Engine Start Control via Resonance Jump-Over Injection

Solution Overview

Problem

The existing engine control systems fail to effectively reduce vibrations in the powertrain during engine start-up, particularly in compression ignition engines, as the engine speed often falls within the resonance speed range, leading to increased vibrations and discomfort for vehicle occupants.

Innovation Solution

The method involves increasing the engine speed to approach the lower limit of the resonance speed range and then significantly exceeding it by adjusting the fuel injection amount based on the detected engine speed and combustion cycle phase, ensuring the engine speed jumps out of the resonance range, thereby reducing vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the resonance speed range is set lower than the idle speed to avoid resonance during idle operation, then resonance during idle operation is prevented, but vibrations occur during engine start-up when engine speed passes through the resonance speed range

Engineering Contradiction:

Improveresonance prevention during idle operationVSAvoidvibrations during engine start-up

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control device performs preliminary action by detecting engine speed during start-up and adjusting ignition timing in advance before the engine speed enters the resonance speed range. The system advances ignition timing when engine speed is approaching the resonance range from below, and retards it when approaching from above, preventing vibrations before they occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device implements feedback control by continuously monitoring engine speed during start-up and dynamically adjusting ignition timing based on real-time speed measurements. The system compares detected engine speed with the predetermined resonance speed range and modifies ignition timing accordingly to keep engine speed outside the resonance range.

Inventive Principle:

Principle #23Feedback

2Loss of time

If ignition timing is advanced to increase engine torque and accelerate engine speed through the resonance speed range rapidly, then the time spent in the resonance range is reduced, but vibrations are still generated during the passage through the resonance range

Engineering Contradiction:

Improvetime spent in resonance speed rangeVSAvoidvibrations during resonance passage

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The control device performs preliminary action by detecting engine speed during start-up and adjusting ignition timing in advance before the engine speed enters the resonance speed range. The system advances ignition timing when engine speed is approaching the resonance range from below, and retards it when approaching from above, preventing vibrations before they occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device implements feedback control by continuously monitoring engine speed during start-up and dynamically adjusting ignition timing based on real-time speed measurements. The system compares detected engine speed with the predetermined resonance speed range and modifies ignition timing accordingly to keep engine speed outside the resonance range.

Inventive Principle:

Principle #23Feedback

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 effectively reduces vibrations and noise in the vehicle by ensuring the engine speed avoids the resonance range during start-up, enhancing occupant comfort and reducing powertrain vibrations.

Implementation Method 1

an engine mount having elastic force

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 2

the vibrations generated in the powertrain are not damped enough by the engine mount

Methodology Applied

Scientific EffectVibration damping: Damping

Implementation Method 3

by executing combustion cycles

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 4

If the frequency of these vibrations is equal to the resonance frequency (i.e. the natural frequency) of the powertrain, resonance occurs

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentEP3511553B1Method and device for controlling starting of engine

Publication Date: 2021.02.24 MAZDA MOTOR CORP

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AI summary

At start of an engine, a fuel injection amount is set to a jump-over injection amount (F2) if the engine speed obtained in each cycle is higher than or equal to a determination threshold value (R0), which is set lower than a lower limit (R1) of a resonance speed range Br of powertrain (PT) by a predetermined reference value. If the engine speed is lower than the value (R0), the fuel injection amount is set to a step-over injection amount (F1) that is smaller than the jump-over injection amount (F2). This setting makes it possible to increase the engine speed such that the engine speed approaches the lower limit of the resonance speed range causing resonance in the powertrain, up to a predetermined range, and then causes the engine speed to jump straight to an engine speed which exceeds the resonance speed range, while in the process of increasing the engine speed by executing the combustion cycles. Vibrations generated in the powertrain at start of the engine are reduced in this manner.