An air intake system having an air filter and a cyclonic pre-cleaner is described. The cyclonic pre-cleaner includes a plurality of fins that cause the air flowing through the pre-cleaner to go from a substantially axial flow to a substantially swirling flow. As the air flow through the pre-cleaner increases, the air is swirled at a faster rate, and some contaminant particles in the air will be forced out of the flow of air before reaching the air filter. The air intake system includes a blower unit having a motor, an impeller, and a controller. The blower unit structured to selectively draw more air through the air intake system to increase the flow of air through the pre-cleaner thereby increasing the efficiency of the pre-cleaner.

An air intake system having an air filter and a cyclonic pre-cleaner is described. The cyclonic pre-cleaner includes a plurality of fins that cause the air flowing through the pre-cleaner to go from a substantially axial flow to a substantially swirling flow. As the air flow through the pre-cleaner increases, the air is swirled at a faster rate, and some contaminant particles in the air will be forced out of the flow of air before reaching the air filter. The air intake system includes a blower unit having a motor, an impeller, and a controller. The blower unit structured to selectively draw more air through the air intake system to increase the flow of air through the pre-cleaner thereby increasing the efficiency of the pre-cleaner.

An apparatus for removing debris from the intake of an engine includes an air cleaner housing with an inlet opening, an air entry cavity, one or more turbulent flow tubes, and at least one outlet opening. The inlet opening in the air cleaner housing is configured to receive an incoming flow of air from a blower. The air entry cavity is coupled with the inlet opening of the air cleaner housing. The one or more turbulent flow tubes configured to divide the flow of air from the air entry cavity and remove debris from the flow of air. The at least one outlet opening in the air cleaner housing is coupled to the one or more turbulent flow tubes and configured to expel the debris from the air cleaner housing. In addition, excess air from the air cleaner housing and/or combustion air is expelled from the air cleaner housing.

An apparatus for removing debris from the intake of an engine includes an air cleaner housing with an inlet opening, an air entry cavity, one or more turbulent flow tubes, and at least one outlet opening. The inlet opening in the air cleaner housing is configured to receive an incoming flow of air from a blower. The air entry cavity is coupled with the inlet opening of the air cleaner housing. The one or more turbulent flow tubes configured to divide the flow of air from the air entry cavity and remove debris from the flow of air. The at least one outlet opening in the air cleaner housing is coupled to the one or more turbulent flow tubes and configured to expel the debris from the air cleaner housing. In addition, excess air from the air cleaner housing and/or combustion air is expelled from the air cleaner housing.

Intake assemblies for an engine are provided. In one aspect, an air intake assembly includes a screen defining a plurality of air passage holes therein, a fan, a flywheel, a crankshaft, and a screen support member coupled to the screen. The fan, the flywheel and the screen support member are coupled to the crankshaft with a single fastener, and the screen, the fan, the flywheel, the crankshaft and the screen support member all rotate together. In one aspect, the screen support member supports the screen a distance away from the fan such that the screen is completely spaced-apart from and does not engage the fan. In one aspect, a screen support member includes a base near one end of the screen support member and a plurality of coupling locations near a second end. The screen couples to the screen support member at the plurality of coupling locations.

Intake assemblies for an engine are provided. In one aspect, an air intake assembly includes a screen defining a plurality of air passage holes therein, a fan, a flywheel, a crankshaft, and a screen support member coupled to the screen. The fan, the flywheel and the screen support member are coupled to the crankshaft with a single fastener, and the screen, the fan, the flywheel, the crankshaft and the screen support member all rotate together. In one aspect, the screen support member supports the screen a distance away from the fan such that the screen is completely spaced-apart from and does not engage the fan. In one aspect, a screen support member includes a base near one end of the screen support member and a plurality of coupling locations near a second end. The screen couples to the screen support member at the plurality of coupling locations.

The invention provides an exhaust purification device capable of suppressing the temporal decrease in NOx catalyst removal efficiency due to soot accumulation. The invention provides an exhaust purification device using an air injection nozzle to inject pressurized air into a casing of a catalyst reactor containing an NOx catalyst as a catalyst and removing soot adhering to the NOx catalyst, wherein it is determined and externally notified that there is abnormal deterioration in the NOx catalyst when the pressure difference P in exhaust between the upstream and downstream sides of the NOx catalyst has increased by at least a first reference pressure difference increase Pt1, which is the allowable amount of pressure difference increase, above the pressure difference Pi in exhaust between the upstream and downstream sides of the catalyst in the initial state at the same exhaust flow rate Ve.

The invention provides an exhaust purification device capable of suppressing the temporal decrease in NOx catalyst removal efficiency due to soot accumulation. The invention provides an exhaust purification device using an air injection nozzle to inject pressurized air into a casing of a catalyst reactor containing an NOx catalyst as a catalyst and removing soot adhering to the NOx catalyst, wherein it is determined and externally notified that there is abnormal deterioration in the NOx catalyst when the pressure difference P in exhaust between the upstream and downstream sides of the NOx catalyst has increased by at least a first reference pressure difference increase Pt1, which is the allowable amount of pressure difference increase, above the pressure difference Pi in exhaust between the upstream and downstream sides of the catalyst in the initial state at the same exhaust flow rate Ve.

A pre-filter assembly for a vehicle arranged with an aspiration duct extending between the pre-filter and a fan of the vehicle. A variable valve element is provided as part of the aspiration duct adjacent the fan, such that the aspiration rate through the duct can be controlled by appropriate variation of the valve element, to control the rate of airflow drawn through the aspiration duct by the fan. This allows for the aspiration rate of the pre-filter to be at least partly independent of the flow rate of the fan, without the need for an additional motor-driven blower unit.

A pre-filter assembly for a vehicle arranged with an aspiration duct extending between the pre-filter and a fan of the vehicle. A variable valve element is provided as part of the aspiration duct adjacent the fan, such that the aspiration rate through the duct can be controlled by appropriate variation of the valve element, to control the rate of airflow drawn through the aspiration duct by the fan. This allows for the aspiration rate of the pre-filter to be at least partly independent of the flow rate of the fan, without the need for an additional motor-driven blower unit.