July 15th, 2010 admin
From Gas Tank To Combustion Chamber: Following The Path Of Automotive Fuel
When most drivers need gasoline, they visit a service station, fill their vehicle’s tank, and never give a second thought regarding what happens next to the gas. Somehow, it travels from the tank to the engine. Within the engine’s cylinders, it mixes with air before being compressed and ignited to generate power.
There are several problems along the way that can prevent fuel from reaching the cylinders. For this reason, it’s worth reviewing the path along which gasoline travels from the tank. We’ll examine its path below, starting with the fuel pump and filter.
Fuel Pumps And Filters Explained
Gasoline remains within your tank until it is pushed out to the fuel line. This is the job of your fuel pump. In most vehicles, this component is mounted inside the tank; in some cars, it is bolted underneath. The pump is designed with an inlet tube on one end and a valve on the opposite end. Gas is pulled into the pump through the inlet tube, and is prevented from passing by the valve. A motor contained within creates pressure. When gas is needed, the valve opens and allows it to enter the fuel line.
A fuel filter lies further down the line, and acts as a crossing guard between the gas tank and engine. A roundish canister is filled with filtering material that prevents contaminants from passing. These contaminants can easily clog the fuel injectors, or cause damage to the engine. The filtering material inside this component cleans the gas, and allows it to pass to the fuel rail.
Fuel filters are inexpensive (usually less than $20). Thus, it is a good idea to have it replaced every two years. Given that it protects your engine from harmful elements, it is one of the best investments you can make toward preserving the life of your vehicle.
From The Filter To The Injectors
Once gasoline has been allowed to pass your fuel filter, it travels to your fuel rail. Along this rail lie your fuel injectors. The injectors are part of a larger system that is controlled by your car’s powertrain control module (PCM). The PCM makes precise adjustments to the amount of fuel allowed to enter the injectors. These adjustments are based on a stream of data received from the oxygen sensor as well as your driving conditions.
Over time, the injectors can become clogged. One of the most common reasons this occurs is due to a wax-like material left behind whenever you turn off your car. The heat around the injectors dissipates while the wax-like material hardens into deposits within the nozzle.
A partially-clogged injector will be unable to deliver the precise amount of fuel measured by the PCM. As a result, the air-fuel mixture within the cylinder will be too lean. You’ll experience a misfire, hesitation while accelerating, and idling problems. Your car’s fuel efficiency will also decline.
Maintaining Your Vehicle’s Fuel System
You can prevent many of the problems noted above by actively maintaining your car’s fuel system. As noted earlier, change the filter every two years. It will eventually accumulate so many contaminants that it becomes unable to do its job properly.
Also, use high-quality gas. Cheap gasoline lacks the detergents that help keep the injectors free of buildup.
If you drive short distances, consider having your injectors cleaned every 30,000 miles. Short-distance driving makes the nozzles more susceptible to heat soak. This is the process through which the waxy material is left behind when you turn off your engine.
Your car’s fuel system seems simple, but is actually complex. The individual components (i.e. pump, filter, injectors, etc.) are located in different areas, and work in unison to ensure your engine receives clean fuel with sufficient pressure. Meanwhile, your PCM controls the amount that ultimately ends up within the cylinders. Take steps to maintain this system since doing so will help prevent expensive damage later.
Muscle Cars
Related posts
Tags: Automotive Fuel, Gas Prices, Gasoline, Save Gas
Posted in Cars | No Comments »
May 4th, 2010 admin
Introduction To Camshafts
If you’re unfamiliar with camshafts, you’re in for a treat. Maybe you’ve overheard mechanics talking about them, and you know they have something to do with car engines, but that’s about it. Well fear not, because you’re about to get a crash course in what exactly this part is and what it does.
Back To Basics
The engine in your vehicle contains two rotating shafts. At the bottom, you’ll find the crankshaft. When your pistons fire (as a result of pressing down on the gas pedal) it causes the crankshaft to turn. That keeps the pistons in a fixed position relative to one another. Because of the way the engine works, only one piston can be at the very top center position at a time. The crankshaft ensures that the pistons will come to that center spot in a specific order at the right time.
