Engineering Magazines

In a conventional marine diesel engine the power is produced by hot compressed air igniting fuel sprayed under very high pressure into the cylinder head. A marine diesel engine does not use a carburetor to mix fuel and air or spark plugs to ignite the mixture. Instead it employs the pistons to compress the air to 3000 kPa which causes it to become extremely hot and the fuel is ignited as soon as it is injected into the cylinder.

Some marine diesel engines are fitted with a heater plug in the inlet manifold or a glow plug in the pre-combustion chamber of each cylinder to provide additional heat to the combustion air during starting.

Diesel engines are heavier and slower revving than petrol engines but they are also more reliable because they do not rely on external carburetion or an electrical spark for ignition.

Newer engines use an electronic fuel injection system whereby fuel and air are mixed more thoroughly in the pre-combustion chamber before entering the cylinder. This system maximizes power and fuel economy and is also less polluting.

Every boater should have an understanding of how their engine works so let’s start by explaining the mechanical cycles.

Most reciprocating piston internal combustion engines work on one of two mechanical cycles-either the four-stroke cycle or the two-stroke cycle. These cycles designate, in correct sequence, the mechanical actions by which the fuel and air gain access to the engine cylinder, the gas pressure – due to combustion – is converted to power and, finally, the burnt gas is expelled from the engine cylinder.

The Basic Four-Stroke Diesel Engine

From its name, it is obvious there are four strokes in one complete engine cycle. A stroke is the movement of the piston through the full length of the cylinder and – since one such movement causes the crankshaft to rotate half a turn – it follows that there are two crankshaft revolutions in one complete engine cycle.

The four strokes in the order they occur are:

1. Inlet stroke. With the inlet valve open and the exhaust valve closed, the piston moves from top dead center (TDC) to bottom dead center (BDC), creating a low-pressure area in the cylinder. Clean, filtered air rushes through the open inlet valve to relieve this low-pressure area, and the cylinder fills with air.

2. Compression stroke. With both valves closed, the piston moves from BDC to TDC, compressing the air. During this stroke the air becomes heated to a temperature sufficiently high to ignite the fuel.

3. Power stroke. At approximately TDC, the fuel is injected, or sprayed, into the hot, compressed air, where it ignites, burns and expands. Both valves remain closed, and the pressure acts on the piston crown, forcing it down the cylinder from TDC to BDC.

4. Exhaust stroke. At approximately BDC the exhaust valve opens and the piston starts to move from BDC to TDC, driving the burnt gas out of the cylinder through the open exhaust valve.

The Two-Stroke Diesel Engine

The two-stroke engine uses two piston strokes to complete one power stroke and, therefore, fire twice as often as a four-stroke engine. A two-stroke engine is smaller and simpler with fewer moving parts. A two-stroke engine has the potential to produce twice as much power as a four-stroke engine of the same size, however, because of the extra fitting required in a two-stroke diesel engine, for example blowers and governors, they become more expensive to produce. There has been a shift towards four stroke diesel engines which have become more efficient and smaller.

Protect Your Marine Diesel Engine

Protect your engine by avoiding long periods (more than 10 minutes) of idling in a “no-load” situation. This is often done to charge batteries or cool refrigeration but if done repeatedly it will glaze the bores of the engine and cause premature engine failure. If the vessel is in a berth the engine can be put in gear to create load at idle.

All boat owners should have an understanding of basic marine diesel engine maintenance to keep themselves and their families safe on the water.

We live in the digital age where technology makes our lives easier each day. Advance medical equipments are created to help doctors treat patients, kitchen tools are innovated to make it easier for home makers, and cars are made smarter to make driving easier for humans.Automotive electronics paved the way for helpful features like anti-lock braking systems (ABS) and automatic weather adjustments which makes driving safer and more comfortable.

Car manufacturers spend about two thousand dollars in automotive electronics for every car that comes out of the assembly line. These automotive electronics transform the car into a vehicle with better performing engine, more adaptive entertainment systems, and safety features that are far more superior than its predecessors.

Automotive Electronics of the Modern Car

Control Area Network or CAN – There are several computers that run a modern car. The CAN is a network of computers that play vital roles in the different functions of the engine and its peripherals. The CAN serves as the bridge for the different computers so they can communicate with one another so everything are well coordinated. CAN controls the functions like cruise control, engine management, and the ABS.

