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design report.doc

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design report.doc

    Hydrogen Conversion Team Final Design Report

     Team

    ; Jonathan Blanco

    ; Joe Branam

    ; Dustin Jones

    ; Justin McBath

    ; Paul Miller

    ; Jonathan Parrish

    ; Nick Rader

    ; Tyler Wolfford

    ; Ed Yates

Table of Contents

    Final Design Concepts ................................................................................ (3-12)

    ; Fuel and Ignition ............................................................................... (3-5)

    ; Fuel Injection .................................................................................... (5-6)

    ; Hydrogen Fuel Plumbing ................................................................. (6-8)

    ; Tank Mount .................................................................................... (8-10)

    ; Range Display .................................................................................... (10)

    ; Fuel Delivery Apparatus............................................................... (10-12) Budget Analysis and Details ..................................................................... (12-14) Procedure Manuals .................................................................................. (15-35)

    ; Engine Management System ....................................................... (15-16)

    ; Hydrogen Plumbing ..................................................................... (17-21)

    o Installation ........................................................................ (17-19)

    o Service ............................................................................... (19-21)

    ; Hydrogen Safety .......................................................................... (22-24)

    o Installation ........................................................................ (22-23)

    o Service ............................................................................... (23-24)

    ; Tank Mounting Structure ........................................................... (24-25)

    ; Range Display Option 1 ............................................................... (25-26)

    ; Range Display Option 2 ............................................................... (27-35) Business Case ............................................................................................ (36-56)

    ; Top Level Description ........................................................................ (36)

    ; Preliminary Specifications ............................................................ (37-40)

    ; Product Value Proposition ........................................................... (40-41)

    ; Team Members and Org Chart .................................................... (41-42)

    ; Team Capabilities Analysis .......................................................... (42-43)

    ; Competitive Analysis .................................................................... (43-52)

    ; Risk Analysis ................................................................................. (52-54)

    ; Out-of-Bounds Criteria ................................................................ (54-56) Appendices ................................................................................................ (57-63)

    ; A. Dual Engine Management Diagram ............................................ (58)

    ; B. Relay Sensor Diagram .................................................................. (59)

    ; C. Fuel Relay Block Diagram ........................................................... (60)

    ; D. Injector Relay Block Diagram ..................................................... (61)

    ; E. Ignition Relay Block Diagram ..................................................... (62) Bibliography .................................................................................................. (63)

Final Design

    This project involves several different components which need to be specifically designed in order to work together properly and effectively.

    Fuel and Ignition

    In designing a vehicle that is capable of operating on gasoline and hydrogen independent of one another, two separate fuel systems must be in place to deliver each fuel efficiently. The plan for our system is to essentially overlap the factory (gasoline) and aftermarket (hydrogen) engine management systems in such a way that the factory PCM will still function for proper operation of the electronically controlled transmission and instrument panel. This operation will be executed using a series of switchable relays to discern which fuel will be delivered. In theory, once the selection switch is tripped to use hydrogen, the Oxygen sensor signals will be diverted from the PCM to the Aftermarket ECU. Along with ignition, injector and fuel pump signals. Therefore the PCM will still pick up engine and wheel speed signals while the aftermarket ECU is actually driving the engine. The following figure is a schematic of how the aftermarket system will work in parallel with the factory system.

    ECU 5V Reference Input SignalO2O2 Sensor 0-5VRelay12V SwitchedAftermarket 5V Reference InputSensors: CKP, 0-5VFactory Sensors: 0-5VMAP, IAT, TPS, 0-5V5V Reference InputIAT, MAF, MAP, 0-5VECT, CAM CKP, CMP, ect.AEM Plug and

    Play ECU12VFactory .5VIgnition Fuel 1.5A.5VECUSelection SwitchAEM Peak Ignition and Hold SwitchDriver12VRelay12V12V.5V2.5 A4 AInjector Relay12V 12V Switched12V Switched12VSource12V

    Gasoline ICM’sInjected HydrogenInjectionHydrogen Injected GasolineHydrogen @ 40psigGasoline @ 40psigInjection

