keep the speed below about 3200 ft/min they will live very well. In a 4 stroke system then are very well lubricated also. The tips seals of the Wankel is it's problem. The shape of the chamber has a much higher surface area to volume ratio than in a piston engine. As such the cooling loses are much higher. As such they get poor fuel economy.[/QUOTE]

The quoting is messed up ... this was LarBear's original message that JohnWilder replied to. To further that ...

"Ecomotors" is the company proposing the opposed-piston two-stroke engine. "Ecotec" (note spelling) is GM's name for their recent conventional-nowadays 4-stroke engines.

Wankel engines are "piston ported" but they are 4-stroke.

Both pistons in the Ecomotors design are attached to the crankshaft. The outer one uses a long set of connecting rods outside the cylinder.

I will grant that the Ecomotors engine is substantially more efficient, and should have substantially lower emissions, than traditional carbureted piston-ported two-strokes. Reason: Scavenging is done with air only, and fuel injection happens after the ports close (or so close to port closure that there is not time for the raw fuel to escape the cylinder). But ... This can also be done with two-stroke engines of the more conventional layout, and it IS done. Evinrude "E-Tec" outboard motors and various snowmobiles produced by Bombardier (who own Evinrude!) use direct-injection two-stroke engines. They use much less fuel and have much lower emissions than the conventional (premixed air and fuel, whether carb or outside-the-cylinder fuel injection) two-strokes that they replaced. BUT ... The emissions are not low enough to comply with automotive emission standards. To my knowledge, in terms of efficiency and emissions, the Ecomotors engine doesn't bring anything to the table that a BRP E-tec snowmobile/outboard motor engine of conventional (for a two-stroke) layout doesn't already have.

BRP is the same company that builds the Can-Am Spyder three-wheeler, a road vehicle. Guess what ... conventional 4-stroke engine with fuel injection and 3-way catalyst in those ... Not a two-stroke E-Tec!
 

nicklockard

Torque Dorque
Joined
Aug 15, 2004
Location
Arizona
TDI
SOLD 2010 Touareg Tdi w/factory Tow PCKG
Thanks, maybe being an antique has some advantages.

Just looked at the ecotech engine, and see that it works on the 2 cycle principle, which is also what the Wankel engine worked on and why no one makes them anymore that I'm aware of. I'm not an engineer, but from the cutaway drawing provided in the article it looks like something that would attract folks who don't understand how engines work. It doesn't matter how much money a person has if they don't have a basic understanding of how an engine works. Two pistons in each cylinder and only one attached to the crankshaft? Sounds great but what do the "free" pistons do?
What free piston? All 4 pistons are attached to the crank. The two outer ones by pull rods, and the innner ones by push rods.
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
I think sooner rather than later we'll see a 4-cylinder TDI from the factory making over 230 HP with one large exhaust turbo charger to support the full rated output of the engine and an electric compressor to eliminate lag completely and allow for peak torque from about 1250 RPM. That would be awesome.
Timely.

VW Shows 272PS 2.0-liter TDI Diesel With Electric Supercharger Boost

More: https://news.google.com/news/rtc?nc...=0&siidp=1086582d82a482931666ee3e9dda49ed3708
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
VW used to rebadge a Toyota (HiLux) truck in certain markets and called it the Taro. Maybe this engine in a Tacoma? :)

 
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