A portable generator includes a CO sensor module to sense CO levels in the environment surrounding the portable generator. The CO sensor module senses high levels of CO and sends a signal to shut down the engine on the portable generator. The CO sensor module alerts the user by emitting an LED light whether the CO sensor module is functioning properly, improperly or if high CO levels are detected. The CO sensor module is removable from a control panel of the portable generator to be replaced or maintained by the user per a replacement or maintenance schedule.

Provided is a flow rate measuring device including a connector portion, a main body portion, an internal flow passage, and a flow rate detection element. The internal flow passage includes a main flow passage and a sub-flow passage. The sub-flow passage includes a flow rate detection element-side flow passage and connection flow passages. The main flow passage includes an introduction portion, a small flow passage sectional area portion, and an exit portion. The connection flow passages include an upstream-side connection flow passage and a downstream-side connection flow passage. The main flow passage and the flow rate detection element-side flow passage are formed so as to be symmetric with respect to a plane having a flow direction of the fluid to be measured flowing through the pipe as a normal. The main flow passage has a portion at the plane of symmetry as the small flow passage sectional area portion.

Provided is a flow rate measuring device including a connector portion, a main body portion, an internal flow passage, and a flow rate detection element. The internal flow passage includes a main flow passage and a sub-flow passage. The sub-flow passage includes a flow rate detection element-side flow passage and connection flow passages. The main flow passage includes an introduction portion, a small flow passage sectional area portion, and an exit portion. The connection flow passages include an upstream-side connection flow passage and a downstream-side connection flow passage. The main flow passage and the flow rate detection element-side flow passage are formed so as to be symmetric with respect to a plane having a flow direction of the fluid to be measured flowing through the pipe as a normal. The main flow passage has a portion at the plane of symmetry as the small flow passage sectional area portion.

An internal combustion engine for being mounted laterally on a saddle-type vehicle includes an AC generator disposed on an end portion of a crankshaft which is supported in a crankcase. An ACG cover covers the AC generator from outside widthwise across the vehicle. The ACG cover includes an electric power transmission line cover bulging portion covering electric power transmission lines extending to the ACG cover and bulging sideways outwardly widthwise across the vehicle. A crank angle sensor is disposed behind the electric power transmission line cover bulging portion in a vehicle front-back direction. The crank angle sensor is thus protected from flying stones, etc. without an increase in the number of parts used and an increase in the weight of the internal combustion engine.

In order to separately evaluate an influence degree of fuel and an influence degree of lubricating oil with respect to particulate matters contained in exhaust gas, an exhaust gas analysis method includes: analyzing particulate matters contained in the exhaust gas exhausted from an engine, thereby making it possible to analyze the particulate matters derived from the lubricating oil by using isooctane as a fuel.

During a hybrid drive, a hybrid vehicle sets an engine required power based on a driving required power and controls an engine to output the engine required power, while controlling a motor to drive the hybrid vehicle with the driving required power. When a catalyst temperature of an exhaust emission control device is equal to or lower than a predetermined temperature that requires warming up, in the state that an output upper limit power which a power storage device is allowed to output is equal to or larger than a predetermined power, the hybrid vehicle sets a power calculated by subtracting the output upper limit power from the driving required power, to the engine required power. In the state that the output upper limit power is smaller than the predetermined power, the hybrid vehicle sets the driving required power to the engine required power.

There is provided an engine rotation speed control device for performing over-speed rotation prevention control to decrease an engine rotation speed if the engine rotation speed exceeds a first upper limit rotation speed. If a gear position of a transmission is a neutral state or an intermediate neutral state in which predetermined gears are not engaged with each other in the middle of a gear change operation of the transmission, a second upper limit rotation speed which is lower than the first upper limit rotation speed is set. If the engine rotation speed at the time when the gear position of the transmission is the neutral state or the intermediate neutral state is higher than the second upper limit rotation speed, the over-speed rotation prevention control is performed.

There is provided an engine rotation speed control device for performing over-speed rotation prevention control to decrease an engine rotation speed if the engine rotation speed exceeds a first upper limit rotation speed. If a gear position of a transmission is a neutral state or an intermediate neutral state in which predetermined gears are not engaged with each other in the middle of a gear change operation of the transmission, a second upper limit rotation speed which is lower than the first upper limit rotation speed is set. If the engine rotation speed at the time when the gear position of the transmission is the neutral state or the intermediate neutral state is higher than the second upper limit rotation speed, the over-speed rotation prevention control is performed.

Systems and methods for operating an internal combustion engine that includes an oxygen sensor are described. In one example, a voltage that is applied to a heating element of an oxygen sensor is integrated to determine a resistance of the heating element. The resistance of the heating element is the basis for adjusting voltage applied to the heating element during subsequent engine starts.

An air bypass system for an internal combustion engine is provided. The internal combustion engine includes an air intake system defining a first air intake chamber and a second air intake chamber coupled in flow communication with the first air intake chamber. The air bypass system includes at least one bypass assembly controlling flow communication between the first air intake chamber and the second air intake chamber, said at least one bypass assembly facilitating air flow from the second air intake chamber into the first air intake chamber during an expansion stroke of the internal combustion engine.