2016 – MX-5 – Engine

FUEL INJECTOR [SKYACTIV-G 2.0]

Purpose, Function

• Promotes atomization of high pressure fuel by injecting it from multiple holes. Atomized fuel mixes actively with air and achieves the optimum air-fuel mix for combustion. At this time, the combustion efficiency has been improved by decreasing the temperature in the combustion chamber and increasing the air density.

• The optimum injection amount is injected at the optimum timing by the PCM control according to the engine condition.

Construction

• The fuel injector is located on the cylinder head to directly inject fuel into the cylinder.

  

• Multi-hole injectors have been adopted for the fuel injectors.

• The fuel injectors have six injection holes in section A shown in the figure.

  

• The fuel injector consists of the needle valve, springs, coil, O-ring.

  

Operation

• The needle valve is opened/closed and fuel is injected by sending electrical current to the coil according to the ON/OFF signal from the PCM. The fuel injection time is determined by the energization time for the coil. The injection times can be controlled by intermittently energizing the coil.

  

Before injection (while injection stopped)

• When there is no energization to the coil, the pressurized fuel sent from the fuel distributor fills the fuel passage. Because pressure is applied to the needle valve at this time, fuel injection is not performed.

Injection starts (needle valve rises)

• A signal is sent from the PCM causing excitation current to pass through the coil and thereby pull up the needle valve, and fuel injection is started.

Injection stops (needle valve lowers)

• When energization to the coil stops, the pressure in the fuel passage increases, the needle valve is pressed down by the spring, and fuel injection stops.

  

• For fuel injection control details, refer to the [CONTROL SYSTEM]. (See FUEL INJECTION CONTROL SYSTEM [SKYACTIV-G 2.0].)

Fail-safe

• Not applicable

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