Diesel Engine Fuel Injection Control Using Reference Cylinder Pressure
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Solution Overview
Problem
Existing systems for adjusting fuel injection in diesel engines require numerous sensors and high computing capacity to correct operational drifts, making them inefficient and resource-intensive.
Innovation Solution
A system that uses a reduced number of sensors and lower computing capacity by employing a reference cylinder pressure sensor, a control unit, and servo-control means to adjust fuel injection based on measured pressure and engine parameters, allowing for efficient correction of fuel flow and rotation speed across cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is installed in each cylinder and high computing capacity microprocessor is used to calculate all data necessary for adjustment, then the precision of fuel injection adjustment is improved, but the device complexity and cost increase
Solution Approach 1:
The invention extracts the measurement function from multiple cylinder pressure sensors and concentrates it in a single reference cylinder pressure sensor. By measuring pressure only in one reference cylinder and using the ratio of indicated powers between cylinders, the system achieves fuel injection adjustment precision without requiring pressure sensors in every cylinder, thus reducing device complexity while maintaining measurement accuracy.
Solution Approach 2:
The single reference cylinder pressure sensor serves multiple functions: it measures compression pressure for compression ratio determination, measures injection pressure for fuel injection characterization, and enables calculation of indicated power ratios. This multi-functional use of one sensor replaces what would traditionally require multiple specialized sensors, reducing overall system complexity.
2Manufacturing precision
If compression pressure is measured in each cylinder to determine compression ratio, then the manufacturing precision of engine operation is improved, but the device complexity increases
Solution Approach 1:
The invention extracts the compression ratio measurement function from multiple cylinder measurements and concentrates it in a single reference cylinder. By measuring compression pressure only in the reference cylinder and using the ratio of indicated powers method, the system achieves accurate compression ratio determination without requiring pressure sensors in all cylinders, thus reducing device complexity while maintaining manufacturing precision.
3Reliability
If fuel injection adjustment is performed for each cylinder individually with full computational analysis, then the reliability of engine operation is improved, but the use of energy and computing resources increases
Solution Approach 1:
The invention implements a feedback mechanism where the measured compression pressure and injection pressure from the reference cylinder are used to calculate indicated power ratios, which then feed back to adjust fuel injection quantities for all cylinders. This feedback loop ensures reliable engine operation by continuously correcting injection drifts while consuming minimal computational energy compared to full computational analysis of all cylinders.
Solution Approach 2:
The invention performs partial measurement and calculation actions - measuring pressure in only one reference cylinder rather than all cylinders, and calculating only the necessary indicated power ratios for adjustment. This partial action approach maintains engine operation reliability by focusing computational resources on the critical measurement and calculation needed for effective fuel injection correction, rather than performing exhaustive analysis of all cylinders.
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
This approach enables precise and efficient fuel injection adjustment with fewer sensors and lower computational demands, effectively addressing the inefficiencies of existing systems while maintaining engine performance.
Implementation Method 1
a deformation sensor 28 with a piezoelectric element inserted in the cylinder head 18a of the reference cylinder 12a or integrated into the glow plug (not shown) thereof, and capable of measuring deformations of the cylinder head 18a under the effect of pressure variations in the combustion chamber 22a of the cylinder 12a
Data Source
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AI summary
The invention relates to a system for controlling the operation of a Diesel engine comprising means for supplying fuel to the cylinders thereof, including means for acquiring the pressure of a reference cylinder and means for controlling the supply means according to this pressure and a predetermined supply setpoint for each cylinder.The control means include means (52, 62) for controlling the fuel supply of the reference cylinder to its setpoint as a function of the acquired pressure, means (64) for acquiring the rotational speeds of the engine shaft generated by the movement of the piston of the reference cylinder and the piston of at least one other cylinder, and means (68, 70, 72, 74, 62) for controlling the fuel supply of this at least one other cylinder as a function of the acquired speeds by controlling the speed associated with this at least one other cylinder to the speed associated with the reference cylinder.