25-08-2017, 09:32 PM
Internal combustion Engines: Carburetor, Fuel injection, valve timing
[attachment=52465]
Carburetors and Fuel injection
• Fuel injection is a system for mixing fuel with air in an internal combustion
engine. It has become the primary fuel delivery system used in gasoline
automotive engines, having almost completely replaced carburetors in the late
1980s.
• The carburetor was invented by Karl Benz (founder of Mercedes‐Benz) in 1885
and patented in 1886.
• Carburetors were the usual fuel delivery method for almost all gasoline (petrol)‐
2
y g p )
fuelled engines up until the late 1980s, when fuel injection became the preferred
method of automotive fuel delivery. In the U.S. market, the last carbureted cars
were the 1990 Oldsmobile Custom Cruiser, Buick Estate Wagon, and Subaru
Justy, and the last carbureted light truck was the 1994 Isuzu. Elsewhere, Lada
cars used carburetors until 1996. A majority of motorcycles still use carburetors
due to lower cost and throttle response problems with early injection set ups, but
as of 2005, many new models are now being introduced with fuel injection.
Carburetors are still found in small engines and in older or specialized
automobiles, such as those designed for stock car racing.
• A fuel injection system is designed and calibrated specifically for the type(s) of
fuel it will handle. Most fuel injection systems are for gasoline or diesel
applications.
Carburetors and Fuel injection
• Fuel injection is a system for mixing fuel with air in an internal combustion
engine. It has become the primary fuel delivery system used in gasoline
automotive engines, having almost completely replaced carburetors in the late
1980s.
• The carburetor was invented by Karl Benz (founder of Mercedes‐Benz) in 1885
and patented in 1886.
• Carburetors were the usual fuel delivery method for almost all gasoline (petrol)‐
2
y g p )
fuelled engines up until the late 1980s, when fuel injection became the preferred
method of automotive fuel delivery. In the U.S. market, the last carbureted cars
were the 1990 Oldsmobile Custom Cruiser, Buick Estate Wagon, and Subaru
Justy, and the last carbureted light truck was the 1994 Isuzu. Elsewhere, Lada
cars used carburetors until 1996. A majority of motorcycles still use carburetors
due to lower cost and throttle response problems with early injection set ups, but
as of 2005, many new models are now being introduced with fuel injection.
Carburetors are still found in small engines and in older or specialized
automobiles, such as those designed for stock car racing.
• A fuel injection system is designed and calibrated specifically for the type(s) of
fuel it will handle. Most fuel injection systems are for gasoline or diesel
applications.
Carburetor Theory
• To further regulate the mixture, two “air regulators” or
butterfly valves are also added:
– These restrict the amount of air flow through the
carburetor‐‐either manually or automatically.
This action decreases the power and speed and
11
» the richness of the mixture within the engine.
– Throttle valves restrict air movement at all speeds and
are generally manually controlled.
– Choke valves restrict air movement at start‐up to
allow for a richer mixture and can be manually or
automatically engaged.
Down‐draft Carburetors
• This carburetor operates with
lower air velocities and larger
passages. This is because
gravity assists the air‐fuel
mixture flow to the cylinder.
18
• The downdraft carburetor can
provide large volumes of fuel
when needed for high speed
and high power output.
[attachment=52465]
Carburetors and Fuel injection
• Fuel injection is a system for mixing fuel with air in an internal combustion
engine. It has become the primary fuel delivery system used in gasoline
automotive engines, having almost completely replaced carburetors in the late
1980s.
• The carburetor was invented by Karl Benz (founder of Mercedes‐Benz) in 1885
and patented in 1886.
• Carburetors were the usual fuel delivery method for almost all gasoline (petrol)‐
2
y g p )
fuelled engines up until the late 1980s, when fuel injection became the preferred
method of automotive fuel delivery. In the U.S. market, the last carbureted cars
were the 1990 Oldsmobile Custom Cruiser, Buick Estate Wagon, and Subaru
Justy, and the last carbureted light truck was the 1994 Isuzu. Elsewhere, Lada
cars used carburetors until 1996. A majority of motorcycles still use carburetors
due to lower cost and throttle response problems with early injection set ups, but
as of 2005, many new models are now being introduced with fuel injection.
Carburetors are still found in small engines and in older or specialized
automobiles, such as those designed for stock car racing.
• A fuel injection system is designed and calibrated specifically for the type(s) of
fuel it will handle. Most fuel injection systems are for gasoline or diesel
applications.
Carburetors and Fuel injection
• Fuel injection is a system for mixing fuel with air in an internal combustion
engine. It has become the primary fuel delivery system used in gasoline
automotive engines, having almost completely replaced carburetors in the late
1980s.
• The carburetor was invented by Karl Benz (founder of Mercedes‐Benz) in 1885
and patented in 1886.
• Carburetors were the usual fuel delivery method for almost all gasoline (petrol)‐
2
y g p )
fuelled engines up until the late 1980s, when fuel injection became the preferred
method of automotive fuel delivery. In the U.S. market, the last carbureted cars
were the 1990 Oldsmobile Custom Cruiser, Buick Estate Wagon, and Subaru
Justy, and the last carbureted light truck was the 1994 Isuzu. Elsewhere, Lada
cars used carburetors until 1996. A majority of motorcycles still use carburetors
due to lower cost and throttle response problems with early injection set ups, but
as of 2005, many new models are now being introduced with fuel injection.
Carburetors are still found in small engines and in older or specialized
automobiles, such as those designed for stock car racing.
• A fuel injection system is designed and calibrated specifically for the type(s) of
fuel it will handle. Most fuel injection systems are for gasoline or diesel
applications.
Carburetor Theory
• To further regulate the mixture, two “air regulators” or
butterfly valves are also added:
– These restrict the amount of air flow through the
carburetor‐‐either manually or automatically.
This action decreases the power and speed and
11
» the richness of the mixture within the engine.
– Throttle valves restrict air movement at all speeds and
are generally manually controlled.
– Choke valves restrict air movement at start‐up to
allow for a richer mixture and can be manually or
automatically engaged.
Down‐draft Carburetors
• This carburetor operates with
lower air velocities and larger
passages. This is because
gravity assists the air‐fuel
mixture flow to the cylinder.
18
• The downdraft carburetor can
provide large volumes of fuel
when needed for high speed
and high power output.