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67 Cards in this Set

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What is the four stroke cycle?
Intake, compression, power, exhaust
What happens in the intake stroke?
Air/Fuel mixture enters the combustion chamber.
What happens in the compression stroke?
Air/Fuel mixture is compressed.
What happens in the power stroke?
Air/Fuel is ignited by spark plug.
What happens in the exhaust stroke?
Burned Air/Fuel gases are forced out of the combustion chamber.
What is the Air/Fuel mixture ratio?
14.7 to 1 for gas mixture.

Varies for the diesel engine depending on how much fuel is injected
What is the ignition method for gas?
Spark
What is the ignition method for diesel?
Compression
What is the funtion of the supercharger?
Enhances engine horsepower by forcing more air in to the cylinders.
What drives the supercharger?
A belt driven by the crankshaft.
What controls the output of the supercharger?
ME control module through an electromagnetic clutch.
What is the maximum charge pressure for the 112 engine?
1100 mbar.
What is the function of the turbo charger?
Enhances engine output by forcing more air in to the cylinders.
Where is the location of the turbo charger?
Normally located on the exhaust manifold of all engines.
What drives the turbo charger?
Exhaust gases.
What controls the turbo charger output?
ME control module.
What is the purpose of the intercooler?
Cools the air heated up by the compression during intake.
Where is the intercooler located?
Below the radiator.
How can engine breathing be enhanced?
Tuning the intake manifolds to optimize the pressure pulses in the intake system.
What is used to increase the efficiency of the intake manifold and broaden the torque range?
Variable Runners.
In variable runners where is the air directed at low RPM's?
The long runners, to increase the airs velocity.
In variable runners where is the air directed at high RPM's?
The short runners, to increase the volume of the incoming air
At high engine load and low rpm the flaps are?
Closed, directing air into the long runners.
At higher rpm the flaps are?
Opened, directing air in to the short runners.
What two engines have swirl flaps?
272 and 648
What three engines have variable intake runners?
112, 113, 272
What is the purpose of swirl flaps?
Improve air/fuel mixture constancy.
Which engine has a intake manifold with integral vacuum reservoir?
272
Exhaust valves are usaully smaller in diameter then intake valves except in...?
Three valve engines like the M112 and M113.
Exhaust valves are filled with sodium to...?
Absorb heat and reduce thermal load on valve.
What two engines have three valves per cylinder?
112 and 113
What two engines have four valves per cylinder?
272 and 648
At what speed does the camshaft turn?
One half the crankshaft speed
What two engines have the single overhead cam?
112 and 113
Which DOHC engine has the bearing caps integrated into the cylinder head cover?
272
What two engines use a dual overhead cams?
272 and OM 648
What is the combustion chamber formed of?
The top of the piston and the cavity in the cylinder head.
What is the specification for the compression test?
12 - 15 bar, less then 1.5 bar between highest and lowest piston.
What is the specification for the leak down test?
Max cylinder leak of 25%
What do you check when installing a timing chain?
Camshafts are timed together.
Camshafts are timed to the crankshaft.
Balance shaft is timed to the crankshaft.
What is the diesel injection pump driven by?
Camshaft via a gear.
What is variable valve timing?
a method that advances or retards camshaft timing to improve engine performance and emissions.
What engine uses variable valve timing?
272 (273)
What is the purpose of the damper?
Reduces engine vibration.
Mounting surface for drive pulley.
What is the purpose of the balance shaft?
Reduces engine vibration.
What direction does the balance shaft rotate?
Opposite of the crankshaft.
What motors use a balance shaft?
Some four cylinders and all V Six engines.
What engines use a balance shaft?
112 and 272
Why doesn't the V8 use a balance shaft?
The two additional power pulses make up for the degress of rotation where no rotational torque is applied.
What technology creates a near perfect junction between the cap and the rod?
Cracking
What forms the walls of the combustion chamber?
Cylinder bores
What drives the oil pump?
Crankshaft
What creates pressure for the lubrication system?
Oil Pump
What is the oil specification at operating temperature?
.7 bar at 700 rpm
3 bar at 3000 rpm
What does the suction fan do?
Pulls air through the radiator to reduce coolant temperature.
What commands the suction fan?
ME SFI control module
What inputs cause the suction fan to come on?
AAC, CAAC, and coolant temperature sensor.
What is the purpose of the auxiliary water pump?
Ensures that water flows through the heater core uniformly, w/o bubbles, even at low speeds.
What are the recommended coolant mixtures?
50/50 or 45/55
What degree are the ring gaps staggered at?
120 degrees
When must the connecting rod bolts be replaced?
If they are longer then specified.
How long do the spark plugs last in a 112/113 engine?
5 years/91,000 miles
How long do spark plugs last in a 272 engine?
5 years/78,000 miles
How long does oil last?
1 year/13,000 miles
How long does the air filter last?
4 years/52,000 miles
How long does the coolant last?
15 years/142,000 miles
During an oil change when is the oil filter replaced?
Before the oil is drained.