De Constant Speed Power Take Off

Improving performance and fuel-efficiency, using a CVT for driving auxiliary equipment on distribution trucks

Daniël de Cloe

Bram VeenhuizenNort Liebrand

Automotive Engineering Science, Technische Universiteit Eindhoven

Friday, 24 September 2004

1. Introduction

2. Working Principle of the CS-PTO

3. Design & Development of the CS-PTO

4. Electromechanical Actuation System and Ratio-Control

5. Testing and Implementation of the CS-PTO

6. Performance results of the CS-PTO

7. Present and future developments

8. Conclusions

Contents of the presentation

The ideal driving principle for auxiliary equipment in distribution trucks:

- The required amount of power is always available when needed- The efficiency of the driving principle is high- The noise emission of the driving principle is low- The total weight of the driving principle is low

1. IntroductionSlide 3/26

85% of the market is using a small diesel-unit as a power source10% of the market is using the truck engine as a power source

Present driving principles for auxiliary equipment in distribution trucks:

1. IntroductionSlide 4/26

available power

0 500 1000 1500 2000 2400 30000

primary engine speed [rpm]

truck enginetruck engine

diesel-unit

1. Introduction

Continuously Variable Transmissionto optimize the required power

Slide 5/26

Truck engine as power source

New regulations concerning emissions (exhaust gases & noise):

Market demand for a silent, clean and efficient driving principle,

that delivers optimal or constant power when needed.

2. Working principle of the CS-PTO

TruckEngine

Variable (PTO)Speed

Optimal or constant output speed

CVTunit

Variableinputspeed

Slide 6/26

Comparison with present driving principles for auxiliary equipment:

Slide 7/26

available power

0 500 1000 1500 2000 2400 30000

primary engine speed [rpm]

diesel-unit

truck engine

diesel-unit

truck engine

CS-PTO

2. Working principle of the CS-PTO

From concept to market introduction in 2 years…

- January 2002: preliminary research & concept design

concept market introduction

5 months

- May 2002: detailed design, prototype development

9 months

- September 2002: 1st prototype, testing and optimization (test-rig)

13 months

- February 2003: implementation in a distribution truck (2nd prototype)

18 months

- July 2003: Start development of new applications

24 months

- January 2004: Presentation new driving principle (market introduction)

3. Design & Development of the CS-PTO Slide 8/26

3. Design & Development of the CS-PTO

CS-PTO development, in cooperation with Aichi Machine Industry Nagoya, Japan:

Specifications Aichi-CVT:

- Dry hybrid belt

- Electromechanical actuation

- Compact & lightweight

- Air cooled

- High efficiency

Slide 9/26

3. Design & Development of the CS-PTO

Development of the first CS-PTO Prototype:

Slide 10/26

4. Electromechanical Actuation System and Ratio-Control

Primary pulley of the electromechanical Actuation System:

Electric motor

Spindle mechanism

transmission gears

Translation of pulley sheave

Slide 11/26

4. Electromechanical Actuation System and Ratio-Control

Secondary pulley of the electromechanical Actuation System:

Air cooling fins

Torque assist

Compression spring

Slide 12/26

Ratio Control System structure:

4. Electromechanical Actuation System and Ratio-Control

Model of actuation system & CVT

Controller

Slide 13/26

Ratio Control System functions:

- Minimize the ratio error

- Prevent slippage of the belt

4. Electromechanical Actuation System and Ratio-Control Slide 14/26

Required input for the controller:

-Primary pulley speed (REV 1)

-Secondary pulley speed (REV 2)

-Primary pulley position (PPS)

5. Testing and Implementation of the CS-PTO

Testing the first CS-PTO Prototype, driving a 15 kW refrigeration-unit:

Digital Analog Control System (DACS) developed by the University (TU/e)

Slide 15/26

5. Testing and Implementation of the CS-PTO

Testing the first CS-PTO Prototype, driving a 15 kW refrigeration-unit:

Slide 16/26

Electric motor(80 kW)

CS-PTO Prototype

Generator & Refrigeration unit(22 kVA & 15 kW)

5. Testing and Implementation of the CS-PTO

Measured CVT efficiency:

The efficiency is higher than 90% when the primary torque is more than 20 Nm…

CS-PTO Application:

The lowest primary torque of the CVT-unit is 24 Nm…

Slide 17/26

Measured performance on the test-rig (European Transient Cycle):

6. Performance results of the CS-PTO Slide 18/26

CVT input speedCVT output speed

Ratio-shift is too slow

(compression spring)

6. Performance results of the CS-PTO

Implementation in a refrigerated distribution truck (DAF CF75):

Slide 19/26

6. Performance results of the CS-PTO

High load torques on the CVT-unit, because of peak currents at start-up

Slide 20/26

6. Performance results of the CS-PTO

Built-in soft-start strategy to reduce the required power at start-up

Slide 21/26

1800 rpm, 30 Hz

unit on unit off

3000 rpm, 50 Hz

The CVT control system sensesthat the unit is on and shifts up

the auxiliary unit switches on at 30 Hz,resulting in much lower load torques

the auxiliary unit runs at 50 Hz, 380 Vequal to electrical power from the net

the auxiliary unit is switched offThe CVT control system senses thatthe unit is off and shifts down to

1800 rpm, 30 Hz

6. Performance results of the CS-PTO

Performance results of the CS-PTO application in city distribution:

Present concept

CS-PTO concept

Slide 22/26

Test-conditions:

mid-summer day

32 degrees Celsius

two distribution trucks

identical routes

6. Performance results of the CS-PTO

Performance of the Constant Speed Power Take Off

Slide 23/26

measured performance

Power always available when needed

ideal driving principle

High efficiency / low fuel consumption

Low noise emission

Low overall weight

5.6% fuel consumption reduction(compared with a truck engine without CS-PTO)

Total weight of the CVT-unit is 25 kg(total weight of the CVT-unit and generator is 100

kg)

Maximum noise emission of 57 dB(A)(officially measured on a CS-PTO driven

refrigeration-unit)

100% power available while driving(maximum truck engine speed range of 4.5 [-])

7. Present and future developments Slide 24/26

Future developments

Development of CS-PTO productionStandard implementation of CS-PTO’s on trucks

Development of a smaller CS-PTO with higher power density

Present developments

Development of (new) CS-PTO applications on different types of trucksDevelopment of new ratio control functions for CS-PTO-applications

Development of easy-adjustable ratio control software

- A new and efficient driving principle for auxiliary equipment on distribution trucks is presented

8. ConclusionsSlide 25/26

- A small and compact CVT-unit is used to transform the variable engine speed into an optimal or constant speed

- The performance of the auxiliary equipment can be optimized to performance, fuel-efficiency or noise-emission

- The CS-PTO has a big market potential and many new applications are developed

- Preparations are made for CS-PTO production in higher numbers

- In cooperation with truck manufacturers, standard implementation of the CS-PTO is discussed

Thank you for your attentionSlide 26/26