Major automakers are constantly improving engines, launching new powertrains on the market. One of the new products of the Hyundai / KIA concern is the CRDi (Common Rail Direct Injection) diesel engine – with a direct injection system.
You can meet such an engine only on Korean cars, but engines similar from a constructive point of view can also be installed on cars of European companies. In this article, we will consider what the CRDi engine is, what advantages and disadvantages it has.
CRDi Engine Analogs
The first step is to talk about analogues of the CRDi motor, similar in design:
- Fiat produces a similar motor under the abbreviation CDTi;
- Ford releases a similar engine called TDCi;
- The General Motors concern produces such motors under the abbreviation CDTi or VCDi;
- Volkswagen calls these engines TDI.
Other companies also have analogues of the CRDi motor from Korean manufacturers, but they are less common than those mentioned above. All of these engines, in general, are close to each other in terms of the general concept. They have some minor differences in design, but they are all diesel and have a direct fuel injection system.
The Principle Of Operation Of The CRDi Engine
A feature of CRDi diesel engines (and analogues) is that fuel is supplied to the injection nozzles from a common tank where the fuel is under high pressure. Thus, this design, in contrast to conventional diesel engines with a fuel pump and cam drive, allows fuel to be supplied at high pressure.
In general, the operation of the CRDi engine is as follows:
- When the ignition key is turned, the diesel fuel in the Common-rail fuel rail is injected using a special pump (this rail is the reservoir indicated above);
- In the rail, the fuel is constantly under pressure for injection due to injection by the pump;
- After that, from this rail, the fuel is directed under pressure to the injector nozzles through the fuel lines.
Advantages Of The CRDi Engine And Its Analogues
A diesel engine of this design, which has a direct injection system, has a number of obvious advantages over conventional engines:
- Increased economy. Due to the high pressure that is constantly stored in the system, it becomes possible to more efficiently direct diesel fuel to work. Combustion of fuel occurs as much as possible, which is why it is spent less on engine operation;
- Environmental friendliness. Reducing the amount of fuel consumed and the most complete combustion of the working mixture leads to the fact that the overall toxicity of the exhaust is reduced;
- Constant fuel pressure. In systems with direct injection, fuel pressure does not depend on the speed of rotation of the crankshaft, fuel volume and other indicators due to the constant pressure buildup in the fuel rail;
- Fuel supply due to the electronic block EDC. The rise of the game in the injector nozzle occurs due to the command of the electronic unit transmitted to the controlled solenoid. That is, this process does not require influence from the fuel;
- Electronic control. Parameters such as the injection advance angle, the amount of injected fuel and the injection pressure are set by software in the electronic control unit. This allows you to choose the optimal values for various engine operating modes. At the software level, among other things, you can set the injection pressure, depending on the parameters of the speed mode, load, and so on;
- Low noise level. In the systems under consideration, phased injection is implemented (up to 9 phases in modern engines). In addition to the advantages for high-speed characteristics, phased injection allows you to reduce the noise level from the engine;
- High fuel pressure. Conventional diesel engines cannot achieve pressures above 300 kg/cm2 for fuel, while in systems with direct injection this value is higher than 2000 kg/cm2.
Disadvantages Of The CRDi Engine And Its Analogues
The CRDi system technology itself is vastly superior to the standard diesel engine. But it is much more complex, which results in a number of disadvantages:
- Sensitivity to fuel quality. Due to the complexity of the system design, there is a high risk of damage if it enters the fuel pump, injector and other elements of various debris that may be present in the fuel. Therefore, for CRDi engines, you need to use high-quality diesel without foreign impurities;
- High price. As can be understood from the description of the CRDi motor, its design is much more complicated than that of a conventional diesel engine. For proper operation of Common Rail, several sensors are required, and it is also necessary to correctly program the operation of the electronic control unit. This greatly increases the cost of a CRDi engine compared to conventional diesel engines;
- Complexity and cost of repair. CRDi motors are much more complicated, and not all service centers undertake their diagnostics and repair. For their quality service, you need to have special equipment and employees with the appropriate qualifications, who understand the principle of operation of Common Rail. At the same time, the system itself is not particularly suitable for repair, and many of its elements are changed only modularly, which increases the cost of maintenance.
There is a common misconception about the low reliability of the CRDi engine and its analogues. It is connected with the fact that the engine has increased requirements for the quality of diesel fuel.