Otto engine, Electronic braking system, hydraulics Flashcards
The 2 operating modes of direct injection petrol engines are homogeneous and layered. What do they mean
Homogeneous: the injection takes place during the intake stroke
Layered: the injection takes place during the compression stroke
What fuel can be used in an Otto engine?
Petrol, Ethanol, LPG, CNG
What does ESP stand for? (relates to ABS)
What is it?
Electronic stability programme
A collection of different systems responsible for ensuring that the vehicle doesn’t go out of control
List 5 of the systems that are part of the ESP
Anti-lock braking system (ABS)
Anti-slip regulation (ASR)
Brake assist system (BAS)
Motor speed regulation (MSR)
Electronic traction system (ETS)
Anti-lock braking prevents the wheels from completely stopping rolling and slows them down at the optimal level.
Does this produce a longer or shorter stopping distance?
Why?
Shorter
Because the skid that occurs when the brakes lock causes the vehicle to travel further
List 3 advantages of ABS
Vehicle can still be controlled while braking
Less tyre wear
Shorter stopping distance
Give one disadvantage of ABS
Vehicle is less economical
What is the role/function of the anti-slip regulation (ASR)?
Ensures that driven wheels do not slip when accelerating by controlling engine power
What is the role/function of the brake assist system (BAS)?
Ensures that the vehicle has the optimum braking pressure
It keeps increasing the braking pressure until the ABS intervenes
What is the role/function of the motor speed regulation (MSR)?
Ensures that the wheels do not slip when slowing down the engine (engine braking) by adding fuel to the engine.
Why is the motor speed regulation needed to prevent the wheels from slipping when slowing down the engine by adding fuel?
When decelerating downhill, the wheels drive the engine and the injection is cut and the engine compression, which continues to happen, can cause the wheels to slip.
What is the role/function of the electronic traction system (ETS) or traction control system (TCS)?
It brakes one wheel more than others when accelerating if it loses its grip, causing the other wheels to gain more traction
In a hydraulic system, what’s a way to increase or decrease the force transmitted without increasing the force produced?
What does this, however, not change?
Adjusting the sizes of the pistons in comparison to each other
Pressure
Give the formula used to calculate the pressure exerted by a piston (using force)
P = F / A
Pressure = Force / Area
Pascals = Newtons / square meters
What is the purpose of the high pressure pump in the braking system?
To ensure that there is enough braking fluid pressure in the ESP when the ESP is acting. The pump is not energised if the ESP does not intervene
