Công ty ô tô Mazda Đào tạo dịch vụ kỹ thuật Gr

TN-CX5-1203 SKYACTIVE-G Principle of thermal efficiency improvement in internal combustion engines In an internal combustion engine, a significant amount of power generated by the combu

February 2012 TN-CX5-1203

Mazda Motor Corporation Technical Service Training Gr

TN-CX5-1203 SKYACTIV technology

SKYACTIV TECHNOLOGY is a blanket term for Mazda’s innovative new-generation technologies that are being developed under the company’s long-term vision for technology development, Sustainable Zoom-Zoom

All the technologies that are developed based on the Building Block Strategy will fall under the SKYACTIV TECHNOLOGY umbrella

Building Block Strategy

Mazda is prioritizing improvement of the base technologies that are responsible for the core performance of our cars while adopting a Building Block Strategy of gradually introducing electric devices such as regenerative braking, hybrid, and other systems

It is forecast that ICE (Internal Combustion Engines) will still account for a high

TN-CX5-1203 Reference

SKYACTIV technologies are introduced into the market in phases

In 2015, 80% or more of global production will be SKYACTIV

After 2015, the second generation of SKYACTIV will adopt lean burn

Reference

If driving performance is to be improved, it usually sacrifices fuel economy This means that Driving performance and Fuel economy bear a trade-off relation Engineers in the field of R&D always have a dilemma to overcome

Mazda’s engineers have been tackling many challenges to innovate new technologies that can balance the two challenges at a higher level

The most popular word used among those Mazda engineers is “Breakthrough” It is spread among all Mazda employees to succeed Mazda’s building block strategy with SKYACTIV technology

TN-CX5-1203 SKYACTIVE-G

Principle of thermal efficiency improvement in internal combustion engines

In an internal combustion engine, a significant amount of power generated by the combustion is lost due to exhaust, cooling, pumping, and mechanical friction losses

Thermal efficiency improvement in internal combustion engines is nothing, but to reduce these losses As indicated in the diagram below, there are six factors that can

be controlled to reduce these losses

Technologies of SKYACTIV-G

SKYACTIVE-G is a new-generation highly-efficient direct-injection gasoline engine that achieves the world's highest gasoline engine compression ratio without abnormal

TN-CX5-1203 Features of SKYACTIV-G

 High compression ratio is obtained by a 4-2-1 exhaust system, cavity pistons, multi-hole injectors and other innovations enable the high compression ratio

 Due to high compression combustion, fuel efficiency and torque is increased by

15 % with regard to the existent engines

 Drivability at low- to mid-engine speeds is improved due to increased engine torque

Merits and issues of high compression ratio

Increasing the compression ratio considerably improves thermal efficiency Theoretically, the thermal efficiency will improve by roughly 9% if the compression ratio is raised from 10:1 to 15:1 But, it is impossible to put it into practice One of the obstacles is the ignition timing retard to prevent pre-ignition and knocking from occurring

These calculations are summarized in the graph below, and as indicated, if the amount of residual gas is reduced from 8% to 4%, the calculated temperature at compression TDC remains the same even when the compression ratio is increased from 11: 1 to 14: 1

Combustion improvement

Combustion duration is shortened to improve resistance to knocking The faster the combustion velocity, the shorter amount of time the unburned air-fuel mixture is exposed to high temperatures This allows for normal combustion to complete before knocking occurs

Homogeneous mixture is formed due to improved fuel spray characteristics by means

of intensifying air flow, increasing injection pressure, and using multi-hole injectors

750°C

25°C

70°C

160°C

TN-CX5-1203 Stable combustion is produced even when the ignition timing after engine-start is considerably retarded This is made possible by a piston cavity and optimizing fuel injection in order to formulate a stratified air-fuel mixture around the spark plug Furthermore, the piston cavity resolved the issue of the initial flame coming in contact with the piston head and generating a cooling loss

Light weight piston and connecting rod contribute to reduce inertia and friction losses

4-2-1 exhaust system

4-2-1 exhaust system is employed to reduce the amount of exhaust gas in the combustion chamber

CX-5 is equipped with SKYACTIV-Drive* It is a high performance transaxle, designed

as a result of pursuant to the ideal transaxles defined by evaluating advantages and disadvantages of STEP-AT, CVT, and DCT

* The SKYACTIV-Drive is named as FW6A-EL (2WD) and FW6AX-EL (4WD)

