Straight-4 - Revision history

Red marquis at 01:05, 12 December 2008

2008-12-12T01:05:20Z

← Older revision		Revision as of 01:05, 12 December 2008
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	#REDIRECT [[~~Inline~~-4]]		#REDIRECT [[Straight-4 engine]]

Red marquis at 10:44, 29 October 2008

2008-10-29T10:44:30Z

← Older revision		Revision as of 10:44, 29 October 2008
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	~~{{merge\|~~Inline-4}}		#REDIRECT [[Inline-4]]

Red marquis at 10:44, 29 October 2008

2008-10-29T10:44:09Z

← Older revision		Revision as of 10:44, 29 October 2008
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	{{~~mergeto~~\|Inline-4}}		{{merge\|Inline-4}}

	The '''straight-4''' or '''inline-4''' is an [[internal combustion engine]] with [[4 (number)\|four]] cylinders aligned in one row. This [[straight engine]] configuration is the most common in [[Automobile\|car]]s with a [[engine displacement\|displacement]] up to 2.2 L. The "practical" limit to the displacement of Straight-4 engines is around 2.5 litres.

	The straight-4 engine is not a [[engine balance\|balanced]] configuration. While a pair of pistons is always moving up at the same time as the other pair is moving down, piston speed - as with all internal combustion engines - is higher through the top 180 degrees of the stroke than the bottom 180 degrees, which leads to a secondary harmonic imbalance. While this is tolerable in a small low-displacement low-power configuration, the vibrations get worse with increasing size and power. Most straight-4 engines below 2.0 L in displacement rely on the damping effect of their engine mounts. Today, most engineers will make use of [[balance shaft]]s above that limit. A 4-cylinder engine needs two balance shafts, rotating at twice the crankshaft frequency, to be smooth. Nonetheless there were several samples of larger straight-4s in production using no balance shafts, such as the [[Citroën DS\|Citroën DS 23]] 2347 cc engine that was a derivative of the [[Citroën Traction Avant\|Traction Avant]] engine, and the 1948 Austin 2660 cc engine used in the [[Austin-Healey 100]] and Austin Atlantic. These engines were generally the result of a long incremental evolution process and their power was kept relatively low regarding their capacity.

	~~== Automobile use==~~
	~~=== Notable straight-4 engines ===~~

	The smallest automobile production straight-4 engine powered the 1961 [[Mazda Carol\|Mazda P360 Carol]] [[keicar]]. Displacing just 358 cc, the ''[[Mazda OHV engine#358\|Mazda OHV]]'' was a conventional but tiny [[pushrod]] engine. Most straight-4 engines, however, have been over 1.0 L in displacement. A practical upper limit could be placed in the 2.5 L range for production cars. Larger engines (up to 4.5 L) have been seen in racing and light [[truck]] use, especially using [[diesel]] fuel (an example is the Mercedes-Benz MBE 904). The use of balance shafts allowed [[Porsche]] to use a 3.0 L (2990 cc) straight-4 engine on road cars like the [[Porsche 968]], but the largest modern non-diesel was the plain 3.2 L (3188 cc) ''195'' in the 1961 [[Pontiac Tempest]].

	In the early 20th century, bigger engines existed, both in road cars and sports cars. Due to the absence of displacement limit regulations, manufacturers took increasing liberties with engine size. In order to achieve power over 100 [[HP\|hp]], most engine builders simply increased displacement, which could sometimes achieve over 10.0 L. One of the biggest straight-4s of its time was [[De Dietrich]] 17000 cc motor. Its cubic capacity is over twice the size of the Cadillac's 500 in<sup>3</sup> 8.2 L [[V8]], which was considered the largest engine of its type in the 1970s. These engines ran at very low RPM, often less than 1500 RPM in maximum, and had a specific output of about 10 [[HP\|hp]]/L.

