What did you learn today about engines? 05/11/14
Keep your answers short and to the point. Thanks.
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Continued stripping down the land rover engines.
Turbulence is used in diesel engines to create a more evenly spread rapid burn across
the crown of the piston.
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There are two types of diesel engines; direct and indirect injection.
There are two types of indirect injection diesel engines these are pre-combustion
chambers and swirl chamber engines.
Direct injection engines usually have a compression ration between 16:1 and 21:1.
Indirect injection engines usually have a compression ration between 22:1 and 25:1.
There are three to five stages of injection to a diesel engine, these can be pre, main
and post injection. This gives the diesel engine a slower burn and reduces diesel
knock.
CI stands for compression ignition, this is a diesel engine.
SI stands for spark ignition, this is a petrol engine.
The chemical equation for complete combustion is CH + O2 + N = CO2 + H2O + N.
The chemical equation for incomplete combustion is CH + O2 + N = CO2 + H2O + N +
CO + NOx.
Lean engines run hotter and produce nitrous oxides.
Rich engines run cooler and produce carbon monoxides.
The perfect ratio for a petrol engine aka LAMBA is 14.7:1.
Fuel does not explode it burns rapidly.
Fuel has an octane rating in the UK this is 97.
The higher the fuel's octane rating the slower it burns in combustion.
Diesel has a cetane rating.
Petrol engines create pressures up to 38 BAR.
today i learnt:
what a swirl chamber is
about volumetric efficiency
direct and indirect injection
incomplete combustion
complete combustion
14.7:1 perfect fuel to air ratio]
13.5:1 rich, runs cooler- carbon monoxide
22:1 lean-runs hot-produces nitrogen oxide
higher the octane -slower combustion speed
pistons have a turbulence ring, conical bottom, piston crown bowl.
v or piston crown bowl distributes the air fuel mixture evenly through turbulence
direct injection is more efficient
indirect injection is quieter and less noisy.
direct injection engine usually have 16:1 compression ratios
indirect injection engines have 20:1 compression ratio diesel- compression ignition
petrol- spark ignition
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petrol engine cylinder pressure diagram
uk fuel octane rating of 97
diesel has a cetane rating
how to remove a cylinder head correctly
3 air turbulence
direct injection
pistion crown ball
corical bottom
turbulance ring
injectors
pre cubustion chamber
indirect injection
pre, main and post injections
ci and si
fule add air = exhaust
rich, lean and perfect combustion
octane levels
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we carried on stripping down the diesel land rover engines
on indirect diesel engines they have a swirl chamber or a pre combustion chamber
on diesel engines turbulence is created to mix the diesel and air to give a better burn
direct diesels have a bowel in the piston crown, conical bottom, and turbulence ring
direct injection diesels have a compression ratio between 16:1 and 21:1
indirect injection diesels have a compression ratio between 22:1 and 25:1
direct diesel have pre injection, main injection, post injection
i have learnt the chemical equations for complete and incomplete combustion
diesel is CI compression ignition
petrol is SI spark ignition
perfect air to fuel mixture for a petrol 14.7:1, which produces no harmful gases
measured by mass
open loop system uses no ECU and is mechanical
closed loop system uses the ECU and is not mechanical
Lambda is 14.7:1 which is the perfect state for petrols
petrol uses an octane rating
higher octane rating the slower the combustion speed
in the uk it is 97
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Cylinder head removed
vacuum pump removed from engine
How to use a puller when removing a rusted pulley
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Swirl chambers distribute the fuel evenly
Direct injection diesel engines have a combustion chamber in the top of the piston
Direct injection diesel engines normally have a compression ratio of 16:1/20:1
Indirect diesel engines normally have a compression ratio of 22:1/ 25:1
Direct injection engines are more efficient than indirect injection engines
Glow plugs have a bigger surface area to heat up in an indirect injection engine
indirect injection engines have to be hotter to ignite the fuel because there is more
surface area
Pre injection is where fuel is injected early in order to start the fuel burning early (to
prevent diesel knock)
Petrol engines are also known as SI engines, spark ignition
Diesel engines are also known as CI engines, Compression ignition
14.7:1 is the ratio of air to fuel mixture
13.5:1 is the ratio of air to fuel when an engine is running rich (running colder,
produces carbon dioxide)
22:1 is the ratio of air to fuel when an engine is running lean (running hot nitrogen
oxides)
The ECU (electronic control unit) Controls whether the engine is runs rich or lean by
receiving data from the 02 sensor, this is known as a closed loop system
Petrol fuel has an octane rating, some engines are designed to run on a specific
octane rating, the higher the octane rating the slower the burn
The octane rating of fuel in the uk is mostly 97 octane rating
Diesel fuel has a cetane rating
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carryed on striping land rover engines
cylinder head
vacuum pump
started on the petrol engine
tried un seizing it
turbulence in the engine
piston has a mark in it
piston crown bowl
conical bottom
turbulence ring
injectors
in-direct engine
compression ratio is between 22.1 and 25.1
direct engine
compression ratio is between 16.1 and 21.1
direct engine is more efficient and used tractors and trucks
in-direct is more quieter and used in cars
swirl chambers
diesel is known as compression ignition
petrol is known as spark ignition
complete combustion is CH+O2+N=CO2+H2O+N
incomplete combustion is CH+O2+N=CO2+H2O+N+CO+NOX
ideal ratio for air fuel mixture is 14.7:1
it can run rich or lean
petrol have an octane rating-97
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diesel have an cetane ratinghigher octane rating=slower combustion speed
pre ignition
main ignition
post ignition
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what a swirl chamber is
about volumetric efficiency
direct and indirect injection
incomplete combustion
complete combustion
14.7:1 perfect fuel to air ratio]
13.5:1 rich, runs cooler- carbon monoxide
22:1 lean-runs hot-produces nitrogen oxide
higher the octane -slower combustion speed
pistons have a turbulence ring, conical bottom, piston crown bowl.
v or piston crown bowl distributes the air fuel mixture evenly through turbulence
direct injection is more efficient
indirect injection is quieter and less noisy.
direct injection engine usually have 16:1 compression ratios
indirect injection engines have 20:1 compression ratio diesel- compression ignition
petrol- spark ignition
petrol engine cylinder pressure diagram
uk fuel octane rating of 97
diesel has a cetane rating
how to remove a cylinder head correctly
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today i learnt:
● what turbulence is and how it effects a diesel engine
● the crown on a piston is shaped to direct the air
● a indirect injection engine has a higher compression ratio between 22:1 and 25:1
● direct injection engines run at a lower compression between 16:1 and 20:1
● what a turbulence ring is
● what a cronical bottom is
● diesel engines can be direct injection or indirect and have a swirl chamber
● indirect injection has a higher compression ratio as more heat is lost to the size of the
surface area.
● diesel knocking is when is when a bit of diesel is injected before the proper injection
● CI- compression ignition
● SI spark ignition
● CH+O2+N=CO2+H2O+N+CO+NO2
● petrol engine fuel air ratio 14.7:1
● rich runs cool
● lean runs hot
● we took of the engine head avacuumcum pump
c1 and ul gases