The five-stroke engine is a
compound internal combustion engine patented by Gerhard Schmitz in 2000.
Concept
The goal of the five-stroke engine is to achieve higher
efficiency
Efficiency is the often measurable ability to avoid making mistakes or wasting materials, energy, efforts, money, and time while performing a task. In a more general sense, it is the ability to do things well, successfully, and without waste.
...
than a
four-stroke engine
A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directi ...
. In order to increase efficiency, a secondary cylinder is added as an expansion processor to extract more energy from the fuel. Schmitz's concept engine uses two primary "high pressure" cylinders with standard four-stroke power cycles, in addition to a larger secondary "low pressure" expansion cylinder. The hot
exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through ...
from the two primary cylinders is fed into the secondary cylinder, halving the volume of gases in the primary cylinders after combustion.
This concept is similar to that of
compound steam engines, which expand steam in high pressure cylinders before exhausting it into low-pressure cylinders in order to extract more energy from the steam. In 1879,
Nicolaus Otto
Nicolaus August Otto (10 June 1832 – 26 January 1891) was a German engineer who successfully developed the compressed charge internal combustion engine which ran on petroleum gas and led to the modern internal combustion engine. The Associa ...
built a 5-stroke engine which was commercially produced, but suffered from poor performance. Two Spanish patents (ES0156621, F Jimeno-Cataneo, 1942; and ES0433850, C Ubierna-Laciana, 1975) describe 5-stroke engines identical to that of Schmitz's design, this engine had a fellowship to Burgundy University to be studied. J.W. Eisenhuth patented an 'air and gas engine' with double expansion (US640890, 1900). A car with this engine was in the
Harrah Collection, though its fate after the collection was dismantled is unknown.
In Schmitz's design, the
compression ratio of the low pressure expansion cylinder is adjustable to achieve an optimal expansion ratio, regardless of the primary cylinders' compression ratio. The prototype has demonstrated an approximately 10% decrease in fuel consumption over a standard gas engine.
Ilmor 5 Stroke Engine – 700cc Turbo 3 Cylinder – 130 bhp, Better Mileage, Less Weight, By Paul Crowe
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The operation of a 5-stroke SI engine is as follows:
1 – Induction
2 – Compression
3 – Power
4 – Initial exhaust/re-expansion
5 – Final exhaust
Prototype
Schmitz's concept was being developed by Ilmor. Ilmor's prototype, intended for motorcycle
A motorcycle (motorbike, bike; uni (if one-wheeled); trike (if three-wheeled); quad (if four-wheeled)) is a lightweight private 1-to-2 passenger personal motor vehicle Steering, steered by a Motorcycle handlebar, handlebar from a saddle-style ...
use and consisting of 2 primary cylinders and 1 secondary cylinder, uses a solid cylinder block
In an internal combustion engine, the engine block is the structure that contains the cylinders and other components. The engine block in an early automotive engine consisted of just the cylinder block, to which a separate crankcase was attach ...
with electrically driven oil and water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
pump
A pump is a device that moves fluids (liquids or gases), or sometimes Slurry, slurries, by mechanical action, typically converted from electrical energy into hydraulic or pneumatic energy.
Mechanical pumps serve in a wide range of application ...
s, two overhead camshafts with standard poppet valves, and turbocharging. Its displacement is without the secondary cylinder and in total, and it can produce at 7,000 rpm and at 5,000 rpm.
See also
* Rotary engine
* Stirling engine
A Stirling engine is a heat engine that is operated by the cyclic expansion and contraction of air or other gas (the ''working fluid'') by exposing it to different temperatures, resulting in a net conversion of heat energy to mechanical Work (ph ...
* Stroke (engine)
In the context of an internal combustion engine, the term stroke has the following related meanings:
* A phase of the engine's cycle (e.g. compression stroke, exhaust stroke), during which the piston travels from top to bottom or vice versa.
* Th ...
** Two- and four-stroke engines
** Two-stroke engine
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a Thermodynamic power cycle, power cycle with two strokes of the piston, one up and one down, in one revolution of the crankshaft in contrast to a f ...
** Four-stroke engine
A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directi ...
** Six-stroke engine
A six-stroke engine is one of several alternative internal combustion engine designs that attempt to improve on traditional two-stroke and four-stroke engines. Claimed advantages may include increased fuel efficiency, reduced mechanical complexit ...
* Thermodynamic cycle
** Atkinson cycle
** Miller cycle
References
External links
Four stroke engine animation
*
Animated Engines, four stroke
, another explanation of the four-stroke engine.
New 4 stroke
{{Aircraft piston engine components
Internal combustion piston engines