FUEL SYSTEM DETAILS

Fuel Pump Assembly (for High Pressure)

1. The fuel pump assembly (for high pressure) consists of a plunger, spill control valve and check valve. A fuel pressure pulsation damper assembly is also installed at the fuel inlet.

2. The plunger is moved up and down by a lobe that is located at the rear end of the exhaust camshaft on the right bank of the engine. This lobe causes three strokes of the pump piston to occur for each camshaft revolution (3 protrusions exist 120 degrees from each other on the same camshaft "lobe").

3. A spill control valve is used to control the pump discharge pressure. The spill control valve is located in the inlet passage of the fuel pump assembly (for high pressure). It is electrically opened and closed by the EDU, based on instructions from the ECM.

4. A check valve is present in the outlet of the fuel pump assembly (for high pressure). As the pressure in the outlet of the pump rises, and becomes high enough to push the check valve off its seat, fuel will begin to flow to the fuel delivery pipe sub-assembly (for direct injection), (minimum pressure to open the check valve is 60 kPa).

   

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   *1	Check Valve	*2	Spill Control Valve
   *3	Fuel Pressure Pulsation Damper Assembly	*4	Plunger
   *5	Fuel Injector Assembly	*6	Fuel Delivery Pipe Sub-assembly
   *7	Fuel Relief Valve Assembly	*8	Fuel Tank Assembly
   *9	Fuel Pump Assembly (for Low Pressure)	-	-
   *a	From Fuel Pump Assembly (for Low Pressure)	*b	To Fuel Tank Assembly
   *c	To Fuel Delivery Pipe Sub-assembly	-	-
   	Low-pressure Fuel		High-pressure Fuel

Fuel Delivery Pipe Sub-assembly

1. Aluminum alloy fuel delivery pipes are used for the fuel delivery pipe sub-assembly.

2. A fuel pressure sensor and a fuel relief valve assembly are installed on the fuel delivery pipe.

3. An injector clamp is provided for each area of the fuel delivery pipe where a fuel injector assembly is installed. This clamp applies a constant spring force to the injector to prevent the injector from moving when the combustion pressure is applied to the injector while the engine is being started, during which the fuel pressure is low. As a result, the clamp increases the sealing performance of the injector, while reducing vibration and noise.

4. O-rings and backup rings are used in the areas in which the fuel injector assembly and fuel delivery pipe are joined. This reduces the transmission of the operating sounds of the fuel injector assembly, enhances quiet operation, and ensures the sealing performance of the joined areas.

   

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   *1	No. 3 Fuel Pipe	*2	Fuel Delivery Pipe RH
   *3	Fuel Delivery Pipe LH	*4	Injector Clamp
   *5	Fuel Injector Assembly	*6	Gasket
   *7	Fuel Relief Valve Assembly	*8	Fuel Pressure Sensor
   *9	No. 2 Fuel Pipe	*10	O-ring
   *11	Backup Ring	-	-

Fuel Injector Assembly

1. High-pressure, slit-nozzle type fuel injector assemblies are used in conjunction with the adoption of the Direct injection 4-stroke gasoline engine (D-4) system.

2. Each injector, based on signals from the ECM, measures the flow of high-pressure fuel. The fuel is injected as a fine-grained mist in a fan shaped pattern, directly to the combustion chamber, via a slit type nozzle.

3. An insulator is used in the area in which the injector comes in contact with the cylinder head, and a Teflon shaft seal is used to seal the injector against the combustion pressure in the cylinders. This is conducted in order to reduce vibration and noise and to enhance sealing performance.

4. Each nozzle hole is coated to reduce the adhesion of deposits.

5. The injectors are actuated by the EDU using high-voltage and a constant-current control based on instructions from the ECM. This control allows the injectors to inject high-pressure fuel in a short amount of time.

   

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   *1	Insulator	*2	Teflon Shaft Seal
   *3	Injection Nozzle	-	-
   *a	Cross Section	*b	Bottom Side View

Cold Start Fuel Injector Assembly (Models with Cold Start Fuel Injector Assembly)

1. A cold start fuel injector assembly is used to improve cold-starting performance. It is provided in the surge tank of the intake manifold and injects fuel when the engine is started and the engine coolant temperature is low.

   

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   *1	Intake Air Surge Tank	*2	Cold Start Fuel Injector Assembly
   *a	Cross Section	-	-

Fuel Tank Assembly

1. A multi-layer plastic fuel tank is used. The multiplex layered plastic fuel tank consists of six layers of four types of materials, and one of those is a recyclable material to address environmental concerns.

2. A fuel drain mark has been provided at the lowest position of the fuel tank assembly. When dismantling (scrapping) the vehicle, drain fuel by drilling a hole at the drain mark.

   

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   *1	Fuel Tank Assembly	*2	High Density Polyethylene (HDPE)
   *3	Regrind Material	*4	Adhesive
   *5	Ethylene Vinyl Alcohol Copolymer (EVOH)	*6	Fuel Drain Mark
   *a	Fuel Tank Outside	*b	Fuel Tank Inside
   *c	Bottom Side View	-	-

3. The fuel tank uses a saddle shape to allow the propeller shaft to pass under the center portion of the tank. Also, a jet pump is used to transfer the fuel from the side of the tank without the fuel pump to the side with the fuel pump.

4. A fuel tank with such a shape tends to cause fuel to be present in both chamber A and chamber B when the fuel level is low. This stops the fuel in chamber B from being pumped out. To prevent this from occurring, a jet pump has been provided to transfer the fuel from chamber B to chamber A.

5. This is accomplished by utilizing the flow of the fuel through the jet pump, so that the pressure difference, which is created by the fuel as it passes through the venturi, is used to suck the fuel out of chamber B and send it to chamber A.

   

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   *1	Engine	*2	Fuel Tank Assembly
   *3	Chamber B	*4	Chamber A
   *5	Fuel Pump	*6	Fuel Filter Assembly
   *7	Fuel Main Valve	*8	Jet Pump
   *a	From Fuel Pump (Return)	*b	From Chamber B
   *c	To Chamber A	-	-