An internal combustion engine includes a crankshaft that is rotatably supported on the crankcase, a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from an outside at a position, lower than the virtual horizontal plane, of a front face of the crankcase that receives air flow, is made to face a trajectory of the to-be-detected body, and generates a pulse signal in response to movement of the to-be-detected body. Thereby provided is a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision in a so-called V-type internal combustion engine.

An internal combustion engine includes a crankshaft that is rotatably supported on the crankcase, a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from an outside at a position, lower than the virtual horizontal plane, of a front face of the crankcase that receives air flow, is made to face a trajectory of the to-be-detected body, and generates a pulse signal in response to movement of the to-be-detected body. Thereby provided is a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision in a so-called V-type internal combustion engine.

A hand-guided power tool is provided with an internal combustion engine that has a cylinder and a piston disposed in the cylinder and delimiting together with the cylinder a combustion chamber. A connecting rod connects the piston and the crankshaft. The piston in operation of the internal combustion engine rotatably drives the crankshaft. An electronic control unit and an ignition device with a spark plug are provided. A support is fixedly connected to the crankshaft and a signal transducer is fixedly connected to the support. The ignition device, utilizing a signal generated by the at least one signal transducer, fires the spark plug at a timing which is predetermined by the electronic control unit. The support has a polygonal conical receptacle and the crankshaft has a corresponding polygonal conical section arranged in the polygonal conical receptacle to fixedly connect the support and the crankshaft to each other.

A signal generating device for an engine may include a rotor and a stator. The rotor may include a reluctor including a first step reluctor and a second step reluctor. The stator may include a stator iron core, a signal coil, and a permanent magnet. The stator may be configured to induce a first signal and a second signal having the same polarity in the signal coil as a result of changes that occur in the magnetic flux when the tip of each of the step reluctors starts to face the magnetic pole of the stator iron core. A deformed part of the first step reluctor and/or the stator iron core may be configured to control the changes in the magnetic flux such that a crest value of the first signal is limitable to a value that is equal to or less than a crest value of the second signal.