145 - MiTo   1.4 16v TJet   INTRODUCTION - LPG FUEL SYSTEM (EURO 5)      

CONSTRUCTION SPECIFICATIONS

The Bosch Motronic ME7.9.10 system, for petrol and LPG dual fuel operation, belongs to the following category of integrated systems:

- inductive discharge, digital, electronic ignition

- solid state distribution

- sequential, phased type electronic injection (1-3-4-2).

The list of additional components for the LPG system is as follows:

- LPG level sensor on tank

- LPG pressure and temperature sensor on the LPG manifold

LPG cut out solenoid valve relay switch on the tank

- LPG cut out solenoid valves on the tank

- solenoid valve and pressure reduction unit/vaporiser

- LPG/petrol switching button and instrument panel with built-in residual LPG level gauge

- LPG injectors

- petrol pump cut out relay

- petrol/LPG injector control SDU (Smart Driver Unit).

Here below are described the components specific to LPG injection; that not included

    See descriptions 1056 PETROL INJECTION SYSTEM

Operating diagram


1. Petrol/LPG integrated injection-ignition electronic control unit

2. Battery

3. Ignition switch

4. Engine compartment junction unit

5. Climate control system relay

6. timing sensor

7. Body Computer (diagnosis socket and Alfa CODE signal)

8. rpm and TDC sensor

9. Spark plugs

10. Engine coolant temperature sensor

11. Throttle control actuator and throttle position sensor

12. Accelerator pedal potentiometer

13. Ignition coils

14. Oxygen sensor (upstream)

15. Injection system failure warning light

16. Rev counter

17. Catalytic converter

18. Oxygen sensor (downstream)

19. Phase transformer pilot solenoid

20. LPG cylinder solenoid valve control relay switch

21. LPG cylinder

22. LPG intake solenoid valve

23. LPG level sensor

24. Pressure reduction unit/vaporiser

25. LPG cut-out solenoid valve

26. LPG filter

27. LPG injector assembly

28. LPG pressure/temperature sensor

29. Knock sensor

30. Petrol/LPG injector control SDU (Smart Driver Unit)

DIAGRAM OF INFORMATION ENTERING/LEAVING THE CONTROL UNIT


1. injector control

2. Petrol injector enablement

3. LPG injector enablement

4. LPG 1 injector

5. LPG 2 injector

6. LPG 3 injector

7. LPG 4 injector

8. Petrol injector 1

9. Petrol injector 2

10. Petrol injector 3

11. Petrol injector 4

LPG COMPONENTS RECOVERY AND SELF-DIAGNOSIS

The ECU carries out the input/output diagnosis, cyclically checking the signals and, in case of malfunctions, storing the relevant codes in the EEPROM (passive self-diagnosis).

The fault diagnosis carried out and the recovery actions in the case of a fault in the following components are reported.

Lpg level sensor on tank

The electronic unit carries out the following electrical fault diagnosis on the signal coming from the LPG level sensor every 0.1 secs.:

- short circuit to earth

- short circuit to battery or open circuit.

If a failure is detected, the control unit implements the following recovery action:

- return to petrol operation and consequent lighting of PETROL mode warning light in the instrument panel.

Lpg pressure and temperature sensor on rail

The electronic unit performs the following electrical diagnosis on the signal from the rail LPG pressure sensor:

- short circuit to earth

- short circuit to battery or open circuit

- LPG pressure signal plausibility.

This diagnosis is possible in all conditions, irrespective of the operating mode.

Both petrol operation and LPG operation and switching between the two operating modes is permitted.

The MIL warning light in the instrument panel comes on at the first cycle (driving cycle) where the LPG low pressure error is confirmed.

The MIL warning light in the instrument panel comes on at the third cycle (driving cycle) where the LPG temperature error is confirmed.

Lpg injectors

The electronic unit cyclically carries out an electrical fault diagnosis on the LPG injectors signalling the following problems:

- injector cold side open circuit

- injector cold side short circuit to earth

- injector cold side short circuit to Vbattery.

If a fault is detected, the control unit implements the following recovery actions:

- return to petrol operating mode

- warning light in instrument panel lit up.

Petrol/lpg injector control sdu (smart driver unit)

The electronic unit performs diagnosis on:

- petrol injectors control.

If a fault is detected, the control unit implements the following recovery actions:

- return to petrol operating mode

- warning light in instrument panel lit up.

