A helmet with an interior element which fits around the head. The interior element has space therein adjacent the front of the head in order to ensure that there is less pressure on the front hair by the interior element and good air circulation inside the helmet, so that the hair is less disheveled and has less of a steamed look when the helmet is worn.

A system for controlling the idling rotational speed of an internal combustion engine controls a control valve for adjusting the opening area of an intake air passage bypassing a throttle valve after cranking of the engine, by the use of control terms including a differential term which is based on a variation in the engine rotational speed and is set and held at zero before a predetermined time period elapses after completion of cranking of the engine.

This device provides an electric signal linearly dependent on the oxygen content of a gas without the need of a reference gas; it is constituted by a solid electrolyte substrate (3) coated with two separate electrodes (1,2) connected to the terminals of an electric voltage source. In the presence of a gas of which the content of oxygen must be measured and when a given voltage is applied between the two electrodes (1,2), oxygen molecules are ionized in the region of the electrolyte close to the ...

An air/fuel ratio feedback control system for internal combustion engines, which is arranged such that when a pulse motor for driving an air/fuel ratio control valve passes the switching point of position detecting means during feedback control operation, a value indicative of the number of steps corresponding to the reference position of the pulse motor, stored in a memory in an electrical circuit for driving the pulse motor is simultaneously shifted to an actual position counter. Air/fuel rati...

A deceleration fuel cut device adapted to interrupt the supply of fuel to an internal combustion engine when a detected actual engine rotational speed is higher than a predetermined value, and simultaneously a detected intake pipe pressure is lower than a predetermined value. The predetermined engine speed value is set to lower values as the detected actual engine temperature increases. The predetermined intake pipe pressure value is determined as a function of the detected actual engine speed. ...

An idling rpm feedback control method for controlling the quantity of supplementary air being supplied to an internal combustion engine, in a feedback manner responsive to the difference between actual engine rpm and desired idling rpm at engine idle. When the engine is decelerated with the throttle valve fully closed and before the feedback control is started, the supplementary air quantity is controlled in decelerating mode in a predetermined manner while the engine speed drops from predetermi...

An air/fuel ratio control system for use in an internal combustion engine, which is adapted to initiate air/fuel ratio control upon concurrent fulfillment of a first condition that a first predetermined period of time which is provided as a period of time from the start of the engine to the warming-up of the engine is determined in dependence on the engine temperature available at the start of the engine by means of a first timer circuit and the first timer circuit finishes counting the first pr...

An air/fuel ratio control system for use with an internal combustion engine, which comprises O.sub.2 sensor activation determining means having a comparator and a timer and adapted to determine the activation of an O.sub.2 sensor for detecting oxygen concentration in engine exhaust gases, to produce an output upon determining the activation, engine temperature determining means adapted to produce an output when an engine temperature detected by an engine temperature sensor exceeds a predetermine...

A control system for use with an internal combustion engine, which includes a timer for producing a trouble indicative signal when there is continued over a predetermined period of time a concurrence of a first signal produced when the pressure in the intake pipe of the engine is lower than a first predetermined value and a second signal produced when the engine speed is lower than a second predetermined value. The first and second predetermined values are set such that they are incompatible wit...

An air/fuel ratio control system for use with an internal combustion engine. The system is provided with an electrical circuit which operatively connects an O.sub.2 sensor with fuel quantity adjusting means in a manner effecting feedback control of the air/fuel ratio of a mixture produced by the fuel adjusting means and being supplied to the engine in response to the output signal of the O.sub.2 sensor. The electrical circuit includes means operable during open loop control of the air/fuel ratio...