Explanation of words that appears in our world

Aspen 2

Petrol for two stroke engines, premixed with 2 % two stroke oil, specially developed for air cooled two stroke engines.

Aspen 4

Petrol for four stroke engines. It can also be mixed with all kinds of two stroke oils, when needed.

Two Stroke Engines

In a two stroke engine the complete cycle is performed in one revolution. The air-fuel mixture in the cylinder is compressed by the piston at the same time as the crank case is filled with a new air-fuel mixture, under the compression stroke. During the expansion stroke the cylinder is filled with the fresh air-fuel mixture at the same time as the exhausts leave through the exhaust port.

Four Stroke Engines

In a four stroke engine it takes two revolutions to perform the whole cycle. During the intake stroke the cylinder I filled with the air-fuel mixture. Then the mixture is compressed during the compression stroke. Under the expansion stroke the air-fuel mixture is combusted and finally the cylinder is emptied during the exhaust stroke.

Air Cooled Engines

Engines cooled by blowing air around the cylinder are called air cooled. Small engines in power tools are generally air cooled, but so are also air craft engines, normally. Air cooled engines tend to run hotter than water cooled engines.


Aldehydes in the engine exhausts are formed by incomplete combustion of hydrocarbons and especially alcohols. Aldehydes are volatile and irritate the eyes and the nose. They can also cause allergies.

Alkanes (Paraffins)

Paraffins are straight or branched saturated hydrocarbons. They are the least hazardous hydrocarbons for health and the environment. Alkylate petrol constists almost entirely of branched paraffins, (isoparaffins), from C4 to C9, like isobutane, isopentane and isooctane.  

Alkenes (Olefins)

Olefins are unsaturated straight or branched hydrocarbons, produced at oil refineries in the cracking process. They are more reactive than paraffins, which reduces shelf life and create gum and deposits in the engines fuel system and combustion chamber. Olefins can form epoxides in the human body. Olefins are used as a blending component in regular petrol, but not in alkylate petrol.

Alkylate Petrol

A cleaner form of petrol without hazardous substances like benzene aromatic and olefinic hydrocarbons. Contains more than 99 % paraffinic hydrocarbons. Contains about ten different substances compared to more than a hundred in normal petrol.


Aromatics are a type of ring shaped hydrocarbons with a high amount of carbon. They often have high octane numbers and create more soot when combusted, than other hydrocarbons. They damage the central nervous system and benzene can cause cancer. About one third of normal petrol consists of aromatics.


The lightest aromatic hydrocarbon in normal petrol, can cause leukemia, or blood cancer according to IARC. Benzene harms the reproduction of water living organisms. It is also considered low to mid reactive regarding the formation of ground level ozone.


To be called biodegradable at least 65% of the substance should have degraded by natural micro organisms into mainly carbon dioxide and water according to the OECD 301 test.

Carbon Dioxide (CO2)

CO2 is the final result from the combustion of carbon containing fuels. The gas is not poisonous, but contributes to climate change.

Carbon Monoxide (CO)

Carbon monoxide is a deadly poisonous combustion product. The gas is odourless and tasteless.


A catalyst is a substance that enhances or starts a chemical reaction, without reacting itself. Catalysts are used for reducing hazardous components like hydrocarbons, carbon monoxide and nitrogen oxides in vehicle exhausts, transforming them to CO2 and water. They are also used when cracking hydrocarbons and increasing the octane in refineries.

Climate Adapted Petrol

Petrol that contains renewable components like ethanol. In Europe petrol may contain up to 10% ethanol.

Commercial petrol

Ordinary commercial petrol is produced by the refining of crude oil. Different fractions are treated separately and then mixed together. Commercial petrol also contains hundreds of different substances, all with different qualities concerning performance, harmful to health and the environment. Many components are very harmful to man and the environment.

Cracked components

Cracked components cause operating problems in engines and increase maintenance. They are harmful to health and the environment. These highly reactive compounds contribute locally to high concentrations of ground level ozone. Cracked components can also react in the body and form carcinogens like epoxides. See cracking.


