Internal Combustion Engine Cylinder Pressure Assessment
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Solution Overview
Problem
Existing methods for assessing the state of an internal combustion engine either require a single pressure sensor per cylinder, leading to errors due to load changes, or multiple sensors, which are costly and complex, making them inefficient and expensive.
Innovation Solution
A method using two pressure sensors, where one measures a reference signal from a reference cylinder and the other measures signals from other cylinders, with the evaluation unit comparing and mathematically correcting these signals to compensate for load changes, allowing for precise analysis without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pressure sensor measures all cylinders sequentially, then device complexity and cost are reduced, but measurement precision deteriorates due to load changes affecting comparisons between cylinders
Solution Approach 1:
The patent uses a single pressure sensor to sequentially measure each cylinder and creates a reference measurement signal from one cylinder. This reference signal is then used to compare and evaluate the state of all other cylinders, eliminating the need for multiple simultaneous sensors while maintaining diagnostic accuracy through mathematical comparison of pressure profiles
Solution Approach 2:
The patent transforms the measurement approach by changing from simultaneous multi-cylinder measurement to sequential single-cylinder measurement with reference comparison. By measuring each cylinder's pressure profile and comparing it against a reference cylinder's profile, the system achieves accurate state assessment without requiring multiple sensors operating simultaneously
2Measurement precision
If pressure sensors are provided for each cylinder simultaneously, then measurement precision improves by capturing all cylinder pressures at the same time, but device complexity and cost increase
Solution Approach 1:
Instead of using multiple physical sensors simultaneously, the patent uses a single sensor to create reference measurement signals that are then applied to evaluate all cylinders. The reference cylinder's pressure profile serves as a template for comparing all other cylinders, reducing hardware complexity while maintaining diagnostic precision
Solution Approach 2:
The patent implements sequential measurement where the single pressure sensor periodically measures each cylinder in turn. By cycling through all cylinders and comparing each against the reference measurement, the system achieves comprehensive monitoring without the complexity of simultaneous multi-sensor operation
Data Source
Figure 1~3
AI summary
The invention relates to a method for assessing the state of an internal combustion engine (1) with multiple cylinders with a first pressure sensor (5) and a second pressure sensor (7) which are connected to an evaluation unit (2), wherein in each case one cylinder pressure is measured using the pressure sensors (5, 7). It is an object of the invention to specify as simple a method as possible for assessing the state of an internal combustion engine. According to the invention, this is achieved in that the first pressure sensor (5) measures a reference measurement signal (A) of a cylinder, assumed as reference cylinder (4), of the internal combustion engine (1), and the second pressure sensor (7) measures a first measurement signal (B) of a first cylinder (8) which differs from the reference cylinder (4), and in that the reference measurement signal (A) of the reference cylinder (4) and the first measurement signal (B) are transmitted to the evaluation unit (2).