Engine Overheat Protection via Periodic Fuel Injection Derating
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Solution Overview
Problem
Internal combustion engines face challenges in protecting against overheating, particularly in air-cooled systems where debris can clog air paths, leading to reduced cooling efficiency and potential engine damage, and mechanical governors lack control over throttle position to manage heat.
Innovation Solution
A control system utilizing a controller with temperature, air-fuel ratio, and air flow sensors to deactivate the fuel injector temporarily, reducing power output and heat generation, even in ungoverned engines, by generating control signals based on sensor data and thresholds to manage engine temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If mechanical governors are used to control engine speed, then engine speed can be regulated, but throttle position cannot be controlled to manage heat
Solution Approach 1:
The patent replaces the mechanical governor system with an electronic control system that uses sensors (temperature sensor, air-fuel ratio sensor, air flow sensor) and an electronic control unit to manage both engine speed and throttle position. This substitution enables precise control of throttle position to manage heat generation while maintaining engine speed regulation, resolving the limitation of mechanical governors that cannot control throttle position for thermal management.
2Temperature
If fuel injection is deactivated to reduce power output and heat generation, then engine temperature is controlled, but engine may stall
Solution Approach 1:
The patent implements periodic derating cycles where fuel injection is temporarily deactivated for a predetermined time period when overheating is detected, then reactivated after the period expires. This periodic on-off control allows the engine to reduce heat generation temporarily to cool down, while ensuring continuous operation by restarting fuel injection before complete shutdown occurs, thus preventing stalling while managing temperature.
Solution Approach 2:
The system continuously monitors engine temperature via a temperature sensor and uses this feedback to control fuel injection. When the temperature exceeds a threshold, the control unit deactivates fuel injection; when temperature drops below the threshold, fuel injection is reactivated. This closed-loop feedback control ensures temperature management while maintaining engine operation continuity.
3Temperature
If air-cooled systems are used, then cooling is provided, but debris can clog air paths reducing cooling efficiency
Solution Approach 1:
The system uses air flow sensors and temperature sensors to continuously monitor cooling system performance. When debris clogs air paths, the air flow sensor detects reduced air flow and the temperature sensor detects rising engine temperature. The control unit responds by adjusting fuel injection to reduce power output and heat generation, compensating for the reduced cooling efficiency caused by debris blockage.
Solution Approach 2:
The patent introduces electronic control as an intermediary between the air-cooled system and the engine power output. When cooling efficiency is reduced due to debris, the electronic control system mediates by adjusting fuel injection timing and quantity to match the reduced cooling capacity, preventing overheating while maintaining optimal engine operation within the compromised cooling conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents engine overheating by reducing power output and heat generation through controlled fuel injection, ensuring engine operation without stalling and alerting operators to potential debris issues, thus extending engine lifespan and maintaining performance.
Implementation Method 1
A temperature sensor, a fuel injector and a controller (e.g., an engine control unit or ECU) are in an air cooled, single cylinder, four stroke cycle, spark ignited engine
Implementation Method 2
A temperature sensor, a fuel injector and a controller (e.g., an engine control unit or ECU) are in an air cooled, single cylinder, four stroke cycle, spark ignited engine
Implementation Method 3
A temperature sensor, a fuel injector and a controller (e.g., an engine control unit or ECU) are in an air cooled, single cylinder, four stroke cycle, spark ignited engine
Implementation Method 4
The controller is configured to provide a control signal to the fuel injector to temporarily stop the fuel injector from injecting fuel into the combustion chamber of the engine
Implementation Method 5
an air cooled, single cylinder, four stroke cycle, spark ignited engine
Implementation Method 6
The core of this process is combusting where chemically energy is release from a mixture of fuel and air. The energy from combustion is converted to work during compressing to apply a force to at least one piston housed in a cylinder
Implementation Method 7
The piston rotates a crankshaft and rotational energy is output
Implementation Method 8
An air cooled, single cylinder, four stroke cycle, spark ignited engine
Data Source
AI summary
An engine includes a single cylinder, at least one sensor, a fuel injector, and a controller. The at least one sensor is configured to generate sensor data for an engine condition. The controller is configured to perform a comparison of the engine condition to a threshold and in response to the comparison, generate a first command to deactivate the fuel injector after a first predetermined time period and a second command to reactivate the fuel injector after a second predetermined time period.