Cars!

You also see a lot of BMWs sticking out of hedges.
Parked in disabled parking places.
Preciously parked across two car parking spaces.
2 inches off my back bumper as I go slower and slower...
etc
etc
If ever we need to cull the human race.. well BMW drivers do tick a lot of the boxes
Note : this does exclude MINI drivers - 'cos we have one

 

What make of car is Industry Average?

 

The problem with 3 cylinder engines is that you do not have a continuous power stroke. To achieve that in a four stroke engine you need at least 4 pistons so one unit is always on the power stroke.
360 degrees 4 pistons one at every 90 degrees. (better with 5 pistons or more)
With three pistons one every 120 degrees you have 30 degrees between each power stroke when the pistons are not driving the engine hence you have created a problem, (several actually) you now have balance problems and power output problems.
To overcome the power output problems they usually stick an extra large flywheel to keep the plant turning. The problem with this is you now have osculating power one moment the engine is driving the flywheel the next the flywheel is driving the engine causing very small slow down and speed ups three times every revolution putting huge strain on the clutch and causing vibration.
With three cylinders the engine crankshaft as with all other components are suffering these osculating forces causing vibration, the running face of the bottom end bearings start getting hammered due to this change of load. So then we get into the issue of balance weights and shafts in the engine to overcome this. Why would you engineer problems into an engine then have to spend time and money trying to overcome this. I have heard the argument less pistons less friction less inertia but I do not think that stands up. It is cheaper to stick a big flywheel in than have a fourth cylinder. It only makes sense to the manufacturer less engineering more profit.

RegardsSandy

 

My take on three cylinder engines:

First off, they have been around for donkeys years. As two strokes (pre war DKW motorcycles, Kawasaki, SAAB) As two stroke diesels (Detroit) Four stroke diesels (Perkins) as well as four stroke motorcycles and cars.

As regards power output. Look at the success DKW, Triumph, Kawasaki, SAAB had with them. They regularly beat things with more cylinders on the track.

Although balance problems do exist, many manufacturers are moving over to them, and for some good reasons:

1) They reduce vehicle weight. That improves both handling, and braking.

2) They have less parts. That makes then both cheaper to produce, and cheaper to repair.

3) They are physically smaller. That can be used to improve vehicle safety.

4) Built correctly, the can deliver very similar mileage to diesels.

5) Emissions can be severely reduced. The (newish) Volvo one for example, is down to 80g from a 150bhp engine...

Most of the problems traditionally associated with triples have now been solved by engineers. For example, Ford have solved the balance question by using a flywheel and harmonic crank pulley. Thats the same way they balanced their V8's 50 or 60 years ago!

Theres only one problem with them. Its the way they are perceived. V8's (my favourite) or V12's, even straight 6's are better than straight 4's, but nobody ever seems to say so.

 

I've allways like the 6's and 8's better than the 4's, hate the 4's with big trubo's in which to get the same hp as the 6's

 

@JWK in that case, you may remember the most famous Trident of them all, the one known as "Slippery Sam"???

 

Engines have been made with 3 , 4 , 6 , 8 etc cylinders. The one that causes problems is a 5 cylinder, getting a balanced firing pattern is difficult . I know Audi developed one ,but not sure of other manufacturers.

 

Better not mention the Honda RC149 that @HarryS just reminded me of...a 5 cylinder 125cc four stroke.

Several manufacturers have used 5's. Volvo might be the best known. @longk will be able to confirm or deny this, but I'm sure Mercedes had a 5 cylinder diesel for a time.

 

I have a 2009 Smart ForTwo and that's as modern as I want to get. 2004 Merc 270cdi - that's got CAN-BUS. Hopefully I'll get my '82 Merc 280SL finished this year - proper Merc!