Ignition System

Before we can fully understand how the ignition system on your car functions, we need to brush up on the basics of internal combustion.Your engine is like a big pump. It pumps air and gas in, then pumps exhaust out. The byproduct is a lot of energy that is sent to your wheels (and exhaust out the tailpipe. That's the basic of all basic descriptions. A little detail helps complete the picture. Your engine mixes air and fuel, then adds a spark to make the explosion. This spark ignites the air-fuel mixture, and is referred to as the ignition. This ignition takes place thanks to a group of components working together, otherwise known as the ignition system. The ignition system consists of an ignition coil, distributor, distributor cap, rotor, plug wires and spark plugs. Older systems used a points-and-condenser system in the distributor, newer (as in most we'll ever see anymore) use an ECU, a little brain in a box, to control the spark and make slight changes in ignition timing. What do all of these components do? We'll explain.

The ignition coil is the unit that takes your relatively weak battery power and turns it into a spark powerful enough to ignite fuel vapor. Inside a a traditional ignition coil are two coils of wire on top of each other. These coils are called windings. One winding is called the primary winding, the other is the secondary. The primary winding gets the juice together to make a spark and the secondary sends it out the door to the distributor.
You'll see three contacts on an ignition coil, unless it has an external plug, in which case the contacts are hidden inside the case. The large contact in the middle is where the coil wire goes (the wire that links the coil to the distributor cap. There is also a 12V+ wire that connects to a positive power source. The third contact communicates information to the rest of the car, like the tachometer.

Once the coil generates that very powerful spark, it needs to send it someplace. That someplace takes the spark and sends it out to the spark plugs, and that someplace is the distributor.
The distributor is basically a very precise spinner. As it spins, it distributes the sparks to the individual spark plugs at exactly the right time. It distributes the sparks by taking the powerful spark that came in via the coil wire and sending it through a spinning electrical contact known as the rotor. The rotor spins because it's connected directly to the shaft of the distributor. As the rotor spins, it makes contact with a number of points (4, 6, 8 or 12 depending on how many cylinders your engine has) and sends the spark through that point to the plug wire on the other end. Modern distributors have electronic assistance that can do things like alter the ignition timing.

After the coil takes the weaker juice and makes a high powered spark, and the distributor takes the powerful spark and spins it to the right outlet, we need a way to take the spark to the spark plug. This is done through the spark plug wires. Each contact point on the distributor cap is connected to a plug wire that takes the spark to the spark plug.
The spark plugs are screwed into the cylinder head, which means that the end of the plug is sitting at the top of the cylinder where the action happen. At just the right time (thanks to the distributor), when the intake valves have let the right amount of fuel vapor and air into the cylinder, the spark plug makes a nice, blue, hot spark that ignites the mixture and creates combustion.
At this point, the ignition system has done its job, a job it can do thousands of times per minute.

In the old days, a distributor relied on a lot of its own "mechanical intuition" to keep the spark timed perfectly. It did this through a setup called a points-and-condenser system. Ignition points were set to a specific gap that created optimum spark while the condenser regulated.
These days this is all handled by computers. The computer that directly regulates your ignition system is called the ignition module, or ignition control module. There is no maintenance or repair procedure for the module, other than replacement.

About Fuel Injection System

In the beginning, gas powered vehicles used a carburetor to get gas into the engine. This worked well, but when fuel injection came along, things changed quickly. Fuel injection, especially electronic fuel injection produces fewer emissions and greatly increases gas mileage.


The carburetor was an ingenious invention in itself. Your car's engine has 4 cycles, and one of them is a "suck" cycle. Put simply, the engine sucks (creates extreme vacuum inside the cylinder) and when it does, the carburetor was there to let the right amount of gas and air get sucked into the engine. While great, this system lacked the precision of a pressurized injection system.

Enter fuel injection. Your engine still sucks, but instead of relying on the suck, fuel injection shoots exactly the right amount of fuel into the chamber. Fuel injection systems have gone through a few evolutions, adding electronics was a big step, but the idea has remained the same: an electrically activated valve (the injector) spraying a metered amount of fuel into your engine.


SINGLE PORT FUEL INJECTION

Single port fuel injection systems spray gas into a central intake, that then sucks the gas and air into the engine all at once. This was sort of an in-between invention that combined a carburetor and fuel injection. Most European and Japanese cars skipped this step and went directly to multi-port fuel injection, while American makes used it.


