Development and Preliminary Combustion Experiments of a Prototype Engine with Sleeve Valves Based on the Focusing Compression Principle Waseda University

Format:

Book

Conference/Event

Author/Creator:

Nishizawa, Tomohiko, author.

Naitoh, Ken, author.

Baba, Shotaro, author.

Ukegawa, Hiraku, author.

Yamada, Sota, author.

Ozono, Yuka, author.

Abiko, Mirei, author.

Suzuki, Yosuke, author.

Hara, Namito, author.

Ito, Yoshikuni, author.

Matsubara, Kosaku, author.

Uenoyama, Kazuyuki, author.

Conference Name:

WCX SAE World Congress Experience (2026-04-14 : Detroit, Michigan, United States)

Language:

English

Subjects (All):

Valvetrains.

Intake systems.

Combustion and combustion processes.

Lean burn engines.

Engines.

Pistons.

Knock.

Local Subjects:

Valvetrains.

Intake systems.

Combustion and combustion processes.

Lean burn engines.

Engines.

Pistons.

Knock.

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2026

Summary:

Our laboratory has proposed the focusing compression principle which employs pulsed super-multi jets of gas colliding around the chamber center. This principle aims to achieve high thermal efficiency by reducing both exhaust and cooling losses. Exhaust loss is minimized due to relatively-silent high compression. Cooling loss is reduced due to thermal insulation caused by fuel-air mixture being confined to the chamber center and the compressible flow effect. In previous studies, we conducted fundamental gasoline combustion experiments on a proof-of-concept opposed-piston engine which incorporated this principle. This engine featured eight intake nozzles in an octagonal configuration and utilized non-sinusoidal and strongly asymmetric piston movements. The results indicated the possibility of high thermal efficiency based on less knocking under high compression, and the potential for stable combustion under lean-burn conditions. As a next step towards practical application with durability, we have developed a new opposed-piston engine with a small displacement of 123 cc which maintains intake ports of octagonal configuration, featuring a unique valve system. This unique valve system is characterized by setting a cylindrical-shaped sleeve-valve in between the inner and outer- cylinders. On operation, these sleeve-valves move along the central axis of cylinders, opening or closing all eight ports on the cylinder walls simultaneously. In this paper, we first show details of the present new engine developed and its preliminary experiments including non-combustion motoring experiments, and also combustion experiments using gasoline. The engine was successfully motored up to 750 rpm with no gas leakage around the sleeve-valve at compression process. Combustion experiments were initially tested from slightly-lean conditions

Notes:

Vendor supplied data

Access Restriction:

Restricted for use by site license