Introduction to ICE Flashcards
Recipicating
Means “gjenntagende”
What types of work can we encounter?
- Shaft work=shaft work delivered to a load= torque*angular speed. Its the ideal work of the sharft.
- Thermodynamic work= Q_in-Q_out= used in closed cycle. Note that for open systems like turbones we use integral of v*dp insted
- Break work=real-world usefull output meassured with dynamometer =Power_break*time. Is the actual work of the shaft
Which unit does energy, power and work have?
Energy has j
power=energy/time=j/s or W
Work has j too!
- Difference between energy and work is that energy is a state, while work is energy doing something/changing from one state to another
How many j/sec in w
1
is hp the same as w?
yes. They both measure power
What is some defining characteristics of ICE?
- wide power range
- Wide range of fuels
- Comparatively high energy utilization
What are the main characteristics of SI-engines?
- Pre-mixed fuel-air mixture
- Ignition by electric spark discharge
- Combustion in flame front
- Behind in flame:combustion products and In front of the flame: unburned fuel-air mixture. This means that the spark plug creates a flamefront that moves from sparkplugs and out in the cylinder.
Describe CI-engine
- Compress air to high temperature
- Inject fuel at high pressure (1000-2500 bar)
- Thermal auto-ignition of fuel-spray
- Mixing of fuel and air controls combustion
Name some types of cylinder configurations
- In line engine: up to 14 cylinders
- V-cylinder: up to 20 cylinders. Has a reduced axial length cs engine power ofc
- Boxer
-Star
Describe the ideal otto cycle
See fig 1
Describe the ideal diesel cycle
See Fig 2
Explain 4-stroke otto cycle mechanics
See fig 3
Explain 4-stroke diesel cycle mechanics
See fig 4
Explain 2-stroke otto cycle mechanics
See fig 5
Explain 2-stroke diesel cycle mechanics
See fig 6
What are some advantages with 2-stroke engines?
Can deliver more power, need less inertia and hence can deliver at lower speeds compared to 4-stroke
What types of air-supply exist and what are their advantages?
- Naturally aspired: air is suplied naturally at 1 bar
- Supercharged: Air is compressed before entering cylinder at higher pressure. The compressor is driven directly from crankshaft motion or by exhaust turbine
- turbocharger: Exhaust turbine converts exhaust energy to mechanical power that drive the turbocharger. turbocharging is a type of supercharging. Its the preffered one, as it utulizes exhaust energy that other ways would be lost.
Explain bore, stroke, TDC, BDC, Connection rod length, cranc radius and CAD
diameter, length of piston motion, top dead center, bottom center, length from tip of crank shaft to connection to piston, radius of crank shaft, degrees from TDC
Define work pr cycle
W= int(p)dV
with other words the area under the graph for a p-V diagram.
What types of non-pollutant and pollutant emission do we have?
Non: H2O, O2 and N2
Pollutant: SOx, CO2, HC, CO, NOx and PM
