Engine Controller Fuel Pump Driving Time Counting
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Solution Overview
Problem
Existing control systems for internal combustion engines struggle to accurately count the number of driving times of a high pressure fuel pump until the crankshaft reaches a predetermined number of rotations, leading to potential fuel injection issues due to incomplete pressure buildup.
Innovation Solution
A control system that utilizes a crank counter counting up at every predetermined crank angle, stores a map associating top dead center of the plunger with crank counter values, and calculates the number of driving times based on these values, allowing for accurate estimation of fuel pressure and timing for fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the number of crankshaft rotations is used to estimate fuel pump driving times, then the system is simple to operate, but the measurement precision of fuel pump driving times deteriorates
Solution Approach 1:
The patent segments the crankshaft rotation into discrete crank angle intervals (e.g., every 10° or 15°), creating a crank counter that increments at each interval. This segmentation allows precise tracking of plunger driving times by counting only those crank angle intervals that correspond to the plunger's reciprocating motion, rather than simply counting full crankshaft rotations. The segmentation enables accurate measurement while maintaining simple controller implementation.
2Ease of operation
If the crank counter starts counting after crank angle identification, then the controller operation is simplified, but the measurement precision of early driving times deteriorates
Solution Approach 1:
The patent performs preliminary action by storing the crank counter value at the moment the engine stops (stop-time counter value) before the crank angle identification occurs after restart. When the engine restarts and crank angle is identified, the controller calculates the number of driving times by finding the difference between the current crank counter value and the stored stop-time counter value. This preliminary storage of counter values ensures that even the early driving times immediately after restart are accurately captured, eliminating the measurement gap that would otherwise occur before crank angle identification.
3Reliability
If the pump cam drives the plunger multiple times per crankshaft rotation, then the fuel pressure buildup is improved, but the measurement precision of driving times deteriorates
Solution Approach 1:
The patent transitions from measuring driving times in the time domain (counting crankshaft rotations or elapsed time) to measuring in the crank angle domain. By creating a crank counter that increments at predetermined crank angle intervals and correlating these intervals with the plunger's reciprocating motion, the system can accurately count multiple driving times within a single crankshaft rotation. This dimensional change from temporal measurement to angular position measurement enables precise tracking of each individual plunger stroke, regardless of how many occur per rotation.
Data Source
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AI summary
A control system includes a controller (100). The controller (100) counts the number of driving times of the high pressure fuel pump (60), which is the number of the reciprocating motions of the plunger (62) based on a crank counter that is counted up at every predetermined crank angle. The controller (100) stores a map in which a top dead center of the plunger (62) is associated with a crank counter value, and store a crank counter value while an engine is stopped as a stop-time counter value. The controller (100) calculates, referring to the map, the number of the crank counter values corresponding to the top dead center of the plunger (62) between a crank counter value and the stop-time counter value, and set a calculated number as the number of driving times.