1. Midterm Review
R. Bortignon

4. Piston port timing VS 4 stroke valve timing
4 stroke engine
piston port engine

5. 2 Stroke Diesel Engines 1
Compression
Power
Exhaust
Scavenging

6. 2 Stroke Diesels VS 2 Stroke Gas Engines

7. Diesel Engine Operation
diesel’s have higher thermal efficiency than gasoline engines
in a diesel, thermal efficiency goes up with increased engine load

8. Main difference between diesel & gasoline injection?

9. Gasoline Injection maintains a nearly constant 14.7:1 air-fuel ratio
the volume of air & fuel is varied to change engine power output
during heavy engine loads (low manifold vacuum) more air/fuel is delivered to the cylinders
during light engine loads (higher manifold vacuum) less air/fuel is fed to the cylinders

10. Reminders… drop off completed mechanical labs in my box
fill in “engine info” sheet on the last engine you worked on
fuel must be drained out of fuel tanks
engine stand brackets need to be removed
Engine Assessment Guide due this week!
should be generic, not manufacturer specific
should be applicable to both 2 or 4 stroke
1 assessment guide handed in per team of 2
“Engines of Unknown Condition” activities
moving away from lab based activity to examining & evaluating engine condition
use your assessment guide on the engine
bringing your own engine in? Peter or I must see it at least twice – once when it comes in, once when it leaves
engine must run – you will use the machine as it was intended
Peter, James, Phil & I will keep daily notes on your progress

11. Reminders… 100 Hour Project
do NOT dump off parts in the auto shop or its parking compound
consult with me 1st for large items that need to be left in the shop
motorcycles, riding mowers should be pressure washed 1st
all fuel should be drained & dumped into the black barrel outside the shop labeled “Stale Gas”
you are welcome to dismantle, clean & examine/modify parts any time I am in the shop & you have free time

12. Scrap Metal Bin any & all scrap metals should be placed in here…
large pieces need to be cut up or properly stacked so volume is maximized
bin is NOT a garbage can!