Abstract: A state of an oil pressure is determined based on combination of activation of an oil pressure switch and information of the temperature detected by a temperature sensor and an engine speed detected by an engine speed sensor such that determination of the oil-pressure state is conducted from a lower engine-speed range in a case in which the temperature detected by the temperature sensor is relatively low, compared with a case in which the temperature detected by the temperature sensor is relatively high. Accordingly, the oil-pressure state can be properly determined not only in a high engine-speed range but in a low engine-speed range, by utilizing the simple oil pressure switch activated to the conductive state in response to the oil pressure.

Abstract: A state of an oil pressure is determined based on combination of activation of an oil pressure switch and information of the temperature detected by a temperature sensor and an engine speed detected by an engine speed sensor such that determination of the oil-pressure state is conducted from a lower engine-speed range in a case in which the temperature detected by the temperature sensor is relatively low, compared with a case in which the temperature detected by the temperature sensor is relatively high. Accordingly, the oil-pressure state can be properly determined not only in a high engine-speed range but in a low engine-speed range, by utilizing the simple oil pressure switch activated to the conductive state in response to the oil pressure.

Abstract: An injector such as a hypodermic syringe and the like is improved in that an amount of injection each time thereof is mechanically determined by a provision of a stopper means disconnectably attached to a plunger of the injector, which stopper means and the plunger are engaged with each other through a projection-recess engagement thereof, in which engagement the stopper means acts also as a wedge-like means inserted between the plunger and a barrel of the injector to make it possible that the stopper means abutting against a rear end of the barrel at a time when the injection operation is completed prevents the plunger from being advanced beyond it predetermined position, under the effect of its wedge action.