Exhaust Gas Sampling Apparatus with Variable Flow Rate Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust gas analysis systems for hybrid vehicles face challenges in maintaining analysis accuracy when the engine is stopped, as they either dilute the exhaust gas or result in insufficient sampling, and are not suitable for tests requiring continuous sampling over a predetermined time.
Innovation Solution
An exhaust gas analysis system with a flow rate changeable mechanism that adjusts the main and sampling flow rates based on the engine's operation state, using a control device to switch between different venturi configurations to maintain a constant ratio and ensure sufficient sampling without dilution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If sampling continues at the same flow rate when the engine is stopped, then the sampling amount in the sampling bag is sufficient, but the exhaust gas is diluted with diluent gas reducing analysis accuracy
Solution Approach 1:
The patent applies dynamics by making the sampling flow rate variable rather than constant. The control device dynamically adjusts the sampling flow rate based on engine operation state: maintaining a first sampling flow rate during engine operation and switching to a second, smaller sampling flow rate when the engine stops. This dynamic adjustment allows continuous sampling without dilution during engine stop conditions while ensuring sufficient sampling amount during operation.
Solution Approach 2:
The patent changes the flow rate parameter of the sampling system based on engine state. By switching between a first sampling flow rate (during operation) and a second sampling flow rate (during stop), the system adapts to different operating conditions. This parameter change enables the system to prevent dilution during engine stop while maintaining adequate sampling volume during operation.
2Measurement precision
If sampling stops when the engine is stopped, then the exhaust gas is not diluted, but the sampling amount becomes insufficient for analysis
Solution Approach 1:
The system dynamically adjusts the sampling flow rate rather than simply stopping sampling. When the engine stops, the control device reduces the sampling flow rate to a smaller second flow rate instead of halting sampling completely. This dynamic adjustment maintains continuous sampling (preventing exhaust gas stagnation) while reducing dilution, and ensures sufficient total sampling amount accumulates in the sampling bag for subsequent analysis.
Solution Approach 2:
The patent maintains continuous sampling action throughout both engine operation and stop states. By switching to a reduced second sampling flow rate during engine stop rather than stopping sampling entirely, the system ensures continuous gas flow through the system (preventing stagnation) while maintaining adequate sampling volume accumulation for analysis.
3Measurement precision
If sampling stops when the engine switches from operation to stop state, then dilution is prevented, but exhaust gas remains in the flow path causing measurement errors
Solution Approach 1:
The patent ensures continuous sampling action by maintaining a second sampling flow rate during engine stop state rather than stopping sampling. This continuous gas flow prevents exhaust gas from remaining stagnant in the flow paths and sampling system, eliminating measurement errors caused by gas stagnation while still preventing dilution by reducing (not eliminating) the sampling flow during engine stop.
Solution Approach 2:
The system dynamically adjusts the sampling flow rate in response to engine state changes. When the engine transitions from operation to stop, the control device switches from the first sampling flow rate to the second sampling flow rate, maintaining continuous but reduced sampling. This dynamic response prevents both dilution (by reducing flow) and gas stagnation (by maintaining continuous flow).
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 solution prevents dilution of exhaust gas in the sampling bag, ensures a sufficient sampling amount, and allows for continuous sampling over a predetermined time, maintaining analysis accuracy and preventing gas stagnation in the analysis system.
Implementation Method 1
a flow rate changeable mechanism that is provided in the main flow path and configured to be able to change a main flow rate
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In order to provide an exhaust gas analysis system that can accurately analyze exhaust gas discharged from an engine of a hybrid vehicle and can also be applied to a test that continues sampling into a sampling bag over a predetermined sampling time, a sampling apparatus 102 is adapted to include: a main flow path ML through which the exhaust gas flows; a sampling flow path SL that is connected to the main flow path ML to sample the exhaust gas into a sampling bag SB; and a constant flow rate mechanism 30 that is provided in the main flow path ML and configured to be able to change a main flow rate that is an exhaust gas flow rate through the main flow path ML. In addition, a control device 40 is adapted to, depending on whether the engine is in an operation state or in a stop state, control the constant flow rate mechanism 30 to change the main flow rate, as well as change a sampling flow rate that is an exhaust gas flow rate through the sampling flow path SL.