Crankshaft Speed Prediction for Engine Reverse Rotation Prevention

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Solution Overview

Problem

Current engine controllers detect reverse rotation events too late, leading to potential engine damage due to continued combustion during reverse rotation, as they fail to predict the change in direction in advance.

Innovation Solution

A control system using a crankshaft trigger wheel with sensors and a controller that predicts reverse rotation by analyzing instantaneous speed and deceleration, setting flags to cease ignition before the event occurs, thereby preventing engine damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the engine controller waits to detect reverse rotation until the change of direction occurs, then the detection is confirmed, but the detection is too late to prevent engine damage

Engineering Contradiction:

Improvereverse rotation detection accuracyVSAvoidtime to prevent engine damage

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The controller performs preliminary action by predicting reverse rotation before it actually occurs. It monitors crankshaft speed and deceleration patterns, and when reverse rotation is predicted, it proactively ceases ignition and fuel injection events before the harmful reverse rotation begins, thus preventing engine damage while maintaining accurate detection

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller applies preliminary anti-action by taking countermeasures before the harmful effect occurs. It predicts the reverse rotation event and preemptively stops ignition and fuel injection, creating a protective effect that prevents the harmful combustion during reverse rotation from occurring in the first place

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If the controller ceases ignition before reverse rotation is confirmed, then engine damage is prevented, but false predictions may cause unnecessary ignition cessation

Engineering Contradiction:

Improveengine protection reliabilityVSAvoidreverse rotation prediction accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The controller uses feedback by continuously monitoring crankshaft speed and deceleration patterns, comparing actual measurements against predicted values. This feedback mechanism allows the controller to refine its predictions and distinguish between normal deceleration and actual reverse rotation indicators, reducing false predictions while maintaining reliable engine protection

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The controller replaces mechanical detection methods with electronic sensing and computational prediction. By using sensors to measure crankshaft speed and processing this data through algorithms that analyze deceleration patterns, the system achieves more precise and reliable reverse rotation prediction compared to traditional mechanical detection approaches

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12577930B1Engine reverse rotation and control

Publication Date: 2026.03.17 ROBERT BOSCH GMBH

AI summary

An apparatus and method for operating an engine. The apparatus includes a crankshaft trigger wheel coupled to a crankshaft and a set of sensors equipped to generate a crankshaft signal associated with an instantaneous speed of the crankshaft trigger wheel. A controller is configured to receive the crankshaft signal corresponding to the instantaneous speed, determine a minimum instantaneous speed for the crankshaft trigger wheel to overcome a top dead center (TDC), and predict a reverse rotation event for the engine when the instantaneous speed falls below the minimum instantaneous speed. After making the prediction, ignition of the engine is prevented prior to the reverse rotation event occurring.