Lpg cut-out solenoid valves relay switch

The electronic unit performs an electrical diagnosis on the LPG cut-off solenoid valve relay switch coils and signals the following faults:

- short circuit to earth or open circuit: this diagnosis is possible only in petrol operating mode

- short circuit to Vbattery: this diagnosis is possible only in LPG operating mode.

If a fault is detected, the control unit implements the following recovery actions:

- return to petrol operating mode

- warning light in instrument panel lit up.

CONTROL UNIT PIN OUT


Connector B

1. Supply (1 A)

2. RF earth

3. Not connected

4. Not connected

5. Not connected

6. Not connected

7. RF earth

8. Sensor earth

9. Sensor earth

10. Not connected

11. Not connected

12. Low speed H-CAN line

13. H-CAN line

14. Main relay supply

15. Not connected

16. Not connected

17. Not connected

18. Not connected

19. Not connected

20. Sensor power supply (+5 V)

21. Not connected

22. Not connected

23. Not connected

24. H-CAN line

25. RF earth

26. Engine earth

27. Main relay supply

28. Engine earth

29. Not connected

30. Not connected

31. Not connected

32. Petrol injector enablement

33. LPG level sensor signal

34. Not connected

35. Not connected

36. Not connected

37. Not connected

38. Low speed L-CAN

39. L-CAN

40. Not connected

41. Not connected

42. Not connected

43. LPG injector enablement

44. Key on

45. Not connected

46. Not connected

47. Not connected

48. Not connected

49. Not connected

50. L-CAN

51. Serial line

52. Not connected

Connector A

53. Not connected

54. Not connected

55. Sensor power supply (+5 V)

56. Petrol 1 injector (driver low side)

57. Petrol 3 injector (driver low side)

58. LPG 4 injector (driver high side)

59. LPG 3 injector (driver low side)

60. Not connected

61. Not connected

62. Sensor earth

63. Petrol 2 injector (driver low side)

64. Petrol 4 injector (driver low side)

65. LPG 4 injector (driver low side)

66. LPG 3 injector (driver high side)

67. Petrol injector enablement

68. Petrol 1 injector (driver high side)

69. Petrol 3 injector (driver high side)

70. Injector control for cylinder 1

71. Cylinder 3 injector control

72. LPG 1 injector (driver high side)

73. LPG 2 injector (driver low side)

74. LPG injector enablement

75. Petrol 2 injector (driver high side)

76. Petrol 4 injector (driver high side)

77. Injector control for cylinder 2

78. Injector control for cylinder 4

79. LPG 1 injector (driver low side)

80. LPG 2 injector (driver high side)

LPG INJECTOR ASSEMBLY

The LPG from the filter enters the connector (1) and supplies the injectors.

The gas is suitably metered and flows out of the injectors through the outlets (2) and reaches the intake manifold, and therefore the engine, through special hoses.

The injectors are controlled by the petrol/LPG injector control SDU (Smart Driver Unit) and linked to it through connectors (4).

The pressure and temperature of the gas in the injector assembly are measured by the sensor (3).


1. LPG inlet

2. LPG outlet

3. LPG temperature/pressure sensor

4. LPG injector connectors

LPG injectors meter LPG to be sent to the intake manifold.

The LPG injectors are supplied through signals from the petrol/LPG injector control SDU (Smart Driver Unit).

The LPG injector operating logic is sequential, timed type. That is, the injection is carried out individually in accordance with the single cylinder intake sequence.

LPG LEVEL SENSOR

The sensor is fitted directly on the tank and the signal, processed by the engine management control unit, allows the LPG level to be displayed on the instrument panel.


1. LPG level sensor float

2. LPG level sensor/gauge

LPG/PETROL SWITCH

The system features an LPG/petrol switch (1) located in the dashboard on the centre console near the DNA lever.


1. LPG/petrol switch

- the fuel in use is indicated by two LEDs (2) and (3);

- if pressed for 5 seconds with the key at MAR-ON, before starting, it allows start-up with gas (green LED (2) on constantly).

2. Green LED

- on constantly: indicates regular gas operation;

- flashing rapidly: it indicates the status of waiting for automatic switching to gas operation when starting (always on petrol);

- flashing slowly: it indicates a system malfunction during gas operation (diagnosis);

- on together with yellow LED: it indicates switching back to petrol. This mode is also signaled by the acoustic signal emitted by the switch.

3. Yellow LED

- on constantly: it indicates petrol operation.

4. Series of LEDs

- The green LEDs indicate the level of gas (divided into quarters) in the tank;

- the red LED indicates the reserve.