Isuzu Motors Limited

Junichiro Nitta

Naoya Ishikawa

A sequential-type, two-stage supercharging system () having a high-pressure-stage turbocharger () and a low-pressure-stage turbocharger (), in which high-pressure-stage exhaust gas bypass passages () for bypassing a high-pressure-stage turbine () is formed by both the first bypass passage () having a small-diameter valve () and the second bypass passage () having a large-diameter valve () with a diameter greater than that of the small-diameter valve (). The effective valve area of the small-diameter valve () is set to 9.5%-26.5% of the passage cross-sectional area required when exhaust gas is at its maximum total flow rate. This allows, in medium speed/medium load operation, fine EGR rate control and air-fuel ratio control.

Two-stage supercharging system for internal combustion engine

An exhaust valve control method for a diesel enginefor switching between a normal combustion mode and a premixed combustion mode according to operating conditions; an exhaust valveis opened only in the exhaust stroke in the normal combustion mode, and two-stage valve opening control is carried out to open the exhaust valvenot only in the exhaust stroke, but also between the latter part of the air inlet stroke and the initial stage of the compression stroke in the premixed combustion mode.

Growing community of inventors

Fujisawa, Japan

Junichiro Nitta