Vehicle Powertrain Mode Switching for Downgrade Fuel Savings
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Solution Overview
Problem
Heavy vehicles experience high fuel consumption due to their power train configurations, and existing methods for reducing fuel consumption on downgrades do not account for situations where the vehicle may accelerate with the engine disconnected from the driveshaft, leading to suboptimal fuel efficiency.
Innovation Solution
A method that determines whether running a vehicle in a mode with the engine connected to the driveshaft but without fuel supply on downgrades would result in a speed increase, and switches to a mode where the engine is disconnected from the driveshaft if so, allowing the vehicle to freewheel and maintain higher speeds, thereby reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is connected to the driveshaft with fuel supply shut off on downgrades, then fuel consumption is reduced, but the vehicle speed may increase uncontrollably
Solution Approach 1:
The system dynamically switches between two operational modes: connecting the engine to the driveshaft to control speed when necessary, and disconnecting the engine to allow freewheeling and reduce fuel consumption when safe. This dynamic adjustment resolves the contradiction by adapting the engine connection state based on real-time speed conditions and downgrade characteristics.
Solution Approach 2:
The invention changes the operational parameter of engine connection status (connected vs. disconnected) based on vehicle speed and road gradient conditions. By monitoring whether the vehicle would accelerate excessively with the engine connected but fuel shut off, the system adjusts this parameter to optimize both fuel economy and speed control.
2Use of energy by moving object
If the engine is disconnected from the driveshaft on downgrades, then fuel consumption is further reduced, but the vehicle may experience higher speeds beyond safe limits
Solution Approach 1:
The control system continuously monitors vehicle speed, engine RPM, and road gradient to determine the optimal engine connection state. Feedback from speed sensors and gradient information allows the system to predict whether disconnecting the engine would cause unsafe speed increases, adjusting the disconnection decision based on real-time conditions to maintain both fuel efficiency and safety.
3Speed
If the engine is kept connected to the driveshaft without fuel supply, then the vehicle can maintain better speed control through engine braking, but fuel consumption is not minimized
Solution Approach 1:
The invention extracts the engine from the drivetrain connection (disconnects it) when conditions permit, eliminating the engine braking effect but gaining significant fuel savings. By selectively removing the engine connection only when speed control can be maintained through other means or when the downgrade is gentle enough, the system achieves fuel minimization while preserving adequate speed control.
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 results in lower fuel consumption by allowing the vehicle to travel further and maintain higher speeds on downgrades, counterbalancing the fuel required to keep the engine running at idling speed, and reduces engine braking forces, leading to reduced retardation and overall fuel savings.
Implementation Method 1
In a situation where the vehicle is or will be travelling downhill... running the vehicle in said second mode if it is determined that running in said first mode would result in a speed increase for said vehicle
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present invention relates to a method for running of a vehicle, such that said vehicle comprises a combustion engine which can selectively be connected to at least one driveshaft (104, 105) to deliver driving force to said driveshaft (104, 105) for propulsion of said vehicle, said vehicle can be run in a first mode (Ml) in which it is run with said engine connected to said driveshaft (104, 105) and in which fuel supply to said engine is substantially shut off, in a second mode (M2) in which it is run with said engine disconnected from said at least one driveshaft (104, 105). In a situation where the vehicle is or will be travelling on a downgrade the method comprises - determining whether running said vehicle on said downgrade in said first mode (Ml) will result in a speed increase for said vehicle, and - running the vehicle in said second mode (M2) if it is determined that running it in said first mode (Ml) would result in a speed increase for said vehicle (100).