Occupant Package Design

Table of Contents

1 Background of Market Segment and Benchmark Vehicles:

2 Exterior and Interior dimensions:

3 Exterior Vehicle layout:

4 Interior package layout:

5 Maximum comfortable reach cross sections:

Background of Market Segment and Benchmark Vehicles:

The vehicle segment which was selected to review during this project was the two-seater luxury sports car. This vehicle is usually purchased by people who are well off financially and are over the age of 50. On average the household income of an individual who is purchasing a luxury sports car is over $145,000 a year. The majority of customers are male with a college education. They are proud of the fact that they have earned the right to purchase a luxury sports car and like to buy a vehicle that shows off their success.

At this point in their career, their kids have already graduated from college or are about to graduate so they have some extra money to spend on their toys. They usually have another vehicle, which is considered their daily driver, and are buying a sports car to have some extra fun on the weekends at the track.

The competitive vehicles which were benchmarked for this project were:

2022 Chevrolet Corvette 3LT
2022 Porsche 911 Carrera
2022 Audi R8 V10

Overall, in size these vehicles are all about the same size, the Corvette is a few inches longer than the Porsche and the Audi. The Porsche is the only rear-engine vehicle both the Audi and the Corvette are mid-engine vehicles. Of all the three vehicles the Porsche is the most fuel-efficient vehicle, while the Audi has the greatest horsepower. However, the Corvette is the overall best deal as it provides comparable if not better performance at a fraction of the cost. An overview of these three vehicles can be seen in the table below.

Vehicle	2022 Chevrolet Corvette 3LT	2022 Porsche 911 Carrera	2022 Audi R8 V10
Vehicle Dimensions	182″ L x 76″ W x 49″H	178″ L x 73″ W x 50″H	174″ L x 76″ W x 49″ H
0-60	2.8	3.5	3.2
MSRP	$79,850	$106,100	$148,700
Max Speed	205 mph	182 mph	204 mph
Fuel Economy	16 City / 24 Highway	18 City / 25 Highway	14 City / 23 highway
Horsepower	495 hp	397hp	602 hp

Exterior and Interior dimensions:

For all measurements taken during this project the standard SAE coordinate system was used, where z=0 at the ground, x = 0 at the front of the car, and y = 0 at the centerline of the vehicle. see the standard SAE coordinate system below.

Several of the basic exterior dimensions for these three vehicles were readily available online, however, information such as Ramp Breakover Angle (SAE A147), Tumblehome Angle (SAE A122), and Windshield Angle (SAE 121-1) required calculations to find. To find these dimensions, the vehicle blueprints were used, and measurements were taken to calculate any missing dimension. Any description field which has an asterisk is estimated based on the measurements and calculations performed by the team. Once all the SAE dimensions were calculated for all of our competitive vehicles, targets were set for our vehicle to ensure all our dimensions selected were within our desired vehicle segment. See the table and blueprints below which contain a look at how our vehicle will compare to the competition in its segment.

Row No.	SAE Dimension code	Description	Units	2022 Corvette 3LT	2022 Porsche 911	2022 Audi R8	Our Vehicle
1	L103	Length	mm	4622.8	4562	4429	4500
2	W103	Width	mm	1930.4	1852	1940	1925
3	H100	Height	mm	1244.6	1270	1244	1250
4	L101	Wheelbase	mm	2723	2456	2650	2700
5	L106	Front Overhang	mm	900	1061	994	950
6	L107	Rear Overhang	mm	1008	1044	782	850
7	H143-1	Cowl point*	mm	630	860	896	800
8	H143-2	Deck Point*	mm	730	975	1005	900
9	H25-1	Belt Height*	mm	457	457	457	457
10	H156	Ground Clearance	mm	135	109	110	125
11	A106-1	Approach Angle	degrees	11.5	9.8	16.6	12
12	A106-2	Departure Angle*	degrees	10.3	13.8	14.3	15
13	A147	Ramp Breakover Angle*	degrees	11.3	12.7	12.5	12
14	A121-1	Windshield Angle*	degrees	64.8	62	67	65
15	A121-2	Backlight Angle*	degrees	79	77	72.3	79
16	A122	Tumblehome Angle*	degrees	28	25.7	25	25
17	H61-1	Effective Head Room – Front	mm	965.2	965.2	978	960
18	W3-1	Front Shoulder Room	mm	1371.6	1372	1400	1380
19	W5-1	Front Hip Room	mm	1320.8	1405	1452	1400
20	L34	Front Leg Room	mm	1087.12	1057	1039	1080

