VP29/30 AND VP44 BOSCH DISTRIBUTOR INJECTOR PUMPS
The difference between VP29/30 pump and VP44 pump is that in VP29/30 pumps high pressure is generated by one piston placed axially, and in VP 44 pumps two or three pistons located radially. Owing to the possibility of generating high pressure values and electronic control system, these pumps were often used for supplying diesel engines with power. Pumps of this construction have an electronic controller, controlling injection dose and the beginning of fuel pumping. As a result of equipping the engine with a range of sensors monitoring a current state of its operation, collecting numerous extra pieces of information is possible. It enables more precise control of an injection pump, considering drive unit?s temporary demand for fuel.
VP 29/30 pump
It is an axial distributor pump equipped with an electronic controller placed on its housing. It has a high pressure solenoid valve, whose activation enables controlling the injection dose. VP 29 pumps are used in engines with indirect injection, VP 30 pumps are used in engines with direct injection. Maximum injection pressure equals 140 MPa.
Adjustment of injection angle in injection pumps VP 29/30 is performed mechanically and hydraulically. Compressed fuel in supply pumps is directed to the piston, whose movement is transmitted to the basket with rollers by means of a tang. Fuel pressure is controlled by means of a solenoid valve, which controls the flow of initially compressed fuel. The rearrangement of basket with rollers by a required angle causes that a cam disc during rotation eventually fits the rollers. It causes the change of starting the fuel compression through piston distributor, enabling acceleration or delay of injection angle.
VP 44 pump with PSG 5 controller
It is an axial distributor injection pump. A blade backing pump, in-built inside the injection pump, collects fuel from a fuel tank, performs initial compression and supplies the section generating high pressure. Some systems may have additional, electrical or mechanical supply pumps. In distributor injector pump VP44, high pressure is generated by radially located pistons. Fuel dose and injection angle are regulated by means of control solenoid valves. Maximum injection pressure equals 180 MPa. VP 44 pump with controller PSG 16, which is characterised by two electrical connections located on the opposite ends of the controller, is not subject to repair because there are neither original spare parts nor repair procedures.
COMMON RAIL SYSTEM HIGH PRESSSURE PUMP BOSCH AND DELPHI
CP1 BOSCH pump
The pump has 3 pumping sections set radially. Regulation of fuel expenditure takes place on the high pressure side. A part of compressed fuel is directed through the opening of a high pressure valve back to the tank. Some constructions of this type are equipped with additional valve enabling deactivation of one pumping section. Maximum pressure equals 135 MPa. In CR systems of first generation solenoid injectors are used.
CP3 BOSCH pump
A basic difference consists in a regulation method of pump expenditure. It is performed owing to the change of fuel dose flowing to pumping sections, that is on the side of low pressure. Solenoid valve is responsible for dose regulation adjusted degreeless. This solution enables eliminating compression losses, fuel temperature reduction and pump efficiency improvement. Inside CP3 pump, toothed backing pump is built-in (supply), responsible for taking fuel from the tank by suction. A former construction required the use of additional supply pump (eg. in fuel tank). The idea of fuel inflow choking on the side of low pressure was used in preparation of CP1 pump with CP1H symbol in the development version. CP1 and CP1H enforced pumps construction enables obtaining the pressure reaching 1800 bar.
In CR systems with CP3 pumps, solenoid injectors or piezoelectric injectors may be used.
CP4 BOSCH pump
CP4 pump has the newest construction. It is a single or double piston radial pump. Pump expenditure regulation is performed on the side of fuel inflow by means of a feeder with solenoid valve (like with CP3 and CP1H). In order to cover the demand for fuel in larger engines, double unit pumps are used. With this structure, pumping units are spread with angle 90? in relation to each other. Owing to CP4 pump, it is possible to obtain pressure exceeding 200 MPa.
CR Delhi Pump
They may differ from Bosch products in terms of construction. Most companies manufacturing high pressure pumps use radial piston system inside them, which moved by a cam located inside the pump, compresses fuel to high pressure. A high pressure pump structure is particularly interesting, in which a disc with pistons is stationary, and external cam ring is rotating. Such pumps are present, among others, in 1,5 dCi engine supply systems manufactured by Renault.
In Common Rail systems with Delphi pumps, solenoid injectors cooperate, operating similarly to Bosch structures.