TN-CX5-1203

SKYACTIV-Drive Development concept

Transaxles’ development is very important not only for improving fuel economy, but for the vehicle driving performance Auto-manufactures have been using a variety of automatic transaxles and selecting ones according to the market’s preference There

is no such thing that one automatic transaxle can meet every needs from every markets

STEP-AT

Helped by creep phenomenon, easy to start up; because of torque converter clutch, fuel economy is comparable with manual transaxles However, due to its characteristics, there is loss of power transmission when start up

CVT

Little shift shock and good fuel economy at lower speed It is well accepted in the markets such as Japan, where drivers need to stop and start the vehicle within short distance This is not well accepted in Europe where vehicles are driven highways

DCT

Basic feature is very manual transaxle/transmission, which a pair of clutch transmits the power in turn within a very short period of time Therefore, it has better fuel economy and good direct feel However, it tends to develop shift shock when shifting to or from 1st or 2nd gear Besides, it is big and heavy, and costly

The basic structure of SKYACTIV-Drive is popular one; mainly consists of torque converter and STEP-AT But, it employs many new technologies such as multiple-disc torque converter clutch, which makes it possible to widen lock-up range; all ranges

feel, resulting in taking advantages of other types of automatic transaxles In another word, SKYACTIV-Drive eliminated the weakness of STEP-AT It is believed that SKYACTIV-Drive is to be accepted by the customers in a variety of markets

SKYACTIV-Drive is aimed to meet all preferences of all markets

New features

Fuel economy

- Widened lock-up range

- High efficient gear train

- Reduced clutch resistance

- Improved solenoid valve response

- Employed direct linear solenoid valves

Widened lock-up range

The graph below shows lock-up ranges of FS5A-EL and SKYACTIV-Drive*: the black colored curves indicate FS5A-EL and the pink colored curves indicate lock-up range

of SKYACTIV-Drive

TN-CX5-1203

* The type of the SKYACTIV-Drive and the vehicle were not known for this test

Obviously, the lock-up range for the SKYACTIV-Drive is widened In this test mode, it

is observed that 49% of driving time for FS5A-EL is in the lock-up range, while SKYACTIV-Drive is 82%

Reference

Japanese test modes for measuring fuel consumption

JC08: It is a Japanese test mode to measure mileages which vehicle is driven with one liter of fuel (km/liter)

10-15 mode: This is another test mode effective in 1991 As this mode does not reflect today’s vehicle driving condition, JC08 mode was established

TN-CX5-1203 Reference

Gear positions that lock-up control is applicable are shown in the table below

Lock-up control is applicable to all 6 speeds for FW6A-EL (SKYACTIV-Drive)

TN-CX5-1203

The development concept was to create a “light and compact MT with improved shift feel and better fuel economy” The goal was to achieve an MX-5-like sporty and brisk shift feel

By pursuing the ideal structure of manual transmissions, 16% at maximum of weight reduction was achieved Furthermore, internal friction losses were significantly reduced to achieve a 1% improvement in fuel economy

 Light in weight and compact size

 Quick and crisp shift feel like that of a sport car

Light and compact MT

Since the structure of an MT is relatively simple, completely new ideas and logical thinking are required to achieve further weight reduction and higher efficiency

The triple-shafted gear train with a common gear for 2nd and 3rd was selected from approximately 30 different configurations due to its potential to achieve lightness, light shift effort, high efficiency, and a wide gear ratio Based on this selection, the lightest structural specifications were selected from over 10,000 alternatives By reviewing the

TN-CX5-1203

Quick and crisp shift feel

To achieve lighter shift effort with a short shift lever stroke, the lever ratio must be increased However, an increased lever ratio reduces the internal stroke To achieve precise synchronizer and torque transmission even with a short internal stroke, a small module* spline is used

* Module: Size of a tooth on the gear or spline

Also, the shift effort gradually reduces through the stroke, providing reassuring resistance as the lever is first pushed, then getting lighter so it feels as if the shift lever

is automatically moving into gear With the current shift lever, shift effort in the select direction (right-left direction) increases with the movement of the shift lever, but with the new shift lever, a constant shift effort is achieved Binding is minimized when shifting diagonally

b Cable

Shift effort gradually reduces

Select direction

Diagonal shifting

Minimized

Technical aims and concept

Feeling of oneness with vehicle

Comfortableness Stability & safety

Yaw-gain: the degree of yaw rate change with respect to the angle of steering

(deg./sec/deg.) The higher the yaw-gain, the more the vehicle tends to turn easily

Lateral-G: the acceleration applying in lateral direction of the vehicle that increase

or decrease in response to turning movement of the vehicle

Yaw rate: the degree of change of turning angle per second that occurs due to

yawing (deg./sec)

