ASA Research Symposium 2016 Measuring Baseline Data for Linear Solenoids used in Late-model Automatic Transmissions Sean Boyle SIUC Automotive Technology

Project description Today’s vehicles have very complicated computer controlled transmissions. Utilize various solenoids to control the quality of the shifts May incorporate as many as 9 solenoids Cost of servicing or overhauling these transmissions can become quite expensive Many repair facilities would replace solenoids during a transmission overhaul as a matter of practice Now it’s cost prohibitive Off-shore replacement product is not as reliable

Project description Reuse a solenoid Pro’s Con’s Save money on overhaul Experienced part Reduce unnecessary waste Con’s Maybe the root cause of failure Borderline solenoids may cause future failure

Project description Replace a solenoid Pro’s Con’s Might be the most reliable solution Match solenoid to the failed component Con’s Potentially wasteful New doesn’t always mean good – Never Ever Worked Increases expense to the overhaul – less profit or high cost of rebuild Aftermarket and OE solenoids might be made in Mexico, China, India – Questionable QC

Project description Testing a solenoid Electrical resistance test Checks the windings for proper resistance No load through the solenoid Does not check the hydraulic or mechanical functions of the solenoid Control via a diagnostic tool Allows control of the solenoid Combined with an amp clamp and voltage drop, it can evaluate the electrical operation Does not verify the hydraulic or mechanical functions of the solenoid Testing on a valve body machine Checks the electrical integrity Verifies the hydraulic and mechanical functions Very expensive

Objective: Can solenoids be adequately tested using the common equipment and tools found in a typical transmission repair facility? Common tools digital storage oscilloscope multi-meter heated cooler flusher Common Solenoids Honda/Acura Clutch Pressure Control Solenoids Dodge/Chrysler 545RFE Solenoids Mercedes 722.6 Solenoids GM/Ford 6F50/6T70 Solenoids

Project Phases: Phase One: Acquire oscilloscope patterns showing frequency and duty cycle ranges of solenoids. Phase Two: Construct test components Heated cooler flusher Adapters for Solenoid Assemblies Orifice plugs Solenoid control box Provide independent frequency and pulse width modulation control. Generate various “ramps” that will alter the PWM in a controlled manner Phase Three: Generate graphs of known-good solenoids Phase Four: Generate graphs of known-bad solenoids

Phase One: GM EPC Solenoid Minimum Line Pressure = 58psi Frequency = 585Hz Duty Cycle = 51%

Phase One: GM EPC Solenoid Minimum Line Pressure = 234psi Frequency = 585Hz Duty Cycle = 12%

Phase One: Honda/Acura CPC Solenoid CPC A Low Duty Cycle = 21% CPC B Low Duty Cycle = 14% Frequency = 244Hz

Phase One: Honda/Acura CPC Solenoid CPC A High Duty Cycle = 48% CPC B High Duty Cycle = 42% Frequency = 244Hz

Phase One: FCA Solenoid Complicated shift strategy. The solenoids operate at different pulse widths AND frequencies depending on the shift phase. 1st 2nd 3rd LR 2/4 UD OD 4th 2

Phase One: 2/4 FCA Solenoid 1 2 3 4 This shift takes place in four stages. This is the 2/4 solenoid, which when OFF applies pressure to the clutch Stage One - Turn solenoid OFF to quickly fill the hydraulic circuits Stage Two – Gradual pulses to softly engage clutch Stage Three – Bring clutch quickly up to line pressure Stage Four – Turn solenoid OFF to allow full line to the clutch

Phase One: FCA Solenoid L/R Duty Cycle = 65% high (35% on time) 2/4 Duty Cycle = 65% high (35% on time) Frequency = 571Hz

Phase One: 2/4 FCA Solenoid 2/4 pulses between 24hz and 18hz initially, then raise to about 75Hz

Phase One: 2/4 FCA Solenoid The long pulse is about 15ms, then it drops to about 3ms.

Phase One: OD FCA Solenoid 1 2 3 The OD shift takes place in three stages. This is the OD solenoid, which when OFF it prevents pressure to the clutch Stage One - PWM solenoid ON to fill hydraulic circuits Stage Two – Modulate line pressure to the clutch for desired application feel Stage Three – PWM solenoid ON to allow full line to the clutch

Phase One: OD FCA Solenoid 1 2 3 OD solenoid is operating at 571Hz at 64% duty cycle (36% on time). Stage one gaps are at 18Hz with a pulse of about 7.5ms. This happens for about 300ms.

Phase One: OD FCA Solenoid 1 2 3 Stage two has “on” pulses that are about 7.7ms long and operate around 50Hz

Phase One: OD FCA Solenoid 1 2 3 Stage Three goes back to “on” pulses about 7.6ms long and duty cycling the solenoid at 65% high at 571Hz.

Phase One: 722.6 Solenoid The Shift Pressure Solenoid varies PWM between 98% (2% on) and 65% (35% on) and operates at a frequency of 1000Hz.

Phase One: 722.6 Solenoid The Line Pressure Solenoid varies PWM between 76% (24% on) and 52% (48% on) and operates at a frequency of 1000Hz.

Phase Two: Construction Test components Heated cooler flusher Adapters for Solenoid Assemblies Orifice plugs Solenoid control box Provide independent frequency and pulse width modulation control. Generate various “ramps” that will alter the PWM in a controlled manner

Phase Two: Heated cooler flusher We do not have a heated cooler flusher, such as the common “hot flush.” I am adapting a flushing system we have to use heated fluid. This involves making an aluminum tank, pickup system and fluid delivery system

Phase Two: Heated cooler flusher

Phase Two: Heated cooler flusher

Phase Two: Adapters for Solenoid Assemblies Adapters need to be constructed for each solenoid tested.

Phase Two: Adapters for Solenoid Assemblies

Phase Two: Adapters for Solenoid Assemblies

Phase Two: Adapters for Solenoid Assemblies

Phase Two: Adapters for Solenoid Assemblies

Phase Two: Adapters for Solenoid Assemblies

Phase Two: Adapters for Solenoid Assemblies

Phase Two: Clutch Feed Orifices The transmissions are researched to find out if any expected leakage (engineered) exists for each solenoid circuit Various plugs need to be constructed for quick-disconnect into the solenoid output lines

Phase Two: Solenoid Control Box As you can see with the captured oscilloscope patterns, the solenoids use various frequencies and pulse width modulation A tool that can mimic the natural control of the solenoids is needed to test the solenoids Arduino components are being researched for this task. I spent a bit of time researching the Parallax system, but it cannot PWM at a steady frequency