Abstract: A multipurpose vehicle includes an engine, a fuel supply unit that supplies fuel to the engine, a gear transmission device that changes speed of power from the engine through a shifting operation, a coupling state detection sensor that detects a coupling state of the gear transmission device, a determination unit that determines whether the coupling state is an incomplete coupling state based on a detection signal from the coupling state detection sensor, and a fuel supply control unit that executes a fuel cut to reduce a fuel supply amount of the fuel from the fuel supply unit to the engine to a value less than a reference value, if the determination unit determines that the coupling state is the incomplete coupling state.

Abstract: A work vehicle includes a travelling state determination unit capable of determining a travelling state of a travelling body, and a control unit that restricts, if it has been determined by the travelling state determination unit that the travelling body is in a reverse travelling state, an upper limit value of a target rotational speed of an engine that is based on an operation on an accelerator operation tool to be a lower value than in a case where it has been determined by the travelling state determination unit that the travelling body is in a forward travelling state.

Abstract: A multipurpose vehicle includes an engine, a fuel supply unit that supplies fuel to the engine, a gear transmission device that changes speed of power from the engine through a shifting operation, a coupling state detection sensor that detects a coupling state of the gear transmission device, a determination unit that determines whether the coupling state is an incomplete coupling state based on a detection signal from the coupling state detection sensor, and a fuel supply control unit that executes a fuel cut to reduce a fuel supply amount of the fuel from the fuel supply unit to the engine to a value less than a reference value, if the determination unit determines that the coupling state is the incomplete coupling state.

Abstract: A work vehicle includes a travelling state determination unit capable of determining a travelling state of a travelling body, and a control unit that restricts, if it has been determined by the travelling state determination unit that the travelling body is in a reverse travelling state, an upper limit value of a target rotational speed of an engine that is based on an operation on an accelerator operation tool to be a lower value than in a case where it has been determined by the travelling state determination unit that the travelling body is in a forward travelling state.

Abstract: A breather apparatus is provided in a cylinder head having an intake camshaft and an exhaust camshaft that drive an intake valve and an exhaust valve, respectively. The breather apparatus includes, spaces separated from each other by partition walls and in communication with each other through an opening formed in the partition walls, the spaces having a blow-by gas flowing from a crankcase side passing sequentially therethrough. The spaces include a first space and a second space. The first space is formed in a region between the intake valve and the exhaust valve in the cylinder head. The second space is provided across the first space from a crankcase side, separated from the first space by a partition wall disposed substantially along a plane including shaft centers of the intake camshaft and the exhaust camshaft, and receives the blow-by gas flowing from the first space.

Abstract: The invention intends to provide a technology which makes it possible to diagnose with higher accuracy whether or not abnormality occurs in a filter regeneration system causing excessive execution frequency of a regeneration process. The filter regeneration system initiates execution of the regeneration process, incase an estimated particulate matter (PM) accumulation amount at the filter reaches a pre-determined regeneration requiring accumulation amount; or in case the pressure upstream of the filter or the differential pressure across the filter reaches a pre-determined regeneration requiring value, the value being larger than the pressure or the differential pressure corresponding to the regeneration requiring accumulation amount. Then, the diagnosis is carried out based on a ratio of an estimated PM accumulation amount at the initiation of the execution of the regeneration process to the regeneration requiring accumulation amount.

Abstract: When the intake air amount is smaller than the specific intake air amount, the unit air-fuel ratio change amount calculated during the engine operation is corrected such that the unit air-fuel ratio change amount increases in the condition that the base unit air-fuel ratio change amount is an upper limit and when the intake air amount is greater than the specific intake air amount, the unit air-fuel ratio change amount calculated during the engine operation is corrected such that the unit air-fuel ratio change amount decreases in the condition that the base unit air-fuel ratio change amount is a lower limit. When the corrected unit air-fuel ratio change amount is greater than the judgment value, it is judged that the inter-cylinder air-fuel ratio imbalance condition occurs.

Abstract: When the intake air amount is smaller than the specific intake air amount, the unit air-fuel ratio change amount calculated during the engine operation is corrected such that the unit air-fuel ratio change amount increases in the condition that the base unit air-fuel ratio change amount is an upper limit and when the intake air amount is greater than the specific intake air amount, the unit air-fuel ratio change amount calculated during the engine operation is corrected such that the unit air-fuel ratio change amount decreases in the condition that the base unit air-fuel ratio change amount is a lower limit. When the corrected unit air-fuel ratio change amount is greater than the judgment value, it is judged that the inter-cylinder air-fuel ratio imbalance condition occurs.

Abstract: The invention intends to provide a technology which makes it possible to diagnose with higher accuracy whether or not abnormality occurs in a filter regeneration system causing excessive execution frequency of a regeneration process. The filter regeneration system initiates execution of the regeneration process, incase an estimated particulate matter (PM) accumulation amount at the filter reaches a pre-determined regeneration requiring accumulation amount; or in case the pressure upstream of the filter or the differential pressure across the filter reaches a pre-determined regeneration requiring value, the value being larger than the pressure or the differential pressure corresponding to the regeneration requiring accumulation amount. Then, the diagnosis is carried out based on a ratio of an estimated PM accumulation amount at the initiation of the execution of the regeneration process to the regeneration requiring accumulation amount.