如果您希望使用动态关联数组：
1.将MAKE添加到字符串前面
1.使用preg_match_all()捕获格式化字符串中的标签和值对
1.使用array_column()将匹配列重新构造为关联数组。
代码：（Demo）

$strings = [
    'Audi MODEL 80 ENGINE 1.9 TDi POWER 90Hk TORQUE 202Nm GEAR man DRIVE 2wd YEAR 1996',
    'Audi MODEL 80 ENGINE 1.9 TDi YEAR 1996 NOTE this engine needs custom stage GEAR auto',
    'Audi MODEL 80 ENGINE 1.9 TDi GEAR man YEAR 1996',
    'Audi MODEL 80 ENGINE 1.9 TDi YEAR 1996 DRIVE 2wd'
];

foreach ($strings as $string) {
    preg_match_all('/\b([A-Z]+)\s+(\S+(?:\s+\S+)*?)(?=$|\s+[A-Z]+\b)/', 'MAKE ' . $string, $m, PREG_SET_ORDER);
    var_export(array_column($m, 2, 1));
    echo "\n---\n";
}

输出：

array (
  'MAKE' => 'Audi',
  'MODEL' => '80',
  'ENGINE' => '1.9 TDi',
  'POWER' => '90Hk',
  'TORQUE' => '202Nm',
  'GEAR' => 'man',
  'DRIVE' => '2wd',
  'YEAR' => '1996',
)
---
array (
  'MAKE' => 'Audi',
  'MODEL' => '80',
  'ENGINE' => '1.9 TDi',
  'YEAR' => '1996',
  'NOTE' => 'this engine needs custom stage',
  'GEAR' => 'auto',
)
---
array (
  'MAKE' => 'Audi',
  'MODEL' => '80',
  'ENGINE' => '1.9 TDi',
  'GEAR' => 'man',
  'YEAR' => '1996',
)
---
array (
  'MAKE' => 'Audi',
  'MODEL' => '80',
  'ENGINE' => '1.9 TDi',
  'YEAR' => '1996',
  'DRIVE' => '2wd',
)
---

这不是一个新概念/技术。唯一需要做的调整是 * 如何 * 识别原始字符串中的键/标签。您可能希望使用explicitly name each label and separate them in the pattern with pipes来代替[A-Z]+。请参阅以下其他演示：

• Parse e-mail addresses with PHP?
• Regex - Ignore some parts of string in match
• Parse a file and use the data to decrypt another file's data
• Parse a formatted string with multiple delimiters into an associative array
• PHP split string into two arrays - values split and delimiters

或者，不使用正则表达式来解析字符串，而是将字符串转换为本地PHP函数可以解析的标准格式。

foreach ($strings as $string) {
    var_export(
        parse_ini_string(
            preg_replace(
                '~\s*\b(MAKE|MODEL|ENGINE|POWER|TORQUE|GEAR|DRIVE|YEAR|NOTE)\s+~',
                "\n$1=",
                'MAKE ' . $string
            )
        )
    );
    echo "\n---\n";
}

要保持关键字包含的"位"不变，您可以使用带有预视的preg_split，预视将在空格后拆分任意一个关键字。例如：

$string = 'Audi MODEL 80 ENGINE 1.9 TDi POWER 90Hk TORQUE 202Nm GEAR man DRIVE 2wd YEAR 1996';

$bits = preg_split('~\s+(?=(MODEL|ENGINE|POWER|TORQUE|GEAR|DRIVE|YEAR|NOTE)\b)~', $string);

结果：

array(8) {
    [0] · string(4) "Audi"
    [1] · string(8) "MODEL 80"
    [2] · string(14) "ENGINE 1.9 TDi"
    [3] · string(10) "POWER 90Hk"
    [4] · string(12) "TORQUE 202Nm"
    [5] · string(8) "GEAR man"
    [6] · string(9) "DRIVE 2wd"
    [7] · string(9) "YEAR 1996"
}

如果你想把这些解析成键/值对，很简单：

// Initialize array; get the "unnamed" make:
$data = [
    'MAKE' => array_shift($bits),
];

// Iterate any other known keys found:
foreach($bits as $bit) {
    $pair = explode(' ', $bit, 2);
    $data[$pair[0]] = $pair[1];
}

结果：

array(8) {
    ["MAKE"] · string(4) "Audi"
    ["MODEL"] · string(2) "80"
    ["ENGINE"] · string(7) "1.9 TDi"
    ["POWER"] · string(4) "90Hk"
    ["TORQUE"] · string(5) "202Nm"
    ["GEAR"] · string(3) "man"
    ["DRIVE"] · string(3) "2wd"
    ["YEAR"] · string(4) "1996"
}

如果你更喜欢非RegEx方法，你也可以把它分解成单独的标记（单词）并构建一个数组。下面的代码对空格做了一些假设，如果它是一个问题，可以通过替换来解决。

// The first group to assign un-prefixed items to
$firstGroup = 'MAKE';

// Every possible word grouping
$wordList = ['ENGINE', 'MODEL', 'POWER', 'TORQUE', 'GEAR', 'DRIVE', 'YEAR'];

// Test string
$string = 'Audi MODEL 80 ENGINE 1.9 TDi POWER 90Hk TORQUE 202Nm GEAR man DRIVE 2wd YEAR 1996';

// Key/value of group name and values
$groups = [];

// Default to the first group
$currentWord = $firstGroup;
foreach (explode(' ', $string) as $word) {

    // Found a special word, reset and continue the hunt
    if (in_array($word, $wordList)) {
        $currentWord = $word;
        continue;
    }

    // Assign. The subsequent for loop could be removed by just doing string concatenation here instead
    $groups[$currentWord][] = $word;
}

// Optional, join each back into a string
foreach ($groups as $key => $values) {
    $groups[$key] = implode(' ', $values);
}

var_dump($groups);

输出：

array(8) {
  ["MAKE"]=>
  string(4) "Audi"
  ["MODEL"]=>
  string(2) "80"
  ["ENGINE"]=>
  string(7) "1.9 TDi"
  ["POWER"]=>
  string(4) "90Hk"
  ["TORQUE"]=>
  string(5) "202Nm"
  ["GEAR"]=>
  string(3) "man"
  ["DRIVE"]=>
  string(3) "2wd"
  ["YEAR"]=>
  string(4) "1996"
}

演示：https://3v4l.org/D4pvl