Төрттен бес цилиндрлі қозғалтқыштар: тарихы мен ерекшеліктері

Type of engine
The straight five engine (also referred to as an inline five engine; abbreviated I5 or L5) is a piston engine with five cylinders mounted in a straight line along the crankshaft. Although less common than straight four engines and straight six engines, straight five engine designs have been used by automobile manufacturers since the late 1930s. The most notable examples include the Mercedes Benz's diesel engines from 1974 to 2006 and Audi's petrol engines from 1979 to the present. Straight five engines are smoother running than straight four engines and shorter than straight six engines. However, achieving consistent fueling across all cylinders was problematic prior to the adoption of fuel injection.

Straight five engines are typically shorter than straight six engines, making them easier to fit transversely in an engine bay. They are also smoother than straight four engines, and flat engines.

Five cylinder engines have a crankshaft with 72 degree angles. Amongst four stroke engines, an advantage of engines with five or more cylinders is that the power strokes are overlapping if the engine has an even firing order.

Most four stroke straight five engines use a firing order of 1 2 4 5 3. This firing order results in the minimal primary (crank speed) rocking couple, and is used by the Volvo Modular engine, VW/Audi straight five engine, General Motors Atlas engine and Honda G engine. Straight five engines typically have a 72 degree crankshaft design. All two stroke straight five engines are limited in having a single firing order for a given crank configuration; because a complete cycle occurs every 360 degrees, there is no chance to share piston phases without having simultaneous ignitions, so the straight five is at no disadvantage in this case. Some two stroke outboard engines, e. g. the Mercury Marine Force 150 engine use a firing order of 1 5 2 3 4.

The use of straight five petrol engines in mass production cars only became truly viable with the advent of reliable fuel injection. This is because of the unavoidable problems of a carburettor supplying an odd number of cylinders and the length of the inlet manifold between the carburetor varying greatly between cylinders at the ends of the engine and those nearer the carburetor. Unlike other engine layouts, these problems are not easily solved by using multiple carburettors. Diesel engines have always used fuel injection, therefore large displacement straight five diesel engines were commonly seen decades before straight five petrol engines.

The 1938 Lancia 3Ro trucks introduced a straight five diesel engine to replace the previous straight three engine. Built for the Italian and German armed forces during World War II and later for civilian usage, the truck remained in production until 1950. The first mass production straight five passenger car engine was the 1974 Mercedes Benz OM617, a naturally aspirated engine introduced in the Mercedes Benz 300D (W114/W115) models. In 1978, a turbocharged version was introduced in the Mercedes Benz 300SD Turbo models. Mercedes Benz continued to produce straight five engines for the next 28 years, until the Mercedes Benz OM647 engine ended production in 2006. In 1978, the Audi 2.0 R5 D engine was introduced in the Audi 100 sedan. In 1983, a turbocharged version was introduced, initially for the U. S. market Audi 100. Several Volvo cars were produced with Audi straight five diesel engines, prior to the introduction of the Volvo D5 turbo diesel engine; this engine was produced from 2001 to 2017 and was used in several diesel hybrid applications (marketed as "twin engine" models). Other mass production straight five diesel engines include the 1999–2001 VM Motori 531 turbo diesel engine, the 1998–2007 Land Rover Td5 turbo diesel engine, the 2006–2019 Ford Duratorq 3.2 turbo diesel engine and the 1998–2009 Fiat JTD 2.4 turbo diesel engine.

Very few motorcycles have used five cylinder engines. However, the 1965 Honda RC148 and 1966 Honda RC149 125 cc four stroke racing motorcycles used straight five engines based on the 50 cc straight twin engine from the Honda RC116 Grand Prix racing motorcycle. These straight five engines were an unusual design in that they were configured as a straight six engine with one of the middle cylinders removed.