Yamaha Hatsudoki Kabushiki Kaisha

Yamaha Motor Company Ltd

Michihisa Nakamura

Noritaka Matsuo

Kousei Maebashi

Tatsuyuki Masuda

Hidenori Suhara

Yu Motoyama

Yoshihiko Moriya

Yuichiro Sawada

Michiyasu Takahashi

Takahiko Hasegawa

Yuichi Sasaki

Miyoshi Ishibashi

Midori Nagata

Hiroyuki Kaminokado

Yuuichirou Sawada

Daisuke Nonaka

Tomoaki Tanaka

Kazuhiro Nara

Kiyoto Tsutsumi

Yasuhiro Fujita

Startability of an internal combustion engine using a mixed fuel of gasoline and alcohol is improved. An intake passage of the engine has a main flow channel provided with a throttle valve and a bypass flow channel for bypassing the throttle valve. A bypass quantity adjusting mechanism adjusts the bypass quantity in the bypass flow channel. A control device detects or estimates the mixing ratio of alcohol of the fuel and controls the bypass quantity adjusting mechanism so that a bypass quantity before a first explosion is smaller than a bypass quantity after the first explosion when the mixing ratio of alcohol is equal to or more than a predetermined value.

Control device for internal combustion engine and straddle type vehicle provided with the same

A straddle-type vehicle that omits a main switch without requiring a special operation to start the engine when battery power is supplied to engine-related electrical components. An electrical circuit has a pickup sensor that detects that the engine is in a start preparation state. An ECU connects an ignition coil, injector and fuel pump with the battery when the start preparation state is detected.

Straddle-type vehicle

An engine control device is provided to reliably detect an abnormality in crank pulses. The device determines that there is an abnormality in crank pulses when the situation, in which a standard pitch crank pulse counter T does not reach a prescribed value Tbetween irregular pitch crank pulses (interval abnormality), repeatedly occurs at least a prescribed value CNTtimes, when an irregular pitch is not detected for a prescribed period of time for the crank pulse counter T to count up to Tor longer, or when the situation, in which a prescribed number or more of clank pulses are not detected for a prescribed period of time, repeatedly occurs at least a count-up value Kof times.

Engine control device

In an engine control system, an accelerating condition is detected from the phase of a crankshaft and an induction air pressure. A stroke condition is detected from a rotational angle of the crankshaft and an induction air pressure. A differential pressure between induction pipe pressures detected at a predetermined crank angle on an exhaust stroke and an induction stroke and induction pipe pressures resulting at the same crank angle on the same strokes is calculated as an induction air pressure difference &#x394;P. When &#x394;Pis equal to or larger than the threshold, an accelerating condition is determined to be occurring, and fuel in acceleration is immediately added to a steady-state fuel injection amount for injection. To improve accelerating condition and the induction air amount detection accuracy, a volume from a throttle valve to an induction port is made equal to or smaller than the volume of the stroke of a cylinder.

Engine control system

An accelerated state is detected as soon as possible at the engine start at which a crank pulse alone is insufficient to identify the stroke, and erroneous detection of the accelerated state is prevented. In a period from cranking start to stroke detection, data on suction air pressure is stored for each crank pulse in a virtual address, and during stroke detection, when the virtual address does not coincide with the normal address corresponding to the stroke, the data on the suction air pressure stored in the virtual address is transferred to the normal address, and thereafter the data on the suction air pressure is stored in the normal address, thereby making it possible to detect the accelerated state by making comparison, immediately after the stroke detection, with the suction air pressure prevailing one cycle before. Further, detection of an accelerated state is inhibited when the engine rpm variation is high wherein the suction air pressure increase state during the closure of the suction air valve does not become stable and also when the engine load is high.

To provide a method of processing intake air pressure signals for accurately detecting the engine load including the accelerating state and the intake air flow rate from the intake air pressure. Intake air pressure signals detected with an intake air pressure sensorare processed with a low-pass filter. The low-pass filter is set to cut off frequencies that are not higher than the frequency corresponding to the wavelength that is four times the length of a pressure guide pipeleading to the pressure sensorand to cut off frequencies that are not lower than the driving frequency of the intake valve, which eliminates electric noises and air column vibration occurring in the pressure guide pipeand makes it possible to obtain smooth and real changes in the intake air pressure commensurate with the strokes.

Engine controller

A number of embodiments of engine controls and engine control methods that employ instantaneous rate of combustion is the combustion chamber at a sensed parameter. Rate of combustion is determined by a linear equation based upon data arrived from combustion chamber pressures. The system is adapted to operate under different control modes so as to provide specific control for normal running, lean burn, maximum torque, cold starting, transient conditions, and/or knock control. The desired rate of combustion is achieved by engine control adjustments.

Engine control system and method

A number of embodiments of engine controls and engine control methods that employ instantaneous rate of combustion is the combustion chamber at a sensed parameter. Rate of combustion is determined by a linear equation based upon data arrived from combustion chamber pressures. The system is adapted to operate under different control modes so as to provide specific control for normal running, lean burn, maximum torque, cold starting, transient conditions, and/or knock control.

An improved method of operating a direct cylinder-injected engine wherein adequate fuel and scavenging can be achieved at mid and high-mid range by injecting the fuel in two increments. Various control strategies are disclosed, and they all particularly lend themselves for use with two-cycle crankcase compression engines.

An engine measurement and control methodology wherein the engine combustion rate and IMEP are measured by measuring the in-cylinder pressure at specific crank angles and utilizing a basic reading of pressure in the combustion chamber when it will be near to atmospheric, and also at at least one point in time after ignition begins and before top dead center. The measured data can be employed for fine tuning the engine control to obtain optimum performance.

An exhaust control valve arrangement for a two cycle internal combustion engine for altering the compression ratio to provide optimum running under all conditions. An arrangement is provided or cleaning the exhaust control valve and its surrounding cooperating surfaces of the engine upon shutting off of the engine to preclude the formations of deposits that can cause sticking of the valve element. The valve element is rotated through a number of cycles after the engine is stopped through a wider range than during its normal valving operation for removing deposits. The number of cycles is chosen in response to an engine condition such as length of time of running or amount of lubricant supplied to the engine. Various valve arrangements are disclosed that improve the cleaning operation and permit cleaning even while the engine is running.

Exhaust control valve for engine

An exhaust control valve arrangement for a two cycle internal combustion engine for altering the compression ratio to provide optimum running under all conditions. An arrangement is provided for cleaning the exhaust control valve and its surrounding cooperating surfaces of the engine upon shutting off of the engine to preclude the formations of deposits that can cause sticking of the valve element. The valve element is rotated through a number of cycles after the engine is stopped through a wider range than during its normal valving operation for removing deposits. The number of cycles is chosen in response to an engine condition such as length of time of running or amount of lubricant supplied to the engine. Various valve arrangements are disclosed that improve the cleaning operation and permit cleaning even while the engine is running.

Growing community of inventors

Iwata, Japan

Michihisa Nakamura