Wednesday, July 27, 2011

Diesels Egines

Who invented the diesel engine and when? 
Rudolf diesel

What fuel pressure would you get from a diesel pump?
15000psi or 1000barHow does the diesel pump work and why do we need to time the pump?
It's purpose pump diesel to the injectors and the reasons for timing is to deliver fuel to the correct injector and the correct time.


How do you time the pump and with what equipment would you use? 
set the cam to top dead center insert DTI  gauge then turn the the flywheel one way read pressure then turn other way read pressure then line up the white marks on the flywheel and block then tighten the cam belt.


What is the purpose of a glow plugs and how do you test the circuit?
Glow are to warm the air inside the combustion chamber to help the start combustion from a cold start.
To test a glow plug 1st use a volt meter and check resistance if in doubt remove glow plug and attack to direct 12v dc current and look a glow starting from the bottom up( a fully functioning glow plug should not have any cold spots a maintain its even glow)


Why do we need an lift pump on diesel engine?
This delivers fuel to the diesel pump fro the tank.Why do we need a electronic fuel shut of valve?
Is a safety precaution in case of malfunction or emergency
What is the knock sensor for and where is it situated?
To prevent engine knock which can cause damage to engine it is situated on the engine at the top near the intake manifoldHow does the diesel injectors work?
They deliver fuel 1 by 1 once they reach manufactures specifications pressure delivered by a diesel fuel pump.Why do you need to bleed a diesel engine after replacing a fuel filter or removing the pump?
The rid fuel lines of air locks/bubbles.How do you bleed the system? 
release nut attached to top of injector one by one until only diesel squirts out then tighten back up againHow does a turbo work?
Exhaust gasses spawl up turbo fins sucking in fresh through different port force feeding engine with oxygen.


Why do we need a turbo fitted to a diesel engine?
To help it run more efficiently and giving it better performance.What is a supercharger?
A belt driven means of forced air driven into intake by two winding screw like shaft


Whats the difference between a turbo and supercharger?
A super charger is belt driven and a turbo is exhaust driven.Why do we need a after- cooler or inter-cooler fitted to a diesel engine?
To cool intake air due to turbo charger running off hot exhaust gasses.


What the difference between  in a direct-injection ( DI,) an indirect-injection ( IDI)?
Direct injection uses a mechanical fuel pump and a indirect uses a electrical pulses to deliver fuel to injectors according to EFI computerWhat is the purpose of an governor?
It controls the set rate of engine speedWhat is the difference between a diesel and a common rail diesel?

A common rail uses one pipe which feeds all injectors and is controlled an ECU. And a diesel has individual pipes feeding each injector from a fuel pump


Wiki 
google
google images 
staparts.co.nz
http://www.dieselduck.net/machine/01%20prime%20movers/diesel_engine/diesel_engine.01.htm
my brain

FUEL INJECTION

ECU- Electronic control unit?


This is a computer that regulates/manages and displays problems of components in your vehicle/vessel.
sensors are located throughout the engine and it's other parts. This can be monitored by a computer that has the correct software either from the manufacturer or the after market software developer.
Mass air flow sensor?
This regulates the air and fuel based on the intake of air being taken into the air intake for best performance.



Air Temp sensor?
This regulates the temprature of the oxygen so the ECU can decide weather more fuel or air is needed to make the best mix. This is important for cold starts on petrol engines and diesel type engines.


TPS throttle position sensor?
This monitors the positon of the throttle found on the butterfly spindle this will make sure the throttle is working correctly




Throttle body?
 This is much like the carb but works differntly because it delivers air and not fuel to engine  


Temp sensor?
helps the ecu senses the air temprature and how dense the air is and will change the ratio of air needed for air/fuel mixture. 



fuel rail?
This is a rail that delivers fuel to the injectors also has a fuel return that sends unneeded fuel back to the tank.

Fuel pressure regulator?
Maintains the needed fuel pressure in the fuel for the injectors the psi is around 30-45.
Injectors?
Delivers fuel to the engine in a pulse and is attached to the engine and fuel rail
Idle air control?
Helps regulate the correct idle speed from deceleration and excelration.
O2 sensor ( lambda sensor)?
Senses the exhaust fume behavior and can relay that information back to the ecu that can then adjust the 


fuel/air mixture.
Map sensor? 
It regulates fuel injection pulses to control the ignition timing.



Plenum chamber?
It is a pressureised housing a gas or fluid/air at pressure greater than surroundings. This is be found on super chargers. A chamber between the throttle body and the runners of the intake manifold. This distributes the intake charge evenly to enhance engine breathing.

Camshaft & Crankshaft sensor?
Detects the camshaft and crank shaft rotational position send information to the ecu to let it know everything is okay.
Who invented fuel injection and when?
Jonas Hasslemen in 1925 and then was further developed by Robert bosch.


Explane how an single and mutli injection system works?




 single: Throttle body injection systems squirts petrol down the throttle body mixing air/fuel.
Multi: Has one injector for each cylinder running off a common fuel rail.

What does EFI stand for?
Electronic fuel injection.


Wiki
Marine bible
http://www.fsrmotorsports.com
google

Carbs

How does the carb work marine four and two stroke?
A carb is situated on the engine, this is to allow fuel and air to be mixed for combustion.
Fuel lines feed the fuel bowl, the float controls how much fuel enters the bowl form there it enters a jet then it enters the venturi. The area of venturi becomes thin to allow fuel/air to mix the is passed on to the engine.