MULTIPLE PORT FUEL INJECTION


Multi-port injection is still widely in use today. So far it's the most efficient method of metering gas into the engine. Multi-port fuel injection, also known as MFI, consists of an injector for each cylinder in the engine. This injector sprays fuel directly through the intake valve or valves into the combustion chamber. Each injector is activated separately by wire. Early versions of this system, such as CIS, Jetronic and Motronic utilized a fuel distributor that metered fuel to the injectors through separate fuel lines. Later versions utilize a single fuel line that connects to a fuel rail on top of the engine. The injectors take gas from the central fuel rail and squirt it into the engine when told to do so.


DIRECT INJECTION DIESEL



With diesel engines making a comeback, there has been more focus in recent years on diesel efficiency. Direct injection diesel engines utilize an injector that sprays fuel directly past the glow plug into the combustion chamber. The technology developed here allows for more complete burning of the diesel fuel, and thus better efficiency and less stinky smoke discharged into the atmosphere



MEASURING AIR

How do fuel injection systems know how much gas to squirt anyway? Somewhere along the line, somebody (probably at Bosch) realized that you could measure how much gas your engine needed by how much air it was sucking in. Once your engine starts, the measuring of air begins. Early fuel injection systems used a vane system, which was basically a flap inside a tube, to measure how much air was being sucked.

Later systems use a "hot wire" to figure it out. When you turn your engine on, the wire becomes red hot. As air is sucked past this wire, it gets a little cooler. The car's brain measures exactly how much cooler it's getting and uses this number to figure out how much air it's sucking. Then it squirts the correct amount of fuel into the engine.

There are lots and lots of variations to fuel injection systems. We've got electrnic fuel injection, mechanical fuel injection, systems with one oxygen sensor, systems with four oxygen sensors ... but the basics remain the same

Brake Problems: Pedal Too Low

Your brakes are probably the most important part of your car. Without an intake system, you'll just sit there. But at least you won't hit a tree while you're just sitting there! Seriously, brakes aren't something to play around with. If your car is having a braking problem, whether it's weak brakes, a mushy pedal, grinding sounds - whatever your brake problem is, you need to troubleshoot and repair it as soon as possible. We'll help you diagnose your braking problem so you know what repairs to make.

Brake Pedal Goes Too Far Down to Stop. If you step on the brake pedal and it feels like it's going too far down before you start to slow, you might have the following problems:

1. Low Brake Fluid Level: Check your brake fluid. If it's low, top it off to the mark on the side of the reservoir.
2. Contaminated Brake Fluid: Even though your brakes operate in a closed system, contaminants can still work there way into the works. Air can enter the system through the smallest hole, and you can end up with water in the system from condensation and other means. There's not really any way to check for this, but bleeding your brakes will remove the bad stuff and replace it with new fluid.
3. Worn Brake Pads: Your brakes should never wear low enough to cause your brake pedal to feel low, they'll scream at you before then. But if they do get very low, you might have this problem. Replace your brake pads as soon as possible. Of course, this can be avoided with regular brake inspection.
4. Bad Brake Power Boost Unit Finally, if your brake booster goes bad you'll have low brake pedal issues. Most brake boosters are vacuum controlled, so a special vacuum measurement device that connects to the brake booster is needed to check it. If it's bad, you'll have to replace the boost unit.

Introductory on the Ground Vehicle

Ground vehicles are those vehicle that are supported by the ground, as contrasted with aircraft and marine craft that in operation are supported by fluid including air or water. Ground vehicle maybe broadly clasified as guided and non-guided. Guided ground vehicles are constrained to move along a fixed path (guideway), such as railway vehicles and tracked levitated vehicle. Non-guided ground vehicles can move by choice in various directions on the ground, such as off-road and road vehicles.

In general, the characteristics of a ground vehicle may be described in terms of its performance, handling and ride. Performance characteristics include the ability of the vehicle to accelerate, to develop drawbar pull, to overcome obstacles and to decelerate. Handling qualities of interest are the response of the vehicle to the driver's command and its ability to stabilize its motion againts external disturbances. Ride characteristics are related to the vibration of the vehicle excited by surface irregularities and its effect on passengers and goods. The theory of ground vehicles is concerned with the study of the performance, handling and ride and their relationships with the design of ground vehicles under various operational environments.