How do car manufacturers decide on engine configurations?

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Mysticf1
Mysticf1
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Re: How do car manufacturers decide on engine configurations?

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yep thats the one autogyro...saw a doco series called "planes that never flew" all about it...very interesting show and seemed a promising design.

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: How do car manufacturers decide on engine configurations?

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F1 with KERS is a dual power plant design of course, as are hybrid road vehicles.
I see that Rover and Jaguar are going to use a small turbine engine to charge the batteries in their EVs as well.
IC lovers had better start taking notice.

Richard
Richard
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Re: How do car manufacturers decide on engine configurations?

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So back to OP

It can't all be about least manufacturing cost for mass production, because manufacturers have introduced technologies that are harder to build such as fuel injection and variable valves. Otherwise people would still be making cars with low compression, push rods and carburettors.

.... hang on a second .... maybe someone should tell GM ;)

DaveKillens
DaveKillens
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Joined: 20 Jan 2005, 04:02

Re: How do car manufacturers decide on engine configurations?

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richard_leeds wrote:So back to OP

It can't all be about least manufacturing cost for mass production, because manufacturers have introduced technologies that are harder to build such as fuel injection and variable valves. Otherwise people would still be making cars with low compression, push rods and carburettors.

.... hang on a second .... maybe someone should tell GM ;)
Exactly. Auto manufacturers spend a lot of money on jigs and tools to construct components, and they seek to maximize the return. But pressures from competition and regulations push the companies into developing new technologies, and this requires spending money. Of course, GM was too slow in hanging on to long, and were late to the game in many important areas.

For instance, when the US EPA mandated engines required 100,000 miles without any major tuneup yet remain withing emissions standards, everyone had to go back to the drawing board. One example is that ring life is critical to maintain emission standards, and thus cylinder walls hade to be stiffer.

FYI autogyro, there's a 163 in the Canadian War Museum at Ottawa. And yes, as a point defence interceptor, it's tightly focused design was immaculate. And unlike the Hunter, both the Komet and Lightning were not capable of adaptation,and spent their lives only in this role. That's not a bad thing, because it shows that the design teams stuck to the original requirements and resisted any compromises.

I like your taste in aircraft, autogyro
Racing should be decided on the track, not the court room.

xpensive
xpensive
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Re: How do car manufacturers decide on engine configurations?

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But none of those could hold a candle to the ME262. :wink:
"I spent most of my money on wine and women...I wasted the rest"

xpensive
xpensive
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Joined: 22 Nov 2008, 18:06
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Re: How do car manufacturers decide on engine configurations?

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xpensive wrote:The ME262 with its BMW engines was way ahead of its time and could, if properly used as a fighter, have had a serioius impact.

On topic; When Porsche release the 3.0 I-4, it had the same power 240 Hp, as the 4.5 V8 had when presented in the 70s. Think about it.
Within reasonable displacements and rpm, there's really no reson to go multicylinder, is it?
"I spent most of my money on wine and women...I wasted the rest"

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: How do car manufacturers decide on engine configurations?

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Pre production and production ME262s were fitted with the Junkers Jumo 004 turbojet engine.
It was only the prototypes that used the BMW 003 engine.

Demands for fuel saving and efficiency will force lower road car engine capacity and reduced friction and number of moving components.

Richard
Richard
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Joined: 15 Apr 2009, 14:41
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Re: How do car manufacturers decide on engine configurations?

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I've just been reminded that Volvo run 5 cylinder engines. Seems a bit counter intuative.

4 cylinders is the minimum for a smooth ride in a 4 stroke engine.
6 cylinders is essentially 2 banks of 3 that balance each other.

So why 5 cylinders? Presumably more expensive manufacturing than 4 cylinders, without the smoothness and power of 6?

Also, regarding manufacturing costs, I'd have thought there will be a cost penalty for Volvo due to low volumes, compared using a 4 cylinder engine as used by the rest of the Ford Europe?

Richard
Richard
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Joined: 15 Apr 2009, 14:41
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Re: How do car manufacturers decide on engine configurations?

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Further to the above ... wiki has a good write up. http://en.wikipedia.org/wiki/Straight-five_engine

5 cylinders means there is slight overlap in the piston firing, but there are more out of balance vibrations compared to even numbered cylinders. The increase in power from the overlap firing strokes is deemed to be of greater benefit than the cost of balancing the vibrations.

