Compression-Ignition Engine Valve Timing for Stable Idle Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Self-igniting internal combustion engines, particularly diesel engines, experience significant mechanical vibrations and acoustic abnormalities during idling due to high idle irregularity, leading to increased fuel consumption and emissions.
Innovation Solution
Adjusting the closing times of intake and exhaust valves during the engine cycle, specifically retarding the intake valve closure and advancing the exhaust valve opening, combined with partial throttle valve closure, to optimize air-fuel ratio and reduce cylinder charge, thereby minimizing vibrations and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine operates with high excess air at idle (throttle-free operation), then fuel consumption is reduced, but mechanical vibrations and acoustic abnormalities increase due to high idle irregularity
Solution Approach 1:
The valve timing is made dynamically adjustable based on operating conditions. The control unit retards the intake valve closing timing specifically during idle operation, creating a dynamic adaptation that reduces idle irregularity and vibrations while maintaining throttle-free operation for fuel efficiency.
Solution Approach 2:
The invention changes the timing parameter of the intake valve closing event during idle operation. By retarding the intake valve closing timing relative to the crankshaft position, the charge amount is reduced, which dampens the strong deceleration during compression and reduces mechanical vibrations and acoustic noise.
2Power
If the intake valve closes earlier in the compression stroke, then the charge amount increases and power output improves, but mechanical vibrations increase during idle due to stronger deceleration
Solution Approach 1:
The valve timing is dynamically adjusted based on operating conditions. During idle, the intake valve closing is retarded to reduce vibrations, while during load operation, it closes earlier to maximize power output. This dynamic adaptation resolves the contradiction between power and vibration reduction.
Solution Approach 2:
The intake valve closing timing parameter is changed based on operating conditions. During idle, it is retarded to reduce the charge amount and dampen mechanical vibrations. During load operation, the timing returns to optimal power settings, allowing the engine to deliver full power output.
3Object-affected harmful factors
If a throttle valve is used to reduce the charge amount during idle, then mechanical vibrations are reduced, but fuel consumption increases by up to 20 percent
Solution Approach 1:
Instead of using a throttle valve, the invention dynamically adjusts the intake valve closing timing to control the charge amount. This maintains the direct connection between the engine and the atmosphere, avoiding the energy losses associated with throttle restriction while still reducing the charge during idle to minimize vibrations.
Solution Approach 2:
The invention replaces the mechanical throttle valve system with a valve timing control system. By using variable valve timing to control the charge amount instead of a throttle valve, the system eliminates the energy losses and fuel consumption penalty associated with throttling while achieving the same vibration reduction effect.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for operating a compression-ignition internal combustion engine (1) with at least one combustion chamber which has an inlet valve (4). The compression-ignition (23) internal combustion engine (1) is operated in an operating state in which the at least one inlet valve (4) is closed at a first time within one working cycle. If the compression-ignition (23) internal combustion engine (1) is operated in the idling mode, the invention provides that the at least one inlet valve (4) is closed in the idling mode at a second time within one working cycle, which time is later than the first time. The invention also relates to an internal combustion engine (1) with compression ignition, comprising a control unit (9) which has a memory in which a control programme is stored, at least one section of which control programme controls the idling mode of the internal combustion engine (1) when the control programme is executed.