Search results
Results From The WOW.Com Content Network
Animation of a two-stroke engine. A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes of the piston (one up and one down movement) in one revolution of the crankshaft in contrast to a four-stroke engine which requires four strokes of the piston in two crankshaft revolutions to complete a power cycle.
Many high performance cars use carefully arranged air intakes and tuned exhaust systems that use pressure waves to push air into and out of the cylinders, making use of the resonance of the system. Two-stroke engines are very sensitive to this concept and can use expansion chambers that return the escaping air-fuel mixture back to the cylinder.
Most car engines have four to eight cylinders, with some high-performance cars having ten, 12 — or even 16, and some very small cars and trucks having two or three. In previous years, some quite large cars such as the DKW and Saab 92 , had two-cylinder or two-stroke engines.
Summary of the main ethanol blends used around the world in 2013. Several common ethanol fuel mixtures are in use around the world. The use of pure hydrous or anhydrous ethanol in internal combustion engines (ICEs) is only possible if the engines are designed or modified for that purpose, and used only in automobiles, light-duty trucks and motorcycles.
Many two-stroke engines use a crankcase-compression design, where a partial vacuum draws the fuel/air mixture into the engine as the piston moves upwards. Then as the piston travels downward, the inlet port is uncovered and the compressed fuel/air mixture is pushed from the crankcase into the combustion chamber.
In petrol (gasoline) engines used in passenger cars for the past 20 years, compression ratios have typically been between 8:1 and 12:1. Several production engines have used higher compression ratios, including: Cars built from 1955 to 1972 which were designed for high-octane leaded gasoline, which allowed compression ratios up to 13:1.
The German company Bosch had been developing a mechanical GDI system for cars since the 1930s [44] and in 1952 it was introduced on the two-stroke engines in the Goliath GP700 and Gutbrod Superior. This system was basically a high-pressure diesel direct-injection pump with an intake throttle valve set up.
Several car manufacturers have functioning HCCI prototypes. The 1994 Honda EXP-2 motorcycle used "ARC-combustion". This had a two stroke engine uses an exhaust valve to mimic a HCCI mode. Honda sold a CRM 250 AR. In 2007–2009, General Motors demonstrated HCCI with a modified 2.2 L Ecotec engine installed in Opel Vectra and Saturn Aura. [31]