Also, the same added power of adding a 6th cylinder is not in proportion to the cost of the extra cylinder.

Interesting that 5 cylinder engines are dominated by diesel engines. Is that simply because current engine investment is focussed on diesel generally? Or does a diesel work better in a straight 5 compared to 4?

xpensive
xpensive
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Joined: 22 Nov 2008, 18:06
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Re: How do car manufacturers decide on engine configurations?

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Volvo have had the I-5 for many years, but I believe that Audi pioneered the concept in the 70s. For a long time, designs like I-5s and V-10s were considered a taboo for balancing reasons, but I think the computer-age changed all that in the 80s, still a straight six is the far and away most naturally balanced, though the induction frequency gives it an equally poor low-down torque.

http://en.wikipedia.org/wiki/Straight-six_engine

http://en.wikipedia.org/wiki/Straight-five_engine
"I spent most of my money on wine and women...I wasted the rest"

Edis
Edis
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Re: How do car manufacturers decide on engine configurations

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richard_leeds wrote:I've just been reminded that Volvo run 5 cylinder engines. Seems a bit counter intuative.

4 cylinders is the minimum for a smooth ride in a 4 stroke engine.
6 cylinders is essentially 2 banks of 3 that balance each other.

So why 5 cylinders? Presumably more expensive manufacturing than 4 cylinders, without the smoothness and power of 6?

Also, regarding manufacturing costs, I'd have thought there will be a cost penalty for Volvo due to low volumes, compared using a 4 cylinder engine as used by the rest of the Ford Europe?
Volvos five cylinder engine is part of Volvos modular engine family and it was developed during the 1980'ties and introduced early in the 1990'ties when Volvo PV was owned by the Volvo group, not Ford. It was made in four, five and six cylinder versions with a few different cylinder sizes by adjusting the bore and stroke slightly. It was designed to have a small bore centers and a long stroke to make it compact.

The six cylinder engine was the first to go into production, and it was first used in Volvo 960. It was also used in transverse installations later but this was only possible in larger models due to the length of the engine.

A five cylinder engine is reasonably vibration free since there are no free forces of either first or second order. Like the three cylinder engine it does however have free moments of both the first and second order. Larger five cylinder engines therefore tend to use balancershafts, much like three cylinder engines.

A paper about the development of the Volvo engine can be found here: http://www.volvoclub.org.uk/tech/850GLT ... chInfo.pdf

rjsa
rjsa
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Re: How do car manufacturers decide on engine configurations

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richard_leeds wrote:Further to the above ... wiki has a good write up. http://en.wikipedia.org/wiki/Straight-five_engine

5 cylinders means there is slight overlap in the piston firing, but there are more out of balance vibrations compared to even numbered cylinders. The increase in power from the overlap firing strokes is deemed to be of greater benefit than the cost of balancing the vibrations.

Also, the same added power of adding a 6th cylinder is not in proportion to the cost of the extra cylinder.

Interesting that 5 cylinder engines are dominated by diesel engines. Is that simply because current engine investment is focussed on diesel generally? Or does a diesel work better in a straight 5 compared to 4?


I drove a fiat Marea that was pushed by a 5 cylinder 2.4L for 8 years, and sold it with lots of pain. It sang beautifully. Now I drive a chocked 4 clinder 2.3L Ford Fusion.

EDIT:Worth mentioning, the stick shift 170HP Marea did around 8Km/l and I can barely get 6Km/l with the hydramatic 160HP Fusion.

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scotty86
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Joined: 04 Dec 2010, 17:03

Re: How do car manufacturers decide on engine configurations

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To answer the original question "how do car manufacturers decide on engine configurations?", i think it is far more simple than has been alluded to in this thread.

Here are my thoughts: initially, manufacturers simply begin development based on past configurations (a sensible place to start for someone who, for the sake of discussion, we are assuming knows absolutely nothing). This then gives them a range of engines, L4's, V6's, turbo diesel engines, and so on. From here, they simply place the appropriate engine in the right car based on costs, performance, etc. Car manufacture is merely a business based around engineering after all...