Hino Motors, Ltd.

Sankyo Radiator Co., Ltd.

Takashi Ishimori

Masayuki Okano

Yoji Yamashita

Amane Yamamoto

Akio Oosawa

A heat exchanger tube is constituted by a flat tube bodyshaped like a plurality of cylindrical tubes arranged mutually proximally in a plane and connected together at mutually proximate portions of the tubes as communicating portions. Cylindrical portionscorresponding to the cylindrical tubes of the flat tube bodyhave inner peripheries formed with swirling-flow-forming protrusionsdirected along spiral trajectories coaxial with central axes O of the cylindrical portionsso that the respective cylindrical portionsmay have individual swirling flows of the exhaust gas

Heat exchanger tube

A cooling-water temperature is detected at startup of an engine. When the detected temperature falls below a set water-temperature, a water pump is stopped independently of a normal control on rotational frequency of the water pump depending on engine operational state. Calculated is a total heat amount required for raising the current water-temperature to the set water-temperature, and integrated is an heat amount lost by the cooling water from the engine from the startup. When an integrated value reaches the total heat amount, the water pump is operated for a required time to uniformize temperature distribution of the cooling water. Then, the cooling-water temperature is detected again. If the detected temperature is still below the set water-temperature, the same control is repeated; if the detected temperature is equal to or greater than the set water-temperature, the normal control is restored.

Engine cold start warmup method

A method for manufacturing a flat pipewith concave-convex shapes on inner and outer surfaces includes making incisions with an expanded shape of the flat pipein a metal thin platesuch that intermediate portions(middle portions) in the expanded shape of the flat pipewidthwise of the expanded shape are left uncut from the thin plate, machining the concave-convex shapes in a range of the expanded shape of the flat pipeand raising the expanded shape of the flat pipefrom the thin plateas cut-and-raised pieceswith the uncut intermediate portionsin between, closing tips of the cut-and-raised piecestogether to form an overall shape of the flat pipe, and separating the uncut intermediate portionsfrom the thin plateto obtain the flat pipe

Method for manufacturing flat pipe

An exhaust gas recirculation (EGR) cooler includes a plurality of tubes and a shell enclosing the tubes. During use, cooling water is supplied to and discharged from the shell, and exhaust gas is guided from a diesel engine into the tubes to be heat exchanged with the cooling water. An inner periphery of each of the tubes is formed with three streaks of spiral protrusions running without crossing and with phases peripherally shifted to each other. A pitch P ratio of each of the spiral protrusions to an inner diameter of each of the tubes is 2.0-4.0, and a ridge height H ratio of each of the spiral protrusions to the inner diameter of each of the tubes is 0.1-0.2.

Growing community of inventors

Tokyo, Japan

Takashi Ishimori