Proposal and Demonstration of a New Spark Ignition Combustion Method with a Gross Indicated Thermal Efficiency Exceeding 53% (First report)
-Concept of Improving Brake Thermal Efficiency-

Koji Morikawa･Takuya Nomura･Yasuo Moriyoshi･Tatsuya Kuboyama (Chiba University)･Atsushi Akamatsu･Yusuke Minami (Cosmo Oil Lubricants Co., Ltd.)･Tomohiro Nakayama･Ryo Muto (SUBARU)

Under the super-high boost conditions of a small pre-chamber gasoline engine, we devised a combustion method in which the super-lean main chamber mixture, which has difficulty in flame propagation, is burned within the range reached by the jet from the pre-chamber, and the remaining mixture is sequentially self-ignited and burned out. We investigated the pre-chamber specifications and engine operating conditions using 3D simulation, and performed actual engine verification, achieving a gross indicated thermal efficiency of 53% or more.

Proposal and Demonstration of a New Spark Ignition Combustion Method with a Gross Indicated Thermal Efficiency Exceeding 53% (Second report)
-Optimization of Combustion using 3D-CFD and Verification on Actual Equipment-

Takuya Nomura･Koji Morikawa･Yasuo Moriyoshi･Tatsuya Kuboyama (Chiba University)･Atsushi Akamatsu･Yusuke Minami (Cosmo Oil Lubricants Co., Ltd.)･Tomohiro Nakayama･Ryo Muto (SUBARU)

In order to establish the combustion method in the first report, the pre-chamber specifications were optimized using 3D-CFD, and it was confirmed that it could be realized at a high load of 2 MPa or more and λ = 3, and that a gross indicated thermal efficiency of 50% or more was possible. Furthermore, a single-cylinder combustion experiment achieved a gross thermal efficiency of 53% or more. It was found that this combustion method can greatly reduce cooling loss and unburned loss.

Intake Characteristics of Multi-Cylinder Gasoline Engines for Small Competition Vehicles
-Fundamental study of the effect of intake geometry-

Takumu Takayama･Shinobu Kasamatsu･Ikkei Kobayashi･Wenbao Wu･Jumpei Kuroda (Tokai University Graduate School)･Kazuki Ogawa (Aichi University of Technology)･Hideaki Kato･Takayoshi Narita (Tokai University)

The authors have been conducting ongoing research on improving the performance of multi-cylinder gasoline engines that can be installed in small competition vehicles. In this report, the authors focused on the shape of the surge tank portion of the intake geometry from the intake to the cylinders with air restrictors, and conducted a basic study on the effect of changing the geometry on the intake characteristics using CFD analysis.

Simulation of a scavenging process for a small 2-stroke gasoline engine

Koichi Hatamura (Hatamura Engine Research Office)･Tadahhige Kawakami (Hosei University)･Kuniyoshi Eto (YAMABIKO)･Akira Iijima (Nihon University)･Keiya Nishida (Hiroshima University)

Performance simulation of 2-stroke gasoline engines is often performed using 3D-CFD, but parameter studies are difficult due to long computation time. Here, we adopted a simulation method that combines 1D-CFD and 3D-CFD, and measured the pressure and other data of each part in actual operation for experimental verification.