This is a relatively new process, to be able to get more petrol from the crude oil. Originally petrol was a just a fraction of the crude oil, produced by simple distillation, but with motoring ever increasing, the demand for petrol has increased and other alternative processes had to be found. Cracking means that the hydrocarbons in the heavy oils (heavy fractions with long carbon chains) are broken down into smaller units, they were quite simply "cracked". The result is small, short unsaturated hydrocarbons, olefins, that can be used in petrol. The disadvantage with these are that they are not stable an can react with oxygen or other olefins. Therefore they are known as "reactive". There are different cracking processes. Catalytic cracking occurs when a relatively small amount of pressure and heat is applied. The resultant petrol contains large amounts of unsaturated hydrocarbons with a high octane level. Catalytic cracking is a relatively expensive process. Even more expensive is hydro cracking, which occurs at high pressure and in a hydrogen atmosphere, to saturate the unsaturated hydrocarbons. Both methods are used when manufacturing commercial petrol and diesel.

Cyclo Alkanes

Cycloalkanes are ring shaped saturated hydrocarbons mainly cyclopentanes and cyclohexanes. Their properties are similar to alkanes.


Density is the weight of a certain volume at a certain temperature, of for instance petrol. The density normally decreases with increasing temperature. Alkylate petrol has a density of 700 kg/m3, and normal petrol between 725 and 775 kg/m3, all at 15 oC.


Distillation is used to separate a blend of liquids into its components, where the components have different boiling points, like in crude oil. The crude is heated to 350-400 oC and the gases are slowly cooled in the refracting tower. As they condensate they are collected in boiling point order at different levels in the tower. So are components for petrol separated from kerosene and diesel fuel.

Eco Toxic

Poisonous or harmful for the environment.

Engine Deposits

Engine deposits are formed by incomplete combustion of carbon containing fuel, especially aromatic and olefinic hydrocarbons. They can restrict the air flow through the engine. In the fuel system reactive hydrocarbons like olefins, cause gum formation in jets and injectors, leading to malfunction.


Certain substances are stored in the human body since they are chemically stable and not soluble in water. Such substances are heavy metals like mercury, lead and cadmium. Man made substances like DDT and PCB are other examples. Species at the top of the food chain, like humans and large predators carry the highest concentrations, since the poisons are enriched in every step of the food chain. Even before they are born, a child carries these substancies in their body tissue.


Epoxides are a large group of compounds containing a three-atom ring, with two carbon and one oxygen atom. Unlike other ethers the epoxides are unstable and reactive and they can form poisonous and carcinogenic substances.


A group of organic compounds deriving from a chemical reaction between an alcohol and an acid. Esters can be used for many purposes and are often present in solvents, engine oils, plastics softeners and as raw material for plastics.


An alcohol often used as a blending component in petrol, to reduce the emissions of fossil CO2. Up to 10 % is allowed in normal petrol in Europe.

Fully Synthetic Oil

An oil that contains only man made hydrocarbons and other base oil molecules, together with additives.

Ground Level Ozone

Ozone is a very poisonous gas, causing reduced lung function, coughing, chest pains and dyspnoea (shortness of breath). Ground Ozone attacks plants and is believed to be the cause of irreparable damage to forests. The gas also attacks crops such as spinach, lettuce, wheat and potatoes with a reduction in yield. Ground level ozone forms in the atmosphere as the result of a chemical reaction between nitrogen oxides and reactive hydrocarbons. Especially during hot and sunny days, since uv radiation causes the reaction.


Gum is formed by polymerization of reactive hydrocarbons, like olefins, and can block fuel filters, jets and injectors.

Heavy Alcohols

Beside methanol and ethanol, heavier alcohols like propanol and butanol can be mixed into normal petrol.

Heavy Aromatics

There are small amount of heavy aromatics in normal petrol. These are known to cause deposits because of their low volatility and high carbon content.

Heavy Paraffins

Can be found in small amounts in petrol. They have low octane and low volatility.


Hydrocarbon is name of a group of compounds that consist of carbon and hydrogen combined in several thousand ways. Various hydrocarbons can have very different properties, not least regarding the impact on health and environment. They are stored in the body tissues, where they can cause anything from nausea to cancer, (benzene). See Alkanes, Alkenes, and Aromatics.