Lateral-G: generated in response to turning movement of the vehicle

Turning motion of the vehicle Yawing

TN-CX5-1203

 Rear cornering power is increased to reduce yaw-gain at high vehicle speeds, ensuring stability A high-geared steering gear is employed to increase yaw-gain at low-to-mid vehicle speeds

(Employed technology)

 The geometry of the rear suspension links is optimized to effectively use compliance steer in order to increase cornering power in rear tires without sacrifice

of the lateral rigidity

The link damper leaning forward absorbs not only up-and-down vibrations, but also forward-and-backward ones

 The timing of the weight transfer in rear tires is advanced by reducing the hysteresis characteristics of the suspension cross mount bushing

Bushing Reaction force Bushing

Input from the road

Rear cornering power

Front cornering power

Yaw gain

Steering angle

TN-CX5-1203 (Continued)

 A high-geared steering gear ratio is employed to increase yaw-gain at low-to-mid vehicle speeds

 Caster angle and caster trail are increased to ensure the proper amount of required steering effort that varies according to the vehicle speed, while the stability of straight-ahead driving is improved

Caster angle in comparison

3°05′ (4WD)

Increased caster angle

Increased caster trail

SKYACTIV-Chassis Existent models

 Welding flanges were removed from the front and rear cross-members to enhance the coupling rigidity of the welded sections

Recession angle Recession angle

Rear trailing

link bushing

Rear trailing link bushing

Bush longitudinal impact shock

Bush longitudinal impact shock

Rigid mount

Welding flange

No welding flange

 For both front and rear suspensions, coupling rigidity of the welded area is

Front: b/n front lower arm attachment position and front cross-member Rear: Rear cross-member longitudinal span

(Existent model)

Front cross-member width

TN-CX5-1203

Aiming to improve all the three items below under any conditions:

 Oneness with the vehicle (controllability)

 Stability & Safety (Brake effectiveness)

 Comfortableness (Brake Noise and Vibration)

For these aims, SKYACTIVE-Chassis combines the following:

 Weight reduction with cooling capability (thermal control)

1) By efficiently directing air to cool down the brake

2) Improving cooling performance of brake disc rotor

 Brake effectiveness with brake noise and vibration

1) By identifying the structure generating the least vibration energy

2) By establishing the brake structure design for suppressing noise

Oneness with the vehicle

Target Existent

Structural change in brake caliper

TN-CX5-1203 Reference

As part of contribution of SKYACTIV-Chassis, a greater anti-lift force than that of existent models is produced

SKYACTIV-BODY

 The highest level of collision safety performance

 Pedestrian protective bonnet

 Realized a light-weight body, while it ensures the world highest level of collision safety performance (Weight of the white body is reduced by 8 % as compared with existent models.)

Chassis dynamics

By improved aerodynamics, the Coefficient of drag (Cd) of 0.335 is realized by, in a well-balanced way, minimizing trailing vortexes, which are generated upward or downward in the rearward of the vehicle This improvement contributes to better fuel economy

Body framework & rigidity

(1) Straight frame: Body framework is straightforwardly and continuously stretched without cutting-off

(2) Rigidity of mounting portions: Rigidity at suspension and engine mounting portions are enhanced

(3) Multi-load path: An ideal framework with the view to collision, chassis dynamic stability, and NVH is realized

49 mm

Brake force

Anti-lift force Anti-lift force

CX-5

Brake force

TN-CX5-1203

For various type of collision possibly happening in the market, an outstanding frontal collision safety is realized by efficiently absorbing collisional energy for frontal collisions that minimizes cabin deformation

A high efficient multi-load path structure, which a frontal impact is dispersed and absorbed in the engine compartment

Upper Path: - A structure for impact absorption by utilizing the apron portion

Mid Path (main): - A high collisional energy absorption and weight reduction are

realized by adopting cruciform section

- Designed a load-dispersive load path that can stably absorb collisional energy by steady deformation

Lower Path: - In addition to body related parts, an extension for impact

absorption is equipped with the front suspension cross member

Existent model

CX-5

TN-CX5-1203

(2) High-tensile steel sheet is used for the load-dispersion load path structure of the cabin site and for the portions where the restricting deformation of the front floor pan is vital

Bonnet pedestrian protection

(1) A sufficient space between the bonnet and engine is provided for absorbing collisional energy

(2) The vertical plate on the front side of the striker lane installed in the forward end has been eliminated Instead, the stiffener's shape is optimized to be squashy at a collision

