Air Intake Device with Communicating Pipe for Torque Gap Elimination

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Solution Overview

Problem

In internal combustion engines with multiple cylinder banks, the recirculation of air from a brake booster into the intake passage can lead to an uneven air-fuel ratio, causing a gap in output torques between cylinder banks when a negative pressure supply port is located in one intake passage.

Innovation Solution

An air intake device with a communicating pipe connecting the pair of intake passages and a negative pressure supply port on this pipe ensures equal negative pressure distribution to both cylinder banks, preventing torque gaps by equalizing air intake between them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the negative pressure supply port for the brake booster is formed in one of the intake passages, then the brake booster can be supplied with negative pressure, but the air recirculated into the intake passage from the brake booster makes the air-fuel ratio of the fuel mixture in one of the cylinder banks lean, causing a gap in output torques between the two cylinder banks

Engineering Contradiction:
Improvebrake booster negative pressure supplyVSAvoidair-fuel ratio uniformity across cylinder banks
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent divides the single negative pressure supply port into two separate supply ports, one located in each intake passage (first and second intake passages). This segmentation ensures that when the brake booster recirculates air, the air is distributed evenly to both cylinder banks through the respective intake passages, preventing the air-fuel ratio from becoming lean in just one bank and thus eliminating the torque gap between cylinder banks.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the fuel supply amount to one cylinder bank is increased to maintain the air-fuel ratio at a constant ratio, then the air-fuel ratio is maintained, but the output torque of this cylinder bank increases, generating a gap between the output torques of the two cylinder banks

Engineering Contradiction:
Improveair-fuel ratio control precisionVSAvoidoutput torque uniformity between cylinder banks
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent segments the negative pressure supply system into two independent supply ports located in separate intake passages. This allows the air recirculation from the brake booster to be distributed evenly to both cylinder banks, maintaining uniform air-fuel ratios across all cylinders without requiring compensatory fuel adjustments that would create torque imbalances.

Inventive Principle:
Principle #1Segmentation

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 maintains a consistent air-fuel ratio across all cylinder banks, minimizing the difference in output torques between them, thereby enhancing engine performance and stability.

Implementation Method 1

The brake booster assists a braking pressure supplied from a master cylinder to brake cylinders by utilizing a difference between an intake negative pressure in the intake passage and atmospheric pressure

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

a communicating pipe connecting the pair of intake passages, and a negative pressure supply port provided on the communicating pipe for supplying negative pressure to a brake booster

Methodology Applied
Scientific EffectNegative pressure distribution: Pressure Gradient

Data Source

PatentEP2050950B1Air intake device for vehicle internal combustion engine
Publication Date: 2011.07.20 NISSAN MOTOR CO LTD
  • EP2050950B1 patent drawingFigure 1
  • EP2050950B1 patent drawingFigure 2
  • EP2050950B1 patent drawingFigure 3~4

AI summary

An internal combustion engine for a vehicle comprises a pair of intake collectors (3A, 3B) and a communicating pipe (13) connecting the pair of intake collectors (3A, 3B). A negative pressure supply port (15) supplying intake negative pressure of the internal combustion engine to a brake booster is provided at an end of the communicating pipe (13). By providing an air amount deviation compensating arrangement which compensates for a deviation in the amounts of air flowing into the pair of intake collectors (3A, 3B) from the brake booster when braking of the vehicle is released, the amounts of air supplied to the internal combustion engine from the pair of the intake collectors (3A, 3B) are equalized.