Engine Torque Calculation During Fuel Cut Return
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Solution Overview
Problem
Conventional engine torque calculation methods fail to accurately account for the difference in gas composition during fuel cut and return, leading to torque shocks and inaccurate torque grasping due to the absence of burned gas in the combustion chamber during fuel cut.
Innovation Solution
An engine controlling apparatus that calculates torque by multiplying the standard torque with a ratio of fresh air introduced during fuel cut return and the remaining air under atmospheric pressure, considering the volume of the combustion chamber, to accurately determine engine torque post-fuel cut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional torque calculation method using only fresh air amount is used, then calculation is simple, but torque calculation accuracy deteriorates during fuel cut return
Solution Approach 1:
The air amount in the combustion chamber is segmented into two distinct components: fresh air amount (introduced during intake stroke) and remaining air amount (trapped air under atmospheric pressure). This segmentation allows the torque calculation to account for both components separately, improving accuracy during fuel cut return when burned gas is absent.
Solution Approach 2:
The calculation method changes parameters based on operating conditions. During fuel cut return, the system switches from using only fresh air amount to using the sum of fresh air amount and remaining air amount. This parameter change adapts the calculation to the specific condition where gas composition in the combustion chamber differs from normal combustion.
2Loss of energy
If fuel supply cut is executed to improve fuel economy, then fuel cost decreases, but torque shock increases upon return
Solution Approach 1:
The system performs preliminary torque calculation using the corrected method that includes remaining air amount before fuel cut return. This preliminary action prepares accurate torque information in advance, enabling smooth torque control and preventing torque shock when fuel supply is resumed.
Solution Approach 2:
The torque calculation system uses feedback from the detection of fuel cut state and engine operating conditions to dynamically adjust the calculation method. When fuel cut return is detected, the system automatically switches to the corrected calculation method, ensuring accurate torque information is provided to the control system for stable torque management.
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
An engine controlling apparatus includes an air amount calculation unit (3b) that calculates an air amount introduced into a combustion chamber of an engine and a fuel supplying controlling unit (1) that executes, if a predetermined fuel cut condition is satisfied, fuel supply cut for cutting fuel supplybut executes, if a predetermined return condition is satisfied, fuel cut return for returning the fuel supply. Further, the engine controlling apparatus includes a torque calculation unit (3) that calculates torque outputted from the engine based on a result of the calculation by the air amount calculation unit (3b) and a controlling unit (2) that controls a driving parameter of the engine based on the torque calculated by the calculation unit (3). The torque calculation unit (3) calculates the torque upon the fuel cut return based on an added value of a first air amount introduced into the combustion chamber in an intake stroke of the engine after the fuel cut and an air amount corresponding to a volume of the combustion chamber under the atmospheric pressure.