Starter Motor Controller Pre-Restart Control for Engine Driving Apparatus

Solution Overview

Problem

The existing engine driving apparatuses face challenges in restarting the engine when the starter motor output is low, particularly during idle reduction in compression or expansion strokes, due to increased temperature and battery degradation, leading to insufficient energy for successful restart.

Innovation Solution

The engine driving apparatus includes a starter motor controller that performs pre-restart control by using the starter motor to open the exhaust valve of the cylinder in the expansion stroke, adjusting the crankshaft torque and crank angle to facilitate engine restart even with low starter motor output, by deriving thresholds based on temperature and battery degradation status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If power to the starter motor is reduced for a predetermined period to reduce power consumption at the time of engine restart, then power consumption is reduced, but the starter motor output becomes insufficient to restart the engine

Engineering Contradiction:

Improvepower consumptionVSAvoidengine restart reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The exhaust valve is opened in advance during the expansion stroke before the compression stroke begins, creating a pressure difference that reduces the energy required for engine restart. This preliminary action prepares the cylinder pressure conditions to facilitate easier cranking of the engine.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The valve timing is dynamically adjusted based on the crankshaft position and engine state. By changing the valve opening timing parameter, the system optimizes the pressure difference between cylinders to reduce restart energy requirements while maintaining reliable engine restart capability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the starter motor operates at high output to ensure reliable engine restart, then engine restart reliability is improved, but power consumption increases

Engineering Contradiction:

Improveengine restart reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The exhaust valve is opened in advance during the expansion stroke before the compression stroke begins, creating a pressure difference that reduces the energy required for engine restart. This preliminary action prepares the cylinder pressure conditions to facilitate easier cranking of the engine.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The valve timing is dynamically adjusted based on the crankshaft position and engine state. By changing the valve opening timing parameter, the system optimizes the pressure difference between cylinders to reduce restart energy requirements while maintaining reliable engine restart capability.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If valve timing is adjusted to optimize engine restart with low starter motor output, then engine restart becomes feasible with low power, but the control system complexity increases

Engineering Contradiction:

Improvepower consumptionVSAvoidcontrol system complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The valve timing is dynamically adjusted based on the crankshaft position and engine state. The control unit varies the valve opening timing according to the expansion stroke progression, creating optimal pressure differences for low-power restart while adapting to real-time engine conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The variable valve timing mechanism serves multiple functions: it optimizes engine restart with low power consumption, maintains normal engine operation, and adapts to different engine states. This multi-functionality reduces the need for separate specialized systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enables successful engine restart even with low starter motor output by optimizing the pre-restart control process, reducing energy consumption and ensuring reliable engine reactivation.

Implementation Method 1

When any one of the plurality of cylinders enters a compression stroke, another one of the cylinders enters an expansion stroke. The starter motor controller performs pre-restart control for adding torque to the crankshaft by using the starter motor to open an exhaust valve of the cylinder in the expansion stroke.

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS11401906B2Engine driving apparatus

Publication Date: 2022.08.02 SUBARU CORP

AI summary

An engine driving apparatus includes an engine, a starter motor, and a starter motor controller. The engine includes a plurality of cylinders. When any one of the plurality of cylinders enters a compression stroke, another one of the cylinders enters an expansion stroke. The starter motor is coupled to a crankshaft of the engine. The starter motor controller is configured to control the starter motor. Before restarting the engine, the starter motor controller performs pre-restart control for adding torque to the crankshaft by using the starter motor to open an exhaust valve of the cylinder in the expansion stroke.