DIRECT FUEL INJECTION SYSTEM [SKYACTIV-G 1.3, SKYACTIV-G 1.5]SM2759873
DIRECT FUEL INJECTION SYSTEM [SKYACTIV-G 1.3, SKYACTIV-G 1.5]

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Outline

• In the direct fuel injection system, the temperature in the combustion chamber is lowered by injecting fuel directly into the combustion chamber using multi-hole injectors and atomizing the fuel. In addition, improved engine output and fuel economy have been realized by increasing the air density during compression.
• High response has been realized because there is no time lag from when the fuel injection starts until the fuel is provided to the combustion chamber.

Structure

• The direct fuel injection system consists of the following parts.

Part name

Reference

High pressure fuel pump
Fuel injector
Fuel distributor
Fuel pressure sensor (SKYACTIV-G 1.3, SKYACTIV-G 1.5 (without EGR cooler))
High fuel pressure sensor (SKYACTIV-G 1.5 (with EGR cooler))
Relief valve


Operation

• Fuel from the high pressure fuel pump is injected directly into the cylinder by the fuel injector via the fuel distributor. There are two injection timings: Case (1) where injection occurs during the intake stroke, and case (2) where injection occurs during the compression stroke. The PCM performs control according to the input signal from each sensor. Injected fuel during the intake stroke is diffused uniformly in the combustion chamber by the flow of intake air, achieving a uniform air-fuel mixture. Fuel during the compression stroke achieves an air-fuel mixture required for combustion around the spark plug. For the fuel injection control, refer to the [CONTROL SYSTEM]. (See FUEL INJECTION CONTROL SYSTEM [SKYACTIV-G 1.3, SKYACTIV-G 1.5].)
• The fuel pressure sensor (SKYACTIV-G 1.3, SKYACTIV-G 1.5 (without EGR cooler))/high fuel pressure sensor (SKYACTIV-G 1.5 (with EGR cooler)) detects the fuel pressure in the fuel distributor and sends a fuel pressure signal to the PCM. Based on the signal from the fuel pressure sensor (SKYACTIV-G 1.3, SKYACTIV-G 1.5 (without EGR cooler))/high fuel pressure sensor (SKYACTIV-G 1.5 (with EGR cooler)), the PCM controls the high pressure fuel pump so that the fuel pressure is in accordance with the driving conditions. For the high pressure fuel pump control, refer to CONTROL SYSTEM. (See HIGH PRESSURE FUEL PUMP CONTROL [SKYACTIV-G 1.3, SKYACTIV-G 1.5].)
• Fuel pressure is adjusted by the spill valve control solenoid valve, and a relief valve is equipped to ensure safety in case of a malfunction. If the fuel pressure in the high pressure fuel pump reaches the set pressure, the relief valve is mechanically opened and fuel is returned to the fuel tank side. For details on the high pressure fuel pump, refer to the [HIGH PRESSURE FUEL PUMP] for the fuel system. (See HIGH PRESSURE FUEL PUMP CONTROL [SKYACTIV-G 1.3, SKYACTIV-G 1.5].)
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