Yanmar Co., Ltd.

Yanmar Power Technology Co., Inc.

Japan Ship Machinery & Equipment Association

Tatsuro Ohsara

Taishi Murakami

Osamu Yamagishi

Ryoichi Hagiwara

Masayoshi Doi

Kazuteru Toshinaga

Koichi Hirose

Keiji Matsumoto

An engine device including an intake manifold configured to supply air into a cylinder; an exhaust manifold configured to output exhaust gas from the cylinder; a gas injector which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve configured to inject a liquid fuel into the cylinder for combustion. At the time of switching from a gas mode in which the gaseous fuel is supplied into the cylinder to a diesel mode in which the liquid fuel is supplied into the cylinder, a supply-start timing of the liquid fuel is delayed relative to a supply-stop timing of the gaseous fuel.

Engine device

An engine device of the present invention includes including: an intake manifold configured to supply air into a cylinder; an exhaust manifold configured to output exhaust gas from the cylinder; a gas injector which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve configured to inject a liquid fuel into the cylinder for combustion. At the time of switching from a gas mode in which the gaseous fuel is supplied into the cylinder to a diesel mode in which the liquid fuel is supplied into the cylinder, a supply-start timing of the liquid fuel is delayed relative to a supply-stop timing of the gaseous fuel.

An engine device includes a main throttle valve disposed at a portion where an outlet of a supercharger and an inlet of an intercooler are coupled to each other, an exhaust bypass flow path configured to couple an outlet of an exhaust manifold to an exhaust outlet of the supercharger, an exhaust bypass valve disposed in the exhaust bypass flow path, an air supply bypass flow path configured to bypass a compressor of the supercharger, and an air supply bypass valve disposed in the air supply bypass flow path. Within a low load range of a load on the engine device, when the load is lower than a predetermined load, feedback control is performed on the main throttle valve, and when the load is higher than the predetermined load, map control based on a data table is performed on the main throttle valve.

An engine device including: an intake manifold configured to supply air into a cylinder; an exhaust manifold configured to output exhaust gas from the cylinder; a gas injector which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve configured to inject a liquid fuel into the cylinder for combustion. At the time of switching the operation mode from one to the other between a gas mode and a diesel mode, an instant switching to the diesel mode is executed when the engine rotation number is determined to approach the upper limit value which leads to an emergency stop of the engine device.

An engine device () including: an intake manifold () configured to supply air into a cylinder (), an exhaust manifold () configured to output exhaust gas from the cylinder; a gas injector () which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve () configured to inject a liquid fuel into the cylinder for combustion. At the time of switching the operation mode from one to another between a gas mode and a diesel mode, a supply amount of a first fuel to be supplied in a post-switching operation mode is increased to a switching threshold value through an increase control which monotonously increases the supply amount, and then is controlled by a speed-governing control based on the engine rotation number. The switching threshold value is set based on the engine rotation number or the engine load.

When a load on an engine device is lower than a first predetermined load falling within a low load range, feedback control is performed on a main throttle valve. When the load is higher than the first predetermined load, map control based on a data table is performed on the main throttle valve. When the load is higher than a second predetermined load higher than the first predetermined load, an opening degree of the main throttle valve is brought to a fully-open opening degree, and each of an exhaust bypass valve and an air supply bypass valve is controlled to allow pressure inside an intake manifold to be adjusted to a target value appropriate to the load.

A gas engine is provided that suppresses fluctuation of the actual air-fuel ratio even when a load fluctuates. A gas engine () in which at least one opening degree (D) selected from the opening degree of an air supply valve () and the opening degree of a bypass valve () is corrected so that an adequate target air-fuel ratio (&#x3bb;t) is achieved, wherein a target gas pressure (Pgt) and a target gas-jetting time (Tt) of a fuel gas are calculated on the basis of fluctuations of an actual load (L), the gas pressure is corrected on the basis of the target gas pressure (Pgt), and at least one opening degree selected from the opening degree of the air supply valve and the opening degree of the bypass valve is corrected on the basis of the amounts of change in the target gas pressure (Pgt) and the target gas-jetting time.

Growing community of inventors

Osaka, Japan

Tatsuro Ohsara