Abstract: When an internal combustion engine (1) is determined to be in a low-temperature start state (an affirmative determination is made in S120), an air-fuel ratio control apparatus (10) controls the temperature of a downstream detection element (17) of a downstream gas sensor (15) to a downstream target temperature by driving a downstream heater (16) of the downstream gas sensor (15) (S170), and feedback-controls the air-fuel ratio of exhaust gas based on the output of the downstream gas sensor (15) (S190). When the engine (1) is determined not to be in the low-temperature start state (a negative determination is made in S120), the air-fuel ratio control apparatus (10) drives an upstream heater (25) of an upstream gas sensor (22) and feedback-controls the air-fuel ratio of exhaust gas based on the output of the upstream gas sensor (22) (S270).

Abstract: When an internal combustion engine (1) is determined to be in a low-temperature start state (an affirmative determination is made in S120), an air-fuel ratio control apparatus (10) controls the temperature of a downstream detection element (17) of a downstream gas sensor (15) to a downstream target temperature by driving a downstream heater (16) of the downstream gas sensor (15) (S170), and feedback-controls the air-fuel ratio of exhaust gas based on the output of the downstream gas sensor (15) (S190). When the engine (1) is determined not to be in the low-temperature start state (a negative determination is made in S120), the air-fuel ratio control apparatus (10) drives an upstream heater (25) of an upstream gas sensor (22) and feedback-controls the air-fuel ratio of exhaust gas based on the output of the upstream gas sensor (22) (S270).

Abstract: The position of a passage separating member in the axial direction of the cylinder bores is determined by causing a spacer to contact a bottom surface of a water jacket. When the separating member is inserted in the water jacket, the width of the separating member is reduced due to elastic deformation, so that the separating member can be arranged in the water jacket. After being arranged, the separating member tightly contacts the inner surface of the water jacket due to elastic restoration force. The tight contact prevents the separating member from moving upward in the water jacket. As a result, coolant is prevented from moving between the upper portion and the lower portion with respect to the separating member. The advantages of separate cooling of the coolant in the upper and lower portions with respect to the separating member are obtained. This reliably reduces the temperature difference along the axial direction of the cylinder bore forming body.

Abstract: A cooling structure of an internal combustion engine includes: a cooling water introducing port provided on one end side of a cylinder block; and a water jacket provided so as to surround a cylinder bore wall, wherein cooling water is introduced from the cooling water introducing port into the water jacket, the cooling water is branched to flow to a portion on an intake side and a portion on an exhaust side of the water jacket of the cylinder block of the internal combustion engine, and the cooling water is supplied from a cylinder block side to a cylinder head side, the cooling structure of the internal combustion engine, further comprising a first regulation portion that regulates a flow of the cooling water supplied to the cylinder head side.

Abstract: A partition member used in a cylinder block of an internal combustion engine is disclosed. The partition member is arranged in a groove-like cooling passage through which a cooling heat medium flows. The partition member includes a separating wall and a flexible lip member. The separating wall divides the cooling passage into an inner passage and an outer passage. The inner passage is located close to the cylinder bores, and the outer passage is located outside of the inner passage. The lip member extends from the separating wall toward the opening of the cooling passage in such a manner that, when the partition member is arranged in the cooling passage, the lip member contacts one of the inner surfaces of the cylinder block forming the cooling passage. When the partition member is arranged in the cooling passage, the distal edge portion of the flexible lip member contacts the inner surface due to force produced through flexible shape restoration of the lip member.

Abstract: A pulley is fixed to a housing of a water pump, the pulley being connected to an output shaft of an internal combustion engine so that the pulley is driven through the output shaft. In the housing, a slider moves to and fro due to a change in pressure in a pressure chamber, which causes the magnetic flux passing through a magnet and an inductor ring of a rotary cylinder to vary, so that the driving force of the internal combustion engine is variably transmitted to the rotary cylinder. The pressure chamber is connected to an intake air passage and an atmospheric air introducing portion through a pressure path, and the state of communication is changed by a VSV. The pressure passage is provided with an orifice for preventing rapid change in pressure in the pressure chamber when the VSV is switched.

