No more 5 cylinders from Volvo

[dme123]

Quite a few large engines have cylinder deactivation now - under light load it can close the valves on some cylinders and keep them closed. The air in the cylinder acts as a spring as it is compressed and expands in the cylinder. GM first did this with the infamous V8-6-4 in the early 80s, but it had serious reliability issues due to the immaturity of the technology - more down to control systems than anything I believe.

The problem with a turbocharged engine running without the turbo is that the compression ratio of the engine is usually very low, so they are very sluggish and inefficient with no boost. Might work better with a LPT. You also have the turbo in the way of the air inlet and restricting breathing even when it's not spinning. The plumbing to take a turbo in and out of circuit would be untidy and complicated. More likely to work with a supercharger and two inlet tracts maybe - boosted and unboosted?

The future of efficient IC engines seems to lie with camless designs - valves activated by solenoids and hydraulics or some other system. Valve by valve infinite control of timing and lift and the removal of the rotating mass and friction of the camshafts. There is a lot of valvegear in a modern engine, maintenance could be much easier in a camless design.

[Naciremus]

Hmm who knows.

[jackd]

Devastated to hear about the loss of the 5 cylinder. To me four cylinders sound flat and dull - even high revving ones. I always thought there was a startling similarity between the sound of a V10 and a 5 Cylinder, for obvious mechanical reasons. 3 Cylinders do interest me also. They have much a more characterful sound than a four cylinder drone. In diesels the difference is more apparent. Nobody would say a four cylinder diesel sounds good. But D5s sound great. Same goes for V6 and Inline 6 diesels. A much more pleasing note to live with every day. My Girlfriend who knows nothing about cars at all thinks my 2.4T C70 five cylinder sounds like a "proper sports car" and I would tend to agree with her, even if it isn't! Please hold onto the 5 cylinder Volvo! For me it's and integral part of the brand!

[AndyPants]

I think it sucks that Volvo are giving up on five cylinders after all this time. I already think that most modern Volvos have lost a lot of character and getting rid of the fifth cylinder is another nail in the coffin Boooooo!!!

[850Chris]

Originally Posted by AndyPants

I think it sucks that Volvo are giving up on five cylinders after all this time. I already think that most modern Volvos have lost a lot of character and getting rid of the fifth cylinder is another nail in the coffin Boooooo!!!

Here, Here!!

[Spike1918]

I don`t know why rotary valves are not being bought into play by mainstream manufacturers, less reciprocating mass and modern materials means not only weight savings but increased reliability, cheaper manufacturing techniques, longer service intervals and even less parts to replace when wear occurs.
For interest:

http://www.coatesengine.com/csrv-advantages.html

Oh and five cylinder engines? In a word, SMOOTH!

[johnjp]

How about the nat. gas csrv in a 940!

[Spike1918]

Ah well you have me there, I didn`t know about that one. Any images or technical details available here?

[johnjp]

http://www.coatesengine.com/natural-gas-generator.html

[Spike1918]

Hahahaha, I see what you mean now.