Engine Torque Estimation Using Asymmetric Exhaust Sensors
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Solution Overview
Problem
Existing engine control strategies face challenges in accurately estimating torque in engines with asymmetric exhaust sensor configurations, leading to confounded air-fuel ratio measurements and increased errors in engine torque estimation.
Innovation Solution
A system comprising an engine with a first and second cylinder group, a linear exhaust gas sensor coupled to the first group, and a switching exhaust gas sensor coupled to the second group, with a controller that operates the engine in different modes and estimates torque based on independent air-fuel ratios from each group using a linear sensor, allowing for robust torque estimation even with confounded sensor readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an asymmetric exhaust sensor configuration is used with different cylinder groups operating at different air-fuel ratios, then fuel economy and engine efficiency are improved through fuel injector cut-out mode, but the air-fuel ratio measurements become confounded and torque estimation accuracy deteriorates
Solution Approach 1:
The exhaust system is segmented into two separate paths, each with its own sensor. The first cylinder group exhaust is monitored by a linear sensor, while the second cylinder group exhaust is monitored by a switching sensor. This segmentation allows independent measurement of air-fuel ratios in each cylinder group, preventing confounded measurements when operating modes differ.
Solution Approach 2:
A switching sensor is introduced as an intermediary device for the second cylinder group that can selectively measure air-fuel ratios in different modes. The switching sensor provides accurate measurements specifically tailored for the second cylinder group's operating conditions, acting as a mediator between the asymmetric sensor configuration and accurate torque estimation.
2Device complexity
If a single linear exhaust gas sensor is used for both cylinder groups, then the system is simple, but it cannot accurately distinguish air-fuel ratios when cylinder groups operate in different modes
Solution Approach 1:
The sensor system is segmented into two independent measurement paths instead of using a single shared sensor. Each cylinder group has its own dedicated sensor, allowing the system to maintain simplicity in each individual measurement path while achieving accurate differentiation of air-fuel ratios across different operating modes.
3Measurement precision
If different sensor types are used for different cylinder groups, then accurate air-fuel ratio measurements can be obtained in various operating modes, but the system complexity increases
Solution Approach 1:
Different sensor types are applied locally to different cylinder groups based on their specific operating requirements. The first cylinder group uses a linear sensor appropriate for its operation mode, while the second cylinder group uses a switching sensor suited for its variable modes. This local optimization achieves accurate measurements without unnecessarily complicating the entire system.
Data Source
AI summary
A system for a vehicle comprising of an engine including a first cylinder group and a second cylinder group; a linear exhaust gas sensor coupled exclusively to the first cylinder group; a switching exhaust gas sensor coupled exclusively to the second cylinder group; and a controller configured to operate the engine in at least a first mode and a second mode, where in the first mode the first and second cylinder groups combust air and fuel, where in the second mode at least one of the first and second cylinder groups combusts air and injected fuel and the other one of the first and second cylinder groups pumps air without injecting fuel, and where the controller is further configured to estimate torque of the engine in each of the first and second modes of operation based on the air-fuel ratio of the first cylinder group and the air-fuel ratio of the second cylinder group independent of the switching sensor and dependent on the linear sensor.