Abstract: The position of a passage separating member in the axial direction of the cylinder bores is determined by causing a spacer to contact a bottom surface of a water jacket. When the separating member is inserted in the water jacket, the width of the separating member is reduced due to elastic deformation, so that the separating member can be arranged in the water jacket. After being arranged, the separating member tightly contacts the inner surface of the water jacket due to elastic restoration force. The tight contact prevents the separating member from moving upward in the water jacket. As a result, coolant is prevented from moving between the upper portion and the lower portion with respect to the separating member. The advantages of separate cooling of the coolant in the upper and lower portions with respect to the separating member are obtained. This reliably reduces the temperature difference along the axial direction of the cylinder bore forming body.

Abstract: A cooling structure of an internal combustion engine includes: a cooling water introducing port provided on one end side of a cylinder block; and a water jacket provided so as to surround a cylinder bore wall, wherein cooling water is introduced from the cooling water introducing port into the water jacket, the cooling water is branched to flow to a portion on an intake side and a portion on an exhaust side of the water jacket of the cylinder block of the internal combustion engine, and the cooling water is supplied from a cylinder block side to a cylinder head side, the cooling structure of the internal combustion engine, further comprising a first regulation portion that regulates a flow of the cooling water supplied to the cylinder head side.

Abstract: A partition member used in a cylinder block of an internal combustion engine is disclosed. The partition member is arranged in a groove-like cooling passage through which a cooling heat medium flows. The partition member includes a separating wall and a flexible lip member. The separating wall divides the cooling passage into an inner passage and an outer passage. The inner passage is located close to the cylinder bores, and the outer passage is located outside of the inner passage. The lip member extends from the separating wall toward the opening of the cooling passage in such a manner that, when the partition member is arranged in the cooling passage, the lip member contacts one of the inner surfaces of the cylinder block forming the cooling passage. When the partition member is arranged in the cooling passage, the distal edge portion of the flexible lip member contacts the inner surface due to force produced through flexible shape restoration of the lip member.

Abstract: A pulley is fixed to a housing of a water pump, the pulley being connected to an output shaft of an internal combustion engine so that the pulley is driven through the output shaft. In the housing, a slider moves to and fro due to a change in pressure in a pressure chamber, which causes the magnetic flux passing through a magnet and an inductor ring of a rotary cylinder to vary, so that the driving force of the internal combustion engine is variably transmitted to the rotary cylinder. The pressure chamber is connected to an intake air passage and an atmospheric air introducing portion through a pressure path, and the state of communication is changed by a VSV.

Abstract: A check valve having a thermostat function is provided between an engine and a thermal storage tank that stores a portion of the coolant circulating in the engine. The check valve restricts the flow of the coolant from the engine to the thermal storage tank, and loosens the restriction when the temperature of the coolant increases. Through such operation of the check valve, the warm coolant is collected in the thermal storage tank and engine preheating may be performed before engine start. Thus, by providing between the engine and the thermal storage tank the check valve that operates in response to the temperature of the coolant, engine preheating can be accomplished with a simple structure and at a low cost, without using a three-way valve and performing an electrical valve switching control.

Abstract: A control apparatus for an internal combustion engine for a vehicle includes a coolant temperature increase device, an operation control device, and an ignition timing retard control device. The coolant temperature increase device increases a coolant temperature. The operation control device executes an engine control in response to an instruction provided by a driver. During the engine control power performance provided by the internal combustion engine in response to an operation performed by the driver is lower than power performance that is normally provided in response to the operation performed by the driver. The ignition timing retard control device executes an ignition timing retard control to prevent knocking. In the control apparatus, when the operation control device executes the engine control, the coolant temperature increase device increases the coolant temperature.

Abstract: A check valve having a thermostat function is provided between an engine and a thermal storage tank that stores a portion of the coolant circulating in the engine. The check valve restricts the flow of the coolant from the engine to the thermal storage tank, and loosens the restriction when the temperature of the coolant increases. Through such operation of the check valve, the warm coolant is collected in the thermal storage tank and engine preheating may be performed before engine start. Thus, by providing between the engine and the thermal storage tank the check valve that operates in response to the temperature of the coolant, engine preheating can be accomplished with a simple structure and at a low cost, without using a three-way valve and performing an electrical valve switching control.