Shroud upper member

Bumper & crash-can

Suspension cross

member crash-can

Impact energy is absorbed

within this range Impact to the engine room is reduced

TN-CX5-1203 Mazda CX-5

Major components of SKYACTIV technology

TN-CX5-1203 Vehicle identification Number (VIN)

TN-CX5-1203 The VIN marking position is located on the floor on the front passenger-side If the VIN plate is adhered to the dashboard, it is located in the position shown in the figure

Engine oil

SKYACTIV-G

API: SG/SH/SJ/SL/SM/SN or ILSAC: GF-2/GF-3/GF-4/GF-5 SAE: 10W-30, 10W-40, 10W-50, 5W-20, 5W-30, 5W-40, 0W-20, 0W-30

SAE: 0W-30, 5W-30

PE02 18 110 (DENSO)

55D23L (Panasonic, GS Yuasa) 75D23L (GS Yuasa)

Q-85 (Panasonic)*

* With i-stop system

TN-CX5-1203

Scheduled maintenance table (for General)

TN-CX5-1203

Required procedure after negative battery cable disconnection/connection

System name

Conditions after disconnecting the negative battery cable

Required procedure

Remark Before

disconnecting negative battery cable

After connecting negative battery cable Power window

system

Reset to initial setting and auto-function is disabled

-

Perform the power window system initial setting

-

Sunroof system Reset to initial

setting and function is disabled

-

Perform the sunroof system initial setting -

Clock and audio Clock display

and audio system memory are reset

Verify the setting content

Set the verified content before disconnecting negative battery cable

decreases

-

Perform the tire pressure monitoring system initialization

-

i-stop system Specified

information

in the PCM cleared and the i-stop does not operate normally

Only vehicles with i-stop

*1: For vehicles with i-stop, if the negative battery cable is disconnected and re-connected, battery condition initial setting (i-stop setting) must be performed

*2: Because the “BATT_SOC” value before disconnecting the negative battery cable is required for the battery condition initial setting (i-stop setting), record the “BATT_SOC” value before disconnecting the negative battery cable

Main beam control LDWS

RVM Auto-dimming mirror

TN-CX5-1203 SKYACTIV-G 2.0

TN-CX5-1203

 Improved the fuel economy by:

Reducing loss by mechanical resistance

Reducing pumping loss

Reducing fuel consumption at idling)

Adopting a piston with cavity

Long stroke

amount detection, improving the accuracy of the intake air amount measurement

- MAF sensor adopted

- MAP sensor adopted

- IAT sensor No.1 and No.2 adopted

sensor and calculates the intake air amount indirectly (D: Druck=Pressure)

 Valve timing control has been adopted on both sides of the intake and exhaust, improving fuel economy and emission performance

Intake side: Electric variable valve timing control

- Intake CMP sensor adopted

- Electric variable valve timing motor/driver adopted

- Electric variable valve timing relay adopted

Exhaust side: Hydraulic variable valve timing control

- Exhaust CMP sensor adopted

 Engine oil control has been adopted reducing engine load

- Engine oil solenoid valve adopted

 Fuel pump control has been adopted improving startability and safety

- Fuel pump control module adopted

 With the adoption of the ion sensor, which detects pre-ignition, engine reliability

has been improved

TN-CX5-1203

Mechanical resistance is substantially reduced

 Improved piston skirt rigidity

 Reduced piston ring expansion force

 Low tension piston ring

 Reduced valve spring loads

 Reduced timing chain tensile force

 High efficient molded plastic water pump impeller

 Reduced resistance of the oil passages

 Decreased hydraulic pressure demanded by hydraulic devices

* FEAD: Front End Auxiliary Drive

Pumping loss is reduced

Variable Valve Timing Intake: electrically-driven, Exhaust hydraulic-driven

Retarded intake valve closed timing

TN-CX5-1203 Engine exploded diagram

TN-CX5-1203 Cylinder head

Cylinder block

Upper cylinder block

Lower cylinder block

Cylinder head bolt

HLA

Intake Exhaust

Intake Exhaust

TN-CX5-1203 Piston

The piston head conducts heat away from the combustion flame, interfering flame propagation The cavity on the piston head helps to grow combustion flame

Left: Position the mark on the piston head in the intake side

Right: It is required only for the oil ring (Side rails and spacer) It is not required for the top and second piston rings to be aligned

Initial flame

Top ring

Second ring

Oil ring Side rail Spacer

Piston center

Piston pin center

Offset Graphite coat

Cavity

Exhaust

Piston pin axis