Vehicle Generator Control for Engine Start Torque Stability
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Solution Overview
Problem
Existing power generation control units for vehicles face challenges in maintaining stable drive torque during engine start-up, leading to potential engine stoppage due to abrupt changes in torque caused by cancellation of gradual excitation, especially in cold conditions.
Innovation Solution
Inhibiting the cancellation of gradual excitation during initial engine start-up and releasing the inhibition based on predetermined voltage or excitation current thresholds to stabilize engine operation, thereby preventing abrupt torque changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gradual excitation is cancelled when battery voltage is reduced to maintain voltage levels, then battery voltage is maintained, but drive torque of the generator drastically increases causing the engine to stop
Solution Approach 1:
The control unit determines in advance whether the generator is in an initial state (immediately after engine start) before applying gradual excitation cancellation. When the initial state is detected, the control unit prevents gradual excitation cancellation despite low battery voltage, thereby avoiding abrupt torque changes that would cause engine stoppage. This preliminary state determination allows the system to maintain engine stability while still managing battery voltage under normal conditions.
2Reliability
If excitation current is increased to raise battery voltage to predetermined level, then battery voltage is improved, but drive torque increases causing engine start failure at low temperatures
Solution Approach 1:
The control unit performs preliminary determination of the generator's operational state (initial vs. normal state) before controlling excitation current. When the initial state is detected (immediately after engine start), the control unit suppresses excitation current increase regardless of battery voltage levels, preventing excessive drive torque that would cause engine stoppage during cold starts. This preliminary state assessment enables the system to prioritize engine startability while still achieving voltage management goals under normal operating conditions.
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 stabilizes the internal combustion engine start-up by preventing engine stoppage and improving startability by maintaining stable drive torque and voltage levels.
Implementation Method 1
a generator (2) whose excitation current is controlled by a power generation control unit (1), so that the generator (2) produces power
Data Source
AI summary
A generation control apparatus for vehicles is provided, in which a drastic change in the drive torque of a generator, which occurs with the cancellation of gradual excitation immediately after starting an internal combustion engine, can be suppressed to prevent stoppage of the internal combustion engine. The generation control apparatus includes an engine-start detection circuit, a gradual excitation circuit, a comparator for gradual-excitation cancellation, and a masking circuit for gradual-excitation cancellation. After detecting an engine start by the engine-start detection circuit, an instruction for gradual-excitation cancellation is released during an initial gradual excitation performed by a gradual excitation circuit, based on an output from the masking circuit for gradual-excitation cancellation. The drastic change in the drive torque occurring with the cancellation of the gradual excitation immediately after the engine start, can thus be suppressed, thereby preventing the engine stop.