ME- Electrical Engines

Electronic Engines

Control Engine Functions; exhaust valves, fuel injection, turbocharger, through electronics

What drove creation of electronic engines?

Increasing fuel costs

Detroit Diesel

Camshaft to mechanically develop injection pressure, solenoid valve to control the beginning and end of fuel injection

Common Rail System

Fuel is pressurized by engine driven high pressure pump (20000 psi), and is fed to the injectors by engine length manifold. Solenoid valve provide the fuel to the injectors HSDE and MSDE

What does the CR remove

The use of cam driven pumps in smaller engines.

Solenoid Valve Parts

Coil, Core, Valve, Spring

Solenoid Valve Function

Electric current moves core and thus valve against the spring to open. The spring then closes the valve once the electricity is switched off

Core

Metal which the coil is wrapped around

EDU

Electric Driver Unit; amplifier- increases power of control signal to solenoid

ECU

Electrical Control Unit- electronic processor; inputs from sensors, outputs signal to EDU to solenoid

What does ECU sense

engine speed, crank position, engine load

Feed Forward

Engine sensor predicting engine load and putting in more fuel ahead of time

Pressure Relief Valve

Avoids over pressurization in Common Rail manifold returns fuel to tank

Main Difference between common rail and mechanical injection

Injection pressure/rate is not dependent on engine speed, and timing and duration can be infinitely adjusted

NOx

N2 + O2 = 2NO; N2 +2O2 = 2NO2; secondary reactions that take place at high temperature and pressure; leads to acid rain and adverse health effects

Address NOx

Controlling the rate of fuel injection at different stages of injection to reduce knocking and thus NOx

What sets pressure of fuel injection in Common Rail

Pressure Relief Valve

MC Engine

Older Mechanical Engines

ME Engines

Newer electrical engines developed in late 2000s early 2010s

Hydraulic Power Supply

Engine Driven Pumps (on engine), Electric Driven Pumps (off engine, only used at low speed); Power to operate exhaust valve and fuel injection. Takes place of camshaft and timing gears/chain

Membrane Accumulator

Membrane with high pressure gas on other side to reduce the water hammer effect.

Exhaust Valve System

Solenoid Electronic Actuator

Membrane Accumulator

Hydraulic Push Rod

Spool Valve

Controlled by Electrical System

Fuel Injection System

Servo Positioning Device

Membrane Accumulator

Hydraulic Piston

Proportional Valve

Controlled by Electrical System

Proportional Valve

Can be toggled from 1-100 as opposed to on or off

Hydraulic System

Reservoir

Suction

Hydraulic Pump

Electric Motor

Pressure Line (1000- 5000 psi)

Control Valve

Operator

Return Line

Unloading Valve

Reservoir

Tank with Hydraulic Fluid- not pressurized

Suction

Pulls Hydraulic Fluid from reservoir and into pump

Directional Control Valve

1. Spool Valve

2. Connected to Operator; Has one Hydraulic fluid inlet and two outlets— one on either side has two ports into the actuator

2. Used to direct the flow of the fluid by means of determining which direction the fluid flows

Operator

Used to toggle the control valve; Can be a lever or a Solenoid

Land

Large piece on Spool that prevents flow in certain directions depending on positioning.

Vane Motor Parts

Vanes

Casing

Rotor

Shaft

Vanes

Free to slide in slots in Rotor; are pushed by high pressure oil/air to generate torque

Rotor

Has slots for vanes, rotates shaft

Shaft

Directs the output from the motor

Vane Motors

Used to direct hydraulic oil everywhere on ships without the risk of creating electrical ignition sources; Used for Starter Motors on engines; 1800 RPM

+Variable Speed

— Wear on the Vanes

Power Unit

Single Motor and Pump dedicated to serving a single actuator

Central Systems

Group of pumps supplies oil continuously to a pipe manifold from which a number of actuators can run

Cylinder Control Units

Controls the fuel injection and exhaust valves for a single cylinder using electronics; supplied with 2900 psi / 200 bar hydraulic oil.

ELFI and ELVA

Hydraulic Oil Loop

Sump

Filter

Engine/Electrical Driven Pumps

Safety and Accumulator Block

Cylinder Control Units

Safety and Accumulator Block

Has Relief Valve and connects up all the separate hydraulic oil lines

Exhaust Valve Timing

Open for Longer for higher loads, open for shorter for lower loads

Change in Exhaust Valve Timing

Function of engine load and operating mode

Constant Pressure

Economy Mode, max power out for minimum fuel used; High NOx output

Double Injection

Low NOx mode; 2% loss in efficiency; required within 200 miles of shore

1st Injection

fuel atomizes, increase temp, auto ignites

Ignition Delay

after which all fuel injected burns rapidly giving peak injection pressure and temp

After 1st Injection

reduced rate of injection until after peak pressure and temperature

2nd Injection Peak

Required to reach needed power output

What determines the rate and timing of injection in mechanical Engines

The profile of the cam and the position of it relative to the crank.

Hydraulic Oil

Lube Oil from Sump

Unloading Valve

Relieves the pressure when the lands of the directional control valve cover the hydraulic oil inlet. Shortcuts circuit and sends fluid back to tank