Most modern cars are equipped with fuel injection systems. There are some modifications in which gasoline is sprayed with nozzles in the intake manifold. There are also models in which fuel is injected directly into the engine cylinder.
Diesel engines work differently from gasoline engines. In it, diesel is fed into the compressed medium in the cylinder. In order to atomize a part of the fuel without obstacles, a mechanism such as a High Pressure Injection Pump is required.
Consider the characteristics of this mechanism, its modified form and signs of malfunction.
What is a high pressure injection pump? What is its purpose?
This mechanism is referred to as the fuel pump for short and is part of the diesel fuel system, but there are also some gasoline-powered models. The only difference between the fuel pump of a diesel engine is that the pressure it generates is much higher than that of a gasoline engine. The reason is the basic characteristics of equipment operation. In the cylinder of a diesel engine, the air is first compressed to a certain degree so that it is heated to the ignition temperature of the fuel.
When the piston reaches top dead center, the nozzle will inject fuel and ignite. The injector must overcome tremendous pressure. In order for the system to work properly, the pump head must be higher than the head in the cylinder.
In addition to the above-mentioned functions, the pump must also supply fuel in batches according to the working mode of the power unit. The rotation of the crankshaft should be considered when determining this parameter. In modern cars, this process is controlled by an electronic control unit.
History of development and improvement
The device was first developed by Robert Bosch in the 1930s. In passenger cars, syringe pumps began to be actively used in the second half of the decade.
Since the first gasoline engines were equipped with carburetors, only diesel engines needed this mechanism. Nowadays, gasoline engines with direct injection systems also have this type of pump (carburetors are already very rare-only used in older cars).
Although the working principle of the pump has remained practically unchanged, the mechanism itself has undergone many upgrades and improvements. The reason is the improvement of environmental standards and internal combustion engine performance. At first, a mechanical injection pump was used, but it was not economical to do so, which resulted in a large amount of harmful substances discharged. Modern electronic pumps show excellent efficiency, allowing transportation to conform to the framework of environmental standards and satisfy humble drivers.
High pressure pump design
There are many improved forms of fuel injection pumps for gasoline engines and diesel analogs. However, in most cases, the main elements of a mechanical pump are:
The filter is installed at the entrance in front of the pump;
The plunger piston located in the cylinder-the so-called. Plunger pair
The main body forming the groove-the fuel is supplied to the plunger pair through them;
Shaft with cam and centrifugal clutch. This element is connected to the timing pulley through a belt drive.
Plunger to drive push rod;
The spring makes the plunger piston return;
Mode regulator-related to the accelerator pedal;
Fuel pump return valve (through it, excess fuel is sent to the return port);
Low pressure pump (pump fuel into the pump).
As mentioned earlier, due to the economy and efficiency of mechanical pumps, they are gradually replaced by electronic modifications. The mechanism itself is difficult to repair and adjust. The electronic pump has its own control unit and multiple electronic valves and sensors.
Most electronic injection pumps have their own diagnostic system, so the device can adapt to failures and errors encountered. Even if one of the sensors fails, this can make the device work normally. A pump like this only stops working when the microprocessor fails.
The high-pressure injection pump operates on the principle of a two-stroke engine. Due to the rotation of the camshaft, the grease nipple connector piston is driven. The diesel enters the sub-plunger space, and the sub-plunger space further enters the highway.