ENGINE UNIT DETAILS CYLINDER BLOCK

  1. CONSTRUCTION

    1. An aluminum cylinder block sub-assembly with a 7 mm (0.276 in.) distance between the cylinder bores is used to realize a compact and lightweight configuration.

    2. It is not possible to bore the block with this liner. The liners are the spiny type, which have been manufactured so that their casting exterior forms a large irregular surface in order to enhance the adhesion between the liners and the aluminum cylinder block sub-assembly. The enhanced adhesion helps heat dissipation, resulting in a lower overall temperature and heat deformation of the cylinder bores.

      W139433C01

      *a

      Cylinder Bore Cross Section

      *b

      Cylinder Bore

      *c

      Irregularly Shaped Outer Casting Surface of Liner

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      V100145

      Spiny Type Liner

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    3. Water passages are provided between the cylinder bores. By allowing the engine coolant to flow between the cylinder bores, this construction enables the temperature of the cylinder walls to be kept uniform.

    4. By enlarging the inlet from the engine water pump assembly, coolant inflow resistance is decreased, contributing to improved fuel efficiency.

      W139434C01

      *a

      A-A Cross Section

      *b

      B-B Cross Section

      *c

      Enlarged Water Passage

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      V100135

      Water Passage

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    5. Through the use of an offset crankshaft, the centerline of the cylinder bores is shifted 8 mm (0.315 in.) towards the intake, in relation to the centerline of the cylinder bores. Thus, the side force to the cylinder walls is reduced when the maximum pressure is applied, which contributes to improved fuel economy.

      W139435C01

      *a

      Bore Centerline

      *b

      Crankshaft Centerline

      *c

      Maximum Pressure

      *d

      Offset Crankshaft

      *e

      Non-offset Crankshaft

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    6. Resin cylinder block water jacket spacers with foam rubber liners are used inside the water jackets of the cylinder block sub-assembly.

    7. The cylinder block water jacket spacers optimize the flow of coolant within the water jackets. The resin cylinder block water jacket spacer is held tightly to the cylinder bores by springs, keeping the temperature of the cylinder bore walls uniform. As a result, deformation due to temperature differences across the cylinder bores is suppressed, reducing friction between the pistons and bores.

      W139436C01

      *1

      No. 1 Cylinder Block Water Jacket Spacer

      *2

      No. 2 Cylinder Block Water Jacket Spacer

      *3

      Spring

      *4

      Cylinder Bore

      *5

      Water Jacket

      *6

      Foam Rubber

      *a

      Cylinder Bore Cross Section

      *b

      Temperature is kept even by foam rubber.