Power equipment with cylinder deactivation engine
The power equipment such as a lawn mower ( 10 ) comprises an internal combustion engine ( 100 ) having a plurality of cylinders, an engine control unit ( 110 ) for selectively deactivating at least one of the cylinders, a work implement such as a cutting blade ( 70 ) connected to the engine in a power transmitting relationship, a clutch ( 80 ) provided in a power transmission path between the engine and the work implement, and a central control unit ( 50 ) for controlling an operation of a propelling device, the clutch and the engine control unit. The central control unit is configured to operate the engine at a prescribed rotational speed with two or more of the cylinders kept activated when the clutch is engaged and the propelling device is propelling the power equipment forward, and to deactivate at least one of the cylinders when an opening of a throttle valve is below a first prescribed value for a prescribed time period.
1. Power equipment, comprising:
an equipment main body provided with a propelling device;
a power source for selectively powering the propelling device;
an internal combustion engine having a plurality of cylinders and supported by the equipment main body, the engine including a throttle valve for adjusting a flow of air or mixture into the cylinders of the engine;
an engine control unit for controlling the throttle valve of the engine, and selectively deactivating at least one of the cylinders;
a work implement connected to the engine in a power transmitting relationship;
a clutch provided in a power transmission path between the engine and the work implement; and
a central control unit for controlling an operation of the propelling device, the clutch and the engine control unit;
wherein the central control unit is configured to cause the engine control unit to operate the engine at a prescribed rotational speed with two or more of the cylinders kept activated when the clutch is engaged and the propelling device is propelling the power equipment forward, and to deactivate at least one of the cylinders when an opening of the throttle valve is below a first prescribed value for a prescribed time period while the clutch is maintained engaged and the propelling device is propelling the power equipment forward, and
wherein the central control unit is configured to reactivate at least one of the cylinders that are previously deactivated when the opening of the throttle valve is above a second prescribed value greater than the first prescribed value, and a rotational speed of the engine is not within a prescribed tolerance range defined as the prescribed rotational speed ± a prescribed value, and
wherein the work implement consists of a cutting blade housed within a mower deck, and the clutch consists of a blade clutch.
2. The power equipment according to claim 1 , wherein the central control unit is configured to reactivate at least one of the cylinders that are previously deactivated when the opening of the throttle valve is above a second prescribed value greater than the first prescribed value.
3. The power equipment according to claim 1 , wherein the central control unit is configured to maintain a rotational speed of the engine at a value lower than the prescribed rotational speed with a plurality of cylinders kept activated when the clutch is engaged and the propelling device is not propelling the power equipment forward.
4. The power equipment according to claim 1 , wherein the central control unit is configured to maintain a rotational speed of the engine at the prescribed rotational speed while at least one of the cylinders is deactivated.
5. The power equipment according to claim 1 , wherein the central control unit is configured to make an air fuel ratio of a mixture supplied to the engine leaner, and to supply an increased amount of mixture to the engine while at least one of the cylinders is deactivated.