Engine Valve Actuator Diagnostics via Exhaust Temperature Sampling
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Solution Overview
Problem
Existing engine systems face challenges in diagnosing the operation of intake and exhaust valve actuators without increasing system cost, as cylinder pressure sensors and valve actuator position sensors are costly and not always effective, leading to potential fuel inefficiency and emission issues due to valve actuator degradation.
Innovation Solution
The method involves rotating the engine without combustion and sampling exhaust system temperature to determine if intake and exhaust valve actuators are functioning correctly by trapping hot gases in deactivated cylinders and observing temperature changes when the valves are activated, allowing for the detection of valve actuator degradation without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cylinder pressure sensors or valve actuator position sensors are deployed to determine valve actuator operation, then measurement precision is improved, but system cost increases significantly
Solution Approach 1:
The exhaust system temperature sensor performs dual functions: monitoring exhaust temperature during normal operation and detecting valve actuator degradation during diagnostic mode. The existing sensor serves itself by providing diagnostic capability without requiring additional measurement devices.
Solution Approach 2:
The exhaust temperature sensor is utilized for both its original purpose (monitoring exhaust temperature) and a new diagnostic purpose (detecting valve actuator degradation). This multi-functionality eliminates the need for separate diagnostic sensors, reducing system cost while maintaining measurement capability.
2Use of energy by moving object
If valve actuators are commanded to deactivate valves to conserve fuel, then fuel efficiency is improved, but reliability deteriorates if actuators fail to switch states properly
Solution Approach 1:
The system commands valve actuators to deactivate and then monitors exhaust temperature to verify the deactivation occurred. This feedback loop allows the control system to detect actuator failures and adjust operation accordingly, improving reliability while maintaining fuel efficiency benefits.
Solution Approach 2:
The system performs periodic diagnostic checks by commanding valve deactivation and monitoring temperature response before normal operation continues. This preliminary verification ensures actuators are functioning properly before relying on them for fuel-saving operations.
3Use of energy by moving object
If valve actuators fail to activate valves when commanded, then fuel consumption decreases due to unintended valve deactivation, but harmful factors increase due to fuel accumulation and emissions
Solution Approach 1:
The system monitors exhaust temperature to detect when valves fail to activate as commanded. This feedback enables the control system to identify actuator degradation and adjust fuel injection or valve commands to prevent fuel accumulation and excessive emissions.
Solution Approach 2:
The diagnostic system detects valve actuator degradation before it causes severe emissions problems. By identifying the issue early, the system can take corrective action to prevent fuel accumulation and harmful emissions from occurring.
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
This approach provides cost-effective diagnostics for engine cylinder valve deactivation systems, reduces engine emissions by identifying and addressing valve actuator degradation, and improves fuel efficiency by ensuring proper valve operation.
Implementation Method 1
sampling a temperature of gases flowing through an exhaust system
Implementation Method 2
air flowing through the cylinders having operating intake and exhaust valves cools gases flowing through the exhaust system
Implementation Method 3
rotating an engine without combusting fuel via a controller
Data Source
AI summary
Systems and methods for determining operation of a cylinder deactivating/reactivating device are disclosed. In one example, a warm engine is rotated without being supplied fuel to determine the presence or absence of valve actuator degradation. Degraded valve actuators may be determined when there is a lack of a temperature rise in the engine exhaust system.