Cylinder Deactivation Engine Control for Fuel Economy
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Solution Overview
Problem
Existing power equipment, such as ride-on mowers, face inefficiencies in fuel consumption as they struggle to optimally allocate power between propelling devices and work implements, leading to suboptimal energy efficiency.
Innovation Solution
The implementation of a power equipment system with a multiple cylinder internal combustion engine that includes a central control unit to selectively deactivate cylinders based on throttle valve openings and engine load conditions, maintaining a prescribed rotational speed and adjusting air-fuel ratios to enhance fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If all cylinders are kept activated to maintain engine power, then the engine can handle increased load, but fuel consumption increases
Solution Approach 1:
The system dynamically adjusts the number of active cylinders based on real-time engine load conditions. The control unit monitors throttle valve opening and automatically activates or deactivates cylinders, making the engine configuration flexible and adaptive to varying operational demands, thereby optimizing fuel consumption while maintaining sufficient power.
Solution Approach 2:
The system changes the operational state parameter of the cylinders (activated vs. deactivated) based on throttle valve opening thresholds. When the throttle opening exceeds a predetermined threshold indicating increased load, cylinders are activated; when below the threshold, cylinders are deactivated, thus adjusting engine power output to match actual demand and reduce fuel consumption.
2Use of energy by moving object
If cylinders are deactivated to reduce fuel consumption, then fuel economy improves, but engine stability may be compromised
Solution Approach 1:
The control unit continuously monitors the throttle valve opening and provides feedback to determine whether to activate or deactivate cylinders. This closed-loop control ensures that cylinder deactivation only occurs when engine load is sufficiently low (throttle opening below threshold), preventing instability while maximizing fuel economy during light-load conditions.
Solution Approach 2:
The system performs preliminary assessment of engine load conditions through throttle valve monitoring before deciding to deactivate cylinders. By anticipating light-load conditions and proactively deactivating cylinders only when appropriate, the system prevents instability while achieving fuel savings, rather than reactively responding to instability after it occurs.
3Power
If the engine operates at prescribed rotational speed with multiple cylinders activated, then power output is sufficient, but energy efficiency decreases under light load
Solution Approach 1:
The engine is segmented into multiple independent cylinders that can be selectively activated or deactivated. This segmentation allows the engine to operate with only the necessary number of cylinders based on load requirements, reducing energy waste from running all cylinders at full capacity during light-load conditions while maintaining sufficient power output when needed.
Data Source
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AI summary
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.