Abstract: A fuel vapor purge system includes a fuel tank, a canister, and an evaporation route, and purges fuel vapor collected in the canister into an intake passage of an internal combustion engine. A failure diagnosis apparatus of the fuel vapor purge system includes a controller having a pressure difference applying unit for applying a pressure difference between the evaporation route and outside air. The controller also detects a level of an influence of the fuel vapor generated in the fuel tank on failure determination of the evaporation route, and detects both a pressure state obtained when the pressure difference applying unit communicates with a reference orifice communicating with the outside air and a pressure state obtained when the pressure difference applying unit communicates with the evaporation route. The failure diagnosis apparatus determines whether there is a failure in the evaporation route in view of the level of the influence by comparing the detected pressure states with each other.

Abstract: A failure test apparatus for a fuel-vapor purging system for adsorbing fuel vapor in a fuel tank into a canister and for purging fuel to an intake system of an internal combustion engine as needed. The purging system has at least one valve. A first test unit provides a differential pressure between the inside and the outside of the fuel-vapor purging system, measures the internal pressure with the fuel-vapor purging system in an airtight condition, and determines whether a leak exists in the fuel-vapor purging system from the behavior of the internal pressure. The test by the first test unit involves a differential-pressure forming process of creating a differential pressure between the inside and the outside of the fuel-vapor purging system, a sealing process of making the fuel-vapor purging system airtight when the differential pressure exists, and a differential-pressure releasing process for releasing the differential pressure.

Abstract: A fuel vapor purge system includes a fuel tank, a canister, and an evaporation route, and purges fuel vapor collected in the canister into an intake passage of an internal combustion engine. A failure diagnosis apparatus of the fuel vapor purge system includes a controller having a pressure difference applying unit for applying a pressure difference between the evaporation route and outside air. The controller also detects a level of an influence of the fuel vapor generated in the fuel tank on failure determination of the evaporation route, and detects both a pressure state obtained when the pressure difference applying unit communicates with a reference orifice communicating with the outside air and a pressure state obtained when the pressure difference applying unit communicates with the evaporation route. The failure diagnosis apparatus determines whether there is a failure in the evaporation route in view of the level of the influence by comparing the detected pressure states with each other.

Abstract: In a diagnostic apparatus and method for a fuel vapor purge system in which fuel vapor generated in a fuel tank trapped in a chamber is purged into an intake passage of an internal combustion engine through a purge path, a first change in a pressure of the purge path is measured after creating a pressure difference between the inside and outside of the purge path and sealing the purge path, and a second change in pressure that varies with an amount of fuel vapor generated in the fuel tank is measured while the purge path is sealed for a first period of time after an atmospheric pressure is introduced into the purge path. Then, it is determined whether leakage is present in the purge path, based on the first change and the second change in the pressure of the purge path.

Abstract: An improved diagnosis apparatus for detecting leakage of a fuel vapor purge system that purges fuel vapor from a fuel tank to an intake passage of an engine. The apparatus includes a pressure sensor and a purge valve. The pressure sensor detects the pressure in the purge system. The purge valve connects the purge system with the intake passage for lowering the purge system pressure to a predetermined pressure level. After the purge system pressure is lowered to the predetermined level, the purge system is sealed. The apparatus measures the rate of pressure change immediately after the purge system is sealed. The apparatus subsequently measures the rate of pressure change when the purge system pressure reaches a second reference pressure value and computes the ratio of the rates. The apparatus diagnoses whether there is a leak in the purge system based on the ratio and the rate of pressure change at the second reference pressure value.

Abstract: A test apparatus for a fuel vapor purge system that performs frequent tests. The testing apparatus detects leakage of fuel vapor from a system passage by sealing the system passage and monitoring changes in the pressure. After the test, the apparatus applies atmospheric pressure to the system passage. Therefore, the pressure in the system passage is quickly restored to atmospheric pressure.

Abstract: In a diagnostic apparatus and method for a fuel vapor purge system in which fuel vapor generated in a fuel tank trapped in a chamber is purged into an intake passage of an internal combustion engine through a purge path, a first change in a pressure of the purge path is measured after creating a pressure difference between the inside and outside of the purge path and sealing the purge path, and a second change in pressure that varies with an amount of fuel vapor generated in the fuel tank is measured while the purge path is sealed for a first period of time after an atmospheric pressure is introduced into the purge path. Then, it is determined whether leakage is present in the purge path, based on the first change and the second change in the pressure of the purge path.