Mazda Motor Corporation

Mazada Motor Corporation

Takuji Kawada

Nobuhide Seo

Kazuho Douzono

Akira Takemoto

There is provided a method of starting an internal combustion engine having a combustion chamber and an intake valve which opens during an intake stroke of an engine cycle to allow air to be inducted into the combustion chamber. The method comprises cranking the internal combustion engine with advanced closing timing and a reduced lift of the intake valve without combustion of air and fuel in the combustion chamber from a stroke of the engine cycle prior to a first intake stroke of the combustion chamber since an engine start request, starting combustion of air and fuel in the combustion chamber after the first intake stroke, and retarding closing timing of said intake valve from the advanced closing timing and increasing the valve lift after the combustion is started. Accordingly, air charge in the combustion chamber may increase properly conforming to the engine speed increase caused by the combustion. Therefore, the torque derived from the combustion of the charged and fuel may increase the engine speed moderately after the beginning of the combustion.

Method of starting internal combustion engine

There is provided a method of controlling a power-train of a hybrid electric vehicle comprising an internal combustion engine, a first electric machine directly driven by the internal combustion engine for generating electricity, and a second electric machine driven at least partly with the electricity for driving the vehicle wheel. The method comprises adjusting the speed and adjusting the torque of the internal combustion engine, while substantially maintaining the intake manifold pressure, in response to a change of the desired electricity from the first electric machine. According to the method, the higher engine efficiency can be maintained, because the engine intake manifold pressure is maintained during adjusting the engine speed and torque. The engine speed may be adjusted corresponding to a speed of the first electric machine with higher efficiency and the desired output electricity. Therefore, both the engine and the first electric machine may achieve the respective higher efficiencies. Consequently, overall efficiency of a series HEV power-train can be improved.

Method of controlling series hybrid electric vehicle powertrain

There is provided a method of stopping an internal combustion engine having a combustion chamber and an intake valve which opens during an intake stroke of an engine cycle to allow air to be inducted into the combustion chamber. The method comprises advancing closing timing and reducing a lift of the intake valve to reduce air charged in said combustion chamber and shutting off fuel to the combustion chamber upon a request of engine stop, maintaining a speed of the internal combustion engine within a predetermined range without supplying fuel to the combustion chamber and with the advanced closing timing and the reduced lift of the intake valve at least for one intake stroke of the combustion chamber, and decreasing the speed of the internal combustion engine with the advanced closing timing and the reduced valve lift of the intake valve from the predetermined range. Accordingly, the air in the combustion chamber can be quickly reduced so that the engine can be stopped without a substantial vibration caused by the compression of the air in the combustion chamber. Therefore, the period to keep the engine speed above the predetermined value can be made shorter so that the energy consumed for that, for example, electric power to operate an electric machine to drive the engine, can be reduced.

Method of stopping internal combustion engine

An internal combustion engine combusts a first fuel or a second fuel. A method for controlling the engine comprises supplying first fuel to at least one combustion chambers of the internal combustion engine, stopping the supply of the first fuel to the combustion chamber in response to an engine operating condition, and fueling with the second fuel to the at least one combustion chamber after a predetermined period, so as to maintain an engine speed within a predetermined range.

Fuel switching for dual fuel engine

There is described a method for controlling a hybrid electric vehicle power-train comprising an internal combustion engine, an electric machine and a transmission, the transmission having a gear set with three rotational elements rotationally coupled to the internal combustion engine, the electric machine and the vehicle driving wheel, a rotational speed of any one of the three rotational elements being mechanically defined by the rotational velocity of the remainder of the three rotational elements. The method comprises adjusting the torque of the electric machine to change the speed of the internal combustion engine and to control the velocity of the electric machine above a predetermined value, and decreasing the torque of the internal combustion engine while substantially maintaining the intake manifold pressure of the internal combustion engine in response to a decrease in the demanded engine output. The method may advantageously improve both of the engine efficiency and the power transmission efficiency, then may improve the operating efficiency of the overall power-train system having the internal combustion engine and the transmission coupling the engine, the electric machine and the driving wheels.

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Canton, MI, United States of America

Takuji Kawada