EXHAUST SYSTEM


  1. CONSTRUCTION


    1. Exhaust Manifold


      1. The exhaust manifold is made of stainless steel to reduce weight and improve rust resistance.

      2. Cooling holes are provided in the heat insulator to reduce the exhaust manifold surface temperature, improving durability.

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        Text in Illustration
        *1 No. 1 Exhaust Manifold Heat Insulator *2 EGR Pipe
        *3 EGR Pipe Gasket *4 Exhaust Manifold To Head Gasket
        *5 Exhaust Manifold *6 Air Fuel Ratio Sensor
        *7 No. 2 Exhaust Manifold Heat Insulator *8 Cooling Hole

    2. Exhaust Pipe


      1. The exhaust pipe is made of stainless steel in order to reduce weight, improve rust resistance, and enhance TWC warm-up capability.

      2. Ball joints are used to join the exhaust manifold to the front exhaust pipe assembly, and the front exhaust pipe assembly to the tail exhaust pipe assembly. As a result, in-vehicle sound has been muffled, vibration has been minimized, and high reliability has been realized.

      3. 2 TWCs are provided at the front of the front exhaust pipe assembly.

      4. A 2-way exhaust control system is provided to reduce noise and vibration from the main muffler.

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        Text in Illustration
        *A Cold Area Specification Models - -
        *1 Ball Joint *2 Gasket
        *3 TWC *4 Sub Muffler
        *5 Front Exhaust Pipe Assembly *6 Tail Exhaust Pipe Assembly
        *7 Main Muffler *8 Exhaust Heat Recirculation System
        *a Exhaust Gas - -

  2. OPERATION


    1. Exhaust Heat Recirculation System (Cold Area Specification Models)


      1. The exhaust heat recirculation system uses the heat of the engine exhaust to the engine coolant in order to enhance heating performance at low temperatures, thus, warm-up capability is further improved.

      2. The exhaust gas control valve, which is operated by the exhaust pipe gas control actuator, is located in the front exhaust pipe assembly. The exhaust gas control valve opens and closes in order to change the flow of the exhaust gas in the front exhaust pipe assembly.

      3. An engine coolant temperature sensor, which is used only for the exhaust heat recirculation system, detects the temperature of the coolant flowing from the front exhaust pipe assembly.

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      4. Wax is sealed into the exhaust pipe gas control actuator. The wax volume changes due to coolant temperature changes, causing the rod to extend (open) or retract (close) the valve built into the front exhaust pipe assembly.


        • When cold: The valve is closed to make exhaust gas flow to the heat recirculation device provided around the exhaust pipe, warming up the engine coolant.


        • When warm: The valve is opened to allow the exhaust gas to flow normally. Thus, only a small amount of heat is transferred.

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        Text in Illustration
        *1 Wax *2 Rod
        *3 Exhaust Gas Control Valve *4 Exhaust Pipe Gas Control Actuator
        *a Valve is closed *b Valve is open
        *c Engine Coolant IN *d Engine Coolant OUT
        A00515J Exhaust Gas Flow A0051E0 Engine Coolant Flow

    2. 2-Way Exhaust Control System


      1. A 2-way exhaust control system is used. This system reduces backpressure by opening and closing a variable valve that is enclosed in the main muffler, thus varying the exhaust backpressure.

      2. The valve opens steplessly in accordance with the operating condition of the engine, thus enabling quieter operation at lower engine speeds, and reducing backpressure at higher engine speeds.

      3. The control valve is enclosed in the main muffler. When the exhaust gas pressure overcomes the spring pressure, the control valve opens steplessly in accordance with the exhaust gas pressure.

      4. When Control Valve is Closed (Low Engine Speed)


        • Since the pressure in the main muffler is low, the control valve is closed. Hence exhaust gas does not pass through the bypass passage, and exhaust noise is decreased in the main muffler.

      5. When Control Valve is Open (Middle to High Engine Speed)


        • The valve opens as the engine speed and backpressure in the muffler increase. This allows a large volume of exhaust gas to pass through the bypass passage, thereby substantially decreasing backpressure.

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        Text in Illustration
        *a Low Engine Speed *b Middle to High Engine Speed
        *c Exhaust Gas *d Control Valve Closed
        *e Control Valve Open - -