Ditch The 3 Cylinder?

[outsydthebox]

Yeah. I'm still "technically" right though. Assume firing at 20°Btdc. It will fire at 220° (first rotation) then 100 and 340 on the second.

I'm not sure that you are, but I am sure it will run smoothly.

 

[carzes]

Not exactly. Remember this is a 4 stroke engine. A 3 fires 2 in one revolution, 1 in the next.

There are ways to smooth em out, but they're not an inherently balanced design.

I did a littl3 research and it seems all the designs I find fire one of the three cylinders at every 240 degrees of rotation versus at 180 degrees for a four cylinder. Little bit longer spacing between sparks but still evenly distributed. They will need 3 coils (unless they intend to use a distributer), since they can't take advantage of having one cylinder on the power stroke and one on the exhaust stroke simultaneously like on a four cylinder. But since a lower percentage of the moving mass is at the same point of rotation at any given time I can't see why it should be inherently more vibration prone. Or maybe I'm misunderstanding something here

 

[CrimsonEclipse]

Even with an older Metro, vibration wasn't really a problem.
My biggest problem is that the A/C compressor would kick in at low RPM destroying an already low acceleration.

 

[Ty]

Your welcome. Speaking of cross dressers, I hear they know how to have a good time. They eat drink and be Mary.

LOL. Well played, sir.

 

[Umaxen]

3 cylinder motor? My friends 1986 Suzuki Swift is a 1 liter, 3 cylinder with 5 speed manual. 30 years old with 259,000 miles and it still gets 54 mpg at a steady 55 mph.

 

[goofyone]

3 cylinder motor? My friends 1986 Suzuki Swift is a 1 liter, 3 cylinder with 5 speed manual. 30 years old with 259,000 miles and it still gets 54 mpg at a steady 55 mph.

The Suzuki three cylinder engine is actually the basis for this new motor. Elio and IAV basically started their design process with that engine and updated it to take advantage of modern engineering and materials to make it lighter and more fuel efficient.

 

[Umaxen]

Like I have posted before, go to EBay and look up either Suzuki Swift or Geo Metro (both came with models of this 1 liter, 3 cylinder engine) Look at the total miles those cars have been driven! I have seen one on EBAY with over 375,000 miles ! Not bad for an engine that probable only weighs 150 pounds and some of which are over 30 years old. In the late 80's, I remember driving a Suzuki Swift in Eastern Europe. With 4 people sitting in that tiny car, I could effortlessly drive 75 mph for over 5000 miles and, even though being overloaded, still was able to manage around 47 mpg on the freeway. When driving alone at 60 mph, the car would get CRAZY mileage, around 55 mpg...

 

[Lil4X]

Even with an older Metro, vibration wasn't really a problem.
My biggest problem is that the A/C compressor would kick in at low RPM destroying an already low acceleration.

I'm sure with modern electronics there are better ways to control the compressor clutch, but my old Opel did it with a simple vacuum diaphragm switch. Open the throttle and vacuum falls to near zero, allowing a spring-loaded diaphragm to open a microswitch that opens the circuit to the electromagnetic clutch on the compressor. The compressor pulley freewheels until you begin to back off the throttle, at which point as vacuum returns, the switch closes again, engaging the clutch. It was a simple, foolproof, and extremely effective way to disconnect the parasitic load of the compressor when you really needed all the power you could get for maximum acceleration.

In the cabin, you never missed the eight or ten seconds of AC.

 

[Critter]

I'm sure with modern electronics there are better ways to control the compressor clutch, but my old Opel did it with a simple vacuum diaphragm switch. Open the throttle and vacuum falls to near zero, allowing a spring-loaded diaphragm to open a microswitch that opens the circuit to the electromagnetic clutch on the compressor. The compressor pulley freewheels until you begin to back off the throttle, at which point as vacuum returns, the switch closes again, engaging the clutch. It was a simple, foolproof, and extremely effective way to disconnect the parasitic load of the compressor when you really needed all the power you could get for maximum acceleration.

In the cabin, you never missed the eight or ten seconds of AC.

The Saturn I had was similar, the AC clicked off during acceleration. Found out when I went back to the dealer to complain. It was very obvious when climbing our hills around here.

 

[Aviator]

Even with an older Metro, vibration wasn't really a problem.
My biggest problem is that the A/C compressor would kick in at low RPM destroying an already low acceleration.

The A/C clutch randomly kicking on and off brings up a good point on power needs. I now drive a car with plenty of power and a 5 speed. There is still a noticeable difference in the power to the wheels when accelerating. The air conditioner pump on my current car I would guess robs around 15hp from the engine when on. When cruising on the highway this is unnoticeable but when pulling out from a light I feel the difference.

I have owned a car that had a good feature with the A/C. Any time the accelerator petal was pushed over 50% the A/C automatically turned off until the gas petal was under 50% then it turned back on. Great feature but I have only seen it on my old V8 that didn't need it. All my other cars I manually turn off the ac before I know I will want the extra few horsepower then turn it back on later.

My current car with a 5 speed when pulling out from a stop if the compressor kicks in at the same time I feel dumb at times "like I just dumped the clutch and almost stalled the car." I do not understand why they are designed to slam on so fast and with out notice. I believe there is no wearable parts involved in the A/C clutch just a magnetic field that locks them together. Seems a controlled power to the clutch over a few seconds would smooth this out. My car actually hits so hard the belt chirps when turning on. I have installed a new belt and worried if I tension it any tighter that I will overload bearings and cause damage. So I live with the chirping.

On more problem I have found with ac. When driving a manual transmission I sometimes don't use the clutch at all when shifting. When upshifting I go to neutral and wait for the rpm's to drop then pop it into the next gear. Downshifting I do a rev match in neutral then take the lower gear. If the ac kicks in during this the expected rpm's drop and I have banged a few teeth in the gear box. Nothing that would hurt the gear box but still don't like the sound of it or the unsmooth lunge of missing 3 to 5 teeth and banging into gear.