Alternator Lockout Circuit for Cold Start Crank Time Reduction
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Solution Overview
Problem
Conventional alternators prolong engine crank times and delay stable idle conditions, especially in cold weather, due to unnecessary mechanical energy drainage when the starter is activated for an extended period.
Innovation Solution
An alternator and regulator system with a lockout circuit that maintains the field coil in a strobe mode until the charging system voltage exceeds a temperature-dependent threshold, preventing premature transition to full field condition and reducing engine load during cold starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the alternator field coils are energized to normal operating levels during engine starting, then the alternator output voltage increases, but the mechanical energy drainage from the engine increases, prolonging crank time
Solution Approach 1:
The lockout circuit is configured to detect the starting condition before the alternator field coils are fully energized, and preemptively prevents full field energization during starting. This preliminary detection and prevention action avoids the harmful effect of mechanical energy drainage before it occurs, thereby shortening crank time without compromising the ability to generate sufficient voltage once the engine is running.
2Power
If the alternator field coils are energized during cold starts, then charging system voltage increases, but the starter requires additional mechanical energy, extending crank time
Solution Approach 1:
The lockout circuit continuously monitors the charging system voltage and engine running status, and provides feedback control by preventing full field energization when the engine is detected to be in a starting condition. This feedback mechanism ensures that the alternator does not draw excessive mechanical energy from the starter during cold starts, thereby reducing starter activation duration while maintaining adequate charging voltage once the engine is running.
3Productivity
If the regulator transitions to normal duty mode during engine starting, then alternator output increases, but mechanical load on the engine increases, delaying stable idle condition
Solution Approach 1:
The lockout circuit detects the starting condition beforehand and preemptively prevents the regulator from transitioning to normal duty mode during engine starting. This preliminary prevention ensures that the alternator remains in a low-power state during the critical starting period, avoiding additional mechanical load that would delay stable idle condition, while still allowing full power output once the engine is running.
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
The system significantly reduces engine crank times and stabilizes idle conditions by minimizing mechanical energy drainage from the engine, effectively shortening the time required to reach a stable idle state.
Implementation Method 1
a field coil rotatable relative to the stator winding and which is adapted to be rotated by mechanical energy from the engine... introduces a pulsed current into the field coil... introduces an electrical current into the field coil at a controllably varied voltage to thereby control the output voltage of the alternator
Data Source
AI summary
A lockout circuit which limits the field voltage in an alternator while the vehicle starter is activated. The lockout circuit may be configured to limit the field voltage while the charging circuit voltage is below a threshold value. A timer circuit may advantageously be employed with the lockout circuit. A temperature compensating function may also be employed to change the threshold value in response to temperature changes. The disclosed circuit is particularly advantageous when employed in cold weather conditions. A method of starting the engine of a vehicle is also disclosed.