    Fuel Pump Hydrogen EngineRef. H2 Flow Chart(Gasoline)Shut-off

    12VSolenoid

    Fuel Relay12V12V Switched

    12V

    Inertia Cut-off 12VSwitch

    Figure 1: Dual Engine Management Diagram

    12V

    The Dual Engine Management and Sensor Relay Block diagrams can be found in larger sizes in appendices A and B. The aftermarket computer being used is the AEM? Plug and Play ECU. This ECU has been chosen because of its wide range of adjustability. It is capable of advancing and retarding the timing of both the fuel and ignition independent of one another. It provides sequential injection which imperative in this type of application. This ECU does not have built-in igniters, which allows for the use of the factory Ignition Control Modules (ICM). It has a built in data logger for the collection of sensory and timing data. Lastly, this ECU requires inputs from the Engine Coolant Temperature Sensor (ECT), Intake Air Temperature Sensor (IAT), and Throttle Position Sensor (TPS), Manifold Absolute Pressure Sensor (MAP), and Cam/Crank Position Sensors (CAM/CKP).

    This ECU was originally designed for a four cylinder vehicle but can be reprogrammed and adapted to engines as large as ten cylinders using an ignition scheme called “wasted spark”. This scheme basically fires multiple spark plugs simultaneously. Using this scheme this application requires three of the five ignition channels for operation. It is important to know which stroke the each cylinder is on at any given time to prevent firing two cylinders, in which one is undergoing a power stroke and the other an intake stroke. This would cause severe back firing and poor engine operation. The desired wasted spark

    operation is to have one cylinder fire on the power stroke while the wasted spark fires on the exhaust stroke where there is no combustible fuel available. To prevent this from happening, a graphical representation of the cylinder motion for all six cylinders has been created using the equations of motion for a slider crank mechanism with an arbitrary

    i connecting rod length.

    Firing Order

    1-4-2-5-3-6

    Power StrokeIntake Stroke

    Piston Position

    0100200300400500600700Compression StrokeExhaust StrokeCrank Angle (degrees)

    Cylinder 1Cylinder 4Cylinder 2Cylinder 5Cylinder 3Cylinder 6

    Figure 2: Firing Diagram

    Figure two illustrates the piston position and stroke of all six cylinders through two revolutions of the crank shaft. Using this graph it can now easily be determine which two cylinders can be set to fire simultaneously with detriment.

    Fuel Injection

    The hydrogen fuel injection system consists of two fuel rails and six gaseous injectors. These components were originally designed for a compressed natural gas (CNG) system,

    stwhich like hydrogen, is also a dry gas. Through 1 law analysis the required mass flow

    rate has been determined for our prescribed testing cycle as seen in the final 385 class report. The following chart shows the flow rates that can be delivered by different sized fuel injectors.

    4.50

    4.00

    3.50

    3.0032CC

    2.5043CC

    2.0052CC

    1.5063CC

    73CC1.00Flow [g/s] @ 3.55Bar100CC0.50

    0.00

    0.005.0010.0015.0020.0025.00

    Injection Time [ms] @ 41.67Hz

    Figure 3: Keihin Gaseous Injector Flow Rates

    in [g/s] 3,4ms / 24ms 6ms / 24ms 24ms / 24ms

    32CC 0.169 0.313 1.329

    43CC 0.231 0.433 1.867

    52CC 0.262 0.491 2.194

    63CC 0.301 0.577 2.683

    73CC 0.353 0.668 3.178

    100CC 0.429 0.863 4.393

    Table 1: Keihin Gaseous Injector Flow Rates

    Keihin injectors are sized in cc (cubic centimeters). The flow rates depicted are in gallons

    per second. The injector distributor recommended the 73cc injector for our application. To verify their recommendation, the required mass flow rate for hydrogen operation from previous analysis was converted to gallons per second, which yielded a value of 2.054

    (gal/s). From table 1, it can be noted that it is well within the operating range of the 73cc

    injector.

    Hydrogen Fuel Plumbing

    Figure 3 is the plumbing diagram for hydrogen gas in the UTC Saturn Vue.

     Storage Compartment

     (behind rear seats)

    3/8'’ SS TubeVents to Cabin Exterior

    Tank (5000psi)(2)3/8'’ SS Tube

    Internal Solenoid Tank Valve With High 3/8'’ SS TubeBuilt In Pressure Pressure ReliefGage(Top of Tank)(6)(3)

    MountedMounted

    Fill Pressure Receptacle RegulatorRange (1)(5000?50 psig)Display (4)Pressure SensorMounted(5)

