Engine Controller Pumping Loss Estimation via Pressure Normalization
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Solution Overview
Problem
Existing internal combustion engine controllers face challenges in accurately estimating pumping loss, particularly when the throttle opening degree changes suddenly, leading to deviations in required charging pressure and inaccurate pumping loss estimation.
Innovation Solution
An internal combustion engine controller that calculates a pumping loss estimated value based on intake air pressure, engine speed, and charging pressure, using a processing circuit to execute a loss estimating process that normalizes these parameters and employs a map to obtain the estimated value, thereby improving estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the throttle opening degree changes suddenly, then the required charging pressure changes, but the pumping loss estimation becomes inaccurate
Solution Approach 1:
The controller performs preliminary actions by detecting throttle opening degree changes and proactively correcting the required charging pressure to a predetermined value before the inaccurate estimation occurs. This preventive approach ensures that the pumping loss estimation remains accurate even during sudden throttle transitions.
Solution Approach 2:
The system continuously monitors the throttle opening degree and uses this feedback to determine when to apply the charging pressure correction. By comparing the current throttle position with previous positions, the controller identifies sudden changes and triggers the appropriate correction mechanism to maintain estimation accuracy.
2Measurement precision
If a sensor for turbine upstream pressure is installed, then the pumping loss estimation accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The controller acts as an intermediary by using existing sensors (throttle position sensor, intake air pressure sensor, charging pressure sensor) to indirectly determine turbine upstream pressure conditions. Instead of directly measuring turbine upstream pressure, the system uses the relationship between charging pressure and turbine upstream pressure to calculate pumping loss, eliminating the need for an additional sensor.
Solution Approach 2:
The system creates a virtual model of turbine upstream pressure conditions by using measurements from existing sensors and the known relationship between charging pressure and turbine upstream pressure. This virtual representation allows accurate pumping loss estimation without physical measurement of turbine upstream pressure.
3Ease of manufacture
If the charging pressure is not normalized, then the calculation is simpler, but the pumping loss estimation becomes inaccurate under varying atmospheric pressure
Solution Approach 1:
The controller changes the parameter of charging pressure by normalizing it with atmospheric pressure to create a dimensionless ratio. This parameter transformation allows the system to maintain accurate pumping loss estimation across varying atmospheric conditions while using a standardized reference (intake air pressure) that is already available in the system.
Data Source
AI summary
An internal combustion engine to which a controller is applied includes a cylinder, a turbocharger, an intake passage, a throttle valve, and an exhaust passage. The turbocharger includes a turbine wheel, a compressor wheel, and a wastegate valve. The controller executes a loss estimating process that calculates an estimated value of a pumping loss of the internal combustion engine from an intake air pressure, which is air pressure at a downstream side of the throttle valve in the intake passage, an engine speed of the internal combustion engine, and a charging pressure.