Identify the components in a carb?
Air horn, Choke plate, external valve vent, choke pull off, throttle body, mounting base, float bowl, vacume nipples, idle mixture screw, fuel inlet, fast idle cam,throttle leaver, internal bowl vent.


What are the holes in the emulsion tube for and how does it work? 
The emulsion tube sits in the main well and mixes the air and fuel from the air bleed and adjustment channel that finds it way to venturi.


How does the manual choke and automatic choke work?
A manual choke is cable that is pulled to open the choke. An automatic choke is an electric solenoid using a spring pulls the choke open. The purpose of this is when the engine is cold it allows more fuel in the venturi to warm the engine.What is the purpose of the float in the carb?

The float regulates the amount of fuel entering the cab to prevent flooding it dickates the needle movement.


What is the purpose and how does  mechanical lift pump work?
This transfers fuel from the fuel tank to the fuel bowl.

How does a vacuum fuel pump working on a two stroke engine? 
The piston creates pressure sucking fuel past the diafram into the fuel bowl.What pressures would you get from these types of pump?
3-5 psiWhat the difference between petrol and diesel fuel?
Petrol is more volatile and ignites at a lower temperature giving it a higher performance to price ratio.
Diesel is a cheaper simpler method of fuel but lacks in performance.
How does the fuel shut off solenoid work?
It is a safety precaution using and electric solenoid opening and closing fuel supply to the carb or injector pumpWhat is the four stroke cycle?
Intake,compression, power and exhaust.What does S.I mean?
Spark ignitionWhat does C.I mean?
compression ignition
When dismantling a carb what precaution should you take?
Detailing disassemble eg. remembering how to put it back together, very clean and organised work surface, keeping carb upwright making sure float doesn't malfunction.How does a bimetallic spring work in a automatic choke work?
Is in a sense like a thermostat where it expands and decreases causing the spring to open and close the choke in the choke housing.What is the purpose of the venturi and how does it work?
Works on atmospheric pressure and is like a aircraft wing design where the aerodynamics work in harmony to draw fuel and air at a balanced rate.Explain how a fuel cut off solenoid is checked and why is it fitted?
Multimeter check. or visual inspection.An engine lacks power. What is likely to cause this problem?
Lack of fuel, air leak, air blockage, malfunctioning springs and parts.How do you adjust the float in a carburetor?
Use a feeler gauge to adjust to the manufactures specificationsWhat is the purpose of a power valve?
Is a spring vacume loaded valve which opens under a high acceleration to allow more fuel into the engine to prevent pre detonation/ignition.What are some of the causes of high fuel consumption?
Running to rich, incorrect float adjustment, worn needle valve, defective choke.
How is the the idle and mixture screw adjusted?
With a screw driver, left is to open which is richer and right is closing and becomes leaner.When refitting a three multiple carburettor what should be done after installing them?
Synchronise carb adjustments together .
References
Car craft.com
Wiki.com
Google images
boatfan.com
Marinestrokefetish.com
boatsgonewild.com/dvd/1stedition.com

Tuesday, July 26, 2011

   TRAILERS

     There two main types of boat trailers.
  • single axle: are for smaller boats and have the advantage of better maneuverability however they have a limited weight capacity.
  • tandem axle: These are for larger heavier boats but have a disadvantage of having to maneuver in larger turning circles.

single axle for smaller boats and tandem axle for larger and heavier boats



Boat length     gross vehicle weight rating( This is the maximum and vehicle axle can handle)
15'-17'            3500lbs
17'-19'          
3500lbs  

17'-19'            5200lbs
19'-21'            3500lbs
19'-21'          
 5200lbs
  






DESIGNS.


There are many boat trailer designs but the two main ones are bunk type and roller type.
Bunk type: 

Bunk types have marine carpet covered planks/skids. Are very stable but usually used smaller lighter crafts




Roller trailers:
Can be used for all types of crafts with and have the advantage of being able to adjust the rollers for the hull shape and the weight. The Disadvantage is the roller maintenance and replacement of rollers.
The trailer designs come in many shapes and forms depending of personal choice and the boat owners choice. A frames balance the center point of weight over the axle. The draw bar is to support the bow and has the winch attached to it.




Materials:
Boat trailers are usually made from Galvanised steel Aluminium.



DIMENSIONS restrictions:
The rules are as follow form New Zealand land transport:
It is not wider than 2.5 metres if they're loaded side by side.
Is not higher than 4.25 metres if they're loaded one above the other.
Is not longer than the standard length or rear overhang limits for that vehicle if they're loaded one behind the other.
If you have an over size load you will need special permission to transport it with pilot and safety vehicles.
SUSPENSION TYPES

Leaf springs fixed and floating
Coil springs with damper
Air bags


Wheels and tyres
Wheels are made from alloy or steel. Types have a recommended load capacity so you should always use the recommended tyre your trailer is going to carry.
A dolly wheel 
Hubs:
These are on the end of the axle and provides a place for the brakes bearings and tyres to be mounted to.

Stubs: These are a tapered steel rod welded to axle to house inner and outer bearings.

Breaks: Are only necessary after a certain weight is being towed and come in:
Disk breaks
Drum Breaks
Electric drum breaks.


Couplings:
These are and the front end of the trailer to lock the trailer on the towbar These can also houses break regulator system for the trailer. They come in two sizes 
50mm and 1/78 inches


Winches:
These to pull the boat onto the trailer to make life easier or if the boat is to heavy.


Lights:
Trailers have a power cord connected to the vehicle that makes the break lights or indicators come on when the car breaks.
Submersible lights are a must on marine trailers.