2.1.10. Systems of injection of fuel


System of injection of K-Jetronic fuel

On engines of cars of the 230 and 280 models the mechanical system of injection of K-Jetronic fuel of Bosch was installed.


Principle of action of system of injection of fuel

The fuel pump takes away fuel from the fuel tank and gives it to the store where fuel pressure in system within 4,5 — 5,2 kg/cm 2 is supported. Fuel via the filter moves under pressure to the fuel batcher distributor.

The pressure head disk of a flowmeter of air fixed on the mobile lever which is established between the air filter and a butterfly valve deviates depending on depression of air in the engine. Shift of a pressure head disk of a flowmeter of air is transferred to a distributive plunger of the batcher distributor of fuel, determining by that amount of the given fuel. The distributor of amount of fuel depending on the provision of a pressure head disk of a flowmeter of air gives continuously to engine cylinders through nozzles the required amount of fuel, providing optimum composition of fuel-air mix. The batcher distributor of fuel and a flowmeter of air form the mix regulator.

The regulator of the operating pressure reduces pressure upon a distributive plunger during warming up of the engine. Decrease in the operating pressure at the same consumption of air leads to increase in supply of fuel and, therefore, to enrichment of gas mixture.

The valve of additional air supply installed in the air channel executed parallel to a butterfly valve brings to the engine additional amount of air at start-up and warming up of the engine that leads to increase in frequency of rotation of a bent shaft of the engine idling.

For simplification of launch of the cold engine the electromagnetic starting nozzle which duration of opening is regulated depending on temperature of cooling liquid by a thermal timer is provided.


Data for adjustment

Characteristic

Value

Fuel pressure in system, kg/cm 2

4,5 — 5,2

The operating pressure on the heated-up engine, kg/cm 2

2,7 — 3,1

The operating pressure during the operation of the heated-up engine idling, kg/cm 2

3,4 — 3,8

The operating pressure on the cold engine depending on temperature of cooling liquid (see Check of system of injection), kg/cm 2

0,5 — 2,0

Residual pressure of fuel in system, not less, than a kg/cm 2

1,7

Frequency of rotation of a bent shaft idling, rpm

900±50

Content of carbon monoxide (SO) in the fulfilled gases, %

  • "230"

1,1

  • "280"

< 3,0


Fuel pump

Electric multisection fuel pump.

Characteristic

Value

Brand and catalog No.

   Bosch 0 580 254 982

Pressure of supply of fuel, kg/cm 2

5,5

Productivity of the pump, l/h

100

Pump productivity when checking on the car with filled on 1/2 fuel tank for 30 with, cm 3

750

Working tension, In

7 — 15

The consumed current, no more, And

4,7


Fuel filter

Characteristic

Value

Brand

Purolator

Type:

  • "280" till August, 1987.

GF 140/1

  • since September, 1987.

GF 140/1

  • "230"

GF 148

Brand and catalog No. Bosch

   0 438 060 043


Fuel store

Characteristic

Value

Brand and catalog No. ("230")

   Bosch 0 580 254 982

Volume of the camera, cm 3 ("280")

20

Residual pressure, kg/cm 2

  • "230"

1,7 — 2,4

  • "280"

5,0


Mix regulator

Characteristic

Value

Brand and catalog No.

  • "230"

      Bosch 0 438 040 088 and 0 438 060 025

  • "280"

      Bosch 0 438 040 009 and 0 438 060 043


Air consumption measuring instrument

Characteristic

Value

Brand and catalog No.

      Bosch 0 438 120 158 and 0 438 120 086

Color index

yellow-violet


Fuel batcher distributor

Characteristic

Value

Brand and catalog No.

   Bosch 0 438 100 108


Injection nozzles

Characteristic

Value

Brand and catalog No.

  • "230"

   Bosch 0 437 502 006

  • "280"

    Bosch 0 437 502 007 EP/LKE 7

Pressure of the beginning of injection, kg/cm 2

2,7 — 3,8

Corner of a cone of a raspyl of fuel ("280")

35 °


Electromagnetic starting nozzle

Characteristic

Value

Brand and catalog No.

