The flashcards below were created by user
on FreezingBlue Flashcards.
Minimum tire tread depth
- Steering axle tires = 4/32"
- Non-steering axle tires = 2/32"
Air Brake Test
- C - Cut In = Air compressor cuts in no lower than 85 psi
- O - Cut Out = Air compressor cuts out no higher than 130 psi (Normal is 110 psi to 120 psi)
- L - Low Air Warning Device = Between 55 & 75 psi
- A - Applied Leak Test - Eng off, Full system, all breaks released, apply pressure to service brakes, let settle, no loss of more than 3 psi over 1 min.
Parking Brake Test
Set Parking brake and try to move vehicle
Allow vehicle to slowly move forward and apply parking brake
What is DEF?
- Diesel Exhaust Fluid
- 32.5% automotive grade urea
- 67.5% distilled water
- Uses 50 to 1 ratio (gallon of diesel fuel to gallon of DEF)
What is SCR?
Selective Catalytic Reduction
What is DPF?
Diesel Particulate Filter
Explain how DEF is used.
DEF (diesel exhaust fluid) is used in the SCR (Selective Catalytic Reduction) to convert NOx emissions in diesel exhaust into nitrogen and water within the exhaust system.
What is DPF Regeneration?
Basically burning off the soot in the DPF.
Passive: naturally occurs when exhaust heat increases above 572 degrees. Normally occurs when engine is over 50% load
Active: ECM (Engine Control Module) modifies engine exhaust temperature by dosing diesel fuel with DEF.