	~~Other notable engines using this configuration include:~~
	* [[Ford Model T engine]] - One of the most-widely produced engines in the world
	* [[BMC A-Series engine\|Austin A-Series engine]] - This engine powered many of the compact vehicles of the [[1950s]]
	* [[Honda E engine#ED\|Honda ED engine]] - First use of Honda's [[CVCC]] technology
	* [[Triumph Slant-4 engine]] - The first mass-produced [[multivalve]] engine for [[Triumph Motor Company\|Triumph]] and an early [[turbo]] engine for [[Saab Automobile\|Saab]]
	* [[GM Quad-4 engine]] - The first [[multivalve]] American engine
	* [[Hyundai Alpha engine]] - The first automobile engine designed in Korea
	* [[Honda F20C engine]] - Its 240 [[HP\|hp]] from 2.0 L was the highest specific output of its time

	~~=== Racing use ===~~

	1913 saw a [[Peugeot]] driven by Jules Goux winning the Indianapolis 500. This car was powered by a straight-4 engine designed by Ernest Henry. This design was very influential for racing engines as it featured for the first time [[Overhead Camshafts\|dual overhead camshafts]] ([[DOHC]]) and 4 [[poppet valve\|valve]]s per cylinder, a layout that would become the standard until today for racing straight-4 engines.

	This Peugeot was sold to the American driver "Wild Bob" Burman who broke the engine in 1915. As Peugeot couldn't deliver a new engine during World War 1, Burman asked [[Harry Arminius Miller]] to build a new engine. With John Edward and [[Fred Offenhauser]], Miller created a Peugeot-inspired straight-4 engine. This was the first version of the engine that would dominate the Indianapolis 500 until 1976 under the brand Miller and later Offenhauser.

	Another engine that played an important role in Racing history is the Straight-4 [[Ferrari]] engine designed by Aurelio Lampredi. This engine was originally designed as a 2 litre [[Formula 2]] engine for the Ferrari 500 but evolved to 2.5 L to compete in [[Formula 1]] in the Ferrari 625. For [[sports car]] racing capacity was increased up to 3.4 L for the Ferrari 860 Monza.

	Yet another very successful engine was the Coventry Climax straight-4 originally designed by [[Walter Hassan]] as a 1.5 L Formula 2 engine. It evolved into the large 2,495 cc FPF that won the Formula One championship in Cooper's chassis.

	~~==Motorcycle use==~~

	[[list of automotive superlatives\|The smallest]] production motorcycle straight-4 engine was the 4-stroke engine powered the 250 cc Benelli/Moto Guzzi 254. For racing, Honda built straight-4 engines as small as a 125 cc for the Honda 125/4. This engine was replaced by a 125 cc [[straight-5]] engine.

Rfujitani at 17:10, 12 October 2006

2006-10-12T17:10:45Z

← Older revision		Revision as of 17:10, 12 October 2006
Line 1:		Line 1:
			{{mergeto\|Inline-4}}

	The '''straight-4''' or '''inline-4''' is an [[internal combustion engine]] with [[4 (number)\|four]] cylinders aligned in one row. This [[straight engine]] configuration is the most common in [[Automobile\|car]]s with a [[engine displacement\|displacement]] up to 2.2 L. The "practical" limit to the displacement of Straight-4 engines is around 2.5 litres.		The '''straight-4''' or '''inline-4''' is an [[internal combustion engine]] with [[4 (number)\|four]] cylinders aligned in one row. This [[straight engine]] configuration is the most common in [[Automobile\|car]]s with a [[engine displacement\|displacement]] up to 2.2 L. The "practical" limit to the displacement of Straight-4 engines is around 2.5 litres.

Carguy at 18:44, 30 June 2006

2006-06-30T18:44:25Z

New page

The '''straight-4''' or '''inline-4''' is an [[internal combustion engine]] with [[4 (number)|four]] cylinders aligned in one row. This [[straight engine]] configuration is the most common in [[Automobile|car]]s with a [[engine displacement|displacement]] up to 2.2 L. The "practical" limit to the displacement of Straight-4 engines is around 2.5 litres.

The straight-4 engine is not a [[engine balance|balanced]] configuration. While a pair of pistons is always moving up at the same time as the other pair is moving down, piston speed - as with all internal combustion engines - is higher through the top 180 degrees of the stroke than the bottom 180 degrees, which leads to a secondary harmonic imbalance. While this is tolerable in a small low-displacement low-power configuration, the vibrations get worse with increasing size and power. Most straight-4 engines below 2.0 L in displacement rely on the damping effect of their engine mounts. Today, most engineers will make use of [[balance shaft]]s above that limit. A 4-cylinder engine needs two balance shafts, rotating at twice the crankshaft frequency, to be smooth. Nonetheless there were several samples of larger straight-4s in production using no balance shafts, such as the [[Citroën DS|Citroën DS 23]] 2347 cc engine that was a derivative of the [[Citroën Traction Avant|Traction Avant]] engine, and the 1948 Austin 2660 cc engine used in the [[Austin-Healey 100]] and Austin Atlantic. These engines were generally the result of a long incremental evolution process and their power was kept relatively low regarding their capacity.