  • "230"

   Bosch 0 280 170 410

  • "280"

      Bosch 0 280 170 405 and 0 280 170 411

Rated voltage, In

12

Working pressure, kg/cm 2

  • "230"

4,5

  • "280"

– 4,5

Working tension, In

7 — 15

Power consumption, W

37

Corner of a cone of dispersion of fuel ("280")

80 °

Volume of injectable fuel, cm 3/mines

95 — 135


Thermal timer

Characteristic

Value

Brand and catalog No.

      Bosch 0 280 130 214 and 0 280 130 220

Rated voltage, In

12

Temperature of disconnection of contacts, °C

+35

Inclusion duration, no more, with

8


Relay of launch of the cold engine

Characteristic

Value

Brand and catalog No.

   Bosch 0 332 003 028


The regulator of the operating pressure

Characteristic

Value

Brand and catalog No.

   Bosch 0 438 140 005

Rated voltage, In

12

The most admissible tension (short-term), In

20

Working tension, In

7 — 15


Valve of additional air supply

Characteristic

Value

Brand and catalog No.

  • "230"

   Bosch 0 280 140 134

  • "280"

   Bosch 0 280 140 100

The minimum tension, In

12

The most admissible tension (short-term), In

20

Working tension, In

7 — 15


System of injection of L-Jetronic fuel

On engines of the 280E cars the system of faltering injection of fuel with electronic control of L-Jetronic of Bosch was applied.


Principle of action of system of injection of fuel

The electric fuel pump takes away fuel from a tank and gives it under pressure of about 2,5 kg/cm 2 via the filter of thin cleaning to the distributive highway connected by hoses to each cylinder of the engine. Established from an end face of the distributive highway, the regulator of pressure of fuel supports the constant pressure of injection and makes discharge of excessive fuel in a tank, i.e. it provides circulation of fuel in system and excludes in it formation of vapors of fuel.

The amount of injectable fuel is defined by an electronic control unit depending on the volume and temperature of the arriving air, the frequency of rotation of a bent shaft and loading of the engine, and also from temperature of cooling liquid. The key parameter defining a fuel dosage is the volume of the soaked-up air measured by the air consumption measuring instrument. The arriving air stream rejects a pressure head disk, overcoming effort of a spring, and displaces it on a certain corner which will be transformed to voltage by means of a potentiometer. The corresponding electric signal is transmitted to the control unit which defines necessary amount of fuel of operation of the engine at present and gives fuel supply time impulses on electromagnetic valves of nozzles. Irrespective of position of inlet valves of a nozzle two times on each turn of the camshaft at the same time inject fuel. If the inlet valve is closed, fuel gathers in space in front of the valve and is soaked up in the cylinder at its following opening along with air.

The valve of additional air supply installed in the air channel executed parallel to a butterfly valve brings to the engine additional amount of air at cold launch and warming up of the engine that leads to increase in frequency of rotation of a bent shaft of the engine idling.

For simplification of launch of the cold engine the electromagnetic starting nozzle which duration of opening changes depending on temperature of cooling liquid a thermal timer is provided.

The system of injection of L-Jetronic fuel consists of the following basic elements:


Data for adjustment

Characteristic

Value

Frequency of rotation of a bent shaft of the engine idling, rpm

900±50

Content of carbon monoxide (SO) in the fulfilled gases, no more, than a %

0,5 — 2,0

Moments of an inhaling of the main threaded connections, кгс.м

Connection type

Value

The fuel supply pipeline union, carving of M 14x1,5 (the greatest residual moment on the case), no more

1,5

Union of the pipeline of discharge of fuel, carving of M 12x1,5

3,0

Sensor of temperature of cooling liquid

1,5

Thermal timer, no more

3,0

Nozzles (on the inlet pipeline), a carving of M 6x16

0,9 — 1,1