Diesel Engine Speed, Fuel, Controls, and Protection Flashcards
The Control of a Diesel Engine is accomplished through what components?
Camshaft
Fuel Injector
Governor
It provides the timing needed to properly inject the fuel
Camshaft
It provides the component that meters and injects the fuel
Fuel Injector
It regulates the amount of fuel that the injector is to inject
Governor
Together, these _______________ ensure that the engine runs at the desired speed
Three major components
Each cylinder has a fuel injector designed to meter and inject fuel into the cylinder at the proper instant. To accomplish this function, the injectors are _______?
Actuated by the engine’s camshaft
The amount of fuel to be injected by each injector is set by a mechanical linkage called the?
Fuel Rack
The fuel rack position is controlled by the engine’s _______?
Governor
The governor provides the engine with the _____ _____ to change speed as needed and to maintain a speed once reached.
Feedback Mechanism
A governor is essentially a _________, designed to maintain a constant engine speed regardless of _______.
Speed-sensitive device
Load Variations
Governors may be classified as?
Speed regulating Governors
In an engine that is required to come up and run at only a single speed regardless of load, the governor is called a?
Constant-speed type governor
If the engine is manually controlled or controlled by an outside device with engine speed being controlled over a range, the governor is called?
Variable-speed type governor
If the engine is designed to keep the engine speed above a minimum and below a maximum, then the governor is a?
Speed limiting type
This type of governor limits fuel to ensure that the engine is not loaded above a specified limit
Load-limiting type
Common starting circuit of a diesel engine
Air motors, electric motors, hydraulic motors, and manual
The start circuit can be a?
Manual start pushbutton or a complex auto-start circuit
The following events must occur for the starting engine to start.
- The start signal is sent to the starting motor
- The starting motor will crank the engine
- The engine will then accelerate to idle speed.
It is located in the cylinder head of the combustion chamber and uses electricity to heat up the electrode. The heat added by it helps ignite the fuel in a cold engine
Glow plug
Large engines usually heat the block or have a?
Powerful starting motor
Some large engines use _________ that inject compressed air into the cylinders which rotates the engine during the start sequence.
Air start manifolds
It is a type of mechanical flyweight that will act to cut off fuel to the engine and alarm at a certain rpm.
Overspeed device (alarm/trip)
It provides early warning of abnormal engine temperature, usually an alarm function only.
High water jacket temperature (alarm)
It indicates an overloading of the engine or possible poor performance due to inadequate scavenging (cooling effect) in the engine
High exhaust temperature (alarm)
It provides setpoints to indicate low pressure in an engine. One setpoint provides early warning of abnormal oil pressure, an alarm function only. The second setpoint can be set to shut down the engine before permanent damage is done.
Low lube oil pressure (alarm/trip)
It is usually caused by excessive blow-by (gas pressure in the cylinder blowing by the piston rings and into the crankcase). The high-pressure condition indicates the engine is in poor condition.
High crankcase pressure (alarm)