Iso Butane

A gaseous hydrocarbon from the crude oil distillation. It is used in LPG and for vapour pressure adjustment in petrol. It is one of the two raw materials for alkylate production. See Alkanes.

Iso Butene

Iso butene is a unsaturated gaseous hydrocarbon, mainly generated in the catalytic cracker. Iso butene is the other major raw material for alkylate production. See Alkenes.

Iso Octane

Iso octane is the most common hydrocarbon in alkylate. About 30 % of the finished alkylate petrol is ios octane. It is also one of the reference fuels for octane measurements, hence the name Octane No. Both RON and MON are 100.

Iso Paraffins

Branched saturated hydrocarbons. The alkylate petrol consists of more than 99 % iso paraffins. See alkanes.


Combustion in an SI engine normally occurs when the flame created by the spark plug moves through the combustion chamber with a constant speed of (10-30 m/s) until the fuel/air mixture is completely used. During combustion the non-combusted gases are compressed ahead of the cone of the flame and the temperature increases. The remaining gases then self-ignite or auto ignite and are burned so quickly (300-500 m/s) that a pressure wave occurs causing the audible knocking. The normal combustion results in effective power while the uncontrolled combustion causes knocking and counteracts normal combustion. The knocking can also cause serious engine damages.


Liquified Petroleum Gas, normally a mixture of propane and butane. These are gases at room temperature but liquifies easily under pressure. The same type of hydrocarbons as in alkylate petrol and the combustions products are similar.


Methyl-Tertiary-Butyl-Ether is a oxygen-containing compound used to enhance the Octane and to improve combustion in petrol. Like all ethers it causes drowsiness, when inhaled.

Max rpm

The maximum rpm an engine can reach at full throttle, without load. Used when debranching with a chain saw

Nitrous Oxide, Laughing Gas (N2O)

Nitrous oxide, or Laughing gas, is formed in small amounts in vehicles’ catalytic converters. The gases contribute strongly to the greenhouse effect. Nitrous oxide is used as a pain killer during child birth.

NOx (Nitrogen Oxides)

During nearly all combustion processes Nitrogen Oxides form. At high temperatures Nitrogen reacts with oxygen in the air and forms Nitrogen oxides, NO and NO2. NOx is a major environmental problem since it participates in the formation of ground level ozone and contributes to acidification in our streams, rivers and lakes.

Nitrogen oxides are also hazardous to human health by causing damage to the lungs.

Octane MON

A measurement of fuels’ ability to withstand knocking combustion, especially at high RPM and pressure.

Octane RON

A measurement of fuels’ ability to withstand knocking combustion especially at low RPM and quick pressure changes.

Oil Classification

Different international quality requirements for engine oils. For two stroke oils JASO and ISO standards are used globally. For outboard engines NMMA TCW3, is the most common. For four stroke engines API and ACEA classifications are widely used.


See alkenes.


A group of organic chemicals that consist of carbon, hydrogen and oxygen, mainly ethers and alcohols. They are used as an octane enhancer in petrol or to introduce renewable components like bioethanol. Oxygenates are not used in alkylate petrol, since they make the engines run leaner, and in some cases, increase aldehyde emissions.


See alkanes.


A paraffinic hydrocarbon, either with a straight chain of C-atoms or a branched chain. The branched chain has a higher Octane No.


Normal petrol is produced by refining crude oil. Different fractions are upgraded separately and finally blended, to achieve the finished product. Ordinary petrol contains more than a hundred different substances, some are very harmful to man and the environment.


Synthetically made paraffinic base oils with excellent lubricity and low and high temperature properties.


A widely used plastic in plastic bags, and in cans for alkylate petrol. Polyethene consists of long carbon chains of the same type as in alkylate petrol, but with several hundred carbon atoms. It is normally produced from crude oil.


See aromatics. 

Volatility and Vapour Pressure

The vapour pressure is a measurement of how easily petrol evaporates. A high vapour pressure means that more vapour is formed and this can cause operational problems at high ambient temperatures. Volatility also includes the front end of the boiling range.

Water Cooled Engines

An engine where the excess heat from the combustion is removed by circulating water or a coolant. The excess heat is then released to the ambient air via the radiator.


See aromatics.