== Automobile use==
=== Notable straight-4 engines ===

The smallest automobile production straight-4 engine powered the 1961 [[Mazda Carol|Mazda P360 Carol]] [[keicar]]. Displacing just 358 cc, the ''[[Mazda OHV engine#358|Mazda OHV]]'' was a conventional but tiny [[pushrod]] engine. Most straight-4 engines, however, have been over 1.0 L in displacement. A practical upper limit could be placed in the 2.5 L range for production cars. Larger engines (up to 4.5 L) have been seen in racing and light [[truck]] use, especially using [[diesel]] fuel (an example is the Mercedes-Benz MBE 904). The use of balance shafts allowed [[Porsche]] to use a 3.0 L (2990 cc) straight-4 engine on road cars like the [[Porsche 968]], but the largest modern non-diesel was the plain 3.2 L (3188 cc) ''195'' in the 1961 [[Pontiac Tempest]].

In the early 20th century, bigger engines existed, both in road cars and sports cars. Due to the absence of displacement limit regulations, manufacturers took increasing liberties with engine size. In order to achieve power over 100 [[HP|hp]], most engine builders simply increased displacement, which could sometimes achieve over 10.0 L. One of the biggest straight-4s of its time was [[De Dietrich]] 17000 cc motor. Its cubic capacity is over twice the size of the Cadillac's 500 in<sup>3</sup> 8.2 L [[V8]], which was considered the largest engine of its type in the 1970s. These engines ran at very low RPM, often less than 1500 RPM in maximum, and had a specific output of about 10 [[HP|hp]]/L.

Other notable engines using this configuration include:
* [[Ford Model T engine]] - One of the most-widely produced engines in the world
* [[BMC A-Series engine|Austin A-Series engine]] - This engine powered many of the compact vehicles of the [[1950s]]
* [[Honda E engine#ED|Honda ED engine]] - First use of Honda's [[CVCC]] technology
* [[Triumph Slant-4 engine]] - The first mass-produced [[multivalve]] engine for [[Triumph Motor Company|Triumph]] and an early [[turbo]] engine for [[Saab Automobile|Saab]]
* [[GM Quad-4 engine]] - The first [[multivalve]] American engine
* [[Hyundai Alpha engine]] - The first automobile engine designed in Korea
* [[Honda F20C engine]] - Its 240 [[HP|hp]] from 2.0 L was the highest specific output of its time

=== Racing use ===

1913 saw a [[Peugeot]] driven by Jules Goux winning the Indianapolis 500. This car was powered by a straight-4 engine designed by Ernest Henry. This design was very influential for racing engines as it featured for the first time [[Overhead Camshafts|dual overhead camshafts]] ([[DOHC]]) and 4 [[poppet valve|valve]]s per cylinder, a layout that would become the standard until today for racing straight-4 engines.

This Peugeot was sold to the American driver "Wild Bob" Burman who broke the engine in 1915. As Peugeot couldn't deliver a new engine during World War 1, Burman asked [[Harry Arminius Miller]] to build a new engine. With John Edward and [[Fred Offenhauser]], Miller created a Peugeot-inspired straight-4 engine. This was the first version of the engine that would dominate the Indianapolis 500 until 1976 under the brand Miller and later Offenhauser.

Another engine that played an important role in Racing history is the Straight-4 [[Ferrari]] engine designed by Aurelio Lampredi. This engine was originally designed as a 2 litre [[Formula 2]] engine for the Ferrari 500 but evolved to 2.5 L to compete in [[Formula 1]] in the Ferrari 625. For [[sports car]] racing capacity was increased up to 3.4 L for the Ferrari 860 Monza.

Yet another very successful engine was the Coventry Climax straight-4 originally designed by [[Walter Hassan]] as a 1.5 L Formula 2 engine. It evolved into the large 2,495 cc FPF that won the Formula One championship in Cooper's chassis.

==Motorcycle use==

[[list of automotive superlatives|The smallest]] production motorcycle straight-4 engine was the 4-stroke engine powered the 250 cc Benelli/Moto Guzzi 254. For racing, Honda built straight-4 engines as small as a 125 cc for the Honda 125/4. This engine was replaced by a 125 cc [[straight-5]] engine.