    Low Pressure Gage(7) Passenger Compartment3/8'’ SS Tube

    ?’’ SS Braided Line

    Fuel Rail StructureFuel Rail Structure

     Engine Compartment

    Fuel RailFuel Rail

    Injector

    Injector

    InjectorInjectors connected to intake with 3/8'’ copper tube Injector

     Hydrogen Flow Chart for Injector Saturn Vue Conversion

    Figure 4: Hydrogen Plumbing Flow Chart Injector

    Due to the possibility of a corrosive environment and the high pressures encountered, the Saturn Vue Intake

    plumbing design requires that fully annealed, seamless stainless steel (SS) tubing rated with a minimum working pressure of 5,000 psia be utilized. The tubing must be fully annealed and seamless to insure a leak-free connection with the compression fittings. The team is specifying 3/8’’ OD SS steel tubing that is rated for a working pressure of 6,500 psia. To mitigate leaks at the tube/fitting intercept, the team specifies a twin ferrule locking design. The team is using Swagelok fittings to meet this requirement. The rated working pressure for all fittings is at least 1.56 times the actual maximum pressure encountered. To insure corrosion resistance, SS is the specified material. An anaerobic type liquid sealant is used on all threads to reduce the possibility of leaks at these points.

    Hydrogen enters the plumbing system from a fill receptacle (1) produced by OPW. This receptacle’s design allows it to be mated to a specific type of nozzle. This limitation is imposed to insure that only hydrogen at 5000 psia versus some other type of alternative fuel is filled into the tank. The receptacle is rated to a maximum design pressure of 6250 psia. A particulate filter is integrated into the receptacle as well as a check valve. Hydrogen gas is stored at 5000 psi in a DOT approved carbon fiber tank (2). The tank is fitted with an internal solenoid shutoff valve (3). The shutoff valve is controlled using 12V DC with a manual override. The valve allows hydrogen at 5000 psia to enter the tank for storage and 5000 psia hydrogen to be sent to the pressure regulator. The solenoid has a separate sensor port. The team will install a pressure transducer for the range display (5) or data collection. If hydrogen data collection is beyond the budgetary limits, then this port will be plugged. The solenoid has a built in pressure release device (PRD) which vents hydrogen to the exterior of the vehicle. The PRD is activated if internal tank temperatures exceed 109 C (228 F). If the PRD is activated, then the entire valve must be replaced.

    Hydrogen is transferred from the tank valve to the pressure regulator (4) at 5,000 psia via 3/8’’ SS. The pressure regulator has an integrated 10-micron filter to insure that debris

    does not degrade the fuel delivery system. The outlet pressure can be regulated from 75 to 0 psia. The pressure regulator has two ports for gages. One port is on the high-pressure side and will be fitted with a high-pressure gage (6). The other port is on the low-pressure side and will be fitted with a low-pressure gage (7). Per ISO 15869 specifications, the gages are rated to read 20% beyond the working pressure. The gages are fluid filled to reduce the effects of vibration on the needles.

    The 3/8’’ stainless steel tubing transports hydrogen from the pressure regulator through the fire wall to ?’’ flexible braided stainless steel hose. The tubing from the regulator to

    the engine compartment has no fittings and is shielded to reduce the possibility of hydrogen leaking directly into the passenger compartment due to tubing abrasions or punctures. This hose is rated for hydrogen use at a working pressure of 3,000 psia. The ?’’ flexible braided stainless steel hose connects to the fuel rail.

    Hydrogen leakage sensors are located in the rear compartment (next to valve components) and in the engine compartment. The sensors will not be hard mounted so that the leak locations can be determined with a greater degree of precision. Both sensors are monitored in the driver’s compartment. Both visual and audible alerts are given at the presence of a hydrogen leak.

    Tank Mount

    The tank will be mounted in the rear compartment of the vehicle using the frame shown in figures 4 and 5.

    Figure 5: Tank Mount Drawing 1

    Figure 6: Tank Mount Complete Assembly Drawing

    This frame is required because the overall length of the hydrogen storage tank is too great to fit between the rear wheel wells in the rear interior if the car. Therefore the tank must

    be raised a minimum of 8” off of the floor in order to fit perpendicular to sides in the rear. This unit is designed to be installed into the spare tire well in the rear of the vehicle and will accept the brackets that are designed to cradle the DOT fuel tank. This frame will be provided courtesy of Cannon Equipment who is the current employer of team member Nick Rader.

    Range Display Concept

    All information and drawings on the range display are located in the procedure manuals. Fuel Delivery Apparatus

    The hydrogen will be delivered into the engine for combustion through six points in a modified component in the intake manifold using copper tubes, as shown in figures 6, 7, and 8.

    Figure 7: Modified Intake Manifold Spacer Block

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