Difference between revisions of "Flat-4"

Revision as of 13:06, 31 March 2006

A flat-4 is a four cylinder internal combustion engine where the cylinders are arranged in a flat configuration. As of today Flat-4 engines are boxer engine, also known as a horizontally opposed engine, in which the corresponding pistons reach top dead centre simultaneously, thus balancing each other with respect to momentum. Flat engines with four or fewer cylinders are most commonly boxer engines. This is not a common configuration, but some brands of automobile have favored such engines and it is a common configuration for smaller aircraft engines such as made by Lycoming or Continental. Although they are considered to be superior to

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-A '''flat-4''' is a four cylinder [[internal combustion engine]] where the cylinders are arranged in a [[flat engine|flat configuration]].  As of today Flat-4 engines are '''boxer engine''', also known as a '''horizontally opposed engine''', in which the corresponding pistons reach [[top dead centre]] simultaneously, thus balancing each other with respect to momentum. Flat engines with four or fewer cylinders are most commonly boxer engines.
+A '''flat-4''' is a four cylinder [[internal combustion engine]] where the cylinders are arranged in a [[flat engine|flat configuration]].  As of today Flat-4 engines are '''boxer engine''', also known as a '''horizontally opposed engine''', in which the corresponding pistons reach [[top dead centre]] simultaneously, thus balancing each other with respect to momentum. Flat engines with four or fewer cylinders are most commonly boxer engines.  This is not a common configuration, but some brands of [[automobile]] have favored such engines and it is a common configuration for smaller [[aircraft engine]]s such as made by [[Lycoming]] or [[Continental Motors|Continental]].  Although they are considered to be superior to
-This is not a common configuration, but some brands of [[automobile]] have favored such engines and it is a common configuration for smaller [[aircraft engine]]s such as made by [[Lycoming]] or [[Continental Motors|Continental]].  Although they are considered to be superior to "inline-fours" in terms of vibrations, they have largely fallen out of favor because they have two cylinder banks thus requiring twice more camshaft than a straight-4 while the crankshaft is as complex to  manufacture. The low [[center of gravity]] of the engine is an advantage. The shape of the engine suits it better for [[mid engine]] or [[rear engine]] designs. With a rear engine body it allows a low-tail body while in [[front engine]] designs the width or the engine will interferes with the ability of the front wheels to steer.
-The open and exposed design of the engine allows air cooling over water cooling, and in air cooled applications fins are often seen machined into the external cylinder block walls.
-==Automobile use==
-[[Image:1955 Porsche 550 Spyder engine.jpg|right|thumb|250px|Flat-4 engine in a 1955 [[Porsche 550 Spyder]]]]
-[[Volkswagen]] used air-cooled flat-4s extensively in their early days, in the [[VW Beetle]] and most early VW designs.  [[Porsche]] also used the VW engine in the early [[Porsche 356]]. This engine was replaced by a Porsche designed flat-4 in the late 356s and the [[Porsche 912|912]]. The [[Porsche 914|914]] that replaced the 912 was built in partnership with VW using a VW engine.  VW used a water-cooled flat-4 in the [[Volkswagen Type 2 (T3)|T3]] until 1991.
-[[Citroën]] used an air-cooled flat-4 on the [[Citroën Ami|Ami Super]], [[Citroën GS|GS]], [[Citroën GS|GSA]] and [[Citroën Axel|Axel]].
-[[Alfa Romeo]] introduced a water cooled flat-4 on the [[Alfa Romeo Alfasud]]. That engine was later used on the [[Alfa Romeo Arna]], the [[Alfa Romeo 33]], the [[Alfa Romeo Sprint]], the [[Alfa Romeo 145|Alfa Romeo 145/146]].
-[[Lancia]] also used a water cooled flat-4 on the high-end [[Lancia Gamma]].
-[[Subaru]] produces water-cooled front mounted flat-4 engines marketed as H-4, by which they mean '''H'''orizontal rather than the H cross-section normally meant by [[H engine]].
-==Motorcycle use==
-[[Honda]] introduced water cooled flat-4 on the [[Honda Gold Wing|Honda 1000 Gold Wing]].
-==Aircraft use==
-[[Lycoming]] developed a very successful series of flat-4 [[aircraft engine]]s, as used in many [[Cessna]] aircraft.  Similar engines are produced by [[Continental Motors]].

Difference between revisions of "Flat-4"

Revision as of 13:06, 31 March 2006

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