Now, when the spark plug fires, it causes the air and gas mixture to burn, and subsequently forces the piston down. When the piston descends, it turns the crankshaft at the bottom. The turning of the crankshaft is what causes the flywheel and drivetrain to turn.
At the top of the engine is the camshaft. It regulates the timing of the opening and closing of the valves. That ensures that when the spark plug fires, there will be gas present. The exhaust is properly emptied so that the air and gas mixture can be reloaded and the entire sequence can occur again (over and over).
The most critical parts are the lobes. While the camshaft is spinning, the lobes are the parts that actually open and close the intake and exhaust valves. They do so in perfect synchronization with the pistons. Interestingly, engine performance at various speeds is directly affected by the shape of the lobes. Therefore, engineers place great emphasis on their production, depending on what type of performance capabilities the vehicle needs to have.
The most common types of camshafts are as follows:
- Single Overhead (SOHC)
- Double Overhead (DOHC)
- Pushrod
Without going into too much detail, here’s a brief overview of the main types:
Single Overhead
This type of camshaft has one cam per head on the engine. In other words, a straight 6 (inline 6 cylinder) engine would have one cam, while a V-6 would have two (one for each of the heads).
Double Overhead
You guessed it; double overhead cam engines have two for each head. So, using the same scenario as above, an inline-6 engine would have two cams, while a V-6 would have four.
Pushrod
The main difference between pushrod cam engines and singe/double cam engines is that pushrod engines have the camshaft actually located inside the engine block, rather than on the head.
If you believe you may be experiencing engine problems due to a malfunctioning camshaft, you should see a mechanic as soon as possible. Even though I describe a lot of these systems in these columns, repairing the components involved requires a trained hand. Unless you’re experienced, check with your mechanic. Most of the problems that involve this part are best left to a technician.
Muscle Cars
Related posts
Tags: Camshafts, Car Maintenance, Car Repair, Cars
Posted in Cars | No Comments »
February 17th, 2010 admin
Why Relying On Your Car’s Tire Pressure Monitor Is Unwise
All drivers realize that their safety depends, in part, on the condition of their car tires. It also depends on the pressure within them. If they’re underinflated, it’s possible to lose control of your vehicle, which can lead to disastrous results. A couple of years ago, the government noted the danger and got involved. They passed a law requiring all new cars, trucks, and SUVs that came off the assembly line to have tire pressure monitors (TPMs) installed.
So, that means there’s no longer a need to check the pressure in your wheels, right? Not quite. In this article, we’ll take a closer look at these systems. I’ll point out their limitations and why relying upon them can leave you and your passengers vulnerable to injury. I’ll also explain the two different types of TPMs available.
Are You Exposed To Danger?
It’s worth noting that a lot of these systems will only display a warning if your wheels are severely underinflated. At the time of writing, automakers are only required to program their tire pressure monitors to alert the driver if the level of underinflation reaches 25% or more. This is a problem. At that point (actually, well before it), your wheels can potentially blow out if you’re carrying enough weight in your car.
Unfortunately, most drivers depend upon their vehicles’ TPMs to warn them of a problem. As long as they don’t see the warning light, they assume they’re safe. If you’re driving with underinflated tires, it takes more time and room to bring your car to a complete stop If you need to brake quickly, you may find you’re unable to do so.
Different Types Of Systems
There are direct and indirect TPMs, though the former is far more expensive. The indirect systems rely on sensors that are a part of your car’s ABS. If one of your wheels is spinning at a quicker rate than the others, the indirect TPM determines that it needs air. As you can imagine, this type of monitoring is not an exact science.
By contrast, a direct tire pressure monitor relies on a gauge that is positioned on the wheel. When there is an underinflation problem, the gauge alerts the computer and the TPM warning light goes on. This type of monitoring is accurate within a few psi. The drawback is that a direct system is expensive.
Building A Good Habit
Relying solely upon your vehicle’s TPM (especially an indirect system) is a bad idea. Because the threshold at which the warning is triggered is set so high, relying on it exposes you and your passengers to unnecessary danger. Instead, get into the habit of periodically checking the air in your wheels. If they’re low, fill them. That way, you’ll help keep yourself, your passengers, and other motorists safe.
Muscle Cars
Related posts
Tags: Car Maintenance, Car Safety, Car Tires
Posted in Cars | No Comments »
