Ameer Randolph
The fuel injection system is an integral part of modern automotive engines, ensuring the engine receives the right quantity of the fuel/air mixture to run smoothly and efficiently. The fuel injector is a key component in this system, delivering fuel into the engine. But does the distributor fire the fuel injector? The answer is yes; the distributor sends a burst of fuel to each injector, which is then fired into the inlet port. This process is controlled by a flap valve that responds to airflow, increasing or decreasing fuel flow to maintain the correct balance of the fuel/air mixture.
| Characteristics | Values |
|---|---|
| What is a fuel injector? | A spray nozzle that performs the final stage in the delivery of fuel into the engine. |
| Where is the fuel injector located? | In the combustion chamber, inlet manifold or throttle body. |
| What are injectors that also control the metering called? | Injection valves. |
| What are injectors that perform all three functions (fuel injection, metering, and ignition) called? | Unit injectors. |
| What is direct injection? | Fuel is injected into the main combustion chamber of each cylinder. |
| What is the difference between direct injection and carburetion? | Direct injection atomizes the fuel through a small nozzle under high pressure, while carburetion relies on suction created by intake air. |
| What are the different types of direct injection? | Conventional helix-controlled injection pump, unit injectors, or a common-rail injection system. |
| What is the most common system in modern automotive engines? | The common-rail injection system. |
| What is multi-point injection? | Injects fuel into the intake ports just upstream of each cylinder's intake valve, using multiple fuel injectors. |
| What is single-point injection? | Uses one injector in a throttle body, similar to a carburettor on an intake manifold. |
| What is the purpose of fuel injection? | To provide the engine with the right quantity of fuel/air mixture to run smoothly and efficiently. |
| What is the role of the distributor? | To send a burst of fuel to each injector, which then fires the fuel into the inlet port. |
Explore related products
What You'll Learn
Fuel injection systems
There are two main functional principles of mixture formation systems for internal combustion engines: internal and external. A fuel injection system that uses external mixture formation is called a manifold injection system. There are two types of manifold injection systems: multi-point (or port) and single-point (or throttle body) injection. Internal mixture formation systems can be separated into several different varieties of direct and indirect injection, the most common being the common-rail injection, a variety of direct injection.
In a common-rail system, fuel from the fuel tank is supplied to a common header (called the accumulator), and then sent through tubing to the injectors, which inject it into the combustion chambers. The accumulator has a high-pressure relief valve to maintain pressure and return the excess fuel to the fuel tank. The fuel is sprayed with the help of a nozzle that is opened and closed with a solenoid-operated needle valve.
In the Lucas system, fuel from the tank is pumped at high pressure to a fuel accumulator. From there, it passes into the fuel distributor, which sends a burst of fuel to each injector, from where it is fired into the inlet port. The airflow is controlled by a flap valve that opens in response to the accelerator pedal. As the airflow increases, the fuel distributor automatically increases the flow of fuel to the injectors to keep the fuel/air mixture correctly balanced.
Direct injection means that the fuel is injected into the main combustion chamber of each cylinder. The air and fuel are mixed only inside the combustion chamber. Therefore, only air is sucked into the engine during the intake stroke. The injection scheme is always intermittent (either sequential or cylinder-individual). This can be done either with a blast of air or hydraulically, with the latter being more common in automotive engines.
Fuel Injector Cost for Mazda CX-7: 2007 Edition
You may want to see also
Explore related products
Injector types
Fuel injectors are available in various styles and designs. They can be divided into two specific categories: top feed and side feed. The designation of top feed and side feed indicates how and where the fuel enters the fuel injector.
Side Feed Fuel Injectors
Side feed fuel injectors are injectors where the injector body is surrounded by fuel. The fuel is fed through a hole or holes in the side of the fuel injector. This category can be subdivided into two groups: throttle body and manifold. Some older vehicles used throttle body fuel injection, also known as TBI. Depending on engine size and performance delivery, manufacturers used one or two TBIs. Some of the aftermarket high-performance setups used as many as four throttle body injectors. In general, the fuel injectors are located in a common fuel rail, which is located at a point on the intake manifold close to the cylinder head. Side feed injector setups tend to be more compact and can be installed in smaller spaces.
