An Experimental Study on HCCI Combustion in a Four-Stroke Gasoline Engine with Reduced Valve Lift Operations State Key Laboratory of Engines, Tianjin University

Format:

Conference/Event

Author/Creator:

He, Bang-Quan, author.

Conference Name:

Powertrain & Fluid Systems Conference & Exhibition (2005-10-24 : San Antonio, Texas, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2005

Summary:

To achieve homogeneous charge compression ignition (HCCI) combustion in the range of low speeds and loads, special camshafts with low intake/exhaust cam lift and short intake/exhaust cam duration were designed. The camshafts were mounted in a Ricardo Hydra four-stroke single cylinder port fuel injection gasoline engine. HCCI combustion was achieved by controlling the amount of trapped residuals from previous cycle through negative valve overlap. The results show that indicated mean effective pressure (IMEP) depends on valve timings, engine speeds and lambda. Early exhaust valve closing (EVC) timings result in high residual fractions in the cylinder and low air mass sucked into the cylinder. As a result, combustion duration increases, IMEP and peak pressure decrease. However, pumping losses decrease. High engine speed has the similar effect on HCCI combustion characteristics as early EVC timings do. But inlet valve opening timings have slight effect on IMEP compared to EVC timings.Irrespective of engine speeds and valve timings, lambda influences gas exchange and combustion processes. Lean mixture decreases the residuals trapped in the cylinder. Furthermore, in the case of lambda 1.05, ignition often occurs early

Notes:

Vendor supplied data

Publisher Number:

2005-01-3736

Access Restriction:

Restricted for use by site license