Hydrocarbon Concentration Calculation in Vehicle Purge Pump
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Solution Overview
Problem
Existing methods for calculating the concentration of hydrocarbon in fuel evaporation gas, particularly in turbocharger-mounted engines and hybrid vehicles, face challenges due to difficulties in generating negative pressure in the intake system, leading to inaccurate concentration calculations.
Innovation Solution
A method and device utilizing a controller to calculate the concentration of hydrocarbon in fuel evaporation gas by determining the first fuel evaporation gas density in a purge pump, filtering it to control rapid changes, and then calculating the second and third fuel evaporation gas densities to determine the hydrocarbon concentration accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a purge system uses negative pressure from the intake system to supply fuel evaporation gas, then the system structure is simple, but turbocharger-mounted engines and hybrid vehicles cannot generate sufficient negative pressure at the front end of the intake valve
Solution Approach 1:
The patent introduces a purge pump as an intermediary device that actively pumps fuel evaporation gas from the canister to the intake manifold, replacing the passive negative pressure-driven system. This mediator enables reliable fuel vapor transport in turbocharger and hybrid vehicles where negative pressure is insufficient.
Solution Approach 2:
The patent replaces the mechanical passive system (relying on intake manifold negative pressure) with an active mechanical pumping system. The purge pump uses a motor-driven impeller to forcibly transport fuel vapor, substituting the insufficient atmospheric pressure-driven mechanism with a powered mechanical system.
2Device complexity
If the fuel evaporation gas density is calculated directly from pressure difference and pump parameters, then the calculation is simple, but rapid changes in density cause inaccurate hydrocarbon concentration calculations
Solution Approach 1:
The patent implements a feedback mechanism where the calculated fuel evaporation gas density is continuously fed back to update the hydrocarbon concentration calculation. The controller uses the density value from the current time step and previous time steps to compute accurate concentration, adjusting for rapid changes dynamically.
Solution Approach 2:
The patent performs preliminary calculations of fuel evaporation gas density at multiple time steps before finalizing the hydrocarbon concentration measurement. By calculating density at the current time step and previous time steps in advance, the system prepares data needed for accurate concentration computation, smoothing out rapid fluctuations.
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
The proposed method and device enable accurate calculation of hydrocarbon concentration in fuel evaporation gas, even under conditions of rapid changes, thereby improving the precision of fuel management in vehicles.
Implementation Method 1
calculating a first fuel evaporation gas density in a purge pump included in an active fuel vapor purge system of the vehicle based on a difference between a pressure signal at a front end of the purge pump and a pressure signal at a rear end of the purge pump
Implementation Method 2
a purge pump that pumps the fuel evaporation gas from the canister to the intake manifold
Implementation Method 3
a solenoid valve that opens or closes a passage through which the fuel evaporation gas flows
Data Source
AI summary
A method includes calculating a first fuel evaporation gas density in a purge pump of a vehicle based on a pressure difference between a front end and a rear end of the purge pump, a radius of a fluid passage of the purge pump, a number of rotations of the purge pump, and an opening amount of a purge control solenoid valve, filtering the first fuel evaporation gas density, calculating a second fuel evaporation gas density in the purge pump based on the filtered first fuel evaporation gas density, calculating a third fuel evaporation gas density in a standard temperature and pressure state based on the second fuel evaporation gas density, a current pressure in the purge pump, and a current temperature in the purge pump, and calculating a concentration of hydrocarbon in a fuel evaporation gas in the purge pump based on the third fuel evaporation gas density.