The turbocharger is cooled using coolant from the primary cooling system. Coolant enters the turbocharger from the block on the bottom of the turbocharger and flows through and out the top of the turbocharger through a line back to the coolant crossover tube.
The wastegate on the DualBoost VGT is vacuum controlled through a solenoid that is controlled by the PCM. The wastegate is only used on the DualBoost turbocharger. The wastegate opens to relieve excessive exhaust pressure at higher RPMs. When the VGT cannot react quickly enough to reduce MAP pressure, the wastegate will open to reduce… Read More »
The 6.7L VGT actuator uses engine oil pressure on a piston to move the vanes on the exhaust turbine. The VGT actuator is commanded by the PCM, based on a desired MAP pressure. This actuator meters engine oil to either side of the piston. This design feature reacts quickly to changes in demand based on… Read More »
During engine operation at high engine speeds and load, there is a great deal of energy available in the exhaust. Excessive boost under high speed, high load conditions can negatively affect component durability. Therefore, the vanes are commanded open preventing turbocharger overspeed. Essentially, this allows the turbocharger to act as a large turbocharger.
During engine operation at moderate engine speeds and load, the vanes are commanded partially open. The vanes are set to this intermediate position to supply the correct amount of boost to the engine for optimal combustion, as well as providing the necessary exhaust pressure to drive exhaust gas.
When the VGT is closed it maximizes the use of the energy that is available at low speeds. Closing the VGT accelerates exhaust gas flow across the vanes of the turbine wheel. This allows the turbocharger to behave as a smaller turbocharger. Closing the vanes also increases the exhaust pressure in the exhaust manifold, which… Read More »
The DualBoost VGT has two intake compressors and one exhaust turbine on a common shaft.
Turbocharger control is based off an air system model that produces a desired intake pressure to meet the power requirements requested by the operator.. The PCM commands the VGT control valve by a feedback loop on the intake pressure to achieve the desired intake pressure to meet the driver’s needs (pedal position, engine load). The… Read More »
Some of the features of the ceramic glow plugs that are used on the 6.7L Power Stroke® diesel are: • End of compression temperature is high enough to auto-ignite the fuel. • The ceramic glow plugs can reach 1250°C (2282°F) in 2 seconds. • The tip of the glow plug is closer to the rim… Read More »
The glow plugs are mounted in the cylinder heads and are accessible through the valve cover. The GPCM supplies the required current to each glow plug, based on commands from the PCM. Ground is provided through the glow plug body to the cylinder head.