Abstract: A spacer fitted inside a water jacket which is formed to surround peripheries of cylinder bores in a cylinder block of an internal combustion engine includes: a spacer main body part partitioning the water jacket into an upper cooling water passage and a lower cooling water passage; and a cooling water outlet and inlet port part continuing to the spacer main body part. A center of a thickness of the cooling water outlet and inlet port part is offset in a radial direction from a center of a thickness of the spacer main body part. Accordingly, when cooling water passes the cooling water outlet and inlet port part, the pressure loss can be reduced in such a way that the cooling water outlet and inlet port part does not interfere with the passage.

Abstract: A V-type engine having a turbocharger located between two banks, and an oil shield between the turbocharger and a valley of the banks. The oil shield blocks the oil spattered from the interbank valley so that flying of the oil to the turbocharger from the interbank valley is prevented. The oil shield may be an oil shielding plate. The oil shielding plate includes a cover portion covering a lower part of the turbocharger, and a plurality of extensions extending from the cover potion to be mounted on the engine. The cover portion has an oil outlet to allow a leakage oil to escape from the cover portion therethrough. An oil drain is formed in the interbank valley, and the leakage oil collected by the cover portion drops onto the interbank valley from the oil outlet of the cover portion and is subsequently discharged from the engine through the oil drain.

Abstract: A compact acoustic apparatus in which a vibrator is arranged in a Helmholtz resonator having a resonance port, and is driven to radiate a resonant acoustic wave so as to perform lower bass sound reproduction, is characterized in that a cabinet is reduced in size by externally projecting the resonance port from the cabinet, and/or a boundary condition change buffer means is arranged at an opening portion of the resonance port to prevent noise caused by an air flow flowing through the resonance port.

Abstract: An acoustic apparatus comprises a Helmholtz resonator which has a cavity and an open duct port for causing the cavity to communicate with an external region thereof and a vibrator which is arranged in the resonator to drive the resonator. In a first aspect, the open duct port comprises an air permeable member having a proper acoustic resistance and a viscoelastic member having no air permeability so that noise caused by an open duct resonant, wind noise, turbulence or the like is prevented. In a second aspect, a viscoelastic member is disposed at the mounting portion between the open duct port and a cabinet defining the cavity so that transmission to the cabinet of derivative vibration causing at the open duct port is prevented.

Abstract: A driving apparatus for driving an electro-acoustic transducer comprises a main body portion and a control information storage body which is arranged independently of the main body portion and is selectively separated from or coupled to the main body portion, as needed. The control information storage body stores a real circuit or information for setting electrical characteristics of the driving apparatus.A driving apparatus further comprises a protection circuit for preventing a disadvantageous result of the driving apparatus and a load caused by an unstable operation and the like when the control information storage body is attached/detached to/from the main body portion or when an inappropriate control information storage body is loaded onto the main body portion.

Abstract: In an acoustic apparatus in which a vibrator is arranged in a Helmholtz's resonator having an open duct port, and the vibrator is driven to radiate a resonant acoustic wave, a duct resonance absorbing means is provided to the open duct port constituting the Helmholtz's resonator so as to remove an unnecessary resonant sound other than a Helmholz's resonant sound caused when the Helmholtz's resonator is driven, thereby removing noise in a radiated acoustic wave and improving distortion characteristics.

Abstract: An acoustic apparatus comprises a plurality of resonators having different resonance frequencies, each of which is constituted by a closed cavity and acoustic mass for causing the cavity to acoustically communicate with an external region. A housing enclosing the plurality cavities is integrally formed. Resonance acoustic radiation portions of the resonators are arranged adjacent to each other on one side of the housing, whereby sound sources which correspond to the acoustic mass can be concentrated.

Abstract: In an acoustic apparatus in which a vibrator which drives a Helmholtz resonator having an open port by one surface thereof and directly radiates an acoustic wave from the other surface thereof is arranged in the Helmholtz resonator, the open port is arranged coaxially with the vibrator, and the vibrator is driven to cancel an air counteraction from the resonator when the resonator is driven. According to this construction, the acoustic apparatus can be rendered compact and the clear sound localization can be realized.

Abstract: An acoustic reproduction range expanding apparatus includes a closed or bass-reflex speaker system which has a low-frequency drive speaker and can reproduce a sound to a predetermined lowest frequeny. A port portion adapter consists of a mounting portion attached to an openng formed in a closed cabinet or a bass-reflex port of a bass-reflex cabinet, and a port portion. The port portion constitutes a Helmholtz's resonator together with the cabinet when the port portion is attached to the cabinet, and has a port shape so that a resonance frequency becomes lower than the lowest frequency. A drive portion adapter consists of an amplifier for driving the low-frequency drive speaker, and eliminates or invalidates an internal impedance inherent to the low-frequency drive speaker. The amplifier generates a negative impedance component in an output impedance.

Abstract: Disclosed is a compact, wide-range acoustic apparatus which can perform lower bass sound reproduction and is free from noise or distortion components. Spatially separated first and second chambers are formed. The first and second chambers communicate with each other through a port, so that the first chamber and a resonance port constitute a Helmholtz resonator. An open port is formed in or a passive vibrating body is arranged on the outer wall surface of the second chamber, so that the second chamber and the opening or the passive vibrating body constitute an essential low-pass type acoustic filter. A vibrator is attached to the outer wall surface of the first chamber, so that the Helmholtz resonator is driven at the inner surface side of the vibrating body of the vibrator, and an acoustic radiation is directly performed from its outer surface side. The vibrator is driven to cancel an air counteraction from the resonator when the Helmholtz resonator is driven.