1) What is the equivalence ratio? Write its formula and its unit.
▪ Equivalence ratio is defined as the actual ratio of fuel-air to ideal or stoichiometric fuel-air.
▪ It is unit less.
= ( FA) /(FA)
act stoich = ( AF ) stoich /( AF ) act
2) What is the engine mean effective pressure? Write its formula and its unit.
▪ It is a theoretical parameter used to measure the performance of an internal combustion
engine used for comparing engines with regard to design or output because it is
independent of both engine size and speed.
▪ It is measured in Kpa. Mep = / = W / V d
3) What is the engine specific power? Write its formula and its unit.
▪ It is the ratio between the brake power to the piston face area of all pistons
.
SP = W p / A p
▪ It is measured in Kw/cm^2.
4) What are the main exhaust emissions of the internal combustion engines?
The four main engine exhaust emissions are:
1. oxides of nitrogen (NOx),
2. carbon monoxide (CO),
3. hydrocarbons (HC),
4. solid particulates (part).
5) Write short notes about the intake manifold.
▪ It is a piping system that delivers incoming air to the cylinders
▪ It is made of cast metal, plastic or composite material.
▪ Sometimes they are heated to enhance fuel evaporation.
▪ In most SI engines fuel is added to the air in the intake manifold system either by fuel
injectors or by carburetor.
, 6) Classify the internal combustion engines be according to engine cycle, valve location,
type of cooling, fuel used, the position of cylinders and the method of fuel input for spark
ignition engines.
▪ according to engine cycle:
1) Four-stroke cycle: has four piston movements over two engine revolution for each
cycle.
2) Two-stroke cycle: has two piston movements over one revolution for each cycle.
3) Three-stroke cycles and six-stroke cycles were also tried in early engine development.
▪ according to valve location:
(a) Valves in (b) Valves in head, (c) One valve in head (d) Valves in block
block, L head. I head. Standard and one valve in on opposite sides of
Old types of and now are block, cylinder, T head.
engines and common in modern F head. Less
automobiles. automobiles. common automobiles.
▪ according to type of cooling
1) Air Cooled
2) Liquid Cooled, Water Cooled
▪ according to fuel used
a) Gasoline b) Diesel Oil or Fuel Oil
c) Gas, Natural Gas, Methane d) LPG
e) Alcohol-Ethyl, Methyl f) Dual Fuel
g) Gasohol
, ▪ according to the position of
cylinders:
a) Single cylinder
b) In-Line
c) V Engine
e) W Engine
f) Opposed Piston Engine
g) Radial Engine
▪ according to the method of fuel input for spark ignition engines:
a) Carbureted.
b) Multipoint port Fuel Injection: One or more injectors at each cylinder intake.
c) Throttle Body Fuel Injection: Injectors upstream in intake manifold.
d) Gasoline Direct Injection: Injectors mounted in combustion chambers with injection
directly into cylinders
7) What are the positive and the negative characteristics of a hybrid automobile?
Positive characteristics of a hybrid automobile:
1. Better fuel mileage. Fuel saving will become even greater because of the higher thermal
efficiency.
2. Fewer emissions. Engines that run at one speed steady-state can be optimized to run much
cleaner.
3. Combustion engines can be shut off when not needed or when the vehicle is momentarily
stopped. When the vehicle is then again started, the startup can be very smooth with the help of
the electric motor. Test automobiles powered totally by IC engines have been developed to run
on this on-off mode of operation.
▪ Equivalence ratio is defined as the actual ratio of fuel-air to ideal or stoichiometric fuel-air.
▪ It is unit less.
= ( FA) /(FA)
act stoich = ( AF ) stoich /( AF ) act
2) What is the engine mean effective pressure? Write its formula and its unit.
▪ It is a theoretical parameter used to measure the performance of an internal combustion
engine used for comparing engines with regard to design or output because it is
independent of both engine size and speed.
▪ It is measured in Kpa. Mep = / = W / V d
3) What is the engine specific power? Write its formula and its unit.
▪ It is the ratio between the brake power to the piston face area of all pistons
.
SP = W p / A p
▪ It is measured in Kw/cm^2.
4) What are the main exhaust emissions of the internal combustion engines?
The four main engine exhaust emissions are:
1. oxides of nitrogen (NOx),
2. carbon monoxide (CO),
3. hydrocarbons (HC),
4. solid particulates (part).
5) Write short notes about the intake manifold.
▪ It is a piping system that delivers incoming air to the cylinders
▪ It is made of cast metal, plastic or composite material.
▪ Sometimes they are heated to enhance fuel evaporation.
▪ In most SI engines fuel is added to the air in the intake manifold system either by fuel
injectors or by carburetor.
, 6) Classify the internal combustion engines be according to engine cycle, valve location,
type of cooling, fuel used, the position of cylinders and the method of fuel input for spark
ignition engines.
▪ according to engine cycle:
1) Four-stroke cycle: has four piston movements over two engine revolution for each
cycle.
2) Two-stroke cycle: has two piston movements over one revolution for each cycle.
3) Three-stroke cycles and six-stroke cycles were also tried in early engine development.
▪ according to valve location:
(a) Valves in (b) Valves in head, (c) One valve in head (d) Valves in block
block, L head. I head. Standard and one valve in on opposite sides of
Old types of and now are block, cylinder, T head.
engines and common in modern F head. Less
automobiles. automobiles. common automobiles.
▪ according to type of cooling
1) Air Cooled
2) Liquid Cooled, Water Cooled
▪ according to fuel used
a) Gasoline b) Diesel Oil or Fuel Oil
c) Gas, Natural Gas, Methane d) LPG
e) Alcohol-Ethyl, Methyl f) Dual Fuel
g) Gasohol
, ▪ according to the position of
cylinders:
a) Single cylinder
b) In-Line
c) V Engine
e) W Engine
f) Opposed Piston Engine
g) Radial Engine
▪ according to the method of fuel input for spark ignition engines:
a) Carbureted.
b) Multipoint port Fuel Injection: One or more injectors at each cylinder intake.
c) Throttle Body Fuel Injection: Injectors upstream in intake manifold.
d) Gasoline Direct Injection: Injectors mounted in combustion chambers with injection
directly into cylinders
7) What are the positive and the negative characteristics of a hybrid automobile?
Positive characteristics of a hybrid automobile:
1. Better fuel mileage. Fuel saving will become even greater because of the higher thermal
efficiency.
2. Fewer emissions. Engines that run at one speed steady-state can be optimized to run much
cleaner.
3. Combustion engines can be shut off when not needed or when the vehicle is momentarily
stopped. When the vehicle is then again started, the startup can be very smooth with the help of
the electric motor. Test automobiles powered totally by IC engines have been developed to run
on this on-off mode of operation.
