🔍 Key Concepts
• Turbocharger operation: how exhaust gas energy drives the turbine and what that does to intake air pressure.
• Manifold pressures vs. engine load: what happens to exhaust and intake pressures at very low load versus full load on a turbocharged four-stroke diesel.
• Flow direction and pressure gradient: for gas to flow through the engine and turbocharger, how must the pressures compare between intake, cylinders, and exhaust.
💭 Think About
• Think about what changes when the engine goes from zero/light load to full load: fuel quantity, exhaust energy, turbo speed, and resulting intake boost.
• Ask yourself: at full load, which side (intake or exhaust) generally needs higher pressure to keep gases flowing correctly through the engine and turbocharger?
• Consider what happens inside the cylinders during the exhaust stroke and intake stroke—how do those processes depend on the relative pressures in the intake and exhaust manifolds?
✅ Before You Answer
• Verify which side of the turbocharger the compressor is on and which side the turbine is on, and what each one does to pressure.
• Check typical trends: as load increases, does boost (intake) pressure increase faster, slower, or about the same as exhaust manifold pressure?
• Make sure the statement you choose makes sense for full load, not idle or zero load—several options may sound plausible at light load but not at high load.