Exterior Vehicle layout:

Based on the exterior dimension calculated in the previous section, the exterior of the vehicle was laid out. Aesthetically the vehicle has exterior styling inspired by both the Bugatti and McLaren supercars. This vehicle is intended to have the mid-engine design which is found in both the Corvette and Audi R8 to ensure better weight distribution and a smoother ride. The exterior envelope of the vehicle is 4500mm L x 1925mm W x 1250mm H. To see a full detailed view of the vehicle please see the blueprint drawing below.

Interior package layout:

The interior of the vehicle was laid out around the occupant. The first thing which was set was the seating reference point (SgRP) and the ball of the foot (BOF) of the driver. Knowing these two key points in addition to the exterior dimension we were able to place the SAE Manikin in roughly the correct seating position to be able to calculate and derive all the interior dimensions. An in-depth look at the calculations will be reviewed in a later section of this report. Below is a pictorial representation of the interior vehicle package. At the top of the following page, each dimension can be reviewed in the table which also calls out what SAE Dimension with their respective value.

Maximum comfortable reach cross sections:

To find the cross sections of maximum comfortable reach in vertical planes parallel to XZ planes at 300mm to the left and 300mm to the right of drivers SgRP; we assumed our H30 and H17 values were 350mm and 511mm respectively (these were calculated in the calculations section at the top of the following page).

Calculations:

G=.00327*H30(350)+.00285(511)-3.21=-.671
HR plane(rearward of AHP)=786-99*G(-.671)=852.4mm
AHP to SgRP-HR=868.7-852.4=16.3mm

Assumptions required to find the appropriate table to use in SAE J287

50/50 male to female population mix
Restrained Hand Reach (occupant was restrained by a lap and shoulder belt)
SgRPz=450.7mm
Driver is utilizing a 3-finger grasp

Table 7:

As can be seen from the table above, the horizontal reach forward of the HR reference plane for maximum comfortable reach for the left hand is 600mm and the right hand is 649mm. To find the value being asked for “Cross sections of the maximum comfortable reach in vertical planes parallel to XZ planes at 300 mm to the left and 300 mm to the right of the driver’s SgRP” we need to add 16.3mm to each of our values from the table. This 16.3 is the distance HR is forward of driver SgRP. The final answers for maximum hand reach in vertical planes parallel to XZ planes at 300mm to the left and 300mm to the right of drivers SgRP are 616.3mm for left hand and 665.3mm for right hand.

Calculations:

To determine many of our vehicle’s dimensions we found blueprints of the appropriate vehicles and used the website imagemeasurement.com to find other dimensions we needed. This website utilizes existing dimensions to understand the scale of the image and accurately determine any dimensions not included in the blueprint. The team utilized the “Occupant Package Dimensions Computations” document found in lecture 4 reference material to determine many of the dimensions for our vehicle. This document had many of the calculations already filled in, and we measured/assumed the required values in the inputs section.

Trig was used to calculate the degrees for approach angle, departure, ramp break over angle, backlite angle, and tumblehome angle. Sample calculations for the 2022 Porsche 911 can be seen below:

The remainder of the interior calculations for our vehicle can be found below, including the SAE reference documents and equations:

Conclusion:

This project allowed us to understand which calculations and assumptions are needed to determine all a vehicle’s important dimensions (interior and exterior). These dimensions were calculated on multiple different sports cars, for comparison purposes. Some of those dimensions from our sports car segment were used to create our own vehicle dimensions.

Our vehicle dimensions were compared to body dimensions of US adults of the 95th percentile male/female to understand if they could fit in our vehicle (from lecture 5 slides, table 13-1) . The results are below:

After reviewing the table above, it can be concluded that our vehicle is not tall enough for a 95% male. The 95% male eye height is below our vehicle’s eye height. The ability to move the seat up, this might make up for this height difference. The width of the vehicle is appropriate to accommodate a 95% female or male at both the hip and elbow height. When comparing our entrance height to the vehicles in our set (2022 Chevrolet Corvette 3LT, 2022 Porsche 911, and Audi R8 V10) they are very similar, with our vehicle fitting in the middle of the set. With this information it can be concluded that these sports cars aren’t necessarily designed to comfortably accommodate a 95% male/female.