Top Feed Fuel Injectors
Top feed injectors are the most abundant and make use of a common fuel rail. Although there is a wide variety of top feed injectors, they all operate on the same basis. The top of the injector is pushed into the fuel rail. An O-ring forms a seal between the injector and the fuel rail. Sometimes the injector is secured to the fuel rail with injector clips. The outlet side of the fuel injector is normally located at a specific angle into the intake manifold. An O-ring or Viton rubber seal forms an airtight seal between the fuel injector outlet and the intake manifold. Top feed fuel injectors are divided into three basic subcategories: hose end, normal top feed, and direct fuel injection injectors. Some of the earlier vehicles were equipped with a hose that connects the injector to the fuel rail. These hose ends were connected by means of a hose clamp to the fuel rail side and a ferrule on the fuel injector side. Some hose-end injectors had hose clamps on both the fuel rail and the fuel injector side.
Single-Point Fuel Injection
Single-point fuel injection is the earliest and simplest type of fuel injection. It replaces the carburettor with one or two fuel-injector nozzles in the throttle body, which is the throat of the engine's air intake manifold. For some automakers, single-point injection was a stepping stone to the more complex multipoint system. Although not as precise as the systems that followed, TBI meters fuel with better control than a carburettor and is less expensive and easier to service.
Multipoint Fuel Injection
Multipoint fuel injection, also known as multi-point fuel injection, devotes a separate injector nozzle to each cylinder, right outside its intake port. This is why the system is sometimes called port injection. Shooting the fuel vapour this close to the intake port almost ensures that it will be drawn completely into the cylinder. The main advantage is that multipoint fuel injection meters fuel more precisely than TBI designs, better achieving the desired air-fuel ratio and improving all related aspects. Some cars have multi-point fuel injection, where each cylinder is fed by its own injector. This is complex and can be expensive. It is more common to have single-point injection, where a single injector feeds all the cylinders, or to have one injector for every two cylinders.
Sequential Fuel Injection
Sequential fuel injection, also called sequential port fuel injection (SPFI) or timed injection, is a type of multiport injection. Although basic multipoint fuel injection employs multiple injectors, they all spray their fuel at the same time or in groups. As a result, the fuel may "hang around" a port for up to 150 milliseconds when the engine is idling. Sequential fuel injection triggers each injector nozzle independently. Timed like spark plugs, they spray the fuel immediately before or as their intake valve opens. This provides efficiency and emissions improvements.
Direct Injection
Direct injection takes the fuel injection concept about as far as it can go, injecting fuel directly into the combustion chambers, past the valves. More common in diesel engines, direct injection is starting to be used in gasoline engine designs, sometimes called DIG for direct-injection gasoline.
Understanding Diesel Injector PSI: Performance and Maintenance
You may want to see also
Explore related products
Fuel/air mixture
The fuel/air mixture is a crucial aspect of an engine's performance, and getting this balance right ensures the engine runs smoothly and efficiently. The process of fuel injection introduces fuel into an internal combustion engine via a fuel injector. The fuel injector acts as a spray nozzle, delivering a fine mist of fuel into the inlet manifold or inlet port. This mist of fuel mixes with the air passing through, creating the fuel/air mixture that enters the combustion chamber.
The fuel injector is located in the combustion chamber, inlet manifold, or throttle body. The location depends on the type of injection system. Single-point injection, for example, uses a single injector in the throttle body, similar to a carburettor, where the fuel and air mix before entering the intake manifold. On the other hand, multi-point injection involves injecting fuel into the intake ports near each cylinder's intake valve, often using multiple fuel injectors.
The amount of fuel injected is meticulously regulated by a flap valve in the engine's air intake. This flap valve is designed to respond to airflow. As the airflow increases, the flap rises, adjusting a shuttle valve within the metering control unit, resulting in an increased amount of fuel being released into the cylinders. This process ensures that the fuel/air mixture remains appropriately balanced.
Additionally, the fuel/air mixture can be adjusted for cold starting. In such cases, a choke or a microprocessor control unit activates a cold-start injector, adding extra fuel to create a richer mixture. Once the engine reaches a certain temperature, a thermoswitch automatically deactivates the cold-start injector, returning the fuel/air mixture to its standard balance.
Fuel Injector Sizing: Understanding Your Car's Needs
You may want to see also
Explore related products
Injector issues
Fuel injectors play a crucial role in ensuring that your vehicle's engine receives the right amount of fuel at the right time. However, over time, fuel injectors can become clogged, worn out, or dirty, leading to various issues. Here are some common problems associated with fuel injector issues:
- Rough Idling and Engine Stalling: Dirty or malfunctioning fuel injectors can cause rough idling, where the engine speed becomes uneven due to an inconsistent supply of fuel to the cylinders. This can also lead to engine stalling, especially after pressing the accelerator.
- Poor Fuel Economy: A faulty injector may not deliver fuel efficiently, either by spraying too much or not enough. This inefficiency results in poor fuel economy as the engine consumes more fuel than necessary or struggles to utilize the fuel effectively.
- Engine Misfire and Performance Issues: When a fuel injector fails, it can cause a cylinder to misfire by receiving an inadequate amount of fuel. This can lead to performance issues such as struggling to accelerate, decreased engine power, and increased emissions.
- Check Engine Light: The check engine light on your dashboard may illuminate or flash, indicating a potential issue with the fuel injector. This warning light is triggered by the vehicle's onboard diagnostic system when it detects imbalances in the air-to-fuel ratio or other problems.
- Erratic RPM Needle: The RPM (Revolutions Per Minute) needle on your dashboard may move erratically due to inconsistent fuel flow caused by a faulty injector. This indicates that the engine speed is fluctuating unexpectedly.
- Vibration and Interruption: When a fuel injector malfunctions on one side, the matching cylinder may not fire, resulting in continuous vibration or interruption of the engine while driving.
- Fuel Leak: Over time, the heat and moisture can take a toll on the fuel injector, causing cracks in the rubber seals or the injector itself, leading to a fuel leak.
To address these issues, it is recommended to regularly clean the fuel injectors and ensure proper maintenance. In some cases, replacing the O-rings or the entire fuel injector may be necessary.
Fuel Injector Cleaner: New Cars, New Maintenance Rules?
You may want to see also
Explore related products
Injection history
The history of fuel injection systems goes back over a century. The first fuel-injected compression-ignition engine was constructed in 1902 and entered production in 1906. This engine, called the Antoinette 8V, was designed by the French inventor and aviation pioneer Léon Levavasseur. It was also the first production V8 in history.
In 1885, British engineer and engine builder Herbert Akroyd Stuart discovered that hot kerosene vapours ignite more easily than liquid kerosene. This discovery led to the construction of the hot-bulb engine, which entered production under licence in 1891.
Rudolf Diesel's prototype ran for the first time in 1894, three years after Akroyd Stuart's engine. The Hornsby-Akroyd engines, as they came to be known, were used in agriculture and shipping.
In the 1920s, Swedish engineer Jonass Hesselman invented the Hesselman engine, a hybrid of petrol and diesel engines. It was first introduced in 1925 and was used in buses and trucks from the late 1920s to the early 1940s. The Hesselman engine was the first direct-injected compression-ignition engine used in road-going vehicles, although it was not a true diesel engine.
Mass-produced diesel engines for passenger cars became available in the late 1930s and early 1940s, becoming the first fuel-injected engines for passenger car use. In the 1960s and 1970s, mechanical fuel injection was used in higher-performance sports cars and sports saloons.
Fuel injection was introduced in passenger car petrol engines in the early 1950s and gradually gained prevalence until it had largely replaced carburetors by the early 1990s. GM introduced its first fuel-injection model to the automotive market in 1957, although the design was dropped from all models except the Corvette the following year. It remained an option in the Corvette until 1965, leading many to remember it as the first successful fuel-injected model.
In the 1970s, automakers struggled to design carburetor technology that could meet clean air demands. Eventually, it became simpler and more efficient to switch to electronic fuel injection, with electronic systems being used to control the metering of fuel since the 1980s. The increased computing power and smaller size of EFI modules in the 1980s allowed for better control in the fuel injection system and more consistent performance in engine design.
Cleaning Cylinder Fuel Injectors: Cost and Maintenance Tips
You may want to see also
Frequently asked questions
A fuel injector is a spray nozzle that performs the final stage in the delivery of fuel into the engine. The injector is located in the combustion chamber, inlet manifold, or throttle body.
Fuel injectors work by introducing fuel into an internal combustion engine via a nozzle. This atomizes the fuel through a small nozzle under high pressure, creating a fine mist that mixes with the air before entering the combustion chamber.
The distributor, or fuel-metering control unit, distributes fuel to each cylinder at the correct time and in the correct amounts. The amount of fuel injected is controlled by a flap valve located in the engine's air intake.
No, the distributor does not fire the fuel injector. The distributor's role is to ensure the correct amount of fuel is delivered to the fuel injector at the right time. The fuel injector then fires the fuel into the inlet manifold or inlet port.
