| 摘要 |
A more efficient multi-stage turbocharging system and method for internal combustion engine systems is set forth. The present invention recovers the loss of a portion of exhaust energy that conventionally occurs in bypassing exhaust flow from one stage to another in a multi-stage turbocharging system. The preferred method of preserving such exhaust energy is through converting a portion of the exhaust energy of the bypassed flow from pressure to kinetic energy (velocity) by passing the bypassed flow through a VGT vane outlet or other variable geometry valve/nozzle, and then not allowing the accelerated flow to dissipate energy before reaching the subsequent stage's turbine wheel, where the accelerated flow may then be converted to a mechanical rotational force by the lower pressure turbine's wheel. Preferred hardware for achieving the object of the invention is also set forth, including a preferred two-volute low pressure turbocharging system with a VGT mechanism in one turbine volute only, or an alternative low pressure turbocharger with two low pressure turbines on a common shaft (again, preferably, with a VGT mechanism in one turbine only). |
