Diagram describing the ideal combustion cycle by Carnot
The Kerr engine at the Anson Engine Museum
Reciprocating engine of a car
The M4+2 engine working cycle animation
Diesel generator for backup power
Bare cylinder block of a V8 engine
Piston, piston ring, gudgeon pin and connecting rod
Valve train above a Diesel engine cylinder head. This engine uses rocker arms but no pushrods.
Engine block seen from below. The cylinders, oil spray nozzle and half of the main bearings are clearly visible.
Diagram showing the operation of a 4-stroke SI engine. Labels:
1 ‐ Induction
2 ‐ Compression
3 ‐ Power
4 ‐ Exhaust
Diagram of a crankcase scavenged 2-stroke engine in operation
Diagram of uniflow scavenging
Bosch magneto
Points and coil ignition
Diagram of an engine using pressurized lubrication
P-V diagram for the ideal Diesel cycle. The cycle follows the numbers 1–4 in clockwise direction.
Turbofan jet engine
Turbine power plant
Brayton cycle
The Wankel rotary cycle. The shaft turns three times for each rotation of the rotor around the lobe and once for each orbital revolution around the eccentric shaft.
One-cylinder gasoline engine, c. 1910
Electric starter as used in automobiles

The term six-stroke engine has been applied to a number of alternative internal combustion engine designs that attempt to improve on traditional two-stroke and four-stroke engines.

- Six-stroke engine

The term internal combustion engine usually refers to an engine in which combustion is intermittent, such as the more familiar four-stroke and two-stroke piston engines, along with variants, such as the six-stroke piston engine and the Wankel rotary engine.

- Internal combustion engine
Diagram describing the ideal combustion cycle by Carnot

2 related topics

Alpha

Four-stroke cycle used in gasoline/petrol engines: intake (1), compression (2), power (3), and exhaust (4). The right blue side is the intake port and the left brown side is the exhaust port. The cylinder wall is a thin sleeve surrounding the piston head which creates a space for the combustion of fuel and the genesis of mechanical energy.

Four-stroke engine

Four-stroke engines are the most common internal combustion engine design for motorized land transport, being used in automobiles, trucks, diesel trains, light aircraft and motorcycles.

Four-stroke engines are the most common internal combustion engine design for motorized land transport, being used in automobiles, trucks, diesel trains, light aircraft and motorcycles.

Four-stroke cycle used in gasoline/petrol engines: intake (1), compression (2), power (3), and exhaust (4). The right blue side is the intake port and the left brown side is the exhaust port. The cylinder wall is a thin sleeve surrounding the piston head which creates a space for the combustion of fuel and the genesis of mechanical energy.
An Otto Engine from 1880s US Manufacture
This 2004 Toyota Prius hybrid has an Atkinson-cycle engine as the petrol-electric hybrid engine
The Atkinson Gas Cycle
Audi Diesel R15 at Le Mans
The idealized four-stroke Otto cycle p-V diagram: the
 intake (A) 
stroke is performed by an isobaric expansion, followed by the
 compression (B) 
stroke, performed as an adiabatic compression. Through the combustion of fuel an isochoric process is produced, followed by an adiabatic expansion, characterizing the
 power (C) 
stroke. The cycle is closed by an isochoric process and an isobaric compression, characterizing the exhaust (D) 
stroke.
The four-stroke cycle
 1=TDC
 2=BDC
 A: Intake  
  B: Compression  
  C: Power  
  D: Exhaust
Top dead center, before cycle begins
1 – Intake stroke
2 – Compression stroke
Fuel ignites
3 – Power stroke
4 – Exhaust stroke

By contrast, a six-stroke engine may reduce fuel consumption by as much as 40%.

As automakers look to meet these standards by 2016, new ways of engineering the traditional internal combustion engine (ICE) have to be considered.

Diagram describing the ideal combustion cycle by Carnot

Beare-head engine

Diagram describing the ideal combustion cycle by Carnot

The Beare-head engine internal combustion engine technology combines a four-stroke engine bottom end and piston, with a ported cylinder head closely resembling that of a two-stroke engine.

This configuration has been described as a six-stroke engine based on adding together the four strokes per cycle of the bottom piston and the two strokes of the cylinder head piston, but there are essentially only 4 strokes, just with an alternative form of valving.