Engine 2 - Fuel, Ignition, Air and Exhaust Flashcards
What is diesel fuel made of?
87% Carbon
11% nitrogen
1% sulfur
What is the meaning of the term flame travel?
Distance across the combustion chamber that the flame of the ignited mixture travels
What does NOx mean?
Nitrogen oxide and nitric oxide
What does the term octane refer to?
Petrol fuel
What does the term cetane refer to?
Diesel fuel
What is the purpose of the catalytic converter and what does it turn harmful gases into?
CO2, H2O, Nitrogen
What type of exhaust leak is each colour:
Blue smoke
White smoke
Black smoke
Oil
Water
Fuel
What does the ‘delay period’ in the combustion process refer to?
The period between fuel being injected into the cylinder and it self-igniting
What does a contactless breaker point do in a distributor?
Sends a message to each of the 4 cylinders to ignite, but not by using contact
What component replaced the distributor?
Carburetor
Referencing ignition, what is low tension and high tension?
Low voltage and high voltage
List the 3 components of a pre-carburetor car on the high tension side of the circuit
Distributor, spark plugs, coil
List the 3 components of a pre-carburetor car on the low tension side of the circuit
Timing control system, ignition switch battery
How is a distributor timed?
Using the camshaft
List the 3 types of contactless breaker point sensors used in electronic distributors
Inductive
Optical
Hall effect
How do inductive sensors work?
Consists of a coil and a magnet
Distributor shaft rotates and magnatically induces voltage in the coil, which turns on and off the primary circuit using transistors
How do optical sensors work?
Laser beams
Hall effect sensors are similar to inductive sensors. What is the difference?
Rather than an electronic and magnetic component, there are 2 magnetic components
What do passive sensors do?
What do active sensors do?
Detect natural emissions from the target
Emit their own energy and detect the reflection
What is the ideal fuel to air ratio inducted into the cylinder?
14.7:1
What is a pulse generator most commonly found in?
An electronic ignition system
What should you do before checking the exhaust emissions of an engine?
Run the engine until it reaches normal operating temperature
What does the injector do in a direct injection compression ignition engine?
Injects the fuel into the cylinder
Why are diesel engines fitted with a speed limiting device?
Prevent over revving
Give one likely cause of an emissions test showing an excessive amount of Carbon Monoxide.
A defective spark plug
What does the term naturally aspirated engine mean?
Air enters the engine at atmospheric pressure
What is octane rating a property of?
Petrol
What is the ‘delay period’ in the combustion cycle of a CI (diesel) engine?
The period before self-ignition when injected fuel absorbs heat
Give one probable cause for engine misfires at all engine speeds?
A defective coil
What fault would most likely highlight a defective coolant temperature sensor?
Excessive fuel consumption
What will increasing the fuel injector pulse width do?
Inject more fuel
What does a hot wire air flow sensor measure?
Airflow mass
If an internal combustion engine compresses the intake air greater than atmospheric pressure what is it? 2 descriptions
Turbo-charged
Which gas in an EGR system is designed to be reduced?
NOx
What does a sequential fuel injection system do?
It delivers fuel to each cylinder in turn
What is meant by the ‘flash point’ of a fuel?
The critical temperature at which the fuel will ignite
What is cetane rating a property of?
Diesel
What is important to do before removing petrol injectors?
Depressurise the fuel pipes
On a D.I.S with a coil pack, when a spark occurs on the exhaust stroke it is described as a:
Wasted spark
Where are the injectors located in multipoint fuel injection systems?
The inlet manifold
What is the name for the fuel injection system which use of a single injector to sprays fuel towards a throttle?
A single point system
List 2 exhaust gas products that are NOT harmful in the environment
CO2 and H2O
What do direct injection S.I Engines inject fuel into?
The engine cylinder
What are the two windings in an ignition coil known as?
Primary and secondary
Severely over advanced ignition timing will cause
Pinking
Where is the sensor that measures engine position and speed found?
Crankshaft or front pulley
Where is the pressure regulator usually located in a multipoint fuel injection system?
On the fuel rail
Why will setting spark plug gaps too wide will cause running problems?
The firing voltage will increase and the spark duration will decrease
A M.A.P sensor changes ignition timing in relation to engine…
Load
What is excessive fuel consumption due to a rich fuel mixture likely to cause?
Black smoke from the exhaust
What do turbo-chargers and super-chargers both do?
Compress more air into a smaller space so that when in the cylinder, the compression stage is more powerful
What are turbo-chargers powered by?
Where do they send air from and to?
A turbine
From exhaust and to intake manifold
What are super-chargers powered by?
Where do they send air from and to?
The crankshaft
From outside air and to inlet manifold
What are turbo-chargers and super-chargers both in the category of? (2 answers)
Forced induction
Dynamic compressors
What is the most common type of supercharger?
Centrifugal supercharger
What is the typical boost in air pressure caused by a turbo?
What is normal atmospheric pressure?
So what kind of increase is this?
6 to 8 or 5 to 10 pounds per square inch (psi)
14.7 psi
About 50% more
What is the typical boost in air pressure caused by a supercharger?
6 to 9 or 5 to 30 psi
List components of a turbo