Fuel Efficiency- automotive electronics can save a car owner hundreds of dollars in fuel consumption. This is done thru the EFI or Electronic Fuel Injection technology which ensures that the engine’s fuel consumption is at its optimal. In hybrid cars, a driver can easily switch from using gas and electronic power supply to run the vehicle.

Safety Devices- Most safety system is controlled by automotive electronics. Devices like the Acceleration Slip Regulation, Traction Control, Electronic Stability and Dynamic Steering wheel ensure the safety of the driver and the passengers. The simple but complicated timing of airbags during a road collision is also controlled by advanced automotive systems.

Added Features- Some cars today can even park themselves without any assistance from the driver. All the calculations are done by a computer making sure the car will not hit anything by making references to other cars and different objects in its surrounding.

One cannot imagine the evolution that took place with automotive electronics. The Apollo 11 which landed on the moon ran on a memory which is 150 kilobytes only. The sound systems of our cars today are running on 500 kilobytes of memory to ensuring our entertainment pleasure. Automotive electronics have gone far beyond entertainment and enhanced modern day vehicles in terms of safety, efficiency, and convenience.

The automotive industry projects billions of investments and sales in developing cars that are smarter, more fuel efficient and more environment-friendly in the future. Modern cars can be the answer to alleviate the adverse condition of the environment and the rising price of fuel all over the globe.

Cars are being developed to scan the traffic, the road, and all hazards so it can drive itself while the driver can do anything that he wants while in motion. The future cars can think for themselves with the aid of advanced automotive electronics. In that way, driving will be more than getting from one place to another.

A decade ago motorcycles had speed, looks, and style. They have certainly improved with each passing year. Year after year motorcycle manufacturers get more innovative, produce faster, lighter and more comfortable motorcycles, and learn what works and what doesn’t. What are the favorites from 2007?

- Yamaha V Star 1300 Tourer.

These motorcycles have a V2 engine with an electric starter and a liquid cooling system. The seat was 28.1 inches and the dry weight was 668 pounds. It was made with a double cradle frame and a telescopic fork front suspension with a swingarm rear suspension. These motorcycles had single disc rear brakes and double disc front brakes. They have a fuel capacity of 4.88 gallons.

- BMW R1200GS

These motorcycles have a two cylinder boxer engine. They also have an electronic fuel injection with an electric starter. These motorcycles had oil and air cooled engines and a 6-speed gearbox. At 438 pounds, they were meant for speed. These off road motorcycles came in desert yellow metallic, rock red metallic, ocean blue metallic, or granite gray metallic. Though the fuel capacity is a whopping 5.28 gallons, the consumption is 1.45 gallons for every 6.2 miles.

- Yamaha WR 450 F

These are also off road motorcycles. They have a single cylinder engine, with a liquid cooling system. At just 246 pounds, it is nearly two-thirds the weight of the BMW R1200GS motorcycles. The front suspension is a telescopic fork, the rear a swingarm. The fuel capacity on these motorcycles is a mere 2.10 gallons. These motorcycles had single disc brake systems for both front and rear.

- Yamaha FZ1 Fazer

These naked motorcycles had in line four engines with an electric starter. They also had a liquid cooling system, a final drive chain transmission, and digital ignition. Like the BMW R1200GS, these Yamaha motorcycles weighed 438 pounds. The frame was aluminum die cast and the front suspension was telescopic upside down forks. The rear a swingarm suspension. These motorcycles had double disc front brakes and single disc rear brakes. Fuel capacity on these motorcycles is 4.76 gallons.

- Harley Davidson VRSCX

These custom or cruiser motorcycles have a V2 engine. They have an electronic sequential port fuel injection system and liquid cooling system. The seat is a mere 27.1 inches high and the weight 637 pounds. These motorcycles are 5-speed with a final drive belt transmission. The front and rear brakes are both single disc four piston. These motorcycles came in two tone mirage orange pearl or brilliant silver pearl. It has a 5 gallon fuel capacity.

- Victory Vegas Jackpot

Like the Harley Davidson VRSCX, these motorcycles are also custom or cruiser motorcycles. With a V2 engine, an air cooling system, and final drive belt transmission, it has many of the same features as the Harley Davidson VRSCX motorcycles. It has an electronic fuel injection system and a 6-speed gearbox. These motorcycles had an even shorter seat at 25.7 inches high. Though the seat was lower, they were a bit heavier weighing 659 pounds. The fuel capacity was 4.5 gallons and colors included black, orange crush, or sunset red.