Direct Injection Fuel Pump Control via Dual Mapping
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Solution Overview
Problem
In direct injection engine systems, existing fuel pump control methods face challenges in providing rapid fuel pressure during start-up while maintaining pump durability and avoiding energy consumption, and prior solutions introduce delays due to default-off states and complex wiring.
Innovation Solution
A method involving an electronically controlled pump with initial and secondary mappings to activate and deactivate the fuel pump, allowing immediate fuel pressure application during start-up without waiting for control system initialization, while managing degradation conditions and reducing wiring requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a default-off state is used for the fuel pump to prevent degradation conditions, then pump reliability is improved, but fuel pressure application time is delayed
Solution Approach 1:
The system performs preliminary initialization of the fuel pump control module independent of the PCM initialization state. The lift pump control module is configured to initialize its internal state machine and prepare for pump operation before the PCM completes its full initialization sequence, enabling the pump to start immediately when commanded without waiting for PCM readiness.
2Device complexity
If a single speed fuel pump is used, then device complexity is reduced, but energy consumption and durability are adversely affected
Solution Approach 1:
The fuel pump control module implements a state machine with multiple operational states (off, low pressure, high pressure, fault) that dynamically adjust pump operation based on system conditions. The controller transitions between these states based on feedback from pressure sensors and system initialization status, enabling variable speed operation that optimizes energy consumption while maintaining pump durability.
3Speed
If complex wiring and communications are implemented for rapid pump activation, then fuel pressure application speed is improved, but device complexity increases
Solution Approach 1:
The control system is segmented into two independent modules: the PCM for high-level fuel management decisions and the lift pump control module for immediate pump execution. This segmentation allows the lift pump control module to operate autonomously based on simple commands from the PCM, eliminating the need for complex communication protocols while enabling rapid pump activation independent of PCM initialization status.
Data Source
AI summary
A method for controlling a direct injection fuel system of a vehicle, the method comprising generating fuel pressure via an electronically controlled lift pump and a second pump, the electronically controlled lift pump actuated responsive to a command during an initial start-up duration, translating the fuel pump command via a first mapping to drive the fuel pump, where the first mapping includes mapping a default signal to active pump operation and after the initial start-up duration, translating the fuel pump command via a second mapping to drive the fuel pump where the second mapping includes mapping the default signal to pump deactivation. This method may achieve near immediate lift pump actuation upon system power-up while preserving favorable degradation modes and maintaining a simple, cost-effective inter-module communication scheme.