Abstract: An auxiliary passage of a relatively small cross-sectional area bypasses the main throttle valve of a usual induction passage to extend to each intake port. The auxiliary passage allows air or an air-fuel mixture to pass therethrough according to the magnitude of vacuum in the intake port and, in its endmost portion, takes the form of a nozzle directioned circumferentially of the intake port, so that the air-fuel mixture flowing in the intake port is agitated to thorough homogenization by a swirling movement of the injected gas particularly efficiently during low load operation of the engine.

Abstract: A coin receiving apparatus for a vending machine capable of accurately checking a coin diameter as well as other coin characteristics such as material and a surface pattern for discriminating a true coin from a false one and receiving the former and rejecting the latter. The diameter and other coin characteristics are detected by examining peak values of output waveshapes of coin detectors by means of a window circuit. A single window circuit is provided for each denomination and upper and lower limit values of the window circuit are automatically changed in accordance with a coin characteristic under examination. Frequencies of excitation signals of the various coin detectors are also automatically changed. If a plurality of coins are successively inserted in the coin receiving apparatus without a sufficient time interval, discrimination of the inserted coins is inhibited and the inserted coins are returned.

Abstract: A coin checking device for a vending machine capable of electrically examining whether an inserted coin is a true coin or a counterfeit one as well as kind of the coin. The device detects a waveform representing passage of the coin and also whether the peak level of the waveform appears in a predetermined window or not and, if the peak level is detected in the window, judges that the inserted coin is a true one.

Abstract: A vending machine adapted to temporarily retain a coin of large denomination which is not usable as a change coin among the deposited coins and store coins of small denominations in coin stacking tubes. When the deposited money is to be returned, coins of the same denominations as the deposited small denomination coins are paid out from the coin stacking tubes while the retained large denomination coin itself is also returned. In event the vending machine is short of change coins, the vending machine vends the required article only when a coin requiring no change is deposited and automatically returns the deposited coin when a coin requiring change is deposited.