Common Rail Direct Injection Work
Common rail systems offer a degree of flexibility that can be used for class-leading emissions control, power and fuel consumption. How does common rail direct injection work It enables original equipment manufacturers (OEMs) to design for optimal performance and exceptional end-user value in a variety of machines and applications.
An increasing number of modern diesel engines use for flexibility while meeting more stringent emission control standards.
In common rail systems, fuel is fed to the engine under pressure with electronically controlled precision. It provides a flexibility to achieve leading levels of emission control, power and fuel consumption.
Perkins uses CRDI technology for its electronic product offerings in the 400, 1100 and 1200 series.
How does CRDI work?
In electronically controlled engines fuel is stored at variable pressure in a cylinder or ‘rail’ with individual pipes connected to the engine’s fuel injectors, a ‘common rail’ for all injectors. The pressure is controlled by the fuel pump but it is the fuel injector that works in parallel with the fuel pump, How does common rail direct injection work which controls the timing of fuel injection and the amount of fuel injected. In contrast, earlier engine systems depended on the fuel pump for pressure, timing, and volume.
Another advantage of the CRDI system is that it injects fuel directly into the combustion chamber. In older engines, indirect injection (ITI) systems injected fuel into the pre-combustion chamber, which was then delivered to the main combustion chamber.
What is the use of CRTI?
CRDI ensures that fuel injection timing, fuel quantity and atomization or fuel spray are controlled electronically using a programmable control module. It allows multiple injections at any pressure at any time (within preset limits), providing flexibility that can used for improved power, fuel consumption and emissions control.
Perkins has considerable experience implementing CRDI in its electronically controlled engines. How does common rail direct injection work The experience gained over the last 10 years ensures that Prime Mover solutions deliver an efficient and effective product.
How would you focus on the benefits of Common Rail?
Timing flexibility results in improvements in noise, vibration and harshness (NVH) with CRDI. Your engine sounds quieter and the sound quality is better. It also runs smoothly. You’ll also see fuel consumption benefits because the higher injection pressure creates a better atomization (atomization) of fuel that burns more efficiently.
Improved combustion efficiency is an important part of meeting emission standards. Less fuel can expelled as soot or particulates and wasted in the engine. A clean-running engine is good for the environment — and the cost of ownership, too. Running cleaner improves the longevity and reliability of your engine.
We have designed our machines to cope with the most stringent operating requirements. For example, improved fuel filtration ensures higher levels of purity in common rail-injected fuel. Clean service procedures are essential to keep your engine running efficiently and within the limits of applicable emission standards.
Common rail fuel injection system
Emissions regulations for diesel engines in applications such as ships, trains and heavy-duty off-road vehicles and gensets around the world are becoming more stringent and require extensive modifications to power units. At the same time, customers continue to demand more economical engines. How does common rail direct injection work Exhaust aftertreatment systems such as SCR catalytic converters (selective catalytic reduction, abbreviated: SCR) or diesel particulate filters are one way to reduce emissions, but require more space and may increase engine maintenance requirements.
For these reasons, the accepted policy is to reduce emissions through internal engine improvements. The combustion of the fuel inside the engine can optimized so that, if possible, emissions not produced in the first place. If necessary, a second phase of emission control can initiated whereby the remaining harmful emissions can removed through exhaust treatment systems. Low emissions due to integration with other key technologies Internal engine design features
Working of CRTI System Injection:
As you can see in the CRDI system diagram, a high pressure pump can used to deliver fuel from the fuel tank to the accumulator or header. If the pressure in the accumulator increases beyond the limit, a high pressure relief valve connected to the accumulator helps to reduce the pressure.
Now, this fuel from the accumulator can supplied to the engine cylinders using fuel lines with the help of solid injectors.
Another spring-loaded high pressure relief valve can used to maintain constant pressure in the system for smooth operation. It returns excess fuel from the accumulator to the fuel tank.
In the diagram, you can see the injection valve. It can used to control the nozzle opening and closing while injecting fuel into the cylinder. The up and down movement of the tip can measured by the cam.
The cam connected to the spring with the help of rocker arm and lever. During the dwell time of the cam, the spring with the help of the injection valve prevents the injection of fuel into the cylinder.
CRTI System Injection
The packing gland ensures fuel level above the valve seat for better injection of fuel into the cylinder.
Wages play an important role in this system. It controls the amount of fuel injected into the cylinder according to the power required by the engine. The wedge can operated by a governor or can operated manually as required.
A common rail is one of the most important components in diesel and gasoline direct injection systems. How does common rail direct injection work The main difference between direct and standard injection can how the fuel can delivered and mixed with the incoming air. In a direct injection system, fuel can injected directly into the combustion chamber, eliminating the lag period in the air intake. Controlled by an electronic unit, the combustion chamber injects the fuel directly into the hot spot so that it burns more evenly and completely.
The main advantages of common rail direct fuel injection can summarized in reduced exhaust and noise emissions, improved fuel efficiency and improved overall engine performance. The system consists of a high pressure pump, injectors, a train and an electronic control unit.
Common rail systems
A common rail is a long metal cylinder. It receives fuel from the pump and delivers it to the injectors at very high pressure. The increase in fuel pressure is a result of recent engine designs. Both diesel and gasoline engines become smaller and lighter for better fuel efficiency and performance, increasing fuel pressure and setting entirely new standards for high-quality common rail production.
First, the geometric accuracy of the components is very important. Precision design contributes to better public rail performance. Even small fluctuations in shape or size can lead to failures. It is necessary to define the correct parameters at the design stage, but what is really important is to strictly adhere to them during the manufacturing process.
Material selection is a point that should not underestimated. Good mechanical properties ensure strength and resist corrosion. Commonly used materials can steel and stainless steel. The common rail for diesel engines can made of steel, while the common rail for petrol engines can made of stainless steel because the fuel can highly corrosive and stainless steel has better corrosion resistance than steel.
The quality of the common rail is paramount. Damage can cause rupture and leakage, causing the vehicle to seize or catch fire. So
Any potential common rail issues should can addressed during manufacturing. Forging plays a major role in effectively preventing end component failures. Forging, and especially hot forging, strengthens the material by closing the voids within the metal during shaping with deformation and local compressive forces. Forged common rail is strong and has high resistance to stress and corrosion.
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Advantages of CRDI System:
- CRDI system can control fuel flow according to engine load and speed.
- A CRDI system is beneficial to the environment by reducing noise, smoke and particulate matter.
- The main advantage of CRDI system is fuel economy.
Disadvantages of CRDI System:
- This system is more complex than MPFI system and requires good engineering work.
- CRDI system may not be compatible with normal machines.
- Maintenance cost of this system is higher than others.
- Vehicles with CRDI system are more